EP0729814B1 - Verfahren zur Herstellung von Spanplatten aus Reisschalen - Google Patents

Verfahren zur Herstellung von Spanplatten aus Reisschalen Download PDF

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Publication number
EP0729814B1
EP0729814B1 EP19950301410 EP95301410A EP0729814B1 EP 0729814 B1 EP0729814 B1 EP 0729814B1 EP 19950301410 EP19950301410 EP 19950301410 EP 95301410 A EP95301410 A EP 95301410A EP 0729814 B1 EP0729814 B1 EP 0729814B1
Authority
EP
European Patent Office
Prior art keywords
furnish
resin
rice husk
phenol
reaction mixture
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
EP19950301410
Other languages
English (en)
French (fr)
Other versions
EP0729814A1 (de
Inventor
George 226/64 243 18th Cross Joseph (Behind
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.)
National Research Development Corp UK
National Research Development Corp of India
Original Assignee
National Research Development Corp UK
National Research Development Corp of India
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 National Research Development Corp UK, National Research Development Corp of India filed Critical National Research Development Corp UK
Priority to ES95301410T priority Critical patent/ES2142453T3/es
Priority to EP19950301410 priority patent/EP0729814B1/de
Publication of EP0729814A1 publication Critical patent/EP0729814A1/de
Application granted granted Critical
Publication of EP0729814B1 publication Critical patent/EP0729814B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27N—MANUFACTURE 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
    • B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres

