CA2122368A1 - Method for the production of particle- or fiberboard - Google Patents
Method for the production of particle- or fiberboardInfo
- Publication number
- CA2122368A1 CA2122368A1 CA 2122368 CA2122368A CA2122368A1 CA 2122368 A1 CA2122368 A1 CA 2122368A1 CA 2122368 CA2122368 CA 2122368 CA 2122368 A CA2122368 A CA 2122368A CA 2122368 A1 CA2122368 A1 CA 2122368A1
- Authority
- CA
- Canada
- Prior art keywords
- catalyst
- binder
- particle
- fiberboard
- nco
- 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.)
- Abandoned
Links
- 239000011094 fiberboard Substances 0.000 title claims abstract description 37
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 28
- 238000000034 method Methods 0.000 title claims abstract description 23
- 239000011230 binding agent Substances 0.000 claims abstract description 60
- 239000003054 catalyst Substances 0.000 claims abstract description 58
- 238000006243 chemical reaction Methods 0.000 claims abstract description 24
- 229920002635 polyurethane Polymers 0.000 claims abstract description 23
- 239000002245 particle Substances 0.000 claims abstract description 17
- 239000000835 fiber Substances 0.000 claims abstract description 15
- 238000003825 pressing Methods 0.000 claims description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 239000000839 emulsion Substances 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims description 4
- 239000007900 aqueous suspension Substances 0.000 claims description 3
- KIQKWYUGPPFMBV-UHFFFAOYSA-N diisocyanatomethane Chemical compound O=C=NCN=C=O KIQKWYUGPPFMBV-UHFFFAOYSA-N 0.000 claims description 3
- 229920001228 polyisocyanate Polymers 0.000 claims description 3
- 239000005056 polyisocyanate Substances 0.000 claims description 3
- 229920000642 polymer Polymers 0.000 claims description 3
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 claims 1
- 125000001302 tertiary amino group Chemical group 0.000 claims 1
- 239000003292 glue Substances 0.000 abstract 1
- 239000004814 polyurethane Substances 0.000 description 21
- 238000007731 hot pressing Methods 0.000 description 9
- 238000003860 storage Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 7
- 239000000654 additive Substances 0.000 description 6
- 150000003512 tertiary amines Chemical class 0.000 description 6
- 229920005830 Polyurethane Foam Polymers 0.000 description 5
- 230000000996 additive effect Effects 0.000 description 5
- 238000004026 adhesive bonding Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 239000000088 plastic resin Substances 0.000 description 5
- 239000011496 polyurethane foam Substances 0.000 description 5
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 5
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 4
- 150000001412 amines Chemical class 0.000 description 4
- 239000012948 isocyanate Substances 0.000 description 4
- 150000002513 isocyanates Chemical class 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- 239000007795 chemical reaction product Substances 0.000 description 3
- GSEJCLTVZPLZKY-UHFFFAOYSA-N Triethanolamine Chemical compound OCCN(CCO)CCO GSEJCLTVZPLZKY-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 229920000768 polyamine Polymers 0.000 description 2
- 229920005862 polyol Polymers 0.000 description 2
- 150000003077 polyols Chemical class 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 230000002588 toxic effect Effects 0.000 description 2
- 231100000563 toxic property Toxicity 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000012190 activator Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- -1 aliphatic amines Chemical class 0.000 description 1
- 239000012223 aqueous fraction Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 239000003995 emulsifying agent Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000000873 masking effect Effects 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 150000003141 primary amines Chemical class 0.000 description 1
- 150000003335 secondary amines Chemical class 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 150000003606 tin compounds Chemical class 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/703—Isocyanates or isothiocyanates transformed in a latent form by physical means
- C08G18/705—Dispersions of isocyanates or isothiocyanates in a liquid medium
- C08G18/706—Dispersions of isocyanates or isothiocyanates in a liquid medium the liquid medium being water
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/08—Processes
- C08G18/16—Catalysts
- C08G18/18—Catalysts containing secondary or tertiary amines or salts thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/08—Processes
- C08G18/16—Catalysts
- C08G18/18—Catalysts containing secondary or tertiary amines or salts thereof
- C08G18/1825—Catalysts containing secondary or tertiary amines or salts thereof having hydroxy or primary amino groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/08—Processes
- C08G18/16—Catalysts
- C08G18/18—Catalysts containing secondary or tertiary amines or salts thereof
- C08G18/1875—Catalysts containing secondary or tertiary amines or salts thereof containing ammonium salts or mixtures of secondary of tertiary amines and acids
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
- C08G18/40—High-molecular-weight compounds
- C08G18/64—Macromolecular compounds not provided for by groups C08G18/42 - C08G18/63
- C08G18/6484—Polysaccharides and derivatives thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L97/00—Compositions of lignin-containing materials
- C08L97/02—Lignocellulosic material, e.g. wood, straw or bagasse
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Materials Engineering (AREA)
- Dispersion Chemistry (AREA)
- Dry Formation Of Fiberboard And The Like (AREA)
Abstract
A B S T R A C T :
In a method for the production of particle- or fiberboard a catalyst accelerating a polyurethan reaction is added to a NCO-groups containing binder. The binder is used to glue lignocellulose containing particles or fibers, which are then formed in the shape of a mat and pressed to form the particle-or fiberboard under the influence of heat.
