CA1195071A - Method of making fibreboards by the dry method technique - Google Patents
Method of making fibreboards by the dry method techniqueInfo
- Publication number
- CA1195071A CA1195071A CA000429443A CA429443A CA1195071A CA 1195071 A CA1195071 A CA 1195071A CA 000429443 A CA000429443 A CA 000429443A CA 429443 A CA429443 A CA 429443A CA 1195071 A CA1195071 A CA 1195071A
- Authority
- CA
- Canada
- Prior art keywords
- fibres
- binder
- hot
- moisture content
- moisture
- 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
Links
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
- B27N3/08—Moulding or pressing
- B27N3/10—Moulding of mats
Abstract
ABSTRACT OF THE DISCLOSURE
A method of making fibreboards by the dry method technique where a lignocellulose-containing fibre material is disintegrated into fibres which are dried and formed into a fibre mat which is hot-pressed. Binding between the fibres is obtained by means of a binder which can be added before or after drying. According to the invention the binder is added before drying and the fibres with the binder are dried to have a moisture content substantially lower than that mois-ture content in the material which is suitable for hot-pressing.
After drying, moisture is added to the fibre material in a degree such as to attain the moisture content suitable for hot-pressing whereby the tackiness of the binder, which has got lost to a great extent during drying, is restored.
A method of making fibreboards by the dry method technique where a lignocellulose-containing fibre material is disintegrated into fibres which are dried and formed into a fibre mat which is hot-pressed. Binding between the fibres is obtained by means of a binder which can be added before or after drying. According to the invention the binder is added before drying and the fibres with the binder are dried to have a moisture content substantially lower than that mois-ture content in the material which is suitable for hot-pressing.
After drying, moisture is added to the fibre material in a degree such as to attain the moisture content suitable for hot-pressing whereby the tackiness of the binder, which has got lost to a great extent during drying, is restored.
Description
The~present invention relates to a method of making fibreboards by the dry method technique, in which a lignocellulose-containing fibre material is disinte-gra~ed into fibres. The fibres are dried and formed into a fibre mat which is hot~pressed~ the binding between the fibres being obtained by means of a binder.
The lignocellulose-containing fibre material is prepared, for instance, by chipping of wood into chips which are defibrated in a per se known manner in a grind-ing apparatus, e.g. a defibra-tort into fibres of desired fineness~ After a binder has been added to the fibres and these have been dried the continued treatment con~
sists in forming the fibres in a forming apparatus into a porous fibre mat oi uniform thickness, eOg. in the or-lS der of 300~D0 mm. To reduce the heiaht of the hydraulic hot press in which the fibre mat is to be consolidated into a considerably thinner board the fibre mat is al-lowed after the forming operation to pass a so-called pre-press where the fibre mat is compressed into a thick-ness in the same region as the ready-pressed fibreboard When the fibreboard leaves the pre-press it rebounds to a certain extent~ and it has been found that the rebound will be considerably less if the added binder has re-tained most of its tackiness.
The binder is often added to the fibre when this is blown by means of steam from the grinding apparatus to the drier where the fibre is dried to have a moisture content of l2~15%. The binder will thus have approxima~e~
ly the same low moisture content as the Eibre material~
PR/BP
which means that the binder loses most of i-ts -tackiness so that the rebound of -the fibre mat increases, as described above. In this connection one might imagine adding moisu-tre afterwards, which in and per se might involve a certain in-crease of the tackiness of the fibres and consequen-tly a reduc-tion of the rebound. However, such adding would increase -the total moisture content of -the fibre ma-t so tha-t -this would be unsuitably high Eor the subsequent hot pressing.
To solve -this problem it is known ins-tead to blow the fibre from the grinding apparatus to -the drier wi-thout any addition of binder and to dry the Eibre -to a considerably lower moisture content, normally 4-6%. The dried fibre is then adm:ixed wi-th binder in a specific apparatus, a so-called 1.5 glue mixer, in which the binder is added a-t a concentra-tion of about 50-55%. Par-t of the wa-ter in the binder solution will be sucked into -the fibres but probably the mois-ture con-ten-t in the binder is still in the range of 30-40%, which means that the binder largely retains its -tackiness. This way of adding binder will thus have the advantage in subsequent opercltions that the rebound oE the fibre ma-t decreases. On tlle other hand, this glueing -technique has a great disadvan-tage, viz. in tha-t fibreboards made in this way will have a stained surface, which involves a deteriora-tion in qua]ity.
