CA1338075C - Process for the preparation of compression molded materials - Google Patents
Process for the preparation of compression molded materialsInfo
- Publication number
- CA1338075C CA1338075C CA000606024A CA606024A CA1338075C CA 1338075 C CA1338075 C CA 1338075C CA 000606024 A CA000606024 A CA 000606024A CA 606024 A CA606024 A CA 606024A CA 1338075 C CA1338075 C CA 1338075C
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- component
- weight
- polyisocyanate
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- polyisocyanates
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/15—Heterocyclic compounds having oxygen in the ring
- C08K5/156—Heterocyclic compounds having oxygen in the ring having two oxygen atoms in the ring
- C08K5/1565—Five-membered rings
-
- 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
- C08G18/166—Catalysts not provided for in the groups C08G18/18 - C08G18/26
- C08G18/168—Organic compounds
-
- 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
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- 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)
- Dry Formation Of Fiberboard And The Like (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
- Polishing Bodies And Polishing Tools (AREA)
- Mechanical Operated Clutches (AREA)
- Polyurethanes Or Polyureas (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Press Drives And Press Lines (AREA)
- Adhesives Or Adhesive Processes (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Cephalosporin Compounds (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Processing Of Solid Wastes (AREA)
- Reinforced Plastic Materials (AREA)
Abstract
This invention relates to a process for the preparation of compression molded materials comprising compressing a substrate with a binder based on polyisocyanates, wherein said binder comprises polyisocyanates, compounds containing at least two isocyanate reactive hydrogen atoms, and alkylene carbonates.
Description
1 338075 Mo3202 LeA 26,007 PROCESS FOR THE PREPARATION OF COMPRESSION MOLDED MATERIALS
BACKGROUND OF THE INVENTION
This invention relates to a process for the production of compression molded materials using polyisocyanate binders or mixtures of polyisocyanates and other binders together with polyether or polyester polyols and mixtures thereof and alkylene carbonates.
Compression molded materials, such as chipboard, composite board, or other such molded products, are con-ventionally produced bv hot pressing inorganic or organic rawmaterials, such as a mass of wood shavings, wood fibers, or other material containing lignocellulose, with various glues or binders. The woodworking industry, which is the largest manufacturer of compression molded materials, still uses what has generally been regarded as the most important binders, including, for example, aqueous dispersions or solutions of urea-form-aldehyde ("aminoplast") or phenol-formaldehyde ("phenoplast") resins.
The use of polyisocyanates or polyisocyanate solutions instead of i-onmaldehyde l~ased resins as ~inders for pressboard is also known (German Offenlegungsschriften 1,271,984, 1,492,507, 1,653,177, and 2,109,686). Polyisocyanates, which have been increasingly used industrially as binders since 1973, improve the stability and moisture rPQ~ rP and increase the mechanical strength of the products. In addition, polyisocyanate binders have extensive process technology advantages, as disclosed in German Offenlegungsschrift 2,109,686.
The large scale industrial production of materials bonded with polyisocyanates, especially materials containing lignocellulose such as wood chipboard, has, however, been hindered at least in part because, in contrast to materials which are bonded with aminoplast resins, chips blended wi~h poly-isocyanates have no intrinsic tackiness (i.e., no capacity for adhesiveness) at room temperature. Even precomæression at room temperature , ("cold pressing") of materials blended wi~h polyisocyanates, but which are still moist, will not yield preforms that are sufficiently stable and self-supporting for the purposes of many production plants. As a result, the universal application of 5 polyisocyanates for the production of compression molded materials is made very difficult.
The molded chips or shavings that are spread over belts, press plates, and the like are transferred to other belts, plates, rolls, or the like on their way to the hot press. These 10 preforms are then discharged from them or the supports are pulled out from under them. In order to enable this process to be carried out without destroying the preforms of chips and without damaging their outer zones, the preforms are subjected to a cold precol~pression. This precompression is also 15 intended to bond the surface chips together so that as the hot press plates are brought together the air escaping between the preforms and the plates will not carry away any chips (i.e., so that no cavities will form on the surfaces due to the escape of air). Prepresses operating continuously and in cycles 20 are available to subject the chips to specific pressures of up to 40 bar for from 10 to 60 seconds.
One object of the present invention is development of a process which eliminates the disadvantage of the lack of cold tack of chips blended with polyisocyanate binders while at 25 the same time not sacrificing the easy pourability of the bonded chips, a characteristic necessary for spreading chips easily into the required shapes of the preforms. The process according to the invention solves this problem in a manner which is surprisingly simple for one skilled in the art.
SUMMARY OF THE INVENTION
This invention relates to a process for the preparation of compression molded materials comprising compressing substrates with binders based on polyisocyanates, wherein said binders comprise (a) polyisocyanates, Mo3202 (b) compounds containing at least two isocyanate reactive hydrogen atoms, and (c) aklylene carbonates, and (d) optionally, other additives.
DETAILED DESCRIPTION OF THE INVENTION
In the preferred embodiments according to the invention, the various constituents can have the following compositions and properties:
(i) the binder can contain from about 10 to about 250 parts by weight (preferably from 20 to 80 parts by weight), based on 100 parts by weight of polyisocyanate, of the compounds (b) and (c) with the weight ratio of component (b) to component (c) being in the range of from about 0.5:1.0 to about 10.0:1.0;
(ii) the alkylene carbonate can be propylene carbonate;
(iii) the compounds containing at least two isocyanate reactive hydrogen atoms are polyethers or polyesters having a molecular weight range of from about 400 to about 10,000 and containing hydroxyl groups;
; (iv) the binder can contain aromatic polyisocyanates;
(v) the aromatic polyisocyanates can be mixtures of diphenylmethane diisocyanates and polyphenyl-polymethylene polyisocyanates obtainable by aniline-formaldehyde condensation followed by phosgenation; and (vi) the binder can additionally contain aqueous condensation products of urea, melamine, phenol, and tannin or any mixtures thereof with formaldehyde and/or sulfite waste liquors.
I
I
Cold tack of chips blended with the above binders, for example, chips of raw materials containing lignocellulose, is achieved using the process of this invention. The advantages afforded by the polyisocyanates as binders for compression molded materials may, therefore, also be applied to production lines in which cold tack of the chips is essential for the preforms. The possibility of reducing the time required for compression in the hot press is of particular economical advantage. The capacity for cold tack of chips blended with the binders according to the invention provides further advantages. Damage in the surface zones of preforms of scattered chips is reduced or prevented; the reduction in losses due to damage at the edges enhances economical utilization of the unfinished boards. The advantages of the process of this invention also makes the process attractive for installations in which cold tack of the chip preforms is not absolutely essential.
Thus, a particular advantage of the process of the invention arising from the cold tack characteristic is that the composition or mixture of substrates and the binder of the invention can be compressed to form a preform without the application of heat.
In a particular embodiment of the process of the invention, the substrate and the binder are mixed, the resultant mixture is compressed, without the application of heat, to form a preform, and the preform is molded under heat and pressure.
The combination of polyols with polyisocyanates as binders (German Offenlegungsschriften 2,538,999 and 2,403,656) and the addition of alkylene carbonates (e.g., propylene carbonate) to polyisocyanate (U.S. Patent 4,359,507i J. Elast. Plast., 16, 206-228 (1984) have been fully described. Such binders, however, cannot be economically used unless the liquids are applied to the chips as a very fine spray. For highly viscous polyols, application is achieved by using a colloidal solution of the polyol component in a liquid medium, such as water (German Offenlegungsschrift 2,538,999).
Alkylene carbonates (e.g., propylene carbonate), because of their low viscosity, may be used as such or together with the polyisocyanate. The behaviour of blended chips using these known methods, however, does not differ from the behaviour of chips blended only with pure polyisocyanate binders. ~oreover, the addition of compounds containing hydroxyl groups leads to the rapid formation of the corresponding polyurethanes. Thus, satisfactory use of these methods under the conditions customarily used in the woodworking industry (i.e., storage of the blended raw material for up to 60 minutes, in part at elevated temperatures) would not be expected.
It must, therefore, be considered all the more surprising to one skilled in the art to find that the addition of polyols and alkylene carbonate to polyisocyanate binders (or mixtures of polyisocyanates with other binders) in quantities of from about 10 to about 250 parts by weight (preferably 20 to 80 - 4a -parts by weight), based on 100 parts by weight of polyisocyanate, results in cold tack of such blended raw materials with retention of good pourability.
The polyol and alkylene carbonate are added in 5 proportions ranging from about 0.5:1.0 to about 10.0:1.0 parts by weight (preferably from 1.0:1.0 to 3.0:1.0 parts by weight). In contrast to raw materials which have been blended using poly-isocyanates alone, the ble~d raw materials according to the invention retain their cold tack in storage.
10 Furthermore, the addition of the polyols and alkylene carbonates according to the invention allows a reduction, often a considerable reduction, of time needed for compressing the materials in the hot press, depending on the temperature of the press, without loss of the physical and mechanical properties of 15 the boards obtained as end products.
Suitable alkylene carbonates include liquid cyclic alkylene carbonates (i.e., cyclic alkylene esters of carboxylic acids), preferably propylene carbonate and butylene carbonate.