In a method for the production of particle- or fiberboard a catalyst accelerating a polyurethan reaction is added to a NCO-groups containing binder. The binder is used to glue lignocellulose containing particles or fibers, which are then formed in the shape of a mat and pressed to form the particle-or fiberboard under the influence of heat.
Description
212236~
Z 423pct /tc 13.04.1994 GLUNZ AG
59063 Hamm, Caldenhofer Weg 159 Method for the production-of particle- or fiberboard The invention relates to a method for the production of particle- or fiberboard, in which lignocellulose containing particles or fibers are glued with an NC0-groups con$aining binder, formed in the shape of a mat, and pressed to form the particle- or fiberboard under the influence of heat.
It is known from the AT-PS 270 189 to produce particle- and fiberboard using a binder containing NC0-groups as reactive groups. In this an isocyanate is brought upon lignocellulose containing particles or fibers. From the particles resp. fibers a mat is then formed, which is hot-pressed to the particle- or fiberboard under the influence of heat. A particle- or fiberboard bonded with a binder having NCO-groups has the advantage of excellent moisture resistance and no emission of ? 2 1 2 2 3 6 8 formaldehyde from the binder. It prooves to be disadvantageous, though, that binders containing NCO-groups have a smaller bonding effect as compared to other binders, which additionally has to be activated by relatively high temperatures and long pressing times during the hot-pressing of the particle- or fiberboard. Correspondingly, the cost of a high binder content in the end product and a small throughput of the hot presses, as well as a relatively high amount of rejects are noticed negatively in the production of particle- or fiberboard using a binder containing NCO-groups. It must be noted that increasing the pressing temperatures, in order to reach the temperature needed to harden the binder inside the mat faster, is limited by the fact that rapidly evaporating substances, especially water vapor, durinq the hot-pressing adversely affect the ~uality of the particle- resp. fiberboard.
It is therefore the object of the invention to further develop a method of the type described above, so that stable particle-or fiberboards are obtainable with a smaller amount of binder and/or that the pressing times can be reduced and/or that the pressing temperatures may be reduced.
In the production of amino plastic resin bonded~particle- and fiberboard it is known to apply various catalysts, especially acids, in order to accelerate the hardening of the amino plastic resin. For instance, it is known from the DE-OS 27 45 809 to use sulfide waste lye with a pH-value of 4.0 in a solid fraction of approximately 10 percent by weight of the amino plastic resin.
So far no catalysts are applied in the production of particle-and fiberboard using a binder containing NCO-groups. This is surprising in view of the long time for which this method is known. The reason is probably that it is feared that a possible catalyst would lead to difficulties in connection with the open storage time of the glued particles resp. fibers between the glueing and the hot-pressing. A hardening of the binder in this open storage time, which lasts typically between 15 and 30 212~368 minutes, reduces its glueing effect. This is considerable especially for the relatively small glueing effect of a binder containing NCO-groups.
In performing the polyurethane reaktion for the production of polyurethane foam material from polyol and isocyanate the use of catalysts is well known. According to the technical manual "Bayer-Polyurethanes", edition 1.79 tertiary amines and organic tin compounds are used as activators for the polyurethane reaction. In this, tertiary amines with NCO-reactive groups are advantageous insofar as tbese are chemically integrated into the polyurethane foam material after performing the polyurethane reaction and therefore deactivated.