?.5 The present invention thus provides a solution oE
th~ prohlem described above and restores the tackiness of the binder so as to obtain the same low rebound aEter pre-pressing as wheil tlle binder has been added after drying, by a suitable treatment oE fibres to which binder has been added prior -to drying so tha-t the binder has los-t i-ts tackiness.
~ 35 ' - 2 -!~
According -to -the inven-tion the binder is added, as mentioned in a per se known manner, to the fibres prior to drying, but drying is carried out to attain a mois-ture con-tent which is lower than the moisture con-tent sui-table for ho-t-pressiny and mois-ture then is added -to the fibres to such a degree that a mois-ture conten-t suitable for ho-t-pressing is a-ttained again. Further characteristic features of the inven-tion will appear from the sub-claims.
It has surprisingly been found tha-t several advan-tages result from the method of the invention in which the Eibres thus are dried by means oE -the added binder -to a con-siderably lower mois-ture conten-t -than tha-t which is suitable Eor hot-pressing and which usually is in the range of 10-15%, lS preEerably 11%, and -the fibres thereupon are moistened to have said moisture content. As the binder is situated on the out-side of the fibres the binder will be given a moisture tha-t is sufficient to restore i-ts tackiness to essentially full extent in spite of the fact that -the tota] moisture conten-t of the material, i.e. -the fibres plus the binder, lies within the range suitable for hot-pressing. The mois-tening of -the bincier has still another posi-tive effect. As the moisture content of the binder increases it will be easier for it to f:low out between the fibres during the hot-pressing opera-tïon and the fibreboards will -thereby be given a higher strength.
~nother way oE expressing the same -thing is to say that a cer-tain strength of the fibreboards can be ob-tained with a smaller amourlt of binder iE the moisture content of -the binder is in-creased prior to ho-t-pressing. As the cost for binders is one oE ttle ~reatest items of expenditure in making -this type of Eibreboards a reduc-tion of -the binder addition can -thus involve importan-t saving in the variable costs.
?7~L
The binder usually consists of a urea resin or a melamine-reinforced urea resin, especially when making fibreboards of medium hardness. To increase the effect of -the moisutre added as described above and to effect a further improve-ment of the tackiness o~ -the fibre the added moisture may con-sist oE a diluted solu-tion or emulsion con-taining a small amoun-t of thermoplastic or -thermose-tting resins, e.g. polyvinyl com-pounds or urea glue. This technique is also suitable for add-ing simul-taneous]y all or part of the hardener subs-tance that would normally be mingled into the binder, e.g. of the -type described above, which is added to the fibre prior -to drying.
The risk that an initial hardening of the binder would occur duriny the drying operatin will -thus also be eliminated to a great extent by this invention.
The lignocellulose-containing fibre material is prepared, for instance, by chipping of wood into chips which are defibrated in a per se known manner in a grind-ing apparatus, e.g. a defibra-tort into fibres of desired fineness~ After a binder has been added to the fibres and these have been dried the continued treatment con~
sists in forming the fibres in a forming apparatus into a porous fibre mat oi uniform thickness, eOg. in the or-lS der of 300~D0 mm. To reduce the heiaht of the hydraulic hot press in which the fibre mat is to be consolidated into a considerably thinner board the fibre mat is al-lowed after the forming operation to pass a so-called pre-press where the fibre mat is compressed into a thick-ness in the same region as the ready-pressed fibreboard When the fibreboard leaves the pre-press it rebounds to a certain extent~ and it has been found that the rebound will be considerably less if the added binder has re-tained most of its tackiness.
The binder is often added to the fibre when this is blown by means of steam from the grinding apparatus to the drier where the fibre is dried to have a moisture content of l2~15%. The binder will thus have approxima~e~
ly the same low moisture content as the Eibre material~
PR/BP
which means that the binder loses most of i-ts -tackiness so that the rebound of -the fibre mat increases, as described above. In this connection one might imagine adding moisu-tre afterwards, which in and per se might involve a certain in-crease of the tackiness of the fibres and consequen-tly a reduc-tion of the rebound. However, such adding would increase -the total moisture content of -the fibre ma-t so tha-t -this would be unsuitably high Eor the subsequent hot pressing.
To solve -this problem it is known ins-tead to blow the fibre from the grinding apparatus to -the drier wi-thout any addition of binder and to dry the Eibre -to a considerably lower moisture content, normally 4-6%. The dried fibre is then adm:ixed wi-th binder in a specific apparatus, a so-called 1.5 glue mixer, in which the binder is added a-t a concentra-tion of about 50-55%. Par-t of the wa-ter in the binder solution will be sucked into -the fibres but probably the mois-ture con-ten-t in the binder is still in the range of 30-40%, which means that the binder largely retains its -tackiness. This way of adding binder will thus have the advantage in subsequent opercltions that the rebound oE the fibre ma-t decreases. On tlle other hand, this glueing -technique has a great disadvan-tage, viz. in tha-t fibreboards made in this way will have a stained surface, which involves a deteriora-tion in qua]ity.