Suitable polyisocyanates used according to the 20 invention include aliphatic, cycloaliphatic, araliphatic, aromatic, and heterocyclic polyisocyanates, such as described by W. Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136, for example, those corresponding to the following formula:
Q(NCO)n wherein Q is an aliphatic hydrocarbon group containing about 2 to about 18 (preferably 6 to 10) carbon atoms; a cycloaliphatic hydrocarbon group containing about 4 to about 15 (preferably 5 to lO) carbon atoms; an aromatic hydrocarbon group containing about 6 to about 15 (preferably 6 to 13) carbon atoms; or an araliphatic hydrocarbon group containing about 8 to about 15 (preferably 8 to 13) carbon atoms; and Mo3202 n is 2 to 4 (preferably 2).
Examples of such polyisocyanates include 1,4-tetramethylene diiso-cyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate and S any mixtures of these isomers, 1-iso-cyanato-3,3,5-trimethyl-5-isocya-natomethylcyclohexane (German Auslegeschrift 1,202,785, U.S. Patent 3,401,190), 2,4- and 2,5-hexahydrotolylene diisocyanate and any mixtures of these isomers, hexahydro-1,3- and/or-1,4-phenylene diisocyanate, perhydro 2,4'- and/or 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene 10 diisocyanate and any mixtures of these isomers, diphenyl-methane-2,4'-and/or-4,4'-diisocyanate, and naphthylene-1,5-diisocyanate.
Other suitable polyisocyanates include triphenylmethane-4,4',4"-triisocyanate; polyphenyl-polymethylene polyisocyanates obtainable by aniline-formaldehyde condensation followed by 15 phosgenation as described, for example, in United Kingdom Patents 874,430 and 848,671, issued 1961 and 1960 (respectively); m- and p-isocyanatophenylsulphonyl isocyanates according to U.S. Patent 3,454,606; perchlorinated aryl polyisocyanates as described, for example, in German Auslegeschrift 1,157,601 (U.S. Patent 3,277,138);
20 polyisocyanates containing carbodiimide groups as described in German Patentschrift 1,092,007 (U.S. Patent 3,152,162) and in Gerrnan Offenlegungssch,irlen 2,504,400, 2,537,685, and 2,552,350; norbomane diisocyanates according to U.S. Patent 3,492,330; polyisocyanates containing allophanate groups as described, for example, in United 25 Kingdom Patent 994,890 issued 1965, Belgian Patent 761,626, and Netherlands Patent 7,102,524; polyisocyanates containing isocyanurate groups as described, for example, in U.S. Patent 3,001,973, German Patentschriften 1,022,789, 1,222,067, and 1,027,394, and in German Offenlegungsschriften 1,929,034 and 2,004,048; polyisocyanates 30 containing urethane groups as described, for example, in Belgian Patent Mo-3202 -6-752,261 or U.S. Patents 3,394,164 and 3,644,457; polyisocyanates containing acylated urea groups acoording to German Patententschrift 1,230,778; polyisocyanates containing biuret groups as described, for example, in U.S. Patents 3,124,605, 3,201,372, and 3,124,605 and UK
Patent 889,050 issued 1962; polyisocyanates containing ester groups as described, for example in UK Patent 965,474, issued 1964, U.S. Patent 3,567,763, and German Patentschrift 1,231,688; reaction products of the above-mentioned isocyanates with acetals according to German Patentschrift 1,072,385; and polyisocyanates containing polymeric faKy acid esters according to U.S. Patent 3,455,883.
Isocyanate-group-containing distillation residues from commercial production of isocyanates may also be used, optionally dissolved in one or more of the above mentioned polyisocyanates. Any mixtures of the above mentioned polyisocyanates may also be used.
Aromatic polyisocyanates are preferred. Particularly preferred are commercially available polyisocyanates, for example, 2,4-and 2,6-tolylene diisocyanate and any mixtures of these isomers ("TDI");
polyphenyl-polymethylene polyisocyanates, which may be prepared by aniline-formaldehyde condensation followed by phosgenation ("crude MDI"), and polyisocyanates containing carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups, or biuret groups ("modified polyisocyanates"), especially those modified poly-isocyanates derived from 2,4- and/or 2,6-tolylene diisocyanates or from 4,4'- and/or 2,4'-diphenylmethane diisocyanate.
The compounds containing at least two isocyanate reactive hydrogen atoms and generally having a molecular weight of from 400 to 10,000 are preferably compounds containing hydroxyl groups, especially compounds containing from 2 to 8 hydroxyl groups, and especially those with molecular weights of from about 1000 to about 8000 (preferably from 1500 to 4000).
Mo-3202 -7-The preferred compounds include polyesters or polyethers containing at least 2 (generally from 2 to 8 and preferably from 2 to 4) hydroxyl groups, such as those known in the art for the production of both homogeneous and cellular polyurethanes.
Suitable hydroxyl-containing polyesters include, for example, reaction products of polyhydric (preferably dihydric) alcohols, optionally together with trihydric alcohols, and polybasic (preferably dibasic) carboxylic acids. Instead of the free polycarboxylic acids, corresponding polycarboxylic acid 10 anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof may he used for the preparation of the polyesters used according to the invention. Suitable polycarboxylic acids include aliphatic, cycloaliphatic, aromatic, and heterocyclic polycarboxylic acids and may he substituted, for 15 example, with halogen atoms, and/or may be unsa~urated.
Examples of carboxylic acids and derivatives thereof that are suitable for preparation of hydroxyl-containing polyesters include succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, 20 trimellitic acid, phthalic acid anhydride, tetrahydrophthalic acid anhydride, hexahydrophthalic acid anhydride, tetra-chlorophthalic acid anhydride, endomethylene tetrahydrophthalic acid anhydride, glutaric acid anhydride, maleic acid, maleic acid anhydride, fumaric acid, dimerized and trimerized unsaturated 25 fatty acids optionally mixed with monomeric unsaturated fatty acids such as oleic acid, dimethylterephthalate, and terephthalic acid bisglycol ester.
Examples of polyhydric alcohols that are suitable for preparation of hydroxyl-containing polyesters include ethylene 30 glycol, 1,2- and 1,3-propanediol, 1,4- and 2,3-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1,4-bis-(hydroxymethyl)cyclohexane, 2-methyl-1,3-propanediol, glycerol, trimethylol propane, 1,2,6-hexanetriol, 1,2,4-butanetriol, trimethylol ethane, pentaerythritol, quinitol, mannitol and 35 sorbitol, formitol, 1,4,3,6-dianhydrosorbitol, methyl glycoside, Mo3202 diethylene glycol, triethylene glycol, tetraethylene glycol and higher polyethylene glycols, dipropylene glycol and higher polypropylene glycols, and dibutylene glycol and higher polybutylene glycols. The polyesters may contain a proportion of 5 carboxyl end groups. Polyesters of lactones, such as -capro-lactone, or of hydroxycarboxylic acids, such as hydroxycaproic acid, may also be used.
Suitable polyethers containing at least 2 (generally 2 to 8 and preferably 2 or 3~ hydroxyl groups include known types 10 that may be prepared, for example, by the polymerization of epoxides, such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, or epichlorohydrin, or polymerization of tetrahydrofuran. Such polymerizations may be carried out using only the monomers, for example, in the presence of Lewis-15 catalysts such as BF3. The polymerization may also be carriedout by chemical addition of the epoxides (preferably ethylene oxide and propylene oxide, optionally as mixtures or successively) to starting components containing reactive hydrogen atoms, such as water, alcohols, ammonia or amines, including, for 20 example, ethylene glycol, 1,3- or 1,2-propanediol, trimethylol propane, glycerol, sorbitol, 4,4'-dihydroxydiphenylpropane, aniline, ethanolamine, or ethylene diamine. It is often preferred to use polyethers in which the OH groups are predominantly (up to about 90~ by weight thereof, based on all 25 the OH groups present in the polyether) primary OH groups.
Also suitable are sucrose polyesters (for example, DE-B
1,176,358 and 1,064,938), and polyethers started on formitol or formose (DE-A 2,639,083). Polybutadienes containing OH groups are also suitable. Mixtures of polyesters and polyethers may, of 30 course, also be used.
Compounds in the molecular weight range of from 32 to 399 containing at least two isocyanate reactive hydrogen atoms may also be used as a component in the process of the invention.
Suitable such compounds are compounds containing hydroxyl groups, 35 amino groups, thiol groups, carboxyl groups, or a combination Mo3202 _g_ thereof (preferably hydroxyl groups and/or amino groups), and are used as chain extenders or crosslinking agents. Such compounds generally contain from about 2 to about 8 (preferably 2 to 4) isocyanate reactive hydrogen atoms. These compounds may also be 5 used as mixtures of different such compounds in the molecular weight range of from 32 to 399 containing at least two isocyanate reactive hydrogen atoms. Examples of such compounds are fully described, for example, in German Offenlegungsschrift 3,430,285, on pages 19 to 23.
Optional components in the process of the invention include auxiliary agents, for example, known catalysts and surface active additives such as emulsifiers and stabilizers.
