EP0570435B1 - Process for the production of wood-fibre boards - Google Patents

Process for the production of wood-fibre boards Download PDF

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Publication number
EP0570435B1
EP0570435B1 EP92903957A EP92903957A EP0570435B1 EP 0570435 B1 EP0570435 B1 EP 0570435B1 EP 92903957 A EP92903957 A EP 92903957A EP 92903957 A EP92903957 A EP 92903957A EP 0570435 B1 EP0570435 B1 EP 0570435B1
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EP
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Prior art keywords
mass
solid resin
binder
bonding agent
liquor
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German (de)
French (fr)
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EP0570435A1 (en
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Ludwig SÜMEGI
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Osterreichische Hiag-Werke GmbH
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Osterreichische Hiag-Werke GmbH
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B27WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27NMANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
    • B27N1/00Pretreatment of moulding material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B27WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27NMANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
    • B27N1/00Pretreatment of moulding material
    • B27N1/02Mixing the material with binding agent

Definitions

  • the invention relates to a process for the production of wood fiber boards, in which the raw material is subjected to fiberization and then glued in a blow line with an aqueous binder liquor, and the glued fiber material obtained in this way is dried after drying to the required residual moisture and spread under mat and under pressure and temperature Plates is pressed.
  • the invention relates to such a method for producing medium-density fiberboard (MDF) and hardboard (HDF), which contain a reduced amount of binder.
  • MDF medium-density fiberboard
  • HDF hardboard
  • a similar process is known from AT-A-366960, however in connection with chipboard.
  • the mechanical properties of wood fiber boards are largely determined by the binder used to bind the fiber material. Under otherwise constant conditions, an increase in the mechanical strength of the plates is accompanied by an increase in the amount of binder used to bind the fiber material.
  • the binder material represents an essential cost factor in the production of fiberboard
  • a reduction in the amount of binder used leads, as already mentioned, to a decrease in the strength of the boards produced thereby.
  • the moisture of the glued chip material which is kept below 12%, is determined by the amount of water applied to the savings material with the binder liquor.
  • this aim is achieved by gluing with a liquor with a solid resin content of 20 to 35% by mass, preferably 25 to 35% by mass, and using an amount of binder which is less than 10% by mass. preferably 7 to 9% by mass of solid resin, based on the total, atro calculated fiber material.
  • the use of highly dilute aqueous binder liquors according to the invention makes it possible to produce wood fiber boards in the dry process, the mechanical values of which very well meet the requirements of the standard, while at the same time a substantial saving in binder is made possible in comparison with the boards produced according to the method of conventional technology.
  • the method according to the invention makes it possible to produce wood fiber boards with a solid resin content of less than 10% by mass, which have sufficient strengths in accordance with the applicable standards.
  • the fiber material is apparently largely coated with binder, which leads to a strong increase in the glueing points essential for the strength development in the boards.
  • Another advantage of this method is that the high dilution of the binder used exerts a cooling effect on the glued fiber, since part of the water contained in the binder mixture evaporates immediately, thereby removing heat from the entire fiber / binder system. This prevents premature pre-curing of the binder on the glued fiber, which pre-curing can also result in a decrease in panel strength.
  • the present method according to the invention can be carried out without a significant change in the process technology.
  • the gluing of the fiber material takes place shortly after it emerges from the defibration machine (refiner) in the blow line in a conventional manner.
  • Suitable hardening substances such as, for example, ammonium chloride, ammonium phosphate, phosphoric acid, formic acid, are added to the glue liquor in order to harden the binder used during the hot pressing process, in the amounts known in the art, which depend on the particular plant conditions.
  • Glue booster based on a lignin sulfonate proven.
  • Additional formaldehyde scavengers such as urea, can also be added to the binder liquor.
  • paraffin emulsion or melted paraffin to make the fiberboard hydrophobic is advantageously carried out before entering the refiner.
  • the fiber material which has been provided with binder in the manner described above, is then dried in a manner known per se to a residual moisture of at most 12%, advantageously at most 10%, before it is pressed into sheets after forming mat webs in conventional heating presses becomes.
  • the pressing to plates can be done in conventional stationary presses at temperatures of around 160 to 190 ° C and pressures up to 35 bar or in contipresses at heating plate temperatures up to 235 ° C and the usual pressure programs.
  • the pressing times correspond to the pressing times which have also been used to date.
  • a preferred embodiment of the process according to the present invention is that the aminoplastic binder used is first diluted with water to a solid resin concentration of approximately 30 to 40% by mass and the necessary additives such as hardening substances, glue booster, formaldehyde scavenger, in a suitable aqueous solution the diluted binder solution only closes just before entering the blow line over a mixing section.
  • MDF medium-density fiberboard
  • a fiber material was used, which had been produced in a manner known per se from wood chips in a fiberising machine (refiner).
  • a binder-containing mixture was metered into the blow line, through which the fiber material is discharged from the refiner, shortly after it emerged from the refiner.
  • This binder-containing mixture was composed as follows: In a mixing container, an aminoplastic E1 glue for fiber board production (HIACOLL MDF 15) was diluted with water to a concentration of 33% by mass of solid resin. A solution was placed in a second mixing container of 30 mass% urea, 10 mass% ammonium chloride and 1 mass% phosphoric acid.
  • the two solutions were combined in a ratio using a static mixer in such a way that the final glue liquor contained a concentration of solid resin of 28.3% by mass.
  • This glue liquor was added to the fiber material in such an amount that a glue factor of 8.2% by mass of solid resin, based on absolutely dry (atro) fiber, was obtained.
  • the glued fiber mixture was then dried in a known manner to a residual moisture content of 10% by mass, formed into a fiber mat and pressed in a heating press under the action of pressure and temperature to form an MDF board.
  • the board produced in this way very well met the requirements of the industry standard for MDF boards (standard type MDF, formaldehyde content class A).
  • a fiber material according to Example 1 was glued in a manner known per se with the following binder-containing mixture: 1,000 kg of HIACOLL MDF 15, 100 kg of urea solution (40% by mass) and 1,000 l of water were mixed in a mixing container, whereby the solid resin concentration of this mixture was 31.4% by mass. 100 kg of HIACOLL K1215 glue booster and 165 l of water were mixed in a second mixing container.
  • the two solutions were mixed together via metering pumps and a static mixer in such a mixing ratio that the final concentration of solid resin in the mixture was 27.0% by mass.
  • This mixture was applied to the fiber material in an amount such that a gluing factor of 7.5% by mass, based on the dry fiber material, was obtained.
  • an MDF board was obtained which, in all test values, very well met the requirements for the standard type MDF, formaldehyde content class A according to the industry standard for MDF boards.
  • Example 3 is a comparative example.
  • a glue liquor of the following composition was used for the gluing of fiber material, which was carried out as described in Examples 1 and 2: 1,000 kg HIACOLL MDF-12, 150 kg urea solution (40% by mass) 40 kg ammonium chloride solution (15% by mass) 50 kg of water.
  • This glue liquor corresponds to the state of the art. It has a solid resin concentration of 53.2% by mass. To achieve the mechanical values required by the industry standard for MDF boards of an MDF board manufactured using this liquor, 235 kg of glue liquor had to be used per 1,000 kg of dry fiber material, which corresponds to a gluing factor of 12.5% by mass, based on dry fiber material .

