DE102010001719A1 - Process for the production of composite materials - Google Patents

Abstract

The present invention relates to processes for the production of composite materials made of cellulose- or lignocellulose-containing material, in particular wood-based materials, which, as a result of pretreating the material with organ-functional silane compounds, have improved properties, such as reduced formaldehyde release, and improved mechanical and / or hygroscopic properties.

Description

The present invention relates to processes for the production of composites of cellulosic or lignocellulosic material, in particular of wood materials, which have improved properties, such as a reduced formaldehyde release, as well as improved mechanical and / or hygroscopic properties as a result of a pretreatment of the material with organo-functional silane compounds.

State of the art

Organosilanes are used directly in the sub-mixing process as a binder in the production of composite materials, in particular of wood-based materials. The advantages of wood-based materials include a simpler processing than wood, higher dimensional stability compared to solid wood and use of leftovers from the wood industry. However, there are concerns about its emission of pollutants, in particular formaldehyde, which is mostly caused by the binder used. Formaldehyde can cause allergies, skin, respiratory or eye irritation, but it is mainly carcinogenic. Therefore, methods are needed in the wood industry to reduce its emissions from wood-based materials. The verification of formaldehyde release from wood-based materials is carried out by means of the standardized WKI bottle method ( EN 717-3 ) carried out.

The wood-based material manufacturers, which are organized in the EPF (European Panel Federation), entered into a voluntary commitment from 01/2009 to reduce the release of formaldehyde from their produced wood-based materials by half. A normative specification from the legislator is still pending. Globally, Japan has introduced new testing methods and limits in recent years (JIS standards). Furthermore, the US state of California also tightened the limits for the formaldehyde release from wood-based materials (CARB standards) from January 2009. Further tightening steps are planned for 2010 and 2011.

DE 10 2006 006 654 A1 discloses specific aminoalkyl silane compounds and their use as replacements for formaldehyde-containing resins in binders used to make composites. The exclusive use of such aminoalkylsilane compounds, a reduction of the formaldehyde release could be achieved. DE 10 2006 006 656 A1 discloses the use of aminoalkyl silane compounds with partially formaldehyde-containing resins in binder mixtures and their use in the manufacture of composites. However, none of these documents discloses a method of making composites in which the cellulosic or lignocellulosic material is pretreated in a first step with only aminoalkyl silane alone. Rather, the material is glued with the aminoalkylsilane together with a binder containing formaldehyde simultaneously in one step and then pressed hot.

DE 10 2006 013 090 A1 discloses the preparation of a composite material using aminoalkylsilanes. In the methods disclosed herein, however, thermoplastic material is used as the binder in the second production step. The release of formaldehyde is not discussed.

WO 2006/094643 discloses processes for the preparation of aminoalkylsilanes.

Since the knowledge of the possible carcinogenic effect of formaldehyde, there has been an attempt to reduce the release of formaldehyde in wood-based materials. The object of the present invention is to provide methods by which composites of cellulose- or lignocellulose-containing material, in particular wood-based materials, can be produced using formaldehyde-containing binders which have a reduced formaldehyde release. A further alternative or additional object of the present invention is to provide a manufacturing method for composite materials having improved mechanical and / or hygroscopic properties.

General description of the invention

As shown in the examples, the inventors have succeeded in significantly reducing the emission of formaldehyde from composites comprising a formaldehyde-containing binder by pretreating wood shavings with commercially available aminoalkyl silanes. For this purpose, in contrast to the previously known methods, the crude chips are treated in advance with a solution of aminoalkylsilanes, dried and reacted. Only then are the pretreated chips in a second step using lower amounts of binder to z. Chipboard or OSB ( oriented strand board). For example, a reduction of formaldehyde release by up to 70% compared to conventionally produced chipboard has been demonstrated. In addition, the particleboard produced according to the invention have a reduced thickness swelling independently of the binder ( EN 317 ), a reduced water absorption, and an increased transverse tensile strength (according to EN 1087 ) compared to conventionally produced particleboard.

Detailed description of the invention

• (a) Behandeln des cellulose- oder lignocellulosehaltigen Materials mit einer Flüssigkeit, die eine Aminoalkylsilan-Verbindung enthält;
• (b) Trocknen des in Schritt (a) behandelten Materials auf mindestens 2% Holzfeuchte;
• (c) Beleimen des in Schritt (b) getrockneten Materials mit einem Bindemittel; und
• (d) Verbringen des in Schritt (c) behandelten Materials in eine gewünschte Form und anschließendes Verpressen unter Hitze zu einem Verbundwerkstoff.