Suitable catalysts include tertiary amines such as triethylamine, tributylamine, N-methylmorpholine, N-ethyl-15 morpholine, N,N,N',N'-tetramethylethylene diamine, penta-methyldiethylene triamine, and higher homologues (German Offenlegungsschriften 2,624,527 and 2,624,528), 1,4-diaza-bicyclo[2.2.2]octane, N-methyl-N'-(dimethylaminoethyl)piperazine, bis(dimethylaminoalkyl)piperazines (German Offenlegungsschrift 20 2,636,787), N,N-dimethylbenzylamine, N,N-dimethylcyclohexylamine, N,N-diethylbenzylamine, bis(N,N-diethylaminoethyl~ adipate, N,N,N',N'-tetramethyl-1,3-butanediamine, N,N-dimethyl- ~phenyl-ethylamine, 1,2-dimethylimidazole, 2-methylimidazole, monocyclic and bicyclic amidines (German Offenlegungsschrift 1,720,633), 25 bis(dialkylamino)alkyl ethers (U.S. Patent 3,330,782, German Auslegeschrift 030,558, and German Offenlegungsschriften 1,804,361 and 2,618,2LO), and tertiary amines containing amide groups (preferably formamide groups) according to German Offenlegungsschrift 2,523,633 and 2,732,292. The catalysts used 30 may also be the known Mannich bases of secondary amines (such as dimethylamine) and aTdehydes (preferably formaldehyde) or ketones (such as acetone) and phenols.
Suitable catalysts also include certain tertiary amines containing isocyanate reactive hydrogen atoms. Examples of such 35 catalysts include triethanolamine, triisopropanolamine, N-methyl-Mo3202 diethanolamine, N-ethyl-diethanolamine, N,N-dimethylethanolamine, their reaction products with alkylene oxides (such as propylene oxide and/or ethylene oxide) and secondary-tertiary amines according to German Offenlegungsschrift 2,732,292.
Sila-amines containing carbon-silicon bonds may also be used as catalysts, for example, those described in German Patentschrift 1,229,290 (corresponding to U.S. Patent 3,620,984).
Examples of suitable sila-amines include 2,2,4-trimethyl-2-silamorpholine and 1,3-dimethylaminomethyl tetramethyldisiloxane.
Suitable catalysts also include nitrogen-containing bases, such as tetraalkylammonium hydroxides; alkali metal hydroxides, such as sodium hydroxide; alkali metal phenolates, such as sodium phenolate; and alkali metal alcoholates, such as sodium methoxide. Hexahydrotriazines (German Offenlegungsschrift 15 1,709,043~ and tertiary amines containing amide groups (preferably formamide groups) (German Offenlegungsschriften 2,523,633 and 2,732,292) may also be used as catalysts. Known Mannich bases of secondary amines (such as dimethylamine) and aldehydes (preferably formaldehyde~ or ketones (such as acetone) 20 and phenols may also be used as catalysts.
Other suitable catalysts include organic metal compounds, especially organic tin compounds. Suitable organic tin compounds include those containing sulfur, such as di-n-octyl tin mercaptide (German Auslegeschrift 1,769,367 and U.S. Patent 25 3,645,927), and, preferably, tin(II) salts of carboxylic acids, such as tin(II) acetate, tin(II) octoate, tin(II~ ethylhexoate, and tin(II) laurate, as well as tin (IV)compounds, such as dibutyl tin dilaurate.
Any of the above-mentioned catalysts may, of course, be 30 used as mixtures.
Further representatives of catalysts to be used according to the invention and details concerning their mode of action are described in Kunststoff Handbuch, Volume VII, published by Vieweg and Hochtlen, Carl Hanser Verlag, Munich 35 1966, e.g., on pages 96 to 102.
Mo3202 ~ The catalysts are generally used in a quantity ranging from about 0.001 to about 10~ by weight, based on the quantity of polyisocyanate.
Suitable surface active additives include emulsifiers 5 and foam stabilizers. Suitable emulsifiers include, for example, the sodium salts of ricinoleic sulfonates and salts of fatty acids with amines, for example, oleic acid diethylamine or stearic acid diethanolamine. Other suitable surface active additives include alkali metal or ammonium salts of sulfonic 10 acids (such as dodecylbenzenesulfonic acid or dinaphthyl-methanedisulfonic acid), of fatty acids (such as ricinoleic acid), or of polymeric fatty acids.
Suitable substrates used in the process of the invention include lignocellulose-containing raw materials that 15 can be bonded with the binders according to the invention.
Examples of suitable lignocellulose-containing materials include wood, woodbark, cork, bagasse,straw, flax, bamboo, esparto, rice husks, and sisal and coconut fibers. Other suitable substrates for compression molding include other organic raw materials (for 20 example, all kinds of plastic waste) and inorganic raw materials (for example, expanded mica or silicate balls). The substrate may be used in the form of granulates, shavings or chips, fibers, spheres, or powder and may have a moisture content of, for example, from about O to about 35% by weight (preferably from 4 25 to 20~ by weight).
It is possible, but less preferred, to apply the components of the binder combination (polyisocyanate, polyether polyol or polyester polyol, and alkylene carbonate) separately to the material which is to be bonded. It is preferable to use the 30 polyether or polyester polyol and the alkylene carbonate as a mixture with the polyisocyanate as binder.
In the process of the invention, the binder is added to the organic and/or inorganic material to be bonded in a quantity of about 0.5 to about 20~ by weight (preferably 2 to 12~ by 35 weight), based on the total weight of the end product. The Mo3202 resultant material is compressed to form boards or three dimensionally shaped molded products, generally under heat and pressure (for example, about 70 to about 250C and about 1 to about 150 bar).
Multilayered boards or molded parts may be produced in analogous manner from veneers, paper, or woven fabrics by treating the layers with the binder as described above and subsequently pressing them, generally at elevated temperature and elevated pressure. Temperatures of from about 100 to about 250C
10 are preferred, with 130 to 200C being most preferred. The initial compression pressure is preferably in the range of from about 5 to about 150 bar, although the pressure in most cases drops towards 0 bar during the compression process.
The binders used according to the invention may also be 15 used in combination with aqueous solutions of condensation products of formaldehyde and urea and/or me~ ine and~r phenol, which are the binders most commonly used in the woodworking industry. In addition, the binders may be combined with less commonly used binders and impregnating agents, for example, those based on 20 polyvinyl acetate or other synthetic resin lattices, sulfide waste liquors, or tannin. When using a mixture of the binders according to the invention with these additional binders, the proportions used are from about 1:20 to about 20:1 (preferably from 1:5 to 5:1). The polyisocyanate mixtures and the additional 25 binders may be used separately or as a mixture.
The following examples further illustrate details for the process of this invention. The invention, which is set forth in the foregoing disclosure, is not to be limited either in spirit or scope by these examples. Those skilled in the art will 30 readily understand that known variations of the conditions of the following procedures can be used. Unless otherwise noted, all temperatures are degrees Celsius and all percentages are percentages by weight.
Mo3202 -DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following polyols are used as starting components in the Examples:
Polyether Polyol I prepared from l,2-propanediol and propylene 5 oxide and having an OH number of 284 and a viscosity of 75 mPas at 25C.
Polyether Polyol II prepared from 1,2-propanediol, propylene oxide, and ethylene oxide and having an OH number of 185 and a viscosity of 130 mPas at 25C.
10 Polyether Polyol III prepared from ethylene diamine and propylene oxide and having an OH number of 60 and a viscosity of 660 mPas at 25C.
Example 1 Face 1 ayer industrial chips (moisture content u = 15.0%
15 by weight oven-dried ("o.d.") wood) (2800 9) and core layer chips (u = 10.0% o.d.) (6400 9) were each sprayed with 5% by weight o.d. of a binder consisting of a mixture of 70~ by weight crude diphenylmethane-4,4'diisocyanate having an isocyanate content of 30~ by weight, 10% by weight polyether polyol I, 10%
20 by weight polyether polyol II, and 10% by weight of propylene carbonate. This material was spread out to form three-layered board preforms and at selected time intervals was compressed both cold and hot under pressure.
Example 2 Boards were prepared as in Example 1 except that the binder was composed of a mixture of 70~ by weight crude diphenylmethane-4,4'diisocyanate having an isocyanate content of 30% by weight, 20% by weight polyether polyol III, and 10% by weight propylene carbonate. The isocyanate and the polyol/
30 alkylene carbonate mixture were sprayed separately on the chips.
Compression molding was performed as in Example 1.
Example 3 Face layer industrial chips (u = 12.0% o.d.) (4200 9) were sprayed with 13% by weight o.d. of a binder consisting of a 35 mixture of 80% by weight crude diphenylmethane-4,4'-diisocyanate Mo3202 having an isocyanate content of 30~ by weight, 12% by weight polyether polyol II, and 8% by weight propylene carbonate. The chips were spread out to form single-layered board preforms and compression molded as in Example 1.
5 Example 4 Boards were prepared as in Example 3 except that one half of the binder was a mixture of 70% by weight crude diphenylmethane-4,4'-diisocyanate having an isocyanate content 30% by weight, 20% by weight polyether polyol I, and 10% by 10 weight polypropylene carbonate and the second half of the binder was a commercial E1 urea-formaldehyde resin. Three percent by weight o.d. of each half portion of binder was sprayed on the chips. Compression molding was performed as in Example 1.