Abstract

In a process for producing wood-fibre boards, the raw material is first defibrated, then mixed with aqueous binder liquor in a blast pipe. The binder-coated fibrous material thus obtained is dried to the required residual-moisture content and then spread out into strips which are converted by the action of pressure and heat into boards. The mixing procedure is carried out using a liquor containing 20-35 % by wt. of solid resin, and the amount of binder used, relative to the total dry weight of the fibre material, is less than 10 % by wt.

Description

Die Erfindung bezieht sich auf ein Verfahren zur Herstellung von Holzfaserplatten, bei dem das Rohmaterial einer Zerfaserung unterworfen anschließend in einer Blasleitung mit einer wäßrigen Bindemittelflotte beleimt wird und das so erhaltene beleimte Fasermaterial nach Trocknen auf die erforderliche Restfeuchte zu Mattenbahnen gestreut und unter Druck und Temperatur zu Platten gepreßt wird. Insbesondere bezieht sich die Erfindung auf solch ein Verfahren zur Herstellung von mitteldichten Faserplatten (MDF-Platten) und von Hartfaserplatten (HDF-Platten), welche eine verminderte Menge an Bindemittel enthalten. Aus der AT-A-366960 ist ein ähnliches Verfahren, allerdings in Zusammenhang mit Spanplatten, bekannt.The invention relates to a process for the production of wood fiber boards, in which the raw material is subjected to fiberization and then glued in a blow line with an aqueous binder liquor, and the glued fiber material obtained in this way is dried after drying to the required residual moisture and spread under mat and under pressure and temperature Plates is pressed. In particular, the invention relates to such a method for producing medium-density fiberboard (MDF) and hardboard (HDF), which contain a reduced amount of binder. A similar process is known from AT-A-366960, however in connection with chipboard.