The use of catalysts which are used in performing the polyurethane reaction in the production of polyurethane foam materials for the production of particle- or fiberboard using a binder containing NCO-groups seems fundamentally impossible to someone skilled in the art. It should be noted that the polyurethane reaction is a fast reaction, which in the production of polyurethane foam materials sets in immediately upon the mixing of the polyol with the isocyanate in the presence of the catalyst, even at low temperatures. It is to be feared that the use of a binder containing NCO-groups with the addition of a catalyst that accelerates polyurethane reactions would make the pressing of the glued particles or fibers into a stable particle- or fiberboard impossible after only minutes of open storage time, since the glueing effect of the binder would have been largely, if not fully, reduced, i. e. used up.
In the production of particle- or fiberboard tertiary amines are not known as catalysts which accelerate the hardening of the binder during the hot-pressing.
The US-PS 4 772 442 discloses a method of the type described above for the production of particle- or fiberboard using a binder containing NCO-groups, in which a fatty substance is used - 2122~
as a separation aid of the hot-pressed particle- or fiberboaxd from the surface of the press. In one embodiment the separation aid is applied as an aqueous solution, to which triethanolamine is added as an emulsifying agent. There is no mention of a catalytic effect of the triethanolamine concerning the binder in the US-PS 4 772 442.
From the De-OS 34 38 735 a binder additive for the production of amino plastic resin bonded particle- and fiberboards is known.
The binder additive is supposed to improve the flame resistivity of the particle- or fiberboard, without impairing its stability.
Constituents of the binder additive apart from boric acid are for instance a water soluble amine or polyamine as well as a further water soluble compound with at least one organically bound hydroxyl group or a liquid alcohol. Isocyanate may also be added to the binder consisting mainly of amino plastic resin as a binder constituent containing NCO-groups. A catalytic effect of the amines or polyamines as such on the hardening of the binder is not seen in the DE-OS 34 38 735 by someone skilled in the art. It does especially not disclose an immediate bonding of the amines with binders containing NCO-groups, insofar as these are used solely as binders.
For these reasons it is surprising that the object of the invention is solved by adding a catalyst that accelerates polyurethane reactions to the binder which contains NCO-groups.
Contrary to all expectations a variety of known catalysts that accelerate the polyurethane reaction in the production of polyurethane foam materials are suitable as an additive to the binder containing NCO-groups as reactive groups used in the production of particle- and fiberboard. Especially the preservation of the glueing effect during the open storage time of the glued particles or fibers, which was so far seen as critical, is found to be unproblematic. Open storage times of up to 30 minutes and more show no noticable influence on the efficiency of the binder, to which the catalyst has been added, during the hot-pressing, when the catalyst has been chosen carefully from the commercially available additives which accelerate a polyurethane reaction. At the same time the pressing times may be reduced by as much as 30 % without a degradation in quality. To the contrary, even an improvement of the mechanical properties of the particle- resp. fiberboard is observed. This is due to the fact that the catalyst causes the formation of urethane bonds between the lignocellulose containing particles resp. fibers and the binder that contains NCO-groups during the hot-pressing of the glued particles resp.
fibers, while the fraction of binder internal polycarbamide bonds is correspondingly reduced. Alternatively or parallel to the reduction of the process time a reduction of the process temperature of up to approximately 30 K is possible. ~his leads to a significantly reduced fraction of rejects due to water vapor damage.
It is understood that not all catalysts accelerating a polyurethane reaction are equally well suited as an additive to the binder in the production of particle- or fiberboard usin~ a binder that contains NCO-groups. In principle all ~nown types of catalysts that accelerate polyurethane reactions can be used, though. Taking into consideration the embodiments of the method for the production of particle- or fiberboards described hereinafter an especially well suited catalyst can be chosen without problems.
The binder may be brought onto the particles or fibers in an aqueous suspension or emulsion, where the catalyst is dissolved in the water. A water soluble catalyst has the advantage that it is evenly distributable in the binder. Smaller amounts of the usually expensive catalyst are then sufficient, than when the catalyst is insoluble in water and must be dispersed in the water. The application of the NCO-groups containing binder onto the particles resp. fibers in the form of an aqueous suspension is a common ~ethod in the production of particle- and fiberboard. Likewise, the use of suspensions resp. emulsions based on toluol is common. Here, the catalyst would accordingly 2~ ~23fi8 be added to the binder by way of the toluol.
The catalyst may have a hydroxyl group. The hydroxyl group of the catalyst is, among other things, an indication of the water solubility of the catalyst.