Definitions

  • This invention relates to a process for producing composite particle boards from rice husk and composite boards produced therefrom.
  • An object of this invention is to propose an improved process for the production of composite particle boards from rice husk and composite boards produced therefrom.
  • Another object of this invention is to propose a process for the production of composite particle boards from rice husk which no longer requires the step of drying of the furnish.
  • Still another object of this invention is to propose a process for the production of composite particle boards from rice husk which no longer is attended with the disadvantage of formation of steam pockets or blisters.
  • a process for producing composite particle boards from rice husk which comprises in blending cleaned rice husk with a substantially moisture-free resin to form a furnish, said resin comprising a condensation product of cashew nut shell liquid and/or cardanol with phenol, paraformaldehyde and an alkaline catalyst, spreading the furnish to form a layer, subjecting the furnish layer to the step of hot pressing and subsequent cooling to form the board.
  • rice husk is of a boat shape. It has now been found that such a rice husk is not receptive to a uniform coating of resin.
  • rice husk may first be subjected to the step of splitting to provide a surface more receptive to resin.
  • Such a step of splitting is important, as in the absence thereof, the bulk density of rice husk would be low and, consequentially, the thickness of furnished mat would be high, and that when such a furnished mat is subjected to the step of pressing, the edges of the mat would tend to spread. As the density in the spread portion would be lower than the main body portion of the board, the spread portion would need to be trimmed and, thereby, resulting in a loss of material.
  • the split rice husk is subjected to the step of cleaning and grading by any known method for removal of dust and other extraneous matter.
  • One of the concepts of the present invention resides in the use of a substantially moisture free resin so that, firstly, the moisture content of the furnish can be controlled and, secondly, the step of drying of the furnish is avoided.
  • the step of control on the moisture content of the furnish is important, as the presence of a correct moisture content provides a board without blisters and steam pockets.
  • the furnish should contain a moisture content of 6 to 15% based on dry weight, and preferably between 8 to 12%.
  • rice husk itself contains a moisture content, which normally is in the proximity of 8 to 12%.
  • the moisture content of rice husk is determined and only, if required, water is added to the blend so that the furnish contains the required moisture content of 6 to 15%, and preferably 8 to 12%.
  • the upper and lower limits of the moisture content contained in the furnish is dependant on the thickness of the board. If the board is thin, for example 6mm, the moisture content can then be upto 15%. However, if the board has a thickness of, for example, 25 mm a moisture content of the lower value of 6% is preferred.
  • a moisture content of 6 to 15% in the furnish is required because when the furnish is subjected to the step of hot pressing, the resin melts but does not flow adequately to wet adjacent particles. Further, to permit a bonding of rice husk to form the board, the surfaces of rice husk must get together, and for which a flexibility of rice husk is required. Such a flexibility is imparted through the moisture contained in the furnish.
  • the moisture content contained in the furnish is greater than 15%, and as temperatures as high as 170 to 180°C are employed in the step of hot pressing, only a negligible amount of moisture is allowed to escape from the edges. Thus, water is entrapped at high temperature during such a step of pressing, which is converted to steam on release or removal of pressure, and which results in the possible formation of blisters.
  • the furnish contains less than 6% of moisture, then the flexibility property is not present and, whereby, the wetting of the rice husk with resin is reduced.
  • rice husk is blended with 5 to 20% of resin to obtain a furnish. If more than 20% of resin is added to rice husk, the process is uneconomical. If the furnish contains less than 5% of resin, the board does not contain enough strength. Preferably, 10 to 12% of resin is added to rice husk.
  • the furnish layer is subjected to the step of hot pressing at a temperature of 150 to 200°C, and preferably at a temperature of 170 to 180°C.
  • the pressure applied to the furnish layer is 5 to 15 kg/cm 2 , and preferably 10 to 12 kg/cm 2 .
  • the density of the particle board may vary from 400 to 1200 kg/m 3 .
  • the board prepared by the process of the present invention may advantageously be used for overlaid and/or reinforced composite particle boards.
  • one or more fibrous materials such as coconut fibre, bamboo slivers and wood strips are incorporated in the board.
  • coconut fibre, bamboo and wood used as reinforcement increases the strength of the boards and incorporation of short length or chopped fibre in the rice husk increases the internal bond strength of the boards prepared therewith.
  • Coconut fibre, bamboo and wood strips may also be used as surface reinforcements for the rice husk particle board. Such surface reinfrocements increases the bonding strength and the decorative value of the resulting board.
  • Rice husk and the reinforcement such as chopped fibre is blended with a coconut shell liquid and/or cardanol-phenol-formaldehyde adhesive resin which is substantially moisture free. This admixture is then spread out evenly to form a layer and then hot pressed to obtain reinforced boards.
  • the reinforcement is coated with coconut shell liquid and/or cardanol-phenol-formaldehyde resin and then embedded in an even layer of resin coated rice husk furnish and hot pressed to form the reinforced board.
  • Overlaying is effected on one side or on both sides to provide a compact overlaid finished board.
  • Known phenolic resin adhesives and resin adhesives compatible with coconut shell liquid and/or cardanol-phenol-formaldehyde resin may be used for bonding the overlays to the rice husk.
  • Overlays such as bamboo mats, coconut fibre felt, wood veneer and the like are coated with a coconut shell liquid cardanol-phenol-formaldehyde resin or a phenol-formaldehyde adhesive resin or any other resin compatible with coconut shell liquid and/or cardanol-phenol-formaldehyde resin.
  • Resin coated rice husk furnish is then spread evenly thereon.
  • Another resin coated overlaying material may be placed over the rice husk furnish layer if overlaying is required on both sides. In each of the overlaying, the layers should have a total moisture content of 6 to 15%. This assembly may then be subjected to hot pressing.
  • This invention further relates to a process for preparing an improved adhesive resin suitable for bonding rice husk which comprises in the steps of admixing cashewnut shell liquid and/or cardanol with phenol, heating the said mixture in presence of an alkaline catalyst, adding para-formaldehyde to the said reaction mixture while the heating is continued to complete the condensation reaction and thereafter cooling the reaction product.
  • the reactants are taken according to the proportion set forth below :- CNSL/Cardanol 20% to 90% by weight Phenol 10% to 80% by weight
  • Alkaline catalyst in the range of 1 to 5% by weight of the CNSL/Cardanol and phenol used.
  • the catalyst is dissolved in 2 to 10 times its weight of water before adding to the condensation mixture.
  • the condensation takes place at the temperature range of 50 to 95°C.
  • the heating is generally continued for a period of 25 to 45 minutes initially.
  • the second stage of condensation after the addition of a further quantity of phenol is carried out at the temperature range of 55 to 95°C for a period of 30 to 45 minutes to complete the condensation reaction.
  • 50 Kg cleaned rice husk is blended with 5 Kg of the adhesive resin of the present invention in a muller for 15 mts. 15 Kg of the furnish so formed is taken out and is spread out in an even layer. This is subjected to hot pressing at 170 °C for 15 minutes to a nominal thickness of 1.2 cm. The board produced is then cooled and the edges trimmed to a nominal size 1.2 m x 1.2 m x 1.2 cm. The board prepared accordingly has a specific gravity of 0.70.
  • 38 Kg of the furnish prepared according to example 1 is laid out as an even mat and hot pressed at 170°C for 25 minutes, to a nominal thickness of 1.9 cm.
  • the board is cooled and trimmed to a nominal size of 1.8 M x 1.2M x 1.9 CM and has a specific gravity of 0.82.
  • bamboo slivers of about 1 mm thick, about 15 mm wide and about 1.4 m to 2 m length are coated with CNSL and/or phenol-formaldehyde resin which is substantially moisture free.
  • 50 Kg. cleaned rice husk is blended with 6 Kg. of CNSL and/or cardanol-phenol-formaldehyde resin substantially free of water.
  • 24 Kg.of the furnish thus produced is spread out as an even layer and the resin coated bamboo slivers are placed over the layer at approximately 10 cm intervals both along and across the length of the furnish layer.
  • Another 24 Kg. of the said furnish is spread over the bamboo slivers in a uniform layer and the assembly pressed at 175-185°C for 30 minutes to a nominal thickness of 2.0 cm.
  • the bamboo reinforced composite rice husk board that is formed is cooled and trimmed to a nominal size of 1.8 m x 1.2 m x 2.0 cm. It has a specific gravity of 0.85.
  • Two bamboo mats of the size 1.5 m x 1.5 m are evenly coated with a CNSL and/or cardanol-phenol-formaldehyde resin which is substantially moisture free.
  • 50 Kg. rice husk is blended with 5.5 Kg. of the said resin and 18 Kg. of the furnish so obtained is spread as an even layer on one of the said resin coated bamboo mats.
  • the other mat is then placed on top of the furnish layer.
  • This assembly is then pressed in a hot press at 160 to 170°C for 20 mts.to obtain a bamboo mat overlaid composite particle board having a nominal thickness of 1.2 cm.
  • the board is cooled and trimmed to a nominal size of 1.2 m x 1.2 m x 1.2 cm. This board has a specific gravity of 0.78.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Dry Formation Of Fiberboard And The Like (AREA)
  • Laminated Bodies (AREA)