Die mechanischen Eigenschaften von Holzfaserplatten werden außer von der Qualität des Zerfaserungsvorganges zu einem wesentlichen Teil durch das für die Bindung des Fasermaterials verwendete Bindemittel bestimmt. Dabei geht unter sonst gleichbleibenden Bedingungen eine Erhöhung der mechanischen Festigkeit der Platten mit einer Erhöhung der zur Bindung des Fasermaterials eingesetzten Bindemittelmenge einher.In addition to the quality of the defibration process, the mechanical properties of wood fiber boards are largely determined by the binder used to bind the fiber material. Under otherwise constant conditions, an increase in the mechanical strength of the plates is accompanied by an increase in the amount of binder used to bind the fiber material.

Da aber das Bindemittelmaterial einen wesentlichen Kostenfaktor bei der Herstellung von Faserplatten darstellt, gibt es das Bestreben, im Hinblick auf die Wirtschaftlichkeit der Faserplattenherstellung, eine möglichst geringe Menge an Bindemittel einzusetzen. Ferner besteht das Bestreben, die Menge an Bindemittel zu vermindern, um die Umweitbelastung durch die bei insbesondere aminoplastischen Bindemitteln auftretende Formaldehydabspaltung herabzusetzen. Bei den herkömmlichen Verfahren zur Herstellung von Holzfaserplatten führt eine Verminderung der eingesetzten Bindemittelmenge, wie bereits erwähnt, jedoch zu einem Abfall in der Festigkeit der dadurch hergestellten Platten.However, since the binder material represents an essential cost factor in the production of fiberboard, there is an effort to use the smallest possible amount of binder in view of the economy of fiberboard manufacture. There is also a desire to reduce the amount of binder in order to reduce the environmental impact caused by the release of formaldehyde which occurs in particular with aminoplastic binders. In the conventional processes for the production of wood fiber boards, however, a reduction in the amount of binder used leads, as already mentioned, to a decrease in the strength of the boards produced thereby.

Um ohne Beeinträchtigung der Festigkeit die Bindemittelmenge reduzieren zu können, wurde bisher versucht, durch Anwendung verschiedener apparativer Maßnahmen bei der Zugabe des Bindemittels in die Blasleitung eine möglichst gute Verteilung des Leimes zu erreichen, d.h. eine möglichst große Anzahl von Verleimungspunkten zu erzielen, welche für die Verleimungsfestigkeit maßgebend sind. Dabei wurden weiterhin Bindemittelflotten mit einem Festharzgehalt von etwa 50 Masse-% eingesetzt.In order to be able to reduce the amount of binder without impairing the strength, attempts have been made to achieve the best possible distribution of the glue by using various apparatus measures when adding the binder to the blow line, i.e. to achieve the greatest possible number of gluing points which are suitable for the Bond strength is decisive. Binder liquors with a solid resin content of about 50% by mass were also used.

Auf dem Gebiet der Holzspanplatten wurde ein Verfahren mit herabgesetzter Bindemittelzugabe beschrieben, worin verdünnte Bindemittelflotten mit einem Festharzgehalt von vorzugsweise 22 bis 30 Masse-% zum Einsatz gebracht werden (EP-B-0 010 537). Durch dieses Verfahren wird eine gleichmäßigere Verteilung des Bindemittels auf Spänen stark unterschiedlicher Größe und damit eine Einsparung der Bindemittelmenge erzielt. Das eingesetzte Rohmaterial wird bei diesem Verfahren zunächst einer Zerspanung und einer darauffolgenden Trocknung auf eine Feuchte von vorzugsweise weniger als 2 % unterworfen, bevor es mit einer wäßrigen Flotte eines Aminoplasts beleimt wird. Die Beleimung der Späne erfolgt in einem Beleimungsmischer. Darüberhinaus werden der Bindemittelflotte Verdickungsmittel, wie Zellulosederivate, zugesetzt, um eine Eindringen des Bindemittels in das Spanmaterial zu vermeiden. Die Feuchtigkeit des beleimten Spanmaterials, welche unter 12 % gehalten wird, wird durch die mit der Bindemittelflotte auf das Sparmaterial aufgebrachte Wassermenge bestimmt. Diese Veröffentlichung betrifft somit ein für die Spanplattenerzeugung übliches Verfahren, bei dem das Rohmaterial zunächst getrocknet und dann beleimt wird, wogegen sich die Erfindung auf Trockenverfahren zur Herstellung von Faserplatten bezieht, bei denen das Ausgangsmaterial zuerst beleimt und anschließend getrocknet wird.In the field of chipboard, a process with reduced addition of binder has been described, in which dilute binder liquors with a solid resin content of preferably 22 to 30% by mass are used (EP-B-0 010 537). This process results in a more even distribution of the binder on chips of widely differing sizes and thus a saving in the amount of binder. In this process, the raw material used is first subjected to machining and subsequent drying to a moisture content of preferably less than 2% before it is glued to an aqueous liquor of an aminoplast. The chips are glued in a glue mixer. In addition, thickeners, such as cellulose derivatives, are added to the binder liquor in order to prevent the binder from penetrating into the chip material. The moisture of the glued chip material, which is kept below 12%, is determined by the amount of water applied to the savings material with the binder liquor. This publication thus relates to a process which is customary for particleboard production, in which the raw material is first dried and then glued, whereas the invention relates to drying processes for the production of fiberboard, in which the starting material is first glued and then dried.