The catalyst may be chemically integrated in the particle- or fiberboard during the pressing. A catalyst tightly bound after the hot-pressing is chemically deactivated. This is of special importance, since polyurethane reactions accelerating catalysts all have strongly irritating or even toxic properties in an unbonded state. These irritating or even toxic properties of the catalyst do not matter after the chemical integration in the particle- or fiberboard, though.
The catalyst may be a tertiary amine. Amines are the best known group of polyurethane reaction accelerating catalysts. In the production of particle- and fiberboard using a NCO-groups containing binder especially tertiary amines are found to be advantageous. These are tightly bonded in the compounds created during the hot-pressing of the glued particles or fibers and therefore chemically deactivated, when the have a NCO-reactive group. Secondary and primary amines are bonded in the NCO-groups containing binder by NH/NCO-reactions.
For the realization of the invention ether- or aliphatic amines seem to be especially well suited.
Should in some instances problems occur with common, commercially available catalysts for a polyurethane reaction with respect to the open storage time in the production of particle- or fiberboards when using a NCO-groups containing binder, these may be overcome by using a blocked catalyst, that is activatable by heat. These catalysts, too, are per se known to accelerate a polyurethane reaction to someone skilled in the art.
~ 2122368 A blocked catalyst that is activatable by heat is easily obtainable by masking the catalyst with an acid. With a suitably chosen acid the reaction product disintegrates at a temperature that lies above the temperature characteristic for the opsn storage time, but in the lower region of temperatures attained during the hot-pressing of the particles resp. fibers.
The catalyst may be applied in a concentration of 0.001 to 2.0 percent by weight, especially 0.005 to 0.5 percent by weight, relative to the NCO-groups containing binder. The low fractions of polyurethane reaction accelerating catalyst which are sufficient to provide the desired effect clearly show that, even though the catalyst is possibly chemically integrated in the reaction product, it is a genuine catalyst in the classical sense and not an actual reaction partner. It is furthermore required that the concentration of the catalyst be small, so that the production of particle- and fiberboard using the catalyst has commercial advantages. It would not make sense if the attainable reduction in the process time of approximately 30 % resp. the reduction of the process temperature by 30 K resp.
the saving of binder would be equaled or surpassed by expenditures for the catalyst.
The NCO-groups containing binder may be a polyisocyanate, especially polymer 4,4'-methylendiisocyanate (PMDI). The PMDI
used at this time in the production of particle- or fiberboard as a NCO-groups containing binder is suited for the production of particle- and fiberboard using a polyurethane reactions accelerating catalyst, without the need of compositional changes.
The invention is further explained with the aid of a preferred embodiment.
In a standard production plant for the production of particle-board using a NCO-groups containing binder a commercially available polyurethane reactions accelerating catalyst was added -- 2122~68 to the binder. The binder, a polymer 4,4'methylendiisocyanate (PMDI) was used in an aqueous solution. The ratio of binder to water was 1:1. The binder was a commercially available, unmodified polyisocyanate (Desmodur 1520 A, Bayer Leverkusen AG). The polyurethane reactions accelerating catalyst was a water-soluble, tertiary amine (Texacat-DPA, Texaco-Chemical Deutschland GmbH) and was added to the water fraction of the binder emulsion in concentration corresponding to 0.5 percent by weight of the PNDI fraction of the emulsion. The particles were glued with the thus enriched emulsion in the usual way.
Following the forming of a mat from the particles and the pressing to a particle-board under the influence of heat, the quality of the resulting particle-boards was examined as a function of the pressing time. Even when remaining approximately 25 % below the usual pressing time, no deteriation of the quality was observed. Instead, an improvement of the mechanical qualities of the particle-board was observed, even when remaining significantly below the usual pressing time.
Concerning the open storage times, no significant reduction of the binding effect oP the binder was found for times up to 30 minutes. This coveres the whole span of common open storage times. All in all, it is found that the new method for the production of particle- or fiberboards using a NC0-groups containing binder and a polyurethane reactions accelerating catalyst can be implemented on existing production plants, yielding an increased output of up to one third at the same level of quality. The financial expenditure for the catalyst is small compared to the advantages attainable. -, , -
Z 423pct /tc 13.04.1994 GLUNZ AG
59063 Hamm, Caldenhofer Weg 159 Method for the production-of particle- or fiberboard The invention relates to a method for the production of particle- or fiberboard, in which lignocellulose containing particles or fibers are glued with an NC0-groups con$aining binder, formed in the shape of a mat, and pressed to form the particle- or fiberboard under the influence of heat.