In a first aspect, the invention relates to a process for producing a composite based on a cellulose- or lignocellulose-containing material, the process comprising the following steps:

• (a) treating the cellulosic or lignocellulosic material with a liquid containing an aminoalkylsilane compound;
• (b) drying the material treated in step (a) to at least 2% wood moisture content;
• (c) gluing the material dried in step (b) with a binder; and
• (d) transferring the material treated in step (c) to a desired shape and then heat-pressing it into a composite material.

Lignocellulose (from Latin lignum = wood or tree) forms the cell wall of woody plants. Here, hemicelluloses and cellulose form a scaffold into which lignin is incorporated during the process of lignification, the so-called lignification. Cellulose is a long stretched polymer of beta-1,4-glycosidically linked monomers of glucose that are aggregated in plants into fibers with partially crystalline regions. Hemicellulose makes up a smaller proportion and is less organized. Hemicellulose is composed of various sugars consisting of polymers which also have branching linkages and therefore do not allow a fibrous arrangement. Lignin consists of various phenylpropane types that are incorporated into the cellulose hemicellulose matrix and linked to the polymer lignin to form lignocellulose.

In a preferred embodiment, the cellulosic or lignocellulosic material is derived from hardwood, softwood, palm, annual, coconut, cotton, flax, hemp, barley, jute, sisal, reed, rice straw, bamboo or straw.

The recovery of lignocellulose for use in the present process is predominantly in the form of fibers or shavings. The extraction of fibers can be done, for example, according to the Asplund process, in which the wood is first crushed into wood chips, then digested by steam at high temperatures (160 to 180 ° C) and pressures (8 to 12 bar) (also called plasticization) and Finally, by means of a two opposing grinding discs existing refiner at about 11 bar is fiberized.

Traditionally, three groups of raw materials in different proportions are used to extract the barrels. For this purpose, about 57% of the required wood raw material from industrial waste wood, such as wood waste of the woodworking and processing industry, including sawdust, wood shavings, shavings, rinds, but also remains of the veneer industry used. Another approx. 23% of the wood raw material is obtained from forest industry wood in the form of harvested logs, which are processed into woodchips or chipped using wood chippers. At around 20%, used or recycled wood, for example used products made of solid wood, wood-based materials or composites with a predominantly wood content of more than 50% by weight, forms the third group of raw materials. At the factory, spangles with defined dimensions are produced from this by means of knife ring chippers, long wood chippers and hammer mills and are usually dried to a moisture content of 1.5 to 3% in tube bundle or tubular drum driers. This is followed by a screening and sifting, wherein the spangle is separated into top and middle layer chips and possible coarse spangle is deposited.

In a preferred embodiment, the cellulosic or lignocellulosic material may be a natural or near-natural material selected from the group consisting of industrial wood, forest industry wood, recycled wood, wood shavings, wood chips, wood fibers, wood wool, wood dust, shavings, wood pellets, wood bark, rinds, veneer waste, Splinters, chipboard material from annual plants and a mixture of at least two materials thereof.

In a first step, the cellulosic or lignocellulosic material is then treated with a liquid containing an aminoalkylsilane compound. The aminoalkylsilane compound may be any of Aminoalkylsilane compound used in the wood processing industry. Preferably, the liquid is water or an aqueous solution.

In a preferred embodiment, the aminoalkylsilane compound is an aminoalkylsilane compound of the formula (I) R ¹ R ² N (CHR ⁴ ) _a Si (R ³ ) _r (OR) _3-r (I), wherein groups R ¹ and R ^{2 are the} same or different and each represents H or a linear, branched or cyclic C ₁ to C ₂₀ alkyl group or an aryl group or an aminocarbyl group, wherein groups R ¹ and R ^{2 may} optionally be substituted groups R ^{4 are the} same or different and R ^{4 is} H or methyl, a is 1 to 10, R ^{3 is} H or a linear or branched C ₁ to C ₈ alkyl group, R is the same or different and R is H or a linear or branched C ₁ to C ₈ alkyl group and r is 0 or 1 or 2; or
at least one co-condensate of at least one aminoalkylsilane of the general formula (I) and at least one further functional silane of the general formula (II) R ⁷ (CHR ⁶ ) _b Si (R ⁵ ) _p (OR) _3-p (II) wherein R ^{7 is} H or a vinyl group or an amino group or a glycidoxy group or an acryloxy group or a methacryloxy group or a mercapto group or a Sulfangruppe or a linear or branched C ₁ to C ₂₀ alkyl group or an aryl group, wherein the group R ⁷ optionally substituted R ^{6 is the} same or different and R ^{6 is} H or methyl, b is 0 to 18, R ^{5 is} H or a linear or branched C ₁ to C ₈ alkyl group, Rs are the same or different and R is H or a linear or branched C ₁ to C ₈ alkyl group and p is 0 or 1 or 2, wherein the amino functions in the cocondensate may be partially or completely neutralized with an inorganic or organic acid; or
an aqueous solution containing at least one aminoalkylsilane compound of the formula (I) or at least one cocondensate based on at least one aminoalkylsilane of the general formula (I) and at least one further functional silane of the general formula (II).