Mit derartigen Trockenverfahren war es bisher nicht möglich, Faserplatten herzustellen, welche trotz eines geringen Bindemittelanteiles eine ausreichende Festigkeit aufweisen. Um eine ausreichende Festigkeit gemäß den gelten Normvorschriften zu erzielen, war es bisher bei nach dem Trockenverfahren hergestellten Faserplatten (sowohl bei MDF-Platten als auch bei HDF-Platten) erforderlich, immer mehr als 12 Masse-% Festharzanteil, bezogen auf atro (absolut trockenes) Fasermaterial, einzusetzen.With such drying processes, it has previously not been possible to produce fiberboard which, despite a small proportion of binder, has sufficient strength. In order to achieve sufficient strength in accordance with the applicable standards, it was previously necessary for fiberboard manufactured using the dry process (both MDF and HDF) to always have more than 12% by mass of solid resin, based on dry (absolutely dry) ) Use fiber material.

Es ist ein Ziel der vorliegenden Erfindung, ein eingangs erwähntes Verfahren zur Herstellung von Holzfaserplatten zu schaffen, mit dem unter anderem eine weiter verbesserte Ausnützung des zur Beleimung des Fasermaterials eingesetzten Bindemittels erreicht werden kann, sodaß zur Erzielung einer bestimmten Plattenfestigkeit bei einem bestimmten vorgegebenen Fasermaterial mit einer geringeren Festharzmenge als bisher das Auslangen gefunden werden kann. Es ist ein weiteres Ziel der vorliegenden Erfindung, ein solches Verfahren zu schaffen, welches ohne prinzipielle Abänderung der für die vorgenannten bekannten Verfahren vorhandenen apparativen Einrichtungen oder ohne wesentliche Veränderung der für das Verfahren erforderlichen Zeit durchführbar sein soll.It is an object of the present invention to provide a method for the production of wood fiber boards mentioned at the outset, with which, among other things, a further improved utilization of the binder used for gluing the fiber material can be achieved, so that to achieve a certain board strength with a certain predetermined fiber material a smaller amount of solid resin than can be found to date. It is a further object of the present invention to provide such a method, which should be able to be carried out without changing the principle of the equipment available for the aforementioned known methods or without substantially changing the time required for the method.

Dieses Ziel wird erfindungsgemäß dadurch erreicht, daß das Beleimen mit einer Flotte mit einem Festharzgehalt von 20 bis 35 Masse-%, vorzugsweise von 25 bis 35 Masse-%, vorgenommen wird und hierbei eine Bindemittelmenge eingesetzt wird, die weniger als 10 Masse-%, vorzugsweise 7 bis 9 Masse-% Festharz, bezogen auf das gesamte, atro gerechnete Fasermaterial, beträgt.According to the invention, this aim is achieved by gluing with a liquor with a solid resin content of 20 to 35% by mass, preferably 25 to 35% by mass, and using an amount of binder which is less than 10% by mass. preferably 7 to 9% by mass of solid resin, based on the total, atro calculated fiber material.

Durch die erfindungsgemäße Verwendung von hochverdünnten wäßrigen Bindemittelflotten ist es möglich, Holzfaserplatten im Trockenverfahren herzustellen, deren mechanische Werte den Normanforderungen sehr gut entsprechen, wobei gleichzeitig gegenüber den nach der Verfahrensweise der herkömmlichen Technologie hergestellten Platten eine wesentliche Einsparung an Bindemittel ermöglicht wird. So ist es durch das erfindungsgemäße Verfahren möglich, Holzfaserplatten mit einem Festharzanteil von weniger als 10 Masse-% herzustellen, welche ausreichende Festigkeiten gemäß den geltenden Normvorschriften besitzen.The use of highly dilute aqueous binder liquors according to the invention makes it possible to produce wood fiber boards in the dry process, the mechanical values of which very well meet the requirements of the standard, while at the same time a substantial saving in binder is made possible in comparison with the boards produced according to the method of conventional technology. Thus, the method according to the invention makes it possible to produce wood fiber boards with a solid resin content of less than 10% by mass, which have sufficient strengths in accordance with the applicable standards.

