WO1987005955A1 - Method of shaping, preferably bending, hardened wood fiber boards - Google Patents

Method of shaping, preferably bending, hardened wood fiber boards Download PDF

Info

Publication number
WO1987005955A1
WO1987005955A1 PCT/SE1987/000159 SE8700159W WO8705955A1 WO 1987005955 A1 WO1987005955 A1 WO 1987005955A1 SE 8700159 W SE8700159 W SE 8700159W WO 8705955 A1 WO8705955 A1 WO 8705955A1
Authority
WO
WIPO (PCT)
Prior art keywords
boards
heating
bending
chemical solution
shaping
Prior art date
Application number
PCT/SE1987/000159
Other languages
French (fr)
Inventor
Bengt Lindgren
Original Assignee
Hammarberg, Lars
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 Hammarberg, Lars filed Critical Hammarberg, Lars
Publication of WO1987005955A1 publication Critical patent/WO1987005955A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27H—BENDING WOOD OR SIMILAR MATERIAL; COOPERAGE; MAKING WHEELS FROM WOOD OR SIMILAR MATERIAL
    • B27H1/00—Bending wood stock, e.g. boards
    • 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
    • B27N7/00—After-treatment, e.g. reducing swelling or shrinkage, surfacing; Protecting the edges of boards against access of humidity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C53/00—Shaping by bending, folding, twisting, straightening or flattening; Apparatus therefor
    • B29C53/02—Bending or folding
    • B29C53/04—Bending or folding of plates or sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31F—MECHANICAL WORKING OR DEFORMATION OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31F1/00—Mechanical deformation without removing material, e.g. in combination with laminating
    • B31F1/36—Moistening and heating webs to facilitate mechanical deformation and drying deformed webs
    • 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
    • D21J1/10—After-treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2711/00—Use of natural products or their composites, not provided for in groups B29K2601/00 - B29K2709/00, for preformed parts, e.g. for inserts
    • B29K2711/12—Paper, e.g. cardboard
    • B29K2711/126—Impregnated

Definitions

  • the present invention relates to a method of shaping, preferably bending, hardened flat fibre boards consisting of cellulose fibres, lignin and hardening oil by moistening, heating, bending and subsequent cooling.
  • Hardened wood fibre boards which comprise short, brittle cellulose fibres and intermediate lignin as well as a percentage of cured hardening oil, which is a drying oil having the task of forming a bridgehead for so-called hydrogen bridges, can be bent principly in two different ways, namely using a high temperature or a low temperature combined with moisture.
  • the fibre boards are normally hardened during the manufacturing process at about 165°C. If the temperature is raised a few degress above 165°C, the board will self-ignite in the presence of oxygen. In such a case the fibres are over-hardened, the hydrogen bridges are broken down and a carbonising process begins, which leads to rapid lowering of the board strength. If the lignin is therefore to be softened up at about 200°C in order to bend the board, this should take place in the absence of oxygen and preferably in an autoclave where steam under pressure is present to ensure the reformation of the hydrogen bridges.
  • the board cannot be bent until it has been completely heated, which means that very hot contact plates are required if this is to take place rapidly with conventional heating, and so that the moisture will remain in the board.
  • the heat from these plates breaks down the surface fibres before the heat has reached the middle of the board. If heating is carried out more slowly and without the presence of moisture and oxygen, a complicated and expensive process is required where hydrogen gas or some other inert gas is continuously supplied.
  • the object of the present invention is to provide a method in bending wood fibre boards of the kind mentioned in the introduction, in which the above-mentioned drawbacks have been eliminated.
  • the moistening is carried out with the aid of a chemical solution, which temporarily dissolves the lignin, facilitates the pene ⁇ tration of liquid and releases the fibre bonds, that the boards are heated to about 80-120°C and that the boards are subsequently bent or moulded to the desired, pre ⁇ determined shape.
  • the fibre board which is to shaped, preferably by bending, is flat, and comprises cellulose fibres, lignin and hardening oil. During a first operation it is moistened by a chemical solution at the zone or zones where it is to be
  • This chemical solution is applied in a suitable ⁇ manner, e.g. by painting on, spraying or the like, on the
  • the solution includes a surfactant, water and an alkali salt.
  • the surfactant is preferably of the alkyl sulphate type and
  • the alkali salt is preferably of the sodium hydroxide type.
  • the chemical mixture suiably comprises about 1-5% alkyl sulphate, 80-95% water and about 5-20% sodium hydroxide.
  • a solution which has been found to be- parti ⁇ cularly suitable may contain 1-3% alkyl sulphate, about
  • the board After applying the chemical solution, the board is heated to about 80-120°C with the aid of heating plates or similar contact heat, heat radiation or by high- frequency induction heat.
  • the board is maintained in the bent state until it is cooled to a suitable temperature for preventing any tendency to return to its original shape. After the board has cooled and has dried out, it is then ready for use in its bent state, where the bend or bends have the same strenght properties as the rest of the board.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Manufacturing & Machinery (AREA)
  • Dry Formation Of Fiberboard And The Like (AREA)
  • Chemical And Physical Treatments For Wood And The Like (AREA)