In a more preferred embodiment, the aminoalkylsilane compound has an aminoalkyl group selected from 3-aminopropyl, 3-amino-2-methylpropyl, N- (2-aminoethyl) -3-aminopropyl, N- (2-aminoalkyl) -3-amino 2-methylpropyl, N- [N '- (2-aminoethyl) -2-aminoethyl] -3-aminopropyl, N - [N' - (2-aminoethyl) -2-aminoethyl] -3-amino-2-methylpropyl , N, N- [di- (2-aminoethyl)] - 3-aminopropyl, N, N- [di (2-aminoethyl)] - 3-amino-2-methylpropyl, N- (n-butyl) -3 aminopropyl or N- (n-butyl) 3-amino-2-methylpropyl.

Such Aminalkylsilan compounds and their preparation are described in DE 10 2006 006 654 and DE 10 2006 006 656 ,

In another preferred embodiment, the amine alkylsilane compound is an aqueous 3-aminopropylsilane hydrolyzate, an organo-functional siloxane oligomer in water, or an amino / alkyl siloxane co-oligomer in water, or a mixture of at least two of these compounds. Examples of a commercially available aqueous 3-aminopropylsilane is Dynasylan ^® HS 1151, for an organ functional siloxane oligomer Dynasylan ^® HS 2627 and Dynasylan ^® HS 2776 and an amino / alkyl siloxane cooligomer in water Dynasylan ^® HS 2909th

wobei R ein divalenter Si-C und Si-N gebundener, gegebenenfalls Cyano- oder halogensubstituierter C₃-C₁₅-Kohlenwasserstoffrest ist, in dem eine oder mehrere, einander nicht benachbarte Methyleneinheiten durch -O-, -CO-, -COO-, -OCO-, oder -OCOO-, -S-, oder -NR^x- ersetzt sein können und in dem eine oder mehrere, einander nicht benachbarte Methineinheiten durch -N=, -N=N-, oder -P= ersetzt sein können,
R^x Wasserstoff oder ein gegebenenfalls halogensubstituierter C₁-C₁₀-Kohlenwasserstoffrest ist, und
R² ein Wasserstoffatom oder ein monovalenter, gegebenenfalls Cyano- oder halogensubstituierter Si-C gebundener C₁-C₂₀-Kohlenwasserstoffrest oder C₁-C₂₀-Kohlenwasserstoffoxyrest ist, in dem jeweils eine oder mehrere, einander nicht benachbarte Methyleneinheiten durch -O-, -CO-, -COO-, -OCO-, oder -OCOO-, -S-, oder -NR^x- ersetzt sein können und in dem eine oder mehrere, einander nicht benachbarte Methineinheiten durch, -N=, -N=N-, oder -P= ersetzt sein können, und
R³ ein monovalenter C₁-C₂₀-Kohlenwasserstoffrest ist, in dem jeweils eine oder mehrere, einander nicht benachbarte Methyleneinheiten durch -O-, -CO-, -COO-, -OCO-, oder -OCOO-, -S-, oder -NR^x- ersetzt sein können und in denen eine oder mehrere, einander nicht benachbarte Methineinheiten durch -N=, -N=N-, oder -P= ersetzt sein können.In another preferred embodiment, the aminalkylsilane compound is an amine alkylsilane compound of the formula (III) and / or of the formula (IV)