Claims (16)

  1. Verfahren zur Herstellung von Verbundspanplatten aus Reishülsen, bei dem gereinigte und gespaltene Reishülsen zur Bildung eines Faserstoffs mit einem weitgehend feuchtigkeitsfreiem Harz vermischt werden, wobei das besagte Harz ein Kondensationsprodukt aus Cashew-Nußschalenöl bzw. Cardanol mit Phenol, Paraformaldehyd und einem alkalischen Katalysator ist, der Faserstoff zur Ausbildung Bildung einer Faserstoffschicht verteilt wird und die Faserstoffschicht für das Verformen zu Spanplatten warm gepreßt und danach abgekühlt wird.
  2. Verfahren gemäß Anspruch 1, bei dem der Faserstoff einen Feuchtegehalt von 6% bis 15% und vorzugsweise von 8% bis 12% aufweist.
  3. Verfahren gemaß Anspruch 1, bei dem die Reishülsen einer Spaltung und anschließenden Mischung mit dem besagten Harz unterworfen werden.
  4. Verfahren gemäß Anspruch 1, bei dem Reishülsen zur Bildung eines Faserstoffs mit 5% bis 20% Harz vermischt werden.
  5. Verfahren gemäß Anspruch 4, bei dem Reishülsen zur Bildung eines Faserstoffs mit 10% bis 12% Harz vermischt werden.
  6. Verfahren gemäß Anspruch 1, bei dem die Faserstoffschicht einer Warmpreßstufe bei einer Temperatur von 150°C bis 200°C und vorzugsweise einer Temperatur von 170°C bis 180°C unterworfen wird.
  7. Verfahren gemäß Anspruch 1, bei dem die Faserstoffschicht einer Warmpreßstufe bei einem Druck von 5 bis 15 kg/cm2 und vorzugsweise von 10 bis 12 kg/cm2 unterworfen wird.
  8. Verfahren gemäß Anspruch 1, bei dem zur Verstärkung z.B. Kokos-, Bambus- und Holzfasern mit besagten Hülsen und dem Harz vermischt werden.
  9. Verfahren gemäß Anspruch 1, bei dem zur Verstärkung Kokos-, Bambus- und Holzschnitzel und - streifen mit Harz beschichtet und zu einer Lage oder Lagen auf einer oder beiden Seiten des besagten Faserstoffs verformt werden und der Gesamt-Feuchtegehalt zwischen 6% und 15% liegt.
  10. Verfahren gemäß Anspruch 1, bei dem das Harz aus einer Reaktionsmischung hergestellt wird, die stufenweise durch Mischen von Cashew-Nußschalenöl bzw. Cardanol mit einem Teil Phenol, Erwärmen der Mischung in Gegenwart eines alkalischen Katalysators, z.B. einer wäßrigen Lösung von Natriumhydroxid, Zusatz von Paraformaldehyd zur besagten Reaktionsmischung unter weiterer Erwärmung zur Vervollständigung der Kondensationsreaktion und nachfolgendes Abkühlen des Reaktionsprodukts gebildet wird.
  11. Verfahren gemäß Anspruch 10, bei dem der Zusatz des restlichen Phenols zur Reaktionsmischung nach Zusatz des Paraformaldehyds erfolgt.
  12. Verfahren gemäß Anspruch 10, bei dem die Reaktionsmischung zunächst 25 Minuten lang auf eine Temperatur im Bereich von 50°C bis 55°C erwärmt wird.
  13. Verfahren gemäß Anspruch 11, bei dem die Reaktionsmischung für einen Zeitraum von 30 Minuten nach Zusatz der weiteren Phenolmenge auf 55°C bis 95°C erwärmt wird.
  14. Verfahren gemäß Anspruch 10, bei dem 20% bis 90% des Cashew-Nußschalenöls einer Menge von 10 Gew.-% bis 80 Gew.-% Phenol zur Harzherstellung durch Kondensation mit Paraformaldehyd zugemischt wird.
  15. Verfahren gemäß Anspruch 10, bei dem der Reaktionsmischung Paraformaldehyd in einer Menge zugesetzt wird, die das Äquivalent von 1,4 bis 2 Mol Formaldehyd bezogen auf die Menge Cashew-Nußschalenöl bzw. Cardanol und Phenol darstellt.
  16. Verfahren gemäß Anspruch 10, bei dem der zugesetzte alkalische Katalysator das Äquivalent von 1 Gew.-% bis 5 Gew.-% bezogen auf die Menge Cashew-Nußschalenöl bzw. Cardanol und Phenol darstellt.
EP19950301410 1995-03-03 1995-03-03 Verfahren zur Herstellung von Spanplatten aus Reisschalen Expired - Lifetime EP0729814B1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
ES95301410T ES2142453T3 (es) 1995-03-03 1995-03-03 Procedimiento para la fabricacion de paneles conglomerados hechos de cascara de arroz.
EP19950301410 EP0729814B1 (de) 1995-03-03 1995-03-03 Verfahren zur Herstellung von Spanplatten aus Reisschalen