Abstract

Method of shaping, preferably bending, hardened, flat wood fiber boards comprising cellulose fibers, lignin and hardening oil by moistening, heating, bending and subsequent cooling. Moistening is carried out with a chemical solution which temporarily dissolves the lignin, facilitates the penetration of liquid and releases the fibre bonds, whereafter the boards are heated to about 80-120°C, subsequent to which they are bent or moulded to the desired, predetermined shape.

Description

Method of shaping, preferably h nr.ing;, hardened wood fibre _____-__J___l≤
The present invention relates to a method of shaping, preferably bending, hardened flat fibre boards consisting of cellulose fibres, lignin and hardening oil by moistening, heating, bending and subsequent cooling.
Hardened wood fibre boards which comprise short, brittle cellulose fibres and intermediate lignin as well as a percentage of cured hardening oil, which is a drying oil having the task of forming a bridgehead for so-called hydrogen bridges, can be bent principly in two different ways, namely using a high temperature or a low temperature combined with moisture.
In the use of the high temperature technique, the fibre boards are normally hardened during the manufacturing process at about 165°C. If the temperature is raised a few degress above 165°C, the board will self-ignite in the presence of oxygen. In such a case the fibres are over-hardened, the hydrogen bridges are broken down and a carbonising process begins, which leads to rapid lowering of the board strength. If the lignin is therefore to be softened up at about 200°C in order to bend the board, this should take place in the absence of oxygen and preferably in an autoclave where steam under pressure is present to ensure the reformation of the hydrogen bridges. The board cannot be bent until it has been completely heated, which means that very hot contact plates are required if this is to take place rapidly with conventional heating, and so that the moisture will remain in the board. However, the heat from these plates breaks down the surface fibres before the heat has reached the middle of the board. If heating is carried out more slowly and without the presence of moisture and oxygen, a complicated and expensive process is required where hydrogen gas or some other inert gas is continuously supplied.
In the use of low temperature technique with heating up to about 100°C, trials have shown that the fibre boards can be bent to desired radii if the boards have "a sufficient moisture content in the zones where bending is to take place. However, it has been found to take a long time as well as being very difficult to get water to penetrate into the boards to the sufficient extent to achieve a moisture content inside the boards which is sufficient for them not to carck during bending.
The object of the present invention is to provide a method in bending wood fibre boards of the kind mentioned in the introduction, in which the above-mentioned drawbacks have been eliminated. Essentially distinguishing for the method in accordance with the invention is that the moistening is carried out with the aid of a chemical solution, which temporarily dissolves the lignin, facilitates the pene¬ tration of liquid and releases the fibre bonds, that the boards are heated to about 80-120°C and that the boards are subsequently bent or moulded to the desired, pre¬ determined shape.
By reson of the invention, there is very rapidly obtained a moisture content inside the boards which is sufficient for bending. Compared with the use of pure water the penetration is increased by about 100 times. In a con¬ tinuous bending process, rapid penetration of moisture into the boards is necessary.
The invention will now be described in detail below with the aid of a preferred embodiment. The fibre board which is to shaped, preferably by bending, is flat, and comprises cellulose fibres, lignin and hardening oil. During a first operation it is moistened by a chemical solution at the zone or zones where it is to be
_- 5 bent. This chemical solution is applied in a suitable \ manner, e.g. by painting on, spraying or the like, on the
*» upper and/or underside of the fait board. The solution includes a surfactant, water and an alkali salt. The surfactant is preferably of the alkyl sulphate type and
10 the alkali salt is preferably of the sodium hydroxide type. The chemical mixture suiably comprises about 1-5% alkyl sulphate, 80-95% water and about 5-20% sodium hydroxide. A solution which has been found to be- parti¬ cularly suitable may contain 1-3% alkyl sulphate, about
15 85% water and about 10-15% sodium hydroxide. After applying the chemical solution, the board is heated to about 80-120°C with the aid of heating plates or similar contact heat, heat radiation or by high- frequency induction heat. The combination of alkyl sulphate and
20 sodium hydroxide achieves high penetration of water into the board.
Compared with pure water, this penetration is increased by up to 100 times. The alkali additive causes swelling of the cellulose fibres, which thus suck up water rapidly in
25 combination with low surface tension caused by the surfactant. There is furthermore achieved softening of the ligno-sulphonic acids in the board in the same way as with sulphate digestion. When the alkali is then neutralised by the acidic substances in the interior of the board, the
30 lignin hardens again after the bending process, the moistening also achieving a concentration of high-frequency energy, if such is used for heating. When the board has been bent to the desired shpae with the aid of suitable surface pressure on one side thereof, with
35 simultaneous counter pressure on the other side thereof, the board is maintained in the bent state until it is cooled to a suitable temperature for preventing any tendency to return to its original shape. After the board has cooled and has dried out, it is then ready for use in its bent state, where the bend or bends have the same strenght properties as the rest of the board.