Durch den im erfindungsgemäßen Verfahren vorgesehenen Einsatz von hochverdünnten Bindemittelflotten erfolgt offensichtlich eine weitestgehende Umhüllung des Fasermaterials mit Bindemittel, wodurch es zu einer starken Vermehrung der für die Festigkeitsausbildung in den Platten wesentlichen Verleimungspunkte kommt.As a result of the use of highly diluted binder liquors provided in the method according to the invention, the fiber material is apparently largely coated with binder, which leads to a strong increase in the glueing points essential for the strength development in the boards.

Ein weiterer Vorteil dieses Verfahrens besteht darin, daß durch die hohe Verdünnung des eingesetzten Bindemittels eine Kühlwirkung auf die beleimte Faser ausgeübt wird, da ein Teil des im Bindemittelgemisches enthaltenen Wassers sofort verdampft, wodurch dem gesamten System Faser/Bindemittel Wärme entzogen wird. Dadurch wird eine vorzeitige Voraushärtung des auf der beleimten Faser befindlichen Bindemittels verhindert, welche Voraushärtung ebenfalls einen Abfall der Plattenfestigkeit zur Folge haben kann.Another advantage of this method is that the high dilution of the binder used exerts a cooling effect on the glued fiber, since part of the water contained in the binder mixture evaporates immediately, thereby removing heat from the entire fiber / binder system. This prevents premature pre-curing of the binder on the glued fiber, which pre-curing can also result in a decrease in panel strength.

Das vorliegende erfindungsgemäße Verfahren kann ohne wesentliche Änderung der Verfahrenstechnik durchgeführt werden. Die Beleimung des Fasermaterials erfolgt dabei kurz nach dessen Austritt aus der Zerfaserungsmaschine (Refiner) in der Blasleitung in herkömmlicher Art und Weise.The present method according to the invention can be carried out without a significant change in the process technology. The gluing of the fiber material takes place shortly after it emerges from the defibration machine (refiner) in the blow line in a conventional manner.

Der Leimflotte werden geeignete Härtersubstanzen, wie beispielsweise Ammoniumchlorid, Ammoniumphosphat, Phosporsäure, Ameisensäure, zur Aushärtung des verwendeten Bindmittels während des Heißpreßvorganges, in den in der Technik bekannten Mengen, welche von den jeweiligen Anlagenbedingungen abhängig sind, zugesetzt. Als besonders vorteilhaft hat sich auch der Zusatz eines speziellen Leimverstärkers auf der Basis eines Ligninsulfonates erwiesen. Weiters können der Bindemittelflotte auch noch zusätzliche Formaldehydfänger, wie beispielsweise Harnstoff, zugestetzt werden. Der Zusatz von Paraffinemulsion oder geschmolzenem Paraffin zur Hydrophobierung der Faserplatten erfolgt dagegen zweckmäßigerweise vor dem Eintritt in den Refiner.Suitable hardening substances, such as, for example, ammonium chloride, ammonium phosphate, phosphoric acid, formic acid, are added to the glue liquor in order to harden the binder used during the hot pressing process, in the amounts known in the art, which depend on the particular plant conditions. The addition of a special has also proven to be particularly advantageous Glue booster based on a lignin sulfonate proven. Additional formaldehyde scavengers, such as urea, can also be added to the binder liquor. In contrast, the addition of paraffin emulsion or melted paraffin to make the fiberboard hydrophobic is advantageously carried out before entering the refiner.

Das Fasermaterial, das in der oben beschriebenen Art und Weise mit Bindemittel versehen wurde, wird dann in an sich bekannter Weise auf eine Restfeuchte von maximal 12%, vorteilhaft maximal 10%, getrocknet, bevor es nach formung von Mattenbahnen in herkömmlichen Heizpressen zu Platten verpreßt wird.The fiber material, which has been provided with binder in the manner described above, is then dried in a manner known per se to a residual moisture of at most 12%, advantageously at most 10%, before it is pressed into sheets after forming mat webs in conventional heating presses becomes.