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19950301410 EP0729814B1 (de) 1995-03-03 1995-03-03 Verfahren zur Herstellung von Spanplatten aus Reisschalen

Publications (2)

Publication Number Publication Date
EP0729814A1 EP0729814A1 (de) 1996-09-04
EP0729814B1 true EP0729814B1 (de) 1999-09-08

Family

ID=8221108

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19950301410 Expired - Lifetime EP0729814B1 (de) 1995-03-03 1995-03-03 Verfahren zur Herstellung von Spanplatten aus Reisschalen

Country Status (2)

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EP (1) EP0729814B1 (de)
ES (1) ES2142453T3 (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU3825499A (en) * 1998-05-02 1999-11-23 Rudolph, Norbert-W. Moulded elements made of hard coconut shell granulate and method for producing same
ID29044A (id) 1998-10-19 2001-07-26 Enigma Nv Resin-resin pengikat
ES2151441B1 (es) * 1999-01-07 2001-07-01 Inst Hispanico Del Arroz S A Tablero de aglomerado de cascarilla de arroz de densidad media.
CN105365025B (zh) * 2015-12-10 2017-11-21 湖南维以环保科技有限公司 一种椰炭纤维板及其制备方法

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB950623A (en) * 1959-10-14 1964-02-26 Philips Electrical Ind Ltd Improvements in or relating to laminated products
GB919549A (en) * 1960-01-12 1963-02-27 Rubber And Asbestos Corp Improvements in structural adhesives
US3660223A (en) * 1968-09-16 1972-05-02 Samuel L Casalina Rigid, flexible and composite solid objects having cellulose containing rice hull particles and radiation induced polymer and method of making same
HU181185B (en) * 1980-09-15 1983-06-28 23 Sz Allami Epitoeipari Valla Method for producing bodies particularly auilding units
JPS5996117A (ja) * 1982-11-24 1984-06-02 Gunei Kagaku Kogyo Kk フエノ−ル系樹脂組成物
JPH05279496A (ja) * 1992-04-03 1993-10-26 Sumitomo Bakelite Co Ltd フェノール樹脂積層板の製造法
US5354621A (en) * 1992-07-02 1994-10-11 Beltec International Biodegradable construction material and manufacturing method

Also Published As

Publication number Publication date
EP0729814A1 (de) 1996-09-04
ES2142453T3 (es) 2000-04-16

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