wherein R is a divalent Si-C and Si-N bonded, optionally cyano- or halogen-substituted C ₃ -C ₁₅ -hydrocarbon radical in which one or more, non-adjacent methylene units represented by -O-, -CO-, -COO-, -OCO-, or -OCOO-, -S-, or -NR ^x - may be replaced and in which one or more mutually non-adjacent methine units by -N =, -N = N-, or -P = may be replaced .
R ^{x is} hydrogen or an optionally halogen-substituted C ₁ -C ₁₀ hydrocarbon radical, and
R ^{2 is} a hydrogen atom or a monovalent, optionally cyano- or halogen-substituted Si-C bonded C ₁ -C ₂₀ -hydrocarbon radical or C ₁ -C ₂₀ -hydrocarbonoxy radical, in each of which one or more non-adjacent methylene units is represented by -O-, -CO-, -COO-, -OCO-, or -OCOO-, -S-, or -NR ^x - may be replaced and in which one or more, mutually non-adjacent methine units by, -N =, -N = N -, or -P = can be replaced, and
R ^{3 is} a monovalent C ₁ -C ₂₀ -hydrocarbon radical in which in each case one or more, mutually non-adjacent methylene units by -O-, -CO-, -COO-, -OCO-, or -OCOO-, -S-, or -NR ^x - may be replaced and in which one or more mutually non-adjacent methine units may be replaced by -N =, -N = N-, or -P =.

Aminoalkylsilane compounds of the formula (III) and / or of the formula (IV) and their preparation are described in WO 2006/094643 ,

Such aminoalkylsilane compounds can be mixed with water in the desired ratio. The above compounds may be mixed first and then optionally diluted with water and / or alcohol. For example, an aminoalkylsilane essentially neutralized with acetic acid or formic acid can be mixed with water in a volume ratio of about 1: 0.5 to 0.5: 5, preferably about 1: 1 to 0.5: 2, in particular about 1: 2 ,

The solution preferably has a water content of 5 to 99.5% by weight, more preferably 50 to 98% by weight, more preferably 60 to 95% by weight, in particular 80 to 95% by weight, based on the composition, wherein the respective components of the solution add up to 100 wt .-%.

The solution may also have a free acid content of <10% by weight, preferably 0 to 7% by weight, particularly preferably 0.001 to 5% by weight, based on the solution. Acid moieties which are present as amino or ammonium salt are to be excluded here in the determination of the so-called free acid moieties.

Furthermore, such a solution may contain an alcohol, in particular methanol, ethanol, n-propanol, i-propanol, 2-methoxyethanol or a mixture thereof.

Preferably, however, the solution is alcohol-free, d. h., That in the solution of free alcohol up to a maximum limit of 3 wt .-% can no longer be detected.

In a further preferred embodiment, in step (a) 0.05-8% by weight of solid-aminoalkylsilane compound, preferably 0.1-7% by weight, more preferably 0.25-6% by weight, of most preferably 0.5-5 wt .-% based on atro cellulose or lignocellulosehaltigem material used.

The so-called "absolute dry wood mass" (short atro) is usually determined by the treatment of cellulose- or lignocellulose-containing material at 103 ° C to constant weight (see. DIN 53 183 such as EN 322 ).

Suitable processes for the treatment of cellulose or lignocellulose-containing material with an aminoalkylsilane compounds are, for example, brushing, rolling, spraying, dipping, flooding, spraying, blowline treatment or treatment in the mixer, for. B. in a free fall mixer. The selection of determining reasons for a suitable method, as well as alternative methods are known in the art. Corresponding devices and systems are also known to the person skilled in the art and commercially available.

For example, the cellulosic or lignocellulosic material may be treated using the recirculation method. For this purpose, the material in a rotating drum, preferably at room temperature or under cooling, as at 4 to 12 ° C, in particular at about 10 ° C, by means of a device operated with compressed air, such as a spray gun with an operating pressure of 0 to 4 bar abs . sprayed with a solution containing aminoalkylsilane compound. As a rule, one obtains such a largely uniformly treated material.

In a preferred embodiment, the cellulose or lignocellulose-containing material is treated in a free-fall mixer.

In a second step, the material treated in the first step is dried to ≤ 2% wood moisture. In a preferred embodiment, the second step (b) comprises gradually increasing the temperature to a maximum temperature of 100-150 ° C, preferably 105-140 ° C, such as 110-130 ° C, and most preferably 120 ° C, so that condensation of the aminoalkylsilane takes place. For this purpose, the dryer is heated to the desired temperature in a first stage. In a second stage, the chip temperature is increased to the desired temperature. Upon reaching the chip temperature at the desired temperature, the third stage begins in which the silanes will react while maintaining the temperature at the desired temperature. In a fourth stage, the chip material is cooled and optionally conditioned. The wood moisture can be determined by means of commercially available moisture meters, z. B. the Moisture Analyzer MA 30, Sartorius, Göttingen.