All board preforms which ~er~ prepressed at room temperature according to Examples 1 to 4 e ~hibited cold ~ac~
in contrast to chips which have been treated with polyisocyanate alone. Under hot pressing conditions, samples prepared according to the invention also have advantages over the comparison samples under identical experimental conditions. Test 20 results are shown in the following Table.
TABLE
Example Gross Density Transverse Tensile 1) of Boa3ds Strength (~Pa) (kg/m ) V20 V100 Comparison experiment 680 0.94 0.27 using 5~ by weight o.d.
Desmodur ~ PU 1520 A
1 680 1.13 0.33 2 680 1.09 0.34 3 850 0.82 4 650 0.84 o.d. = calculated percent by weight based on absolutely dry, oven dried wood Trans-~erse tensile strength V 20 and V 100 tested according to German Standard DIN 68763 (flat pressed particle boards for building) The following binders were used in Example 5.
Binder I: a prepolymer comprising 70 parts by weight of crude diphenylmethane-4,4'-diisocyanate having an isocyanate content of 30% by weight and a viscosity of 300 mPa.s at 25-C, and a mixture of 10 parts by weight of polyether polyol I and 10 parts by weight of polyether polyol II. V~scosity of about 52,000 mPa.s/25-C.
Binder II: the prepolymer of binder I containing 10 parts by weight of propylene carbonate. Viscosity of about 9300 mPa.s/
25-C.
Binder III: an in-situ mixture of 70 parts by weight of crude diphenylmethane-4,4'-diisocyanate having an isocyanate content of 30% by weight and a viscosity of 300 mPa.s at 25-C, 10 parts by weight of polyether polyol I, 10 parts by weight of polyether polyol II, and 10 parts by weight of propylene carbonate (corresponds to binder used ln Example 1, and illustrative of the invention).
:
A batch of face layer industrial chips (moisture content u=14.0% by weight oven dried wood) (3950 9) was sprayed with binder II or binder III in amounts of 10.4% by weight o.d.
(quantity of binder based on prepolymer of diphenylmethane-4,4'-diisocyanate/polyol). The chips were spread out to form single-layer board preforms and were compressed at specific intervals in the cold state, after which the cold tack was determined.
Binder I, the prepolymer, was not usable due to its lo high viscosity (about 52,000 mPa.s/2~-C after 14 days).
Binder II, the prepolymer diluted with 10 parts by weight of propylene carbonate, has a viscosity of about 9300 mPa.s/25-C, which is still too high. Binder II can only be applied with great difflculty using high pressure spraying and is therefore not practical for indus~rial use. Upon exposure to atmospheric moisture, Binder II very quickly forms a skln on its surface and it has a tendency to foam.
Binder II and Binder III display almost the same degree of cold tack when the chlps are blended therewith and compressed in the cold state.
Binder III has the advantages of being easy to handle and use, and economical to produce as the production costs associated with prepolymerization are dispensed with. ~he customer needs only to use one type of diphenyl-4,4'-dliso-cyanate, to which polyether polyol and propylene carbonate can if necessary be added in the required quantities, depending on the type of applications involved.
; 30
BACKGROUND OF THE INVENTION
This invention relates to a process for the production of compression molded materials using polyisocyanate binders or mixtures of polyisocyanates and other binders together with polyether or polyester polyols and mixtures thereof and alkylene carbonates.
Compression molded materials, such as chipboard, composite board, or other such molded products, are con-ventionally produced bv hot pressing inorganic or organic rawmaterials, such as a mass of wood shavings, wood fibers, or other material containing lignocellulose, with various glues or binders. The woodworking industry, which is the largest manufacturer of compression molded materials, still uses what has generally been regarded as the most important binders, including, for example, aqueous dispersions or solutions of urea-form-aldehyde ("aminoplast") or phenol-formaldehyde ("phenoplast") resins.
The use of polyisocyanates or polyisocyanate solutions instead of i-onmaldehyde l~ased resins as ~inders for pressboard is also known (German Offenlegungsschriften 1,271,984, 1,492,507, 1,653,177, and 2,109,686). Polyisocyanates, which have been increasingly used industrially as binders since 1973, improve the stability and moisture rPQ~ rP and increase the mechanical strength of the products. In addition, polyisocyanate binders have extensive process technology advantages, as disclosed in German Offenlegungsschrift 2,109,686.
The large scale industrial production of materials bonded with polyisocyanates, especially materials containing lignocellulose such as wood chipboard, has, however, been hindered at least in part because, in contrast to materials which are bonded with aminoplast resins, chips blended wi~h poly-isocyanates have no intrinsic tackiness (i.e., no capacity for adhesiveness) at room temperature. Even precomæression at room temperature , ("cold pressing") of materials blended wi~h polyisocyanates, but which are still moist, will not yield preforms that are sufficiently stable and self-supporting for the purposes of many production plants. As a result, the universal application of 5 polyisocyanates for the production of compression molded materials is made very difficult.
The molded chips or shavings that are spread over belts, press plates, and the like are transferred to other belts, plates, rolls, or the like on their way to the hot press. These 10 preforms are then discharged from them or the supports are pulled out from under them. In order to enable this process to be carried out without destroying the preforms of chips and without damaging their outer zones, the preforms are subjected to a cold precol~pression. This precompression is also 15 intended to bond the surface chips together so that as the hot press plates are brought together the air escaping between the preforms and the plates will not carry away any chips (i.e., so that no cavities will form on the surfaces due to the escape of air). Prepresses operating continuously and in cycles 20 are available to subject the chips to specific pressures of up to 40 bar for from 10 to 60 seconds.
One object of the present invention is development of a process which eliminates the disadvantage of the lack of cold tack of chips blended with polyisocyanate binders while at 25 the same time not sacrificing the easy pourability of the bonded chips, a characteristic necessary for spreading chips easily into the required shapes of the preforms. The process according to the invention solves this problem in a manner which is surprisingly simple for one skilled in the art.
SUMMARY OF THE INVENTION
This invention relates to a process for the preparation of compression molded materials comprising compressing substrates with binders based on polyisocyanates, wherein said binders comprise (a) polyisocyanates, Mo3202 (b) compounds containing at least two isocyanate reactive hydrogen atoms, and (c) aklylene carbonates, and (d) optionally, other additives.
DETAILED DESCRIPTION OF THE INVENTION
In the preferred embodiments according to the invention, the various constituents can have the following compositions and properties:
(i) the binder can contain from about 10 to about 250 parts by weight (preferably from 20 to 80 parts by weight), based on 100 parts by weight of polyisocyanate, of the compounds (b) and (c) with the weight ratio of component (b) to component (c) being in the range of from about 0.5:1.0 to about 10.0:1.0;
(ii) the alkylene carbonate can be propylene carbonate;
(iii) the compounds containing at least two isocyanate reactive hydrogen atoms are polyethers or polyesters having a molecular weight range of from about 400 to about 10,000 and containing hydroxyl groups;
; (iv) the binder can contain aromatic polyisocyanates;
(v) the aromatic polyisocyanates can be mixtures of diphenylmethane diisocyanates and polyphenyl-polymethylene polyisocyanates obtainable by aniline-formaldehyde condensation followed by phosgenation; and (vi) the binder can additionally contain aqueous condensation products of urea, melamine, phenol, and tannin or any mixtures thereof with formaldehyde and/or sulfite waste liquors.
I
I
Cold tack of chips blended with the above binders, for example, chips of raw materials containing lignocellulose, is achieved using the process of this invention. The advantages afforded by the polyisocyanates as binders for compression molded materials may, therefore, also be applied to production lines in which cold tack of the chips is essential for the preforms. The possibility of reducing the time required for compression in the hot press is of particular economical advantage. The capacity for cold tack of chips blended with the binders according to the invention provides further advantages. Damage in the surface zones of preforms of scattered chips is reduced or prevented; the reduction in losses due to damage at the edges enhances economical utilization of the unfinished boards. The advantages of the process of this invention also makes the process attractive for installations in which cold tack of the chip preforms is not absolutely essential.
Thus, a particular advantage of the process of the invention arising from the cold tack characteristic is that the composition or mixture of substrates and the binder of the invention can be compressed to form a preform without the application of heat.
In a particular embodiment of the process of the invention, the substrate and the binder are mixed, the resultant mixture is compressed, without the application of heat, to form a preform, and the preform is molded under heat and pressure.
The combination of polyols with polyisocyanates as binders (German Offenlegungsschriften 2,538,999 and 2,403,656) and the addition of alkylene carbonates (e.g., propylene carbonate) to polyisocyanate (U.S. Patent 4,359,507i J. Elast. Plast., 16, 206-228 (1984) have been fully described. Such binders, however, cannot be economically used unless the liquids are applied to the chips as a very fine spray. For highly viscous polyols, application is achieved by using a colloidal solution of the polyol component in a liquid medium, such as water (German Offenlegungsschrift 2,538,999).