Die Verpressung zu Platten kann sowohl in herkömmlichen stationären Pressen bei Temperaturen von etwa 160 bis 190°C und Drücken bis zu 35 bar oder in Contipressen bei Heizplattentemperaturen bis zu 235°C und den üblichen Druckprogrammen erfolgen. Die Preßzeiten entsprechen beim erfindungsgemäßen Verfahren den auch bisher angewandten Preßzeiten.The pressing to plates can be done in conventional stationary presses at temperatures of around 160 to 190 ° C and pressures up to 35 bar or in contipresses at heating plate temperatures up to 235 ° C and the usual pressure programs. In the process according to the invention, the pressing times correspond to the pressing times which have also been used to date.

Eine bevorzugte Ausführungsform des Verfahrens gemäß der vorliegenden Erfindung besteht darin, daß man das zum Einsatz gelangende aminoplastische Bindemittel zunächst mit Wasser auf eine Festharzkonzentration von ungefähr 30 bis 40 Masse-% verdünnt und die erforderlichen Zusätze wie Härtersubstanzen, Leimverstärker, Formaldehydfänger, in geeigneter wäßriger Lösung der verdünnten Bindemittellösung erst unmittelbar vor da Eintritt in die Blasleitung über eine Mischstrecke zusetzt.A preferred embodiment of the process according to the present invention is that the aminoplastic binder used is first diluted with water to a solid resin concentration of approximately 30 to 40% by mass and the necessary additives such as hardening substances, glue booster, formaldehyde scavenger, in a suitable aqueous solution the diluted binder solution only closes just before entering the blow line over a mixing section.

Die Erfindung wird nun an Hand von Beispielen weiter erläutert, ohne auf diese beschränkt zu sein.The invention will now be further explained on the basis of examples, without being restricted to these.

BEISPIEL 1:EXAMPLE 1:

Für die Herstellung von mitteldichten Faserplatten (MDF-Platten) wurde ein Fasermaterial verwendet, das in an sich bekannter Weise aus Kiefernhackgut in einer Zerfaserungsmaschine (Refiner) hergestellt worden war. In die Blasleitung, durch welche das Fasermaterial aus dem Refiner ausgetragen wird, wurde kurz nach dem Austritt aus dem Refiner ein Bindemittel-hältiges Gemisch zudosiert. Dieses Bindemittel-hältige Gemisch setzte sich wie folgt zusammen:
In einem Mischbehälter wurde ein aminoplastischer E1-Leim für die Faserplattesproduktion (HIACOLL MDF 15) mit Wasser auf eine Konzentration von 33 Masse-% an Festharz verdünnt. In einem zweiten Mischbehälter wurde eine Lösung von 30 Masse-% Harnstoff, 10 Masse-% Amoniumchlorid und 1 Masse-% Phosphorsäure bereitet. Mit Hilfe von Dosierpumpen wurden die beiden Lösungen über einen Statikmischer in solch einem Verhältnis vereinigt, daß die endgültige Leimflotte eine Konzentration an Festharz von 28,3 Masse-% enthielt. Diese Leimflotte wurde in solch einer Menge zum Fasermaterial zugesetzt, daß ein Beleimungsfaktor von 8,2 Masse-% an Festharz, bezogen auf absolut trockene (atro) Faser erhalten wurde. Das beleimte Fasergemisch wurde anschließend in bekannter Art und Weise auf eine Restfeuchte von 10 Masse-% getrocknet, zu einer Fasermatte geformt und in einer Heizpresse unter Einwirkung von Druck und Temperatur zu einer MDF-Platte gepreßt. Die so hergestellte Platte entsprach sehr gut den Anforderungen der Industrienorm für MDF-Platten (Normtyp MDF, Formaldehydgehalt Klasse A).
For the production of medium-density fiberboard (MDF), a fiber material was used, which had been produced in a manner known per se from wood chips in a fiberising machine (refiner). A binder-containing mixture was metered into the blow line, through which the fiber material is discharged from the refiner, shortly after it emerged from the refiner. This binder-containing mixture was composed as follows:
In a mixing container, an aminoplastic E1 glue for fiber board production (HIACOLL MDF 15) was diluted with water to a concentration of 33% by mass of solid resin. A solution was placed in a second mixing container of 30 mass% urea, 10 mass% ammonium chloride and 1 mass% phosphoric acid. With the aid of metering pumps, the two solutions were combined in a ratio using a static mixer in such a way that the final glue liquor contained a concentration of solid resin of 28.3% by mass. This glue liquor was added to the fiber material in such an amount that a glue factor of 8.2% by mass of solid resin, based on absolutely dry (atro) fiber, was obtained. The glued fiber mixture was then dried in a known manner to a residual moisture content of 10% by mass, formed into a fiber mat and pressed in a heating press under the action of pressure and temperature to form an MDF board. The board produced in this way very well met the requirements of the industry standard for MDF boards (standard type MDF, formaldehyde content class A).