?.5 The present invention thus provides a solution oE
th~ prohlem described above and restores the tackiness of the binder so as to obtain the same low rebound aEter pre-pressing as wheil tlle binder has been added after drying, by a suitable treatment oE fibres to which binder has been added prior -to drying so tha-t the binder has los-t i-ts tackiness.
~ 35 ' - 2 -!~
According -to -the inven-tion the binder is added, as mentioned in a per se known manner, to the fibres prior to drying, but drying is carried out to attain a mois-ture con-tent which is lower than the moisture con-tent sui-table for ho-t-pressiny and mois-ture then is added -to the fibres to such a degree that a mois-ture conten-t suitable for ho-t-pressing is a-ttained again. Further characteristic features of the inven-tion will appear from the sub-claims.
It has surprisingly been found tha-t several advan-tages result from the method of the invention in which the Eibres thus are dried by means oE -the added binder -to a con-siderably lower mois-ture conten-t -than tha-t which is suitable Eor hot-pressing and which usually is in the range of 10-15%, lS preEerably 11%, and -the fibres thereupon are moistened to have said moisture content. As the binder is situated on the out-side of the fibres the binder will be given a moisture tha-t is sufficient to restore i-ts tackiness to essentially full extent in spite of the fact that -the tota] moisture conten-t of the material, i.e. -the fibres plus the binder, lies within the range suitable for hot-pressing. The mois-tening of -the bincier has still another posi-tive effect. As the moisture content of the binder increases it will be easier for it to f:low out between the fibres during the hot-pressing opera-tïon and the fibreboards will -thereby be given a higher strength.
~nother way oE expressing the same -thing is to say that a cer-tain strength of the fibreboards can be ob-tained with a smaller amourlt of binder iE the moisture content of -the binder is in-creased prior to ho-t-pressing. As the cost for binders is one oE ttle ~reatest items of expenditure in making -this type of Eibreboards a reduc-tion of -the binder addition can -thus involve importan-t saving in the variable costs.
?7~L
The binder usually consists of a urea resin or a melamine-reinforced urea resin, especially when making fibreboards of medium hardness. To increase the effect of -the moisutre added as described above and to effect a further improve-ment of the tackiness o~ -the fibre the added moisture may con-sist oE a diluted solu-tion or emulsion con-taining a small amoun-t of thermoplastic or -thermose-tting resins, e.g. polyvinyl com-pounds or urea glue. This technique is also suitable for add-ing simul-taneous]y all or part of the hardener subs-tance that would normally be mingled into the binder, e.g. of the -type described above, which is added to the fibre prior -to drying.
The risk that an initial hardening of the binder would occur duriny the drying operatin will -thus also be eliminated to a great extent by this invention.
Claims (6)
1. A method of making fibreboards by the dry method technique, in which a lignocellulose-containing fibre material is disintegrated into fibres and the fibres are dried and formed into a fibre mat which thereupon is hot-pressed, the binding between the fibres being obtained by means of a binder added to the fibres prior to drying and the drying operation being effected to provide a moisture content lower than a pre-determined moisture content suitable for hot-pressing, and thereupon adding moisture to the fibres in a degree such as to attain said moisture content suitable for hot-pressing.
2. A method as claimed in claim 1, which comprises adding the moisture substantially in the form of water.
3. A method as claimed in claim 1, which comprises adding the moisture in the form of a diluted solution or emul-sion including a thermoplastic or thermosetting resin.
4. A method as claimed in claim 3, in which the resin is selected from polyvinyl compounds and urea glue.
5. A method as claimed in claim 1, 2 or 3, in which a binder containing hardener substances is used, all or part of the hardener substance being added in connection with moistening.