Alkylene carbonates (e.g., propylene carbonate), because of their low viscosity, may be used as such or together with the polyisocyanate. The behaviour of blended chips using these known methods, however, does not differ from the behaviour of chips blended only with pure polyisocyanate binders. ~oreover, the addition of compounds containing hydroxyl groups leads to the rapid formation of the corresponding polyurethanes. Thus, satisfactory use of these methods under the conditions customarily used in the woodworking industry (i.e., storage of the blended raw material for up to 60 minutes, in part at elevated temperatures) would not be expected.
It must, therefore, be considered all the more surprising to one skilled in the art to find that the addition of polyols and alkylene carbonate to polyisocyanate binders (or mixtures of polyisocyanates with other binders) in quantities of from about 10 to about 250 parts by weight (preferably 20 to 80 - 4a -parts by weight), based on 100 parts by weight of polyisocyanate, results in cold tack of such blended raw materials with retention of good pourability.
The polyol and alkylene carbonate are added in 5 proportions ranging from about 0.5:1.0 to about 10.0:1.0 parts by weight (preferably from 1.0:1.0 to 3.0:1.0 parts by weight). In contrast to raw materials which have been blended using poly-isocyanates alone, the ble~d raw materials according to the invention retain their cold tack in storage.
10 Furthermore, the addition of the polyols and alkylene carbonates according to the invention allows a reduction, often a considerable reduction, of time needed for compressing the materials in the hot press, depending on the temperature of the press, without loss of the physical and mechanical properties of 15 the boards obtained as end products.
Suitable alkylene carbonates include liquid cyclic alkylene carbonates (i.e., cyclic alkylene esters of carboxylic acids), preferably propylene carbonate and butylene carbonate.
Suitable polyisocyanates used according to the 20 invention include aliphatic, cycloaliphatic, araliphatic, aromatic, and heterocyclic polyisocyanates, such as described by W. Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136, for example, those corresponding to the following formula:
Q(NCO)n wherein Q is an aliphatic hydrocarbon group containing about 2 to about 18 (preferably 6 to 10) carbon atoms; a cycloaliphatic hydrocarbon group containing about 4 to about 15 (preferably 5 to lO) carbon atoms; an aromatic hydrocarbon group containing about 6 to about 15 (preferably 6 to 13) carbon atoms; or an araliphatic hydrocarbon group containing about 8 to about 15 (preferably 8 to 13) carbon atoms; and Mo3202 n is 2 to 4 (preferably 2).
Examples of such polyisocyanates include 1,4-tetramethylene diiso-cyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate and S any mixtures of these isomers, 1-iso-cyanato-3,3,5-trimethyl-5-isocya-natomethylcyclohexane (German Auslegeschrift 1,202,785, U.S. Patent 3,401,190), 2,4- and 2,5-hexahydrotolylene diisocyanate and any mixtures of these isomers, hexahydro-1,3- and/or-1,4-phenylene diisocyanate, perhydro 2,4'- and/or 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene 10 diisocyanate and any mixtures of these isomers, diphenyl-methane-2,4'-and/or-4,4'-diisocyanate, and naphthylene-1,5-diisocyanate.
Other suitable polyisocyanates include triphenylmethane-4,4',4"-triisocyanate; polyphenyl-polymethylene polyisocyanates obtainable by aniline-formaldehyde condensation followed by 15 phosgenation as described, for example, in United Kingdom Patents 874,430 and 848,671, issued 1961 and 1960 (respectively); m- and p-isocyanatophenylsulphonyl isocyanates according to U.S. Patent 3,454,606; perchlorinated aryl polyisocyanates as described, for example, in German Auslegeschrift 1,157,601 (U.S. Patent 3,277,138);
20 polyisocyanates containing carbodiimide groups as described in German Patentschrift 1,092,007 (U.S. Patent 3,152,162) and in Gerrnan Offenlegungssch,irlen 2,504,400, 2,537,685, and 2,552,350; norbomane diisocyanates according to U.S. Patent 3,492,330; polyisocyanates containing allophanate groups as described, for example, in United 25 Kingdom Patent 994,890 issued 1965, Belgian Patent 761,626, and Netherlands Patent 7,102,524; polyisocyanates containing isocyanurate groups as described, for example, in U.S. Patent 3,001,973, German Patentschriften 1,022,789, 1,222,067, and 1,027,394, and in German Offenlegungsschriften 1,929,034 and 2,004,048; polyisocyanates 30 containing urethane groups as described, for example, in Belgian Patent Mo-3202 -6-752,261 or U.S. Patents 3,394,164 and 3,644,457; polyisocyanates containing acylated urea groups acoording to German Patententschrift 1,230,778; polyisocyanates containing biuret groups as described, for example, in U.S. Patents 3,124,605, 3,201,372, and 3,124,605 and UK
Patent 889,050 issued 1962; polyisocyanates containing ester groups as described, for example in UK Patent 965,474, issued 1964, U.S. Patent 3,567,763, and German Patentschrift 1,231,688; reaction products of the above-mentioned isocyanates with acetals according to German Patentschrift 1,072,385; and polyisocyanates containing polymeric faKy acid esters according to U.S. Patent 3,455,883.
Isocyanate-group-containing distillation residues from commercial production of isocyanates may also be used, optionally dissolved in one or more of the above mentioned polyisocyanates. Any mixtures of the above mentioned polyisocyanates may also be used.
Aromatic polyisocyanates are preferred. Particularly preferred are commercially available polyisocyanates, for example, 2,4-and 2,6-tolylene diisocyanate and any mixtures of these isomers ("TDI");
polyphenyl-polymethylene polyisocyanates, which may be prepared by aniline-formaldehyde condensation followed by phosgenation ("crude MDI"), and polyisocyanates containing carbodiimide groups, urethane groups, allophanate groups, isocyanurate groups, urea groups, or biuret groups ("modified polyisocyanates"), especially those modified poly-isocyanates derived from 2,4- and/or 2,6-tolylene diisocyanates or from 4,4'- and/or 2,4'-diphenylmethane diisocyanate.
The compounds containing at least two isocyanate reactive hydrogen atoms and generally having a molecular weight of from 400 to 10,000 are preferably compounds containing hydroxyl groups, especially compounds containing from 2 to 8 hydroxyl groups, and especially those with molecular weights of from about 1000 to about 8000 (preferably from 1500 to 4000).
Mo-3202 -7-The preferred compounds include polyesters or polyethers containing at least 2 (generally from 2 to 8 and preferably from 2 to 4) hydroxyl groups, such as those known in the art for the production of both homogeneous and cellular polyurethanes.
Suitable hydroxyl-containing polyesters include, for example, reaction products of polyhydric (preferably dihydric) alcohols, optionally together with trihydric alcohols, and polybasic (preferably dibasic) carboxylic acids. Instead of the free polycarboxylic acids, corresponding polycarboxylic acid 10 anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof may he used for the preparation of the polyesters used according to the invention. Suitable polycarboxylic acids include aliphatic, cycloaliphatic, aromatic, and heterocyclic polycarboxylic acids and may he substituted, for 15 example, with halogen atoms, and/or may be unsa~urated.
Examples of carboxylic acids and derivatives thereof that are suitable for preparation of hydroxyl-containing polyesters include succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, 20 trimellitic acid, phthalic acid anhydride, tetrahydrophthalic acid anhydride, hexahydrophthalic acid anhydride, tetra-chlorophthalic acid anhydride, endomethylene tetrahydrophthalic acid anhydride, glutaric acid anhydride, maleic acid, maleic acid anhydride, fumaric acid, dimerized and trimerized unsaturated 25 fatty acids optionally mixed with monomeric unsaturated fatty acids such as oleic acid, dimethylterephthalate, and terephthalic acid bisglycol ester.
Examples of polyhydric alcohols that are suitable for preparation of hydroxyl-containing polyesters include ethylene 30 glycol, 1,2- and 1,3-propanediol, 1,4- and 2,3-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1,4-bis-(hydroxymethyl)cyclohexane, 2-methyl-1,3-propanediol, glycerol, trimethylol propane, 1,2,6-hexanetriol, 1,2,4-butanetriol, trimethylol ethane, pentaerythritol, quinitol, mannitol and 35 sorbitol, formitol, 1,4,3,6-dianhydrosorbitol, methyl glycoside, Mo3202 diethylene glycol, triethylene glycol, tetraethylene glycol and higher polyethylene glycols, dipropylene glycol and higher polypropylene glycols, and dibutylene glycol and higher polybutylene glycols. The polyesters may contain a proportion of 5 carboxyl end groups. Polyesters of lactones, such as -capro-lactone, or of hydroxycarboxylic acids, such as hydroxycaproic acid, may also be used.
Suitable polyethers containing at least 2 (generally 2 to 8 and preferably 2 or 3~ hydroxyl groups include known types 10 that may be prepared, for example, by the polymerization of epoxides, such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, or epichlorohydrin, or polymerization of tetrahydrofuran. Such polymerizations may be carried out using only the monomers, for example, in the presence of Lewis-15 catalysts such as BF3. The polymerization may also be carriedout by chemical addition of the epoxides (preferably ethylene oxide and propylene oxide, optionally as mixtures or successively) to starting components containing reactive hydrogen atoms, such as water, alcohols, ammonia or amines, including, for 20 example, ethylene glycol, 1,3- or 1,2-propanediol, trimethylol propane, glycerol, sorbitol, 4,4'-dihydroxydiphenylpropane, aniline, ethanolamine, or ethylene diamine. It is often preferred to use polyethers in which the OH groups are predominantly (up to about 90~ by weight thereof, based on all 25 the OH groups present in the polyether) primary OH groups.