BEISPIEL 2:EXAMPLE 2:

Ein Fasermaterial gemäß Beispiel 1 wurde in an sich bekannter Art mit dem folgenden Bindemittel-hältigen Gemisch beleimt:
In einem Mischbehälter wurden 1.000 kg HIACOLL MDF 15, 100 kg Harnstofflösung (40 Masse-%) und 1.000 l Wasser gemischt, wodurch die Festharzkonzentration dieses Gemisches 31,4 Masse-% betrug. In einem zweiten Mischbehälter wurden 100 kg Leimverstärker HIACOLL K1215 und 165 l Wasser gemischt. Die beiden Lösungen wurden über Dosierpumpen und einen Statikmischer in solch einem Mischungsverhältnis zusammengemischt, daß die endgültige Konzentration an Festharz im Gemisch 27,0 Masse-% betrug. Dieses Gemisch wurde in einer Menge auf das Fasermaterial aufgebracht, daß ein Beleimungsfaktor von 7,5 Masse-%, bezogen auf atro Fasermaterial, erhalten wurde. Nach Trocknung auf ca 10% Restfeuchte, Formung einer Fasermatte und Heißpressung wurde eine MDF-Platte erhalten, die in allen Prüfwerten sehr gut den Anforderungen an den Normtyp MDF, Formaldehydgehalt-Klasse A gemäß der Industrienorm für MDF-Platten entsprach.
A fiber material according to Example 1 was glued in a manner known per se with the following binder-containing mixture:
1,000 kg of HIACOLL MDF 15, 100 kg of urea solution (40% by mass) and 1,000 l of water were mixed in a mixing container, whereby the solid resin concentration of this mixture was 31.4% by mass. 100 kg of HIACOLL K1215 glue booster and 165 l of water were mixed in a second mixing container. The two solutions were mixed together via metering pumps and a static mixer in such a mixing ratio that the final concentration of solid resin in the mixture was 27.0% by mass. This mixture was applied to the fiber material in an amount such that a gluing factor of 7.5% by mass, based on the dry fiber material, was obtained. After drying to approx. 10% residual moisture, shaping a fiber mat and hot pressing, an MDF board was obtained which, in all test values, very well met the requirements for the standard type MDF, formaldehyde content class A according to the industry standard for MDF boards.

BEISPIEL 3:EXAMPLE 3

Bei Beispiel 3 handelt es sich um ein Vergleichsbeispiel.Example 3 is a comparative example.

Für die Beleimung von Fasermaterial, welche wie in Beispiel 1 und 2 beschrieben, durchgeführt wurde, wurde eine Leimflotte folgender Zusammensetzung verwendet:
   1.000 kg HIACOLL MDF-12,
   150 kg Harnstofflösung (40 Masse-%)
   40 kg Ammoniumchlorid-Lösung (15 Masse-%)
   50 kg Wasser.
A glue liquor of the following composition was used for the gluing of fiber material, which was carried out as described in Examples 1 and 2:
1,000 kg HIACOLL MDF-12,
150 kg urea solution (40% by mass)
40 kg ammonium chloride solution (15% by mass)
50 kg of water.

Diese Leimflotte entspricht in ihrer Zusammensetzung dem Stande der Technik. Sie weist eine Festharzkonzentration von 53,2 Masse-% auf. Zur Erreichung der nach der Industrienorm für MDF-Platten geforderten mechanischen Werte einer unter Verwendung dieser Flotte gefertigten MDF-Platte mußten je 1.000 kg atro Fasermaterial 235 kg Leimflotte eingesetzt werden, was einem Beleimungsfaktor von 12,5 Masse-%, bezogen auf atro Fasermaterial entspricht.The composition of this glue liquor corresponds to the state of the art. It has a solid resin concentration of 53.2% by mass. To achieve the mechanical values required by the industry standard for MDF boards of an MDF board manufactured using this liquor, 235 kg of glue liquor had to be used per 1,000 kg of dry fiber material, which corresponds to a gluing factor of 12.5% by mass, based on dry fiber material .