6. A method as claimed in claim 1, 2 or 3, which comprises carrying out drying to a moisture content which is substantially below 10-15%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8203516A SE442724B (en) | 1982-06-07 | 1982-06-07 | SET FOR MANUFACTURING FIBER DISKS ACCORDING TO THE DRY METHOD |
| SE8203516-3 | 1982-06-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1195071A true CA1195071A (en) | 1985-10-15 |
Family
ID=20346996
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000429443A Expired CA1195071A (en) | 1982-06-07 | 1983-06-01 | Method of making fibreboards by the dry method technique |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS59501006A (en) |
| CA (1) | CA1195071A (en) |
| DE (1) | DE3390039T1 (en) |
| FI (1) | FI73380C (en) |
| SE (1) | SE442724B (en) |
| WO (1) | WO1983004387A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE8506018L (en) * | 1985-12-19 | 1987-06-20 | Sunds Defibrator | MANUFACTURING FIBER DISCS |
| SE461962B (en) * | 1987-12-16 | 1990-04-23 | Sunds Defibrator Ind Ab | SET AND DEVICE FOR MANUFACTURING FIBER BOARD DISKS |
| DE19647240B4 (en) * | 1996-11-15 | 2005-06-09 | Fritz Homann Gmbh & Co. Kg | Wood fiber board and process for its production |
| EP1317508A2 (en) * | 2000-09-09 | 2003-06-11 | Thiam Huay Gary Choo | Moulding mixture for manufacture of mouldable product |
| DE10054163A1 (en) | 2000-11-02 | 2002-06-06 | Wacker Polymer Systems Gmbh | Process for the production of pressed wood panels |
| US7368037B2 (en) | 2003-05-21 | 2008-05-06 | Masonite Corporation | Refiner steam separation system for reduction of dryer emissions |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1135610A (en) * | 1978-07-20 | 1982-11-16 | Krishan K. Sudan | Waferboard process |
-
1982
- 1982-06-07 SE SE8203516A patent/SE442724B/en not_active IP Right Cessation
-
1983
- 1983-06-01 CA CA000429443A patent/CA1195071A/en not_active Expired
- 1983-06-06 JP JP50206983A patent/JPS59501006A/en active Pending
- 1983-06-06 WO PCT/SE1983/000231 patent/WO1983004387A1/en active IP Right Grant
- 1983-06-06 DE DE19833390039 patent/DE3390039T1/en not_active Withdrawn
-
1984
- 1984-01-30 FI FI840379A patent/FI73380C/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| FI840379A0 (en) | 1984-01-30 |
| FI840379A (en) | 1984-01-30 |
| WO1983004387A1 (en) | 1983-12-22 |
| FI73380C (en) | 1987-10-09 |
| JPS59501006A (en) | 1984-06-07 |
| DE3390039T1 (en) | 1984-08-23 |
| FI73380B (en) | 1987-06-30 |
| SE8203516L (en) | 1983-12-08 |
| SE442724B (en) | 1986-01-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Blanchet et al. | Particleboard made from hammer milled black spruce bark residues | |
| US5134023A (en) | Process for making stable fiberboard from used paper and fiberboard made by such process | |
| US2831794A (en) | Process for manufacturing veneer panels | |
| Ihnát et al. | Waste agglomerated wood materials as a secondary raw material for chipboards and fibreboards. Part II: Preparation and characterization of wood fibres in terms of their reuse | |
| AU638729B2 (en) | Improved sheeting material and method of manufacturing the same | |
| EP0647174B1 (en) | Manufacture of board | |
| CA1195071A (en) | Method of making fibreboards by the dry method technique | |
| KR20010021695A (en) | Manufacture of composite boards | |
| CA1284090C (en) | Process for the production of wood fibre panels | |
| JPH03207602A (en) | Manufacture of molded parts | |
| EP1121231A1 (en) | Process for the production of articles from treated lignocellulosic particles and binder | |
| Akbulut et al. | Some advantages of three-layer medium-density fibreboard as compared to the traditional single-layer one | |
| US3130114A (en) | Process of manufacturing fibreboards and pressings from lignocellulose material | |
| DE102004024566A1 (en) | Water-resistant wooden construction material, e.g. chipboard or fiberboard for furniture production, having binder comprising formaldehyde resin and modified and/or destructured cereal flour | |
| WO1992012836A1 (en) | Building substrate and method of manufacturing same | |
| Chen | Bonding flakeboards of southern species with copolymer resins of forest and agricultural residue extracts | |
| EP0186503B1 (en) | Improved method of making dimensionally stable composite board | |
| DE2811833B2 (en) | Panel consisting predominantly of fiber material and at least one binding agent, as well as processes for their production | |
| CA1158825A (en) | Utilisation of fibrous waste | |
| DD205382A1 (en) | METHOD FOR ACTIVATING WOODEN PARTICLES FOR WOOD PRODUCTION OF MATERIALS | |
| Myers | Hardboards from Mixtures of Colombian and Ghanaian Hardwoods | |
| JPH11147212A (en) | Manufacture of fiber board | |
| DE7808239U1 (en) | PLATE |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEC | Expiry (correction) | ||
| MKEX | Expiry |