Claims

1. Method of shaping, preferably bending, hardened, flat wood fibre boards comprising cellulose fibres, f* ligning and hardening oil by moistening, heating, bending
/ and subsequent cooling, characterized in that the 5 moistening is carried out with the aid of a chemical solution which temporarily dissolves the ligning, facilities liquid penetration and releases the fibre bonds, in that the boards are heated to about 80-120°C and in that the boards are then bent or moulded to the 10 desired, predetermined shape.
2. Method as claimed in claim 1, characterized in that the chemical solution is applied to the upper and/or undersides of the flat boards at the zones which are to be shaped, the solution including a surfactant of preferably
15 the alkyl sulphate type, water and an alkali salt of preferably the sodium hydroxide type.
3. Method as claimed in claim 1 or 2, characterized in that the chemical solution comprises about 1-5% sulphate, 80-95% water and 5-20% sodium hydroxide.
20 4. Method as claimed in claim 1 or 2, characterized in that the chemical solution comprises 1-3% alkyl sulphate, about 85% water and 10-15% sodium hydroxide.
5. Method as claimed in claim 1, characterized in that heating takes place with the aid of heating plates or a 25 like contacting heating arrangement.
6. Method as claimed in claim 1, characterized in that heating takes place using high-frequency heating.
7. Method as claimed in claim 1, characterized in that heating takes place by heat radiation.
PCT/SE1987/000159 1986-03-27 1987-03-27 Method of shaping, preferably bending, hardened wood fiber boards WO1987005955A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8601453A SE452036B (en) 1986-03-27 1986-03-27 PROCEDURE FOR SHAPING, PREFERRED BENDING, OF HARD FIBER DISC
SE8601453-7 1986-03-27

Publications (1)

Publication Number Publication Date
WO1987005955A1 true WO1987005955A1 (en) 1987-10-08

Family

ID=20364005

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1987/000159 WO1987005955A1 (en) 1986-03-27 1987-03-27 Method of shaping, preferably bending, hardened wood fiber boards

Country Status (3)

Country Link
AU (1) AU7169987A (en)
SE (1) SE452036B (en)
WO (1) WO1987005955A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998045099A1 (en) * 1997-04-10 1998-10-15 Mdf Inc. Method of manufacturing a molded door skin from a wood composite, door skin produced therefrom, and door manufactured therewith
US6312540B1 (en) 1998-07-29 2001-11-06 Mdf, Inc. Method of manufacturing a molded door skin from a flat wood composite, door skin produced therefrom, and door manufactured therewith
US6689301B1 (en) 1997-04-10 2004-02-10 Mdf, Inc. Method of manufacturing a molded door skin from a wood composite, door skin produced therefrom, and door manufactured therewith
EP1512507A3 (en) * 1997-04-10 2005-07-20 Masonite Entry Door Corporation A molded door skin and door with such a door skin
WO2012056045A1 (en) * 2010-10-29 2012-05-03 Brav-O-Tech Wetting agents
US8597455B1 (en) 2009-10-02 2013-12-03 Metacomb, Inc. Translucent building material comprising corrugated cardboard