It is known from the AT-PS 270 189 to produce particle- and fiberboard using a binder containing NC0-groups as reactive groups. In this an isocyanate is brought upon lignocellulose containing particles or fibers. From the particles resp. fibers a mat is then formed, which is hot-pressed to the particle- or fiberboard under the influence of heat. A particle- or fiberboard bonded with a binder having NCO-groups has the advantage of excellent moisture resistance and no emission of ? 2 1 2 2 3 6 8 formaldehyde from the binder. It prooves to be disadvantageous, though, that binders containing NCO-groups have a smaller bonding effect as compared to other binders, which additionally has to be activated by relatively high temperatures and long pressing times during the hot-pressing of the particle- or fiberboard. Correspondingly, the cost of a high binder content in the end product and a small throughput of the hot presses, as well as a relatively high amount of rejects are noticed negatively in the production of particle- or fiberboard using a binder containing NCO-groups. It must be noted that increasing the pressing temperatures, in order to reach the temperature needed to harden the binder inside the mat faster, is limited by the fact that rapidly evaporating substances, especially water vapor, durinq the hot-pressing adversely affect the ~uality of the particle- resp. fiberboard.
It is therefore the object of the invention to further develop a method of the type described above, so that stable particle-or fiberboards are obtainable with a smaller amount of binder and/or that the pressing times can be reduced and/or that the pressing temperatures may be reduced.
In the production of amino plastic resin bonded~particle- and fiberboard it is known to apply various catalysts, especially acids, in order to accelerate the hardening of the amino plastic resin. For instance, it is known from the DE-OS 27 45 809 to use sulfide waste lye with a pH-value of 4.0 in a solid fraction of approximately 10 percent by weight of the amino plastic resin.
So far no catalysts are applied in the production of particle-and fiberboard using a binder containing NCO-groups. This is surprising in view of the long time for which this method is known. The reason is probably that it is feared that a possible catalyst would lead to difficulties in connection with the open storage time of the glued particles resp. fibers between the glueing and the hot-pressing. A hardening of the binder in this open storage time, which lasts typically between 15 and 30 212~368 minutes, reduces its glueing effect. This is considerable especially for the relatively small glueing effect of a binder containing NCO-groups.
In performing the polyurethane reaktion for the production of polyurethane foam material from polyol and isocyanate the use of catalysts is well known. According to the technical manual "Bayer-Polyurethanes", edition 1.79 tertiary amines and organic tin compounds are used as activators for the polyurethane reaction. In this, tertiary amines with NCO-reactive groups are advantageous insofar as tbese are chemically integrated into the polyurethane foam material after performing the polyurethane reaction and therefore deactivated.
The use of catalysts which are used in performing the polyurethane reaction in the production of polyurethane foam materials for the production of particle- or fiberboard using a binder containing NCO-groups seems fundamentally impossible to someone skilled in the art. It should be noted that the polyurethane reaction is a fast reaction, which in the production of polyurethane foam materials sets in immediately upon the mixing of the polyol with the isocyanate in the presence of the catalyst, even at low temperatures. It is to be feared that the use of a binder containing NCO-groups with the addition of a catalyst that accelerates polyurethane reactions would make the pressing of the glued particles or fibers into a stable particle- or fiberboard impossible after only minutes of open storage time, since the glueing effect of the binder would have been largely, if not fully, reduced, i. e. used up.
In the production of particle- or fiberboard tertiary amines are not known as catalysts which accelerate the hardening of the binder during the hot-pressing.
The US-PS 4 772 442 discloses a method of the type described above for the production of particle- or fiberboard using a binder containing NCO-groups, in which a fatty substance is used - 2122~
as a separation aid of the hot-pressed particle- or fiberboaxd from the surface of the press. In one embodiment the separation aid is applied as an aqueous solution, to which triethanolamine is added as an emulsifying agent. There is no mention of a catalytic effect of the triethanolamine concerning the binder in the US-PS 4 772 442.
From the De-OS 34 38 735 a binder additive for the production of amino plastic resin bonded particle- and fiberboards is known.
The binder additive is supposed to improve the flame resistivity of the particle- or fiberboard, without impairing its stability.