Also suitable are sucrose polyesters (for example, DE-B
1,176,358 and 1,064,938), and polyethers started on formitol or formose (DE-A 2,639,083). Polybutadienes containing OH groups are also suitable. Mixtures of polyesters and polyethers may, of 30 course, also be used.
Compounds in the molecular weight range of from 32 to 399 containing at least two isocyanate reactive hydrogen atoms may also be used as a component in the process of the invention.
Suitable such compounds are compounds containing hydroxyl groups, 35 amino groups, thiol groups, carboxyl groups, or a combination Mo3202 _g_ thereof (preferably hydroxyl groups and/or amino groups), and are used as chain extenders or crosslinking agents. Such compounds generally contain from about 2 to about 8 (preferably 2 to 4) isocyanate reactive hydrogen atoms. These compounds may also be 5 used as mixtures of different such compounds in the molecular weight range of from 32 to 399 containing at least two isocyanate reactive hydrogen atoms. Examples of such compounds are fully described, for example, in German Offenlegungsschrift 3,430,285, on pages 19 to 23.
Optional components in the process of the invention include auxiliary agents, for example, known catalysts and surface active additives such as emulsifiers and stabilizers.
Suitable catalysts include tertiary amines such as triethylamine, tributylamine, N-methylmorpholine, N-ethyl-15 morpholine, N,N,N',N'-tetramethylethylene diamine, penta-methyldiethylene triamine, and higher homologues (German Offenlegungsschriften 2,624,527 and 2,624,528), 1,4-diaza-bicyclo[2.2.2]octane, N-methyl-N'-(dimethylaminoethyl)piperazine, bis(dimethylaminoalkyl)piperazines (German Offenlegungsschrift 20 2,636,787), N,N-dimethylbenzylamine, N,N-dimethylcyclohexylamine, N,N-diethylbenzylamine, bis(N,N-diethylaminoethyl~ adipate, N,N,N',N'-tetramethyl-1,3-butanediamine, N,N-dimethyl- ~phenyl-ethylamine, 1,2-dimethylimidazole, 2-methylimidazole, monocyclic and bicyclic amidines (German Offenlegungsschrift 1,720,633), 25 bis(dialkylamino)alkyl ethers (U.S. Patent 3,330,782, German Auslegeschrift 030,558, and German Offenlegungsschriften 1,804,361 and 2,618,2LO), and tertiary amines containing amide groups (preferably formamide groups) according to German Offenlegungsschrift 2,523,633 and 2,732,292. The catalysts used 30 may also be the known Mannich bases of secondary amines (such as dimethylamine) and aTdehydes (preferably formaldehyde) or ketones (such as acetone) and phenols.
Suitable catalysts also include certain tertiary amines containing isocyanate reactive hydrogen atoms. Examples of such 35 catalysts include triethanolamine, triisopropanolamine, N-methyl-Mo3202 diethanolamine, N-ethyl-diethanolamine, N,N-dimethylethanolamine, their reaction products with alkylene oxides (such as propylene oxide and/or ethylene oxide) and secondary-tertiary amines according to German Offenlegungsschrift 2,732,292.
Sila-amines containing carbon-silicon bonds may also be used as catalysts, for example, those described in German Patentschrift 1,229,290 (corresponding to U.S. Patent 3,620,984).
Examples of suitable sila-amines include 2,2,4-trimethyl-2-silamorpholine and 1,3-dimethylaminomethyl tetramethyldisiloxane.
Suitable catalysts also include nitrogen-containing bases, such as tetraalkylammonium hydroxides; alkali metal hydroxides, such as sodium hydroxide; alkali metal phenolates, such as sodium phenolate; and alkali metal alcoholates, such as sodium methoxide. Hexahydrotriazines (German Offenlegungsschrift 15 1,709,043~ and tertiary amines containing amide groups (preferably formamide groups) (German Offenlegungsschriften 2,523,633 and 2,732,292) may also be used as catalysts. Known Mannich bases of secondary amines (such as dimethylamine) and aldehydes (preferably formaldehyde~ or ketones (such as acetone) 20 and phenols may also be used as catalysts.
Other suitable catalysts include organic metal compounds, especially organic tin compounds. Suitable organic tin compounds include those containing sulfur, such as di-n-octyl tin mercaptide (German Auslegeschrift 1,769,367 and U.S. Patent 25 3,645,927), and, preferably, tin(II) salts of carboxylic acids, such as tin(II) acetate, tin(II) octoate, tin(II~ ethylhexoate, and tin(II) laurate, as well as tin (IV)compounds, such as dibutyl tin dilaurate.
Any of the above-mentioned catalysts may, of course, be 30 used as mixtures.
Further representatives of catalysts to be used according to the invention and details concerning their mode of action are described in Kunststoff Handbuch, Volume VII, published by Vieweg and Hochtlen, Carl Hanser Verlag, Munich 35 1966, e.g., on pages 96 to 102.
Mo3202 ~ The catalysts are generally used in a quantity ranging from about 0.001 to about 10~ by weight, based on the quantity of polyisocyanate.
Suitable surface active additives include emulsifiers 5 and foam stabilizers. Suitable emulsifiers include, for example, the sodium salts of ricinoleic sulfonates and salts of fatty acids with amines, for example, oleic acid diethylamine or stearic acid diethanolamine. Other suitable surface active additives include alkali metal or ammonium salts of sulfonic 10 acids (such as dodecylbenzenesulfonic acid or dinaphthyl-methanedisulfonic acid), of fatty acids (such as ricinoleic acid), or of polymeric fatty acids.
Suitable substrates used in the process of the invention include lignocellulose-containing raw materials that 15 can be bonded with the binders according to the invention.
Examples of suitable lignocellulose-containing materials include wood, woodbark, cork, bagasse,straw, flax, bamboo, esparto, rice husks, and sisal and coconut fibers. Other suitable substrates for compression molding include other organic raw materials (for 20 example, all kinds of plastic waste) and inorganic raw materials (for example, expanded mica or silicate balls). The substrate may be used in the form of granulates, shavings or chips, fibers, spheres, or powder and may have a moisture content of, for example, from about O to about 35% by weight (preferably from 4 25 to 20~ by weight).
It is possible, but less preferred, to apply the components of the binder combination (polyisocyanate, polyether polyol or polyester polyol, and alkylene carbonate) separately to the material which is to be bonded. It is preferable to use the 30 polyether or polyester polyol and the alkylene carbonate as a mixture with the polyisocyanate as binder.
In the process of the invention, the binder is added to the organic and/or inorganic material to be bonded in a quantity of about 0.5 to about 20~ by weight (preferably 2 to 12~ by 35 weight), based on the total weight of the end product. The Mo3202 resultant material is compressed to form boards or three dimensionally shaped molded products, generally under heat and pressure (for example, about 70 to about 250C and about 1 to about 150 bar).
Multilayered boards or molded parts may be produced in analogous manner from veneers, paper, or woven fabrics by treating the layers with the binder as described above and subsequently pressing them, generally at elevated temperature and elevated pressure. Temperatures of from about 100 to about 250C
10 are preferred, with 130 to 200C being most preferred. The initial compression pressure is preferably in the range of from about 5 to about 150 bar, although the pressure in most cases drops towards 0 bar during the compression process.
The binders used according to the invention may also be 15 used in combination with aqueous solutions of condensation products of formaldehyde and urea and/or me~ ine and~r phenol, which are the binders most commonly used in the woodworking industry. In addition, the binders may be combined with less commonly used binders and impregnating agents, for example, those based on 20 polyvinyl acetate or other synthetic resin lattices, sulfide waste liquors, or tannin. When using a mixture of the binders according to the invention with these additional binders, the proportions used are from about 1:20 to about 20:1 (preferably from 1:5 to 5:1). The polyisocyanate mixtures and the additional 25 binders may be used separately or as a mixture.
The following examples further illustrate details for the process of this invention. The invention, which is set forth in the foregoing disclosure, is not to be limited either in spirit or scope by these examples. Those skilled in the art will 30 readily understand that known variations of the conditions of the following procedures can be used. Unless otherwise noted, all temperatures are degrees Celsius and all percentages are percentages by weight.
Mo3202 -DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following polyols are used as starting components in the Examples:
Polyether Polyol I prepared from l,2-propanediol and propylene 5 oxide and having an OH number of 284 and a viscosity of 75 mPas at 25C.
Polyether Polyol II prepared from 1,2-propanediol, propylene oxide, and ethylene oxide and having an OH number of 185 and a viscosity of 130 mPas at 25C.
10 Polyether Polyol III prepared from ethylene diamine and propylene oxide and having an OH number of 60 and a viscosity of 660 mPas at 25C.