In a third step, the material dried in the second step (b) is glued with a binder.

In a preferred embodiment, preferably, the binder comprises a formaldehyde-containing binder or an isocyanate (pMDI). More preferably, most preferably, the formaldehyde-containing binder comprises an organic resin selected from the group consisting of phenol-formaldehyde resin (PF resin), melamine-urea-phenol-formaldehyde resin (MUPF resin), urea Formaldehyde resin (UF resin), tannin-formaldehyde resin (TF resin), melamine-formaldehyde resin (MF resin), melamine-urea-formaldehyde resin (MUF resin), resorcinol-formaldehyde resin (RF) and phenol-resorcinol-formaldehyde resin (PRF).

In a still more preferred embodiment, preferably, the binder is an isocyanate. In a still more preferred embodiment, preferably, the binder is a formaldehyde-containing binder. In a still more preferred embodiment, preferably, the binder is a phenol-formaldehyde (PF) resin. In a still more preferred embodiment, preferably, the binder is a melamine-urea-phenol-formaldehyde (MUPF) resin. In a still more preferred embodiment, preferably, the binder is a urea-formaldehyde resin (UF resin). In a still more preferred embodiment, preferably, the binder is a tannin-formaldehyde (TF) resin. In a still more preferred embodiment, preferably, the binder is a melamine-formaldehyde resin (MF resin). In a still more preferred embodiment, preferably, the binder is a melamine-urea-formaldehyde (MUF) resin. In a still more preferred embodiment, preferably, the binder is a resorcinol-formaldehyde resin (RF). In a still more preferred embodiment, preferably, the binder is a phenol-resorcinol-formaldehyde resin (PRF).

Suitable methods of treating the dried material with a binder include, for example, brushing, rolling, spraying, dipping, flooding, spraying, blow-line treatment, or treatment in a mixer. The selection of determining reasons for a suitable method, as well as alternative methods are known in the art. Corresponding devices and systems are also known to the person skilled in the art and commercially available. For example, the gluing can be done in a tray mixer, plowshare mixers, blender mixers and after the blowline process. In a preferred embodiment, the gluing takes place in a free-fall mixer. In a particularly preferred embodiment, the first step and the third step comprise treating the material in a tumbler mixer.

In a fourth step, the glued in the third step material is placed in a desired shape and then pressed under heat to form a composite material. For this purpose, the thus treated material to a cake, such as a chip cake or non-woven fabric, spread, combed and at a temperature of up to 250 ° C, preferably 150 to 220 ° C, a pressure to 9 N / mm ² , preferably 4 to 7 N. / mm ² , and a time to 300 s per mm of the desired plate thickness, preferably 5 to 60 s / mm, particularly preferably 8 to 40 s / mm, are pressed. The production of other molded parts, such as extruded or cuboidal parts or more specific moldings, is also possible.

Alternatively, however, the glued material can also initially be pre-compressed or pre-compressed, for example with a prepressing pressure of 0.2 to 0.6 N / mm ² . In addition, you can the glued material, before, during or after the pre-pressing, and thus also. be preheated, for example, to 60 to 80 ° C before the actual pressing. Such a thermal and / or mechanical pretreatment of the cake or the glued material before the actual pressing step may be beneficial to the later quality of the product. In addition, it is advantageous to subject the molded parts obtained during the pressing step to a post-conditioning or tempering, whereby a standardization and homogenization of the composite materials can be achieved. So you can, for example, plates a stack storage. In addition, you can also frequency heating, z. B. by means of microwave technology, perform. Alternatively, the plates can be cooled, for example, for 20 to 30 minutes in a star chiller.

In a further preferred embodiment, the method further comprises adding at least one further constituent in the third step (c), wherein the constituent is selected from the group consisting of a hardener, a wax or paraffin-based hydrophobing agent, a flame retardant, a curing agent , a biocidal substance, dye and / or fragrance.

Preferred hardeners are ammonium sulfate, ammonium nitrate and ammonium chloride. The skilled person, however, also known other hardeners.

In a more preferred embodiment, the process in the third step (c) comprises adding a wax in an amount of up to 4% by weight, preferably 0.05 to 3% by weight, more preferably 0.1 to 2% by weight. %, and most preferably 0.25-1% by weight, based on atrocellulose or lignocellulose-containing material.