Constituents of the binder additive apart from boric acid are for instance a water soluble amine or polyamine as well as a further water soluble compound with at least one organically bound hydroxyl group or a liquid alcohol. Isocyanate may also be added to the binder consisting mainly of amino plastic resin as a binder constituent containing NCO-groups. A catalytic effect of the amines or polyamines as such on the hardening of the binder is not seen in the DE-OS 34 38 735 by someone skilled in the art. It does especially not disclose an immediate bonding of the amines with binders containing NCO-groups, insofar as these are used solely as binders.
For these reasons it is surprising that the object of the invention is solved by adding a catalyst that accelerates polyurethane reactions to the binder which contains NCO-groups.
Contrary to all expectations a variety of known catalysts that accelerate the polyurethane reaction in the production of polyurethane foam materials are suitable as an additive to the binder containing NCO-groups as reactive groups used in the production of particle- and fiberboard. Especially the preservation of the glueing effect during the open storage time of the glued particles or fibers, which was so far seen as critical, is found to be unproblematic. Open storage times of up to 30 minutes and more show no noticable influence on the efficiency of the binder, to which the catalyst has been added, during the hot-pressing, when the catalyst has been chosen carefully from the commercially available additives which accelerate a polyurethane reaction. At the same time the pressing times may be reduced by as much as 30 % without a degradation in quality. To the contrary, even an improvement of the mechanical properties of the particle- resp. fiberboard is observed. This is due to the fact that the catalyst causes the formation of urethane bonds between the lignocellulose containing particles resp. fibers and the binder that contains NCO-groups during the hot-pressing of the glued particles resp.
fibers, while the fraction of binder internal polycarbamide bonds is correspondingly reduced. Alternatively or parallel to the reduction of the process time a reduction of the process temperature of up to approximately 30 K is possible. ~his leads to a significantly reduced fraction of rejects due to water vapor damage.
It is understood that not all catalysts accelerating a polyurethane reaction are equally well suited as an additive to the binder in the production of particle- or fiberboard usin~ a binder that contains NCO-groups. In principle all ~nown types of catalysts that accelerate polyurethane reactions can be used, though. Taking into consideration the embodiments of the method for the production of particle- or fiberboards described hereinafter an especially well suited catalyst can be chosen without problems.
The binder may be brought onto the particles or fibers in an aqueous suspension or emulsion, where the catalyst is dissolved in the water. A water soluble catalyst has the advantage that it is evenly distributable in the binder. Smaller amounts of the usually expensive catalyst are then sufficient, than when the catalyst is insoluble in water and must be dispersed in the water. The application of the NCO-groups containing binder onto the particles resp. fibers in the form of an aqueous suspension is a common ~ethod in the production of particle- and fiberboard. Likewise, the use of suspensions resp. emulsions based on toluol is common. Here, the catalyst would accordingly 2~ ~23fi8 be added to the binder by way of the toluol.
The catalyst may have a hydroxyl group. The hydroxyl group of the catalyst is, among other things, an indication of the water solubility of the catalyst.
The catalyst may be chemically integrated in the particle- or fiberboard during the pressing. A catalyst tightly bound after the hot-pressing is chemically deactivated. This is of special importance, since polyurethane reactions accelerating catalysts all have strongly irritating or even toxic properties in an unbonded state. These irritating or even toxic properties of the catalyst do not matter after the chemical integration in the particle- or fiberboard, though.
The catalyst may be a tertiary amine. Amines are the best known group of polyurethane reaction accelerating catalysts. In the production of particle- and fiberboard using a NCO-groups containing binder especially tertiary amines are found to be advantageous. These are tightly bonded in the compounds created during the hot-pressing of the glued particles or fibers and therefore chemically deactivated, when the have a NCO-reactive group. Secondary and primary amines are bonded in the NCO-groups containing binder by NH/NCO-reactions.
For the realization of the invention ether- or aliphatic amines seem to be especially well suited.
Should in some instances problems occur with common, commercially available catalysts for a polyurethane reaction with respect to the open storage time in the production of particle- or fiberboards when using a NCO-groups containing binder, these may be overcome by using a blocked catalyst, that is activatable by heat. These catalysts, too, are per se known to accelerate a polyurethane reaction to someone skilled in the art.
~ 2122368 A blocked catalyst that is activatable by heat is easily obtainable by masking the catalyst with an acid. With a suitably chosen acid the reaction product disintegrates at a temperature that lies above the temperature characteristic for the opsn storage time, but in the lower region of temperatures attained during the hot-pressing of the particles resp. fibers.