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2338685A (en) * 1938-05-16 1944-01-04 Dee Herbert Cyril Process of bending grainless lignocellulose fiberboard
US2595501A (en) * 1946-07-27 1952-05-06 Allis Chalmers Mfg Co Method of molding insulating material
US3675692A (en) * 1968-01-25 1972-07-11 Graham Wilton Jeans Methods of making articles from fiber board
US3948708A (en) * 1973-03-26 1976-04-06 Van Dresser Corporation Method of forming a panel
US4073672A (en) * 1974-12-30 1978-02-14 Masonite Corporation Post-press embossing of a consolidated man-made board

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2338685A (en) * 1938-05-16 1944-01-04 Dee Herbert Cyril Process of bending grainless lignocellulose fiberboard
US2595501A (en) * 1946-07-27 1952-05-06 Allis Chalmers Mfg Co Method of molding insulating material
US3675692A (en) * 1968-01-25 1972-07-11 Graham Wilton Jeans Methods of making articles from fiber board
US3948708A (en) * 1973-03-26 1976-04-06 Van Dresser Corporation Method of forming a panel
US4073672A (en) * 1974-12-30 1978-02-14 Masonite Corporation Post-press embossing of a consolidated man-made board

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1512507A3 (en) * 1997-04-10 2005-07-20 Masonite Entry Door Corporation A molded door skin and door with such a door skin
US6073419A (en) * 1997-04-10 2000-06-13 Premdor, Inc. Method of manufacturing a molded door skin from a wood composite, door skin produced therefrom, and door manufactured therewith
US6079183A (en) * 1997-04-10 2000-06-27 Mdf, Inc. Method of manufacturing a molded door skin from a wood composite, door skin produced therefrom, and door manufactured therewith
WO1998045099A1 (en) * 1997-04-10 1998-10-15 Mdf Inc. Method of manufacturing a molded door skin from a wood composite, door skin produced therefrom, and door manufactured therewith
US6689301B1 (en) 1997-04-10 2004-02-10 Mdf, Inc. Method of manufacturing a molded door skin from a wood composite, door skin produced therefrom, and door manufactured therewith
US9109393B2 (en) 1998-07-29 2015-08-18 Masonite Corporation Method of manufacturing a molded door skin from a flat wood composite, door skin produced therefrom, and door manufactured therewith
US9464475B2 (en) 1998-07-29 2016-10-11 Masonite Corporation Method of manufacturing a molded door skin from a flat wood composite, door skin produced therefrom, and door manufactured therewith
US7856779B2 (en) 1998-07-29 2010-12-28 Masonite Corporation Method of manufacturing a molded door skin from a flat wood composite, door skin produced therefrom, and door manufactured therewith
US6312540B1 (en) 1998-07-29 2001-11-06 Mdf, Inc. Method of manufacturing a molded door skin from a flat wood composite, door skin produced therefrom, and door manufactured therewith
US8833022B2 (en) 1998-07-29 2014-09-16 Masonite Corporation Method of manufacturing a molded door skin from a flat wood composite, door skin produced therefrom, and door manufactured therewith
US8650822B2 (en) 1998-07-29 2014-02-18 Masonite Corporation Method of manufacturing a molded door skin from a flat wood composite, door skin produced therefrom, and door manufactured therewith
US8597455B1 (en) 2009-10-02 2013-12-03 Metacomb, Inc. Translucent building material comprising corrugated cardboard
US9796153B1 (en) 2009-10-02 2017-10-24 Metacomb, Inc. Translucent building material comprising corrugated cardboard
US10434743B2 (en) 2009-10-02 2019-10-08 Metacomb, Inc. Translucent building material
US11472155B2 (en) 2009-10-02 2022-10-18 Metacomb, Inc. Translucent building material
CN103209811A (en) * 2010-10-29 2013-07-17 布瑞沃技术有限公司 Wetting agents
US9192898B2 (en) 2010-10-29 2015-11-24 Bravo-O-Tech Gmbh Wetting agents
EA024125B1 (en) * 2010-10-29 2016-08-31 Брав-О-Тек Гмбх Wetting agents
WO2012056045A1 (en) * 2010-10-29 2012-05-03 Brav-O-Tech Wetting agents

Also Published As

Publication number Publication date
SE452036B (en) 1987-11-09
AU7169987A (en) 1987-10-20
SE8601453L (en) 1987-09-28
SE8601453D0 (en) 1986-03-27

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