In a second aspect, the invention relates to a composite material according to the invention, wherein the formaldehyde release after 24 h incubation time, determined according to the WKI bottle method, EN 717-3 is reduced by at least 15% compared to a comparable composite material whose preparation was not treated with an aminoalkyl silane prior to gluing with a formaldehyde-containing binder.

In a preferred embodiment, the composite is a wood material, preferably a chipboard, fiberboard, ultra-light fiberboard, light fiberboard, medium density fiberboard, high density fiberboard, oriented strand board, veneer board, plywood board, engineered wood product, a press molding, in particular for the automotive interior lining, a technical timber construction material, an insulating material, a wood pellet, a wood briquette or a plant pot is; in particular wherein the composite material does not contain a thermoplastic material.

Examples of an Engineered Wood Product are laminated beach lumber (LSL), veneer stripwood (PSL) and laminated veneer lumber (LVL).

The composite material produced according to the invention preferably has a bulk density of 150 to 1200 kg / m ³ . The determination of the density is carried out according to EN 323 ,

In a preferred embodiment, the composite material produced according to the invention exhibits a thickness swelling after 24 hours of storage in the water according to EN 317 of less than 11%, such as 10.5%, preferably less than 10%, more preferably less than 9%, such as 8.9%, 8.8%, 8.7%, or less than 8.6% ,

Additionally or alternatively, the composite material produced according to the invention has a thickness swelling after 72 hours storage in water of less than 15.5%, less than 15%, preferably less than 14.5%, less than 14%, more preferably less than 13.5%. and most preferably less than 13%.

In another preferred embodiment, the water absorption of the composite according to the invention after 24 hours storage in water is less than 35%, preferably less than 34%, less than 32%, less than 31%, more preferably less than 30%, less than 29% , less than 28%, and most preferably less than 28%, by weight of the composite.

Additionally or alternatively, the water uptake of the composite of this invention after 72 hours storage in water is less than 55%, preferably less than 52%, less than 51%, less than 50%, more preferably less than 49%, less than 48%, less as 47%, and most preferably less than 46%, based on the weight of the composite.

In a further preferred embodiment, the transverse tensile strength of the composite material according to the invention after 2 hours storage in boiling water according to EN 1087 more than 0.35 N / mm ² , preferably more than 0.37 n / mm ² , more than 0.4 N / mm ^2, and most preferably more than 0.45 N / mm ² .

Brief description of the figures

1 shows the formaldehyde release after 3 h incubation time, determined according to the WKI bottle method ( EN 717-3 ) to 1-ply PF adhesive bonded chipboard made from silanized chips.

2 shows the formaldehyde release after 24 h incubation time, determined according to the WKI bottle method ( EN 717-3 ) to 1-ply PF adhesive bonded chipboard made from silanized chips.

Examples

The following examples are intended to further illustrate the invention. However, they should not be construed as limiting the invention.

Production of particleboard from silanized chips

For the production of single-layer chipboards from silanized chips, industrial middle-layer chips were treated with differently concentrated solutions of various silane systems in a commercially available free-fall mixer. A total of 4 different silane systems were used as aqueous solutions in the concentrations 1%, 3% and 5% solid silane. The application to the chips was also carried out with 1%, 3% and 5% solid-silane solution to absolutely dry wood pulp (atro). This was followed by the drying of the chip material and the condensation of the silane systems in a recirculating air dryer from HB Drying Systems, Almelo / Holland. The chips were exposed to a maximum temperature increase of 120 ° C when the temperature was gradually increased. In a first stage, the heating of the dryer was carried out at 120 ° C. The second stage served to increase the chip temperature to 120 ° C. After a chip temperature of 120 ° C was determined by several sensors, the third stage began in which the actual reacting of the silanes was carried out while maintaining the temperature at a constant 120 ° C. The final fourth stage was the cooling and conditioning of the chip material.