The catalyst may be applied in a concentration of 0.001 to 2.0 percent by weight, especially 0.005 to 0.5 percent by weight, relative to the NCO-groups containing binder. The low fractions of polyurethane reaction accelerating catalyst which are sufficient to provide the desired effect clearly show that, even though the catalyst is possibly chemically integrated in the reaction product, it is a genuine catalyst in the classical sense and not an actual reaction partner. It is furthermore required that the concentration of the catalyst be small, so that the production of particle- and fiberboard using the catalyst has commercial advantages. It would not make sense if the attainable reduction in the process time of approximately 30 % resp. the reduction of the process temperature by 30 K resp.
the saving of binder would be equaled or surpassed by expenditures for the catalyst.
The NCO-groups containing binder may be a polyisocyanate, especially polymer 4,4'-methylendiisocyanate (PMDI). The PMDI
used at this time in the production of particle- or fiberboard as a NCO-groups containing binder is suited for the production of particle- and fiberboard using a polyurethane reactions accelerating catalyst, without the need of compositional changes.
The invention is further explained with the aid of a preferred embodiment.
In a standard production plant for the production of particle-board using a NCO-groups containing binder a commercially available polyurethane reactions accelerating catalyst was added -- 2122~68 to the binder. The binder, a polymer 4,4'methylendiisocyanate (PMDI) was used in an aqueous solution. The ratio of binder to water was 1:1. The binder was a commercially available, unmodified polyisocyanate (Desmodur 1520 A, Bayer Leverkusen AG). The polyurethane reactions accelerating catalyst was a water-soluble, tertiary amine (Texacat-DPA, Texaco-Chemical Deutschland GmbH) and was added to the water fraction of the binder emulsion in concentration corresponding to 0.5 percent by weight of the PNDI fraction of the emulsion. The particles were glued with the thus enriched emulsion in the usual way.
Following the forming of a mat from the particles and the pressing to a particle-board under the influence of heat, the quality of the resulting particle-boards was examined as a function of the pressing time. Even when remaining approximately 25 % below the usual pressing time, no deteriation of the quality was observed. Instead, an improvement of the mechanical qualities of the particle-board was observed, even when remaining significantly below the usual pressing time.
Concerning the open storage times, no significant reduction of the binding effect oP the binder was found for times up to 30 minutes. This coveres the whole span of common open storage times. All in all, it is found that the new method for the production of particle- or fiberboards using a NC0-groups containing binder and a polyurethane reactions accelerating catalyst can be implemented on existing production plants, yielding an increased output of up to one third at the same level of quality. The financial expenditure for the catalyst is small compared to the advantages attainable. -, , -
Claims (10)
1. Method for the production of particle- or fiberboard, in which lignocellulose containing particles or fibers are glued with a NCO-groups containing binder, formed in the shape of a mat, and pressed to form the particle- or fiberboard under the influence of heat, wherein a catalyst accelerating a polyurethan reaction is added to the binder.
2. Method according to claim 1, wherein the binder is brought onto the particles or fibers in an aqueous suspension or emulsion, where the catalyst is dissolved in the water.
3. Method according to claim 1 or 2, wherein the catalyst has a hydroxyl group.
4. Method according to one of the claims 1 to 3, wherein the catalyst is chemically integrated in the particle- or fiberboard during the pressing.
5. Method according to one of the claims 1 to 4, wherein the catalyst is a tertiary amine.
6. Method according to claim 5, wherein the catalyst is an ether- or aliphatic amine.
7. Method according to one of the claims 1 to 6, wherein the catalyst is a blocked catalyst, activatable by heat.
8. Method according to the claims 3 to 7, wherein the catalyst is masked by an acid.
9. Method according to one of the claims 1 to 8, wherein the catalyst is applied in a concentration of 0.001 to 2.0 percent by weight, especially 0.005 to 0.5 percent by weight, relative to the NCO-groups containing binder.