Example 1 Face 1 ayer industrial chips (moisture content u = 15.0%
15 by weight oven-dried ("o.d.") wood) (2800 9) and core layer chips (u = 10.0% o.d.) (6400 9) were each sprayed with 5% by weight o.d. of a binder consisting of a mixture of 70~ by weight crude diphenylmethane-4,4'diisocyanate having an isocyanate content of 30~ by weight, 10% by weight polyether polyol I, 10%
20 by weight polyether polyol II, and 10% by weight of propylene carbonate. This material was spread out to form three-layered board preforms and at selected time intervals was compressed both cold and hot under pressure.
Example 2 Boards were prepared as in Example 1 except that the binder was composed of a mixture of 70~ by weight crude diphenylmethane-4,4'diisocyanate having an isocyanate content of 30% by weight, 20% by weight polyether polyol III, and 10% by weight propylene carbonate. The isocyanate and the polyol/
30 alkylene carbonate mixture were sprayed separately on the chips.
Compression molding was performed as in Example 1.
Example 3 Face layer industrial chips (u = 12.0% o.d.) (4200 9) were sprayed with 13% by weight o.d. of a binder consisting of a 35 mixture of 80% by weight crude diphenylmethane-4,4'-diisocyanate Mo3202 having an isocyanate content of 30~ by weight, 12% by weight polyether polyol II, and 8% by weight propylene carbonate. The chips were spread out to form single-layered board preforms and compression molded as in Example 1.
5 Example 4 Boards were prepared as in Example 3 except that one half of the binder was a mixture of 70% by weight crude diphenylmethane-4,4'-diisocyanate having an isocyanate content 30% by weight, 20% by weight polyether polyol I, and 10% by 10 weight polypropylene carbonate and the second half of the binder was a commercial E1 urea-formaldehyde resin. Three percent by weight o.d. of each half portion of binder was sprayed on the chips. Compression molding was performed as in Example 1.
All board preforms which ~er~ prepressed at room temperature according to Examples 1 to 4 e ~hibited cold ~ac~
in contrast to chips which have been treated with polyisocyanate alone. Under hot pressing conditions, samples prepared according to the invention also have advantages over the comparison samples under identical experimental conditions. Test 20 results are shown in the following Table.
TABLE
Example Gross Density Transverse Tensile 1) of Boa3ds Strength (~Pa) (kg/m ) V20 V100 Comparison experiment 680 0.94 0.27 using 5~ by weight o.d.
Desmodur ~ PU 1520 A
1 680 1.13 0.33 2 680 1.09 0.34 3 850 0.82 4 650 0.84 o.d. = calculated percent by weight based on absolutely dry, oven dried wood Trans-~erse tensile strength V 20 and V 100 tested according to German Standard DIN 68763 (flat pressed particle boards for building) The following binders were used in Example 5.
Binder I: a prepolymer comprising 70 parts by weight of crude diphenylmethane-4,4'-diisocyanate having an isocyanate content of 30% by weight and a viscosity of 300 mPa.s at 25-C, and a mixture of 10 parts by weight of polyether polyol I and 10 parts by weight of polyether polyol II. V~scosity of about 52,000 mPa.s/25-C.
Binder II: the prepolymer of binder I containing 10 parts by weight of propylene carbonate. Viscosity of about 9300 mPa.s/
25-C.
Binder III: an in-situ mixture of 70 parts by weight of crude diphenylmethane-4,4'-diisocyanate having an isocyanate content of 30% by weight and a viscosity of 300 mPa.s at 25-C, 10 parts by weight of polyether polyol I, 10 parts by weight of polyether polyol II, and 10 parts by weight of propylene carbonate (corresponds to binder used ln Example 1, and illustrative of the invention).
:
A batch of face layer industrial chips (moisture content u=14.0% by weight oven dried wood) (3950 9) was sprayed with binder II or binder III in amounts of 10.4% by weight o.d.
(quantity of binder based on prepolymer of diphenylmethane-4,4'-diisocyanate/polyol). The chips were spread out to form single-layer board preforms and were compressed at specific intervals in the cold state, after which the cold tack was determined.
Binder I, the prepolymer, was not usable due to its lo high viscosity (about 52,000 mPa.s/2~-C after 14 days).
Binder II, the prepolymer diluted with 10 parts by weight of propylene carbonate, has a viscosity of about 9300 mPa.s/25-C, which is still too high. Binder II can only be applied with great difflculty using high pressure spraying and is therefore not practical for indus~rial use. Upon exposure to atmospheric moisture, Binder II very quickly forms a skln on its surface and it has a tendency to foam.
Binder II and Binder III display almost the same degree of cold tack when the chlps are blended therewith and compressed in the cold state.
Binder III has the advantages of being easy to handle and use, and economical to produce as the production costs associated with prepolymerization are dispensed with. ~he customer needs only to use one type of diphenyl-4,4'-dliso-cyanate, to which polyether polyol and propylene carbonate can if necessary be added in the required quantities, depending on the type of applications involved.
; 30
Claims (12)
1. A process for the preparation of a compression molded material comprising (i) compressing a composition comprising a lignocellulose-containing material and a polyisocyanate based binder to form a preform, wherein said binder comprises:
(a) an aromatic polyisocyanate selected from the group consisting of toluene diisocyanate, polyphenyl polymethylene polyisocyanates, and modified aromatic polyisocyanates, (b) a polyester or polyether containing at least two hydroxyl groups and having a molecular weight of from about 400 to about 10,000, and (c) an alkylene carbonate, wherein the total amount of components (b) plus (c) is from about 10 to about 250 parts by weight per 100 parts by weight of component (a), and wherein the weight ratio of component (b) to component (c) is from about 0.5:1.0 to about 10.0:1.0, to form a preform, said composition exhibiting cold tack when compressed without application of heat, and molding said preform under heat and pressure.
(a) an aromatic polyisocyanate selected from the group consisting of toluene diisocyanate, polyphenyl polymethylene polyisocyanates, and modified aromatic polyisocyanates, (b) a polyester or polyether containing at least two hydroxyl groups and having a molecular weight of from about 400 to about 10,000, and (c) an alkylene carbonate, wherein the total amount of components (b) plus (c) is from about 10 to about 250 parts by weight per 100 parts by weight of component (a), and wherein the weight ratio of component (b) to component (c) is from about 0.5:1.0 to about 10.0:1.0, to form a preform, said composition exhibiting cold tack when compressed without application of heat, and molding said preform under heat and pressure.
2. The process of Claim 1 wherein component (b) plus component (c) comprises from about 20 to about 80 parts by weight.
3. The process of Claim 1 or 2 wherein the aromatic polyisocyanate is a polyphenyl-polymethylene polyisocyanate obtainable by aniline-formaldehyde condensation followed by phosgenation.
4. The process of Claim 1 or 2 wherein said aromatic polyisocyanate is toluene diisocyanate.
5. The process of Claim 1 wherein (i) component (a) is a polyisocyanate from the group selected from diphenylmethane diisocyanates, polyphenyl-polymethylene polyisocyanates obtainable by aniline-formaldehyde condensation followed by phosgenation, and mixtures thereof, (ii) component (b) is a polyether or polyester having a molecular weight range of from about 400 to about 10,000 and containing hydroxyl groups, (iii)component (c) is propylene carbonate, and (iv) component (b) plus component (c) totals from 20 to 80 parts per 100 parts of component (a).
6. A process according to Claim 1, 2 or 5 wherein said composition further comprises particulates of waste plastics.
7. A process for the preparation of compression molded materials comprising:
(i) mixing a lignocellulose-containing material with a polyisocyanate based binder, wherein said binder comprises:
(a) an aromatic polyisocyanate selected from the group consisting of toluene diisocyanate, polyphenyl polymethylene polyisocyanates, and modified aromatic polyisocyanates, (b) a polyester or polyether containing at least two hydroxyl groups and having a molecular weight of from about 400 to about 10,000, and (c) an alkylene carbonate, wherein the total amount of components (b) plus (c) is from about 10 to about 250 parts by weight per 100 parts by weight of component (a), and wherein the weight ratio of component (b) to component (c) is from about 0.5:1.0 to about 10.0: 1 .0, (ii) compressing the resultant mixture without the application of heat to form a preform, and (iii) molding said preform under heat and pressure.
(i) mixing a lignocellulose-containing material with a polyisocyanate based binder, wherein said binder comprises:
(a) an aromatic polyisocyanate selected from the group consisting of toluene diisocyanate, polyphenyl polymethylene polyisocyanates, and modified aromatic polyisocyanates, (b) a polyester or polyether containing at least two hydroxyl groups and having a molecular weight of from about 400 to about 10,000, and (c) an alkylene carbonate, wherein the total amount of components (b) plus (c) is from about 10 to about 250 parts by weight per 100 parts by weight of component (a), and wherein the weight ratio of component (b) to component (c) is from about 0.5:1.0 to about 10.0: 1 .0, (ii) compressing the resultant mixture without the application of heat to form a preform, and (iii) molding said preform under heat and pressure.
8. The process of Claim 7 wherein component (b) plus component (c) comprises from about 20 to about 80 parts by weight.
9. The process of Claim 7 or 8 wherein the aromatic polyisocyanate is a polyphenyl-polymethylene polyisocyanate obtainable by aniline-formaldehyde condensation followed by phosgenation.