Claims (4)

  1. Process for the production of wood fibre boards, in which the raw material is subjected to defibration, is subsequently glue-treated with an aqueous bonding agent liquor in a blow pipe, and the resultant glue-treated fibre material, after drying to the required residual moisture, is spread into mat courses and is moulded under pressure and temperature to form boards, characterized in that the glue treatment takes place using a liquor having a solid resin content of 20 to 35% by mass and, in so doing, a quantity of bonding agent is used which amounts to less than 10% by mass of solid resin, relative to the total calculated absolutely dry fibre material.
  2. Process according to claim 1, characterized in that the liquor has a solid resin content of 25 to 35% by mass and the quantity of bonding agent used amounts to 7 to 9% by mass of solid resin, relative to the total calculated absolutely dry fibre material.
  3. Process according to claim 1 or claim 2, characterized in that the bonding agent is an aminoplastic bonding agent, which is diluted with water to a solid resin concentration of 30 to 40% by mass and to which are added additives such as hardeners, glueing accelerators and formaldehyde interceptors in an appropriate aqueous solution.
  4. Process according to claim 3, characterized in that the additives are added to the dilute aminoplastic bonding agent along a mixing section prior to the entry into the blow pipe.
EP92903957A 1991-02-08 1992-02-07 Process for the production of wood-fibre boards Revoked EP0570435B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AT278/91 1991-02-08
AT0027891A AT403023B (en) 1991-02-08 1991-02-08 METHOD FOR PRODUCING WOOD FIBER PANELS
PCT/AT1992/000016 WO1992013688A1 (en) 1991-02-08 1992-02-07 Process for the production of wood-fibre boards

Publications (2)

Publication Number Publication Date
EP0570435A1 EP0570435A1 (en) 1993-11-24
EP0570435B1 true EP0570435B1 (en) 1995-05-03

Family

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EP92903957A Revoked EP0570435B1 (en) 1991-02-08 1992-02-07 Process for the production of wood-fibre boards

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EP (1) EP0570435B1 (en)
CN (1) CN1063837A (en)
AT (1) AT403023B (en)
AU (1) AU1225692A (en)
DE (1) DE59202092D1 (en)
DK (1) DK0570435T3 (en)
ES (1) ES2074874T3 (en)
IE (1) IE67381B1 (en)
NZ (1) NZ241508A (en)
PT (1) PT100106A (en)
SI (1) SI9210125A (en)
TR (1) TR26826A (en)
WO (1) WO1992013688A1 (en)
ZA (1) ZA92874B (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2774068B2 (en) * 1994-08-19 1998-07-09 光洋産業株式会社 Hot-press forming method of aggregate
CA2317513A1 (en) * 1998-08-05 2000-02-17 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V. Method for producing medium density fibre panels
DE10249581A1 (en) * 2002-10-24 2004-05-13 Kronotec Ag support plate

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT366960B (en) * 1978-06-02 1982-05-25 Oesterr Hiag Werke Ag METHOD FOR PRODUCING WOOD CHIPBOARDS
DE3025522A1 (en) * 1980-07-05 1982-02-18 Basf Ag, 6700 Ludwigshafen Formaldehyde-free wood material prodn. - with thermosetting binder mixt. contg. aq. epoxy! resin dispersion and aq. poly:amine-amide! dispersion
DE3042813A1 (en) * 1980-11-13 1982-06-09 Basf Ag, 6700 Ludwigshafen METHOD FOR PRODUCING AMINOPLASTIC CONDENSATES
US4407771A (en) * 1982-04-26 1983-10-04 The Celotex Corporation Blow line addition of isocyanate binder in fiberboard manufacture
DE3609506A1 (en) * 1985-03-25 1986-10-30 Koppers Co., Inc., Pittsburgh, Pa. Process for producing a composition from cellulose particles and resin for the production of fibre boards
DK77287D0 (en) * 1987-02-16 1987-02-16 Novopan Traeindustri CHEWING PLATE AND PROCEDURES FOR PRODUCING THEREOF
EP0389201B1 (en) * 1989-03-20 1993-12-22 Medite Of Europe Limited Apparatus and method of manufacturing synthetic boards including fire-retardant boards

Also Published As

Publication number Publication date
AU1225692A (en) 1992-09-07
TR26826A (en) 1994-08-12
IE67381B1 (en) 1996-03-20
ES2074874T3 (en) 1995-09-16
ATA27891A (en) 1992-11-15
WO1992013688A1 (en) 1992-08-20
PT100106A (en) 1993-03-31
DE59202092D1 (en) 1995-06-08
NZ241508A (en) 1994-05-26
EP0570435A1 (en) 1993-11-24
IE920406A1 (en) 1992-08-12
SI9210125A (en) 1995-04-30
ZA92874B (en) 1992-11-25
AT403023B (en) 1997-10-27
DK0570435T3 (en) 1995-09-11
CN1063837A (en) 1992-08-26

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