10. Method according to one of the claims 1 to 9, wherein the NCO-groups containing binder is a polyisocyanate, especially polymer 4,4'-methylendiisocyanate (PMDI).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4229396.0 | 1992-09-03 | ||
| DE19924229396 DE4229396C2 (en) | 1992-09-03 | 1992-09-03 | Process for the production of chipboard or fiberboard |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2122368A1 true CA2122368A1 (en) | 1994-03-17 |
Family
ID=6467120
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2122368 Abandoned CA2122368A1 (en) | 1992-09-03 | 1993-09-01 | Method for the production of particle- or fiberboard |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0618854A1 (en) |
| CA (1) | CA2122368A1 (en) |
| DE (1) | DE4229396C2 (en) |
| WO (1) | WO1994005475A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6007649A (en) * | 1996-01-31 | 1999-12-28 | Bayer Aktiengesellschaft | Method of producing press-moulding materials with polyisocyanate binders and using latent, heat-activable catalysts |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9417502D0 (en) * | 1994-08-31 | 1994-10-19 | Smith & Nephew | Water curable compositions |
| DE19646879A1 (en) * | 1995-11-23 | 1997-05-28 | Henkel Kgaa | Reactive one-component polyurethane adhesive with good bonding time |
| US6124278A (en) * | 1998-04-03 | 2000-09-26 | The Regents Of The University Of California | Acylbenzoxazines for enhancing synaptic response |
| WO2000046306A1 (en) * | 1999-02-08 | 2000-08-10 | Sappi Limited | Timber process and product |
| DE10047485A1 (en) * | 2000-09-26 | 2002-04-11 | Bayer Ag | Storage-stable latent catalysts containing isocyanate binders |
| WO2015034938A1 (en) | 2013-09-03 | 2015-03-12 | The Willamette Valley Company | Composite wood particulate products with aldehyde-free adhesives and method for making same |
| DE102015210569A1 (en) * | 2015-06-09 | 2016-12-15 | Georg-August-Universität Göttingen Stiftung Öffentlichen Rechts | Increasing the reactivity of isocyanate adhesives by amine / ammonium compounds |
| EP4015173B1 (en) | 2020-12-21 | 2023-09-06 | Georg-August-Universität Göttingen | Increasing the reactivity of isocyanate adhesives by ammonium compounds |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA794435A (en) * | 1965-11-27 | 1968-09-10 | A. Sharp John | Particle board prepared with a polyisocyanate-pine resin extract adhesive |
| GB1309075A (en) * | 1969-04-02 | 1973-03-07 | Gen Foam Products | Production of moulded articles and board |
| US4101466A (en) * | 1976-12-01 | 1978-07-18 | Texaco Development Corp. | Bis (dimethylaminopropyl)-amine derivatives as polyurethane catalysts |
| DE2711958B2 (en) * | 1977-03-18 | 1981-08-13 | Bayer Ag, 5090 Leverkusen | Binding or impregnating agent for lignocellulosic materials |
| EP0039137A1 (en) * | 1980-04-30 | 1981-11-04 | Imperial Chemical Industries Plc | Isocyanate reactions |
| DE3328662A1 (en) * | 1983-08-09 | 1985-02-21 | Bayer Ag, 5090 Leverkusen | METHOD FOR THE PRODUCTION OF COMPRESSED MATERIALS WITH POLYISOCYANATE BINDING AGENTS USING LATENTS, HEAT-ACTIVATABLE CATALYSTS |
| US4609513A (en) * | 1984-08-15 | 1986-09-02 | Jim Walter Research Corp. | Binder composition for manufacture of fiberboard |
| DE4200324A1 (en) * | 1992-01-09 | 1993-07-15 | Bayer Ag | USE OF A SUGAR PRODUCT CONTAINING ISOCYANATE GROUPS AS A BINDER IN THE COMPRESSION OF SUBSTRATES FOR THE PRODUCTION OF COMPRESSED MATERIALS |
-
1992
- 1992-09-03 DE DE19924229396 patent/DE4229396C2/en not_active Expired - Lifetime
-
1993
- 1993-09-01 CA CA 2122368 patent/CA2122368A1/en not_active Abandoned
- 1993-09-01 EP EP93919235A patent/EP0618854A1/en not_active Withdrawn
- 1993-09-01 WO PCT/EP1993/002358 patent/WO1994005475A1/en not_active Ceased
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6007649A (en) * | 1996-01-31 | 1999-12-28 | Bayer Aktiengesellschaft | Method of producing press-moulding materials with polyisocyanate binders and using latent, heat-activable catalysts |
Also Published As
| Publication number | Publication date |
|---|---|
| DE4229396A1 (en) | 1994-03-10 |
| DE4229396C2 (en) | 1997-06-05 |
| EP0618854A1 (en) | 1994-10-12 |
| WO1994005475A1 (en) | 1994-03-17 |
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