• – Plattendicke 16 mm
• – Zielrohdichte: 680 Kg/m³
• – Klebstoff: PF-Klebstoff HW 1842 der Firma Hexion
• – Beleimungsgrad: 8,5% (atro)
• – Hydrophobierungsmittelzugabe: 1% (atro) Hydrowax der Firma Sasol
• – Härterzugabe: 6% (auf Feststoff Klebstoff) Kaliumcarbonat-Lösung (50%ig)
• – Presstemperatur: 220°C
• – Presszeit: 15 s/mm

After the chips were silanized, the chipboards were made. For this purpose, the silanized chips were glued in a commercial freefall mixer with a commercial phenol-formaldehyde adhesive and then pressed into wood-based materials. The most important parameters of chipboard production are listed below:

• - Plate thickness 16 mm
• - Target density: 680 kg / m ³
• - Adhesive: PF adhesive HW 1842 from Hexion
• - Gluing degree: 8.5% (atro)
• Hydrophobizing agent addition: 1% (hydro) Hydrowax from Sasol
• - Hardener addition: 6% (on solid adhesive) potassium carbonate solution (50%)
• - Pressing temperature: 220 ° C
• - Press time: 15 s / mm

Determination of formaldehyde release according to the WKI bottle method ( EN 717-3 The determination of the release of formaldehyde is carried out according to the method of the bottle according to European standard 717-3 , In addition to the incubation time of 3 h proposed in the standard, the test procedure was increased to 24 h in order to be able to demonstrate greater differences between the individual series with regard to the release of formaldehyde.

The formaldehyde release is determined on test specimens of known mass, which were fixed at a constant 40 ° C over water in a closed container. This has the consequence that the formaldehyde emitted by the test specimens during the test period is absorbed by the water. The formaldehyde present in the water is then determined photometrically by the acetylacetone method, as described in Sundin, B. and Roffael, E. (1992). Wood as Raw Material 50 (10): 383-386 , The result is expressed in milligrams of formaldehyde per kilogram of absolutely dry wood pulp.

Results of the formaldehyde tests according to EN 717-3

The formaldehyde release according to the WKI bottle method of the test specimens after 3 h incubation time is in 1 shown. The differences in the formaldehyde release after 3 h incubation from the particle board test specimens in comparison to the test series which was produced without silanized chips can be taken from the following Table 1. Table 1: Change in the formaldehyde release compared to the conventionally prepared test specimens after 3 h incubation in a drying cabinet (in percent). silane silane 1% 3% 5% HS 1151 +16 -32 -79 HS 2627 -5 -22 -31 HS 2776 +38 0 -32 HS 2909 -13 -59 -74

The formaldehyde release according to the WKI bottle method of the test specimens after 24 h incubation time is in 2 shown. The differences in the formaldehyde release after 24 h incubation from the chipboard test specimens in comparison to the test series, which was prepared without silanized chips, is shown in Table 2 below. Table 2: Change in formaldehyde release compared to the conventionally prepared test bodies after 24 h incubation in a drying cabinet (in percent). silane silane 1% 3% 5% HS 1151 -31 -58 -70 HS 2627 -16 -25 -37 HS 2776 -5 -22 -44 HS 2909 -2 -36 -52

Conversion of the formaldehyde release determined by the bottle method after 3 h into the formaldehyde release by the perforator method (EN 120) according to the formula of Sundin / Roffael (1992)

After Sundin / Roffael ( Wood As Raw Material 50 (10): 383-386 (1992) ), the formaldehyde release values correlate EN 717-3 to a large extent with results by means of the perforator method EN 120 were determined. The coefficient of determination for the correlation was given as 92%. The theoretical perforator value is given by the formula: y = 0.467x - 0.5

y

= Formaldehydabgabe nach der Flaschenmethode in mg/l

x

= Formaldehydgehalt nach der Perforatormethode in mg/100 g atro Platte

Where:

y

= Formaldehyde release by the bottle method in mg / l

x

= Formaldehyde content according to the perforator method in mg / 100 g atro plate

After transformation of this equation, it is possible to calculate the theoretical perforator value from the results of the bottle method after 3 h of incubation. The perforator values apply to a material moisture content of 6.5%. For chipboard with different material moisture results after EN 3112: 2003 the final formaldehyde content of the tested sample from a multiplication by a factor (F), which can be calculated as follows: F = -0.113H + 1.86 where (H) is the respective material moisture.