10. The process of Claim 7 or 8 wherein said aromatic polyisocyanate is toluene diisocyanate.
11. The process of Claim 7 wherein (i) component (a) is a polyisocyanate from the group selected from diphenylmethane diisocyanates, polyphenyl-polymethylene polyisocyanates obtainable by aniline-formaldehyde condensation followed by phosgenation, and mixtures thereof, (ii) component (b) is a polyether or polyester having a molecular weight range of from about 400 to about 10,000 and containing hydroxyl groups, (iii) component (c) is propylene carbonate, and (iv) component (b) plus component (c) totals from 20 to 80 parts per 100 parts of component (a).
12. The process of Claim 7, 8 or 11 wherein particulates of waste plastics are added to the lignocellulose-containing material before mixing with said polyisocyanate based binder.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3825320.8 | 1988-07-26 | ||
| DE3825320A DE3825320A1 (en) | 1988-07-26 | 1988-07-26 | METHOD FOR PRODUCING COMPRESSED MATERIALS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1338075C true CA1338075C (en) | 1996-02-20 |
Family
ID=6359554
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000606024A Expired - Fee Related CA1338075C (en) | 1988-07-26 | 1989-07-18 | Process for the preparation of compression molded materials |
Country Status (13)
| Country | Link |
|---|---|
| EP (1) | EP0352558B1 (en) |
| JP (1) | JP2678496B2 (en) |
| AT (1) | ATE101631T1 (en) |
| AU (1) | AU616026B2 (en) |
| BR (1) | BR8903675A (en) |
| CA (1) | CA1338075C (en) |
| DE (2) | DE3825320A1 (en) |
| DK (1) | DK170753B1 (en) |
| ES (1) | ES2049780T3 (en) |
| FI (1) | FI99121C (en) |
| NO (1) | NO173876C (en) |
| NZ (1) | NZ230054A (en) |
| ZA (1) | ZA895641B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8895643B2 (en) | 2010-09-30 | 2014-11-25 | Bayer MateralScience LLC | Cold-pressed mats of lignocellulosic material having improved cold tack and a process for their production |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2894107B2 (en) * | 1992-09-30 | 1999-05-24 | 松下電器産業株式会社 | Illuminated rotary operation type electronic components |
| AU651285B2 (en) * | 1992-10-12 | 1994-07-14 | Foong Intellectual Properties Sdn Bhd | Cellulosic bodies |
| US6368714B1 (en) * | 1993-10-14 | 2002-04-09 | John Russell Robertson | Moisture-activated adhesive compositions |
| US5442034A (en) * | 1994-06-01 | 1995-08-15 | Huntsman Corporation | Spray polyurea elastomers containing organic carbonates to improve processing characteristics |
| US6294117B1 (en) * | 1998-12-17 | 2001-09-25 | Bayer Corporation | Mixed PMDI/solid novolac resin binders for the production of wood composite products |
| EP1201695A1 (en) * | 2000-10-23 | 2002-05-02 | Huntsman International Llc | The use of polyisocyanate compositions as a binder for composite lignocellulosic materials |
| DE10141209A1 (en) * | 2001-08-22 | 2003-03-06 | Bayer Ag | Manufacturing process for press materials |
| US7331352B2 (en) | 2003-09-05 | 2008-02-19 | L'oreal | Device for applying a product to hair |
| CN1712481A (en) * | 2004-06-21 | 2005-12-28 | 日本聚氨酯工业株式会社 | Binder for composition and production of plant fiber plates |
| DE102006020612B4 (en) † | 2006-05-02 | 2019-03-14 | SWISS KRONO Tec AG | Process for the production of wood-based materials with reduced emission of volatile organic compounds, wood-based materials obtainable therewith and the use of certain additives for reducing the release of volatile organic compounds from wood-based materials and wood-pulp products of lignocelluloses |
| DE102006027540B4 (en) * | 2006-06-14 | 2010-07-22 | Glunz Ag | Process and device for producing shaped articles, in particular sheets, from lignocellulose-containing fibers |
| DE102007025801A1 (en) * | 2007-06-02 | 2008-12-04 | Glunz Ag | Process for the preparation of a light flexible molded article based on lignocellulose-containing fibers |
| JP5783888B2 (en) * | 2011-11-22 | 2015-09-24 | 三井化学株式会社 | Adhesive composition for forming composite material with high water resistance, composite material, production method thereof, and adhesive for forming composite material with high water resistance |
| PL2620475T3 (en) * | 2012-01-26 | 2015-10-30 | SWISS KRONO Tec AG | Adhesive compounds and use of same |
| JP6464732B2 (en) * | 2014-12-25 | 2019-02-06 | Dic株式会社 | Polyisocyanate composition for two-component non-drying adhesive, polyol composition for two-component non-drying adhesive, non-drying adhesive, and laminated film |
| CN105936736A (en) * | 2016-01-07 | 2016-09-14 | 吴春喜 | Production process of phenol-formaldehyde bakelite powder from straw powder instead of wood powder |
| CN107363964A (en) * | 2016-05-12 | 2017-11-21 | 中国林业科学研究院木材工业研究所 | One kind is without aldehyde environmental protection particieboard and its manufacture method |
| PL3672771T3 (en) * | 2017-08-23 | 2023-10-30 | Basf Se | Method for the preparation of lignocellulose materials in the presence of caprolactam and its oligomers |
| EP3733368B1 (en) * | 2019-04-30 | 2024-05-22 | Fritz Egger GmbH & Co. OG | Adhesive for manufacture of wood boards |
| EP3733366B1 (en) * | 2019-04-30 | 2022-11-16 | Fritz Egger GmbH & Co. OG | Adhesive for manufacture of wood boards |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2538999C3 (en) * | 1975-09-02 | 1981-10-22 | Lignotock Verfahrenstechnik Gmbh, 1000 Berlin | Binder component for polyurethane binders |
| US4414361A (en) * | 1981-08-17 | 1983-11-08 | Atlantic Richfield Company | Organic polyisocyanate-cyclic alkylene carbonate adhesive binder compositions |
| US4359507A (en) * | 1981-11-19 | 1982-11-16 | Atlantic Richfield Company | Mixed ethylene and propylene carbonate-containing organic polyisocyanate adhesive binder composition |
| US4731427A (en) * | 1987-04-01 | 1988-03-15 | Arco Chemical Company | Method for the preparation of rigid reaction injection molded thermoset polyurethane modified polyisocyanurate compositions |
-
1988
- 1988-07-26 DE DE3825320A patent/DE3825320A1/en not_active Withdrawn
-
1989
- 1989-06-30 AU AU37290/89A patent/AU616026B2/en not_active Ceased
- 1989-07-11 NO NO892864A patent/NO173876C/en unknown
- 1989-07-13 DE DE89112837T patent/DE58906971D1/en not_active Expired - Fee Related
- 1989-07-13 EP EP89112837A patent/EP0352558B1/en not_active Expired - Lifetime
- 1989-07-13 ES ES89112837T patent/ES2049780T3/en not_active Expired - Lifetime
- 1989-07-13 AT AT89112837T patent/ATE101631T1/en not_active IP Right Cessation
- 1989-07-18 CA CA000606024A patent/CA1338075C/en not_active Expired - Fee Related
- 1989-07-24 JP JP1189020A patent/JP2678496B2/en not_active Expired - Fee Related
- 1989-07-24 NZ NZ230054A patent/NZ230054A/en unknown
- 1989-07-24 FI FI893543A patent/FI99121C/en not_active IP Right Cessation
- 1989-07-25 ZA ZA895641A patent/ZA895641B/en unknown
- 1989-07-25 DK DK366489A patent/DK170753B1/en not_active IP Right Cessation
- 1989-07-25 BR BR898903675A patent/BR8903675A/en not_active Application Discontinuation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8895643B2 (en) | 2010-09-30 | 2014-11-25 | Bayer MateralScience LLC | Cold-pressed mats of lignocellulosic material having improved cold tack and a process for their production |
Also Published As
| Publication number | Publication date |
|---|---|
| DE58906971D1 (en) | 1994-03-24 |
| DK366489A (en) | 1990-01-27 |
| EP0352558A2 (en) | 1990-01-31 |
| NZ230054A (en) | 1990-10-26 |
| FI893543A0 (en) | 1989-07-24 |
| ZA895641B (en) | 1990-05-30 |
| DK366489D0 (en) | 1989-07-25 |
| EP0352558A3 (en) | 1990-10-10 |
| AU616026B2 (en) | 1991-10-17 |
| JPH0286404A (en) | 1990-03-27 |
| AU3729089A (en) | 1990-02-01 |
| FI893543A (en) | 1990-01-27 |
| ES2049780T3 (en) | 1994-05-01 |
| JP2678496B2 (en) | 1997-11-17 |
| EP0352558B1 (en) | 1994-02-16 |
| BR8903675A (en) | 1990-03-13 |
| ATE101631T1 (en) | 1994-03-15 |
| FI99121C (en) | 1997-10-10 |
| DK170753B1 (en) | 1996-01-08 |
| NO892864D0 (en) | 1989-07-11 |
| NO892864L (en) | 1990-01-29 |
| NO173876B (en) | 1993-11-08 |
| DE3825320A1 (en) | 1990-02-01 |
| NO173876C (en) | 1994-02-16 |
| FI99121B (en) | 1997-06-30 |
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