The theoretical formaldehyde contents can be determined by means of the formula of Sunding / Roffael (1992) , supra, using the in 1 calculate the results shown. The theoretical formaldehyde contents, which were determined according to the perforator method with a probability of 92%, are shown in Table 3 below. Table 3: Theoretical release of formaldehyde by the perforator method of the investigated silanized chipboard (mg / 100 g atro plate). silane Silane additive (solid silane on dry material) 0% 1% 3% 5% HS 1151 3.0 3.3 2.4 1.5 HS 2627 3.8 3.6 3.2 2.9 HS 2776 3.0 3.7 3.0 2.4 HS 2909 2.9 2.7 1.9 1.6

Mechanical and hygroscopic properties of chipboard made from amino / alkyl siloxane cooligomer (HS 2909) treated chips

Wood chips were pretreated with an amino / alkyl siloxane cooligomer (HS 2909). The chip drying was carried out with a horizontal batch dryer of the type HTC 140, the company AVA-Huep GmbH and Co. KG, Herrsching. A vacuum pump (about 50 mbar) was generated in the dryer, which led to a reduction in the boiling point of the water. Subsequently, the actual curing of the silane compounds at> 120 ° C. Curing was terminated when the measured chip moisture (for example, as determined by a moisture meter of the company Satorius type MA 30) was ≤ 2%. For the reference sample, untreated chips were used. In addition, for comparison, chipboard was produced from chips in which either 1%, 3% or 5% paraffin emulsion was added in the sub-mixing process of the size liquor, as is customary today in the chipboard industry.

Production parameters at a glance:

• Kauramine glue 534 liquid from BASF AG (MUPF),
• - degree of gluing 15% (solid binder on atro chip),
• Hardener: 4% ammonium sulphate (33% in water [m / m]) (solid hardener on solid binder),
• Pressing temperature 200 ° C for 15 s / mm,
• - 16 mm chipboard (single layer) after 15 mm sanding,

EN 317 is described in Kloeser, L. (2008): Use of organofunctional silanes for the production of wood-based materials. Sierke-Verlag. Goettingen. ISBN: 978-3868440270 ,

EN 1087 is described in Grigoriou A (1997) Bark extractives from Pinus halepensis Mill. Fortified with polymeric diisocyanates for exterior grade particleboards. European Journal of Wood and Wood Products 55 (2): 269 , Table 4: Thickening after 24 h (EN 317) and 72 h storage in water description 24 hours (%) s 72 h (%) s reference 18.1 2.1 19.4 1.9 1% HS 2909 8.4 1.5 15.0 2.0 3% HS 2909 8.0 1.0 13.7 1.3 5% HS 2909 8.6 2.0 12.8 1.3 Table 5: Water absorption after 24 h and 72 h storage in water description 24 hours (%) s 72 h (%) s reference 65.9 7.1 72.0 6.4 1% HS 2909 30.6 3.3 50.8 7.0 3% HS 2909 26.0 3.5 45.4 4.9 5% HS 2909 27.4 2.4 46.1 5.8 Table 6: Transverse tensile strength after storage for 2 h in boiling water (EN 1087) description N / mm ² s reference 0.12 0.03 1% HS 2909 0.46 0.07 3% HS 2909 0.50 0.05 5% HS 2909 0.49 0.11 1% paraffin emulsion 0.21 0.05 3% paraffin emulsion 0.19 0.04 5% paraffin emulsion 0.23 0.05

The data shows that chipboard produced with chips pretreated with HS2909 show reduced thickness swelling and reduced water absorption compared to the reference sample. In addition, the chipboards so produced exhibit increased transverse tensile strength after storage for 2 hours in boiling water against a reference sample and against chipboard made using a paraffin emulsion. It is clear from this that even a conventional paraffin addition to the size liquor, even in very high concentrations, does not lead to the effect, as by a silanization (with only 1% silane) of the chips before gluing and hot pressing.

Bibliography

• DE 10 2006 006 654 A1
• DE 10 2006 006 656 A1
• DE 10 2006 013 090 A1
• WO 2006/094643
• Sundin, B. and Roffael, E. (1992). Wood as Raw Material 50 (10): 383-386 ,
• Kloeser, L. (2008): Use of organofunctional silanes for the production of wood-based materials. Sierke-Verlag. Goettingen. ISBN: 978-3868440270 ,
• Grigoriou A (1997) Bark extractives from Pinus halepensis Mill. Fortified with polymeric diisocyanate for exterior grade particleboards. European Journal of Wood and Wood Products 55 (2): 269 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102006006654 A1 [0004]
• DE 102006006656 A1 [0004]
• DE 102006013090 A1 [0005]
• WO 2006/094643 [0006, 0021]
• DE 102006006654 [0018]
• DE 102006006656 [0018]

Cited non-patent literature

• EN 717-3 [0002]
• EN 317 [0008]
• EN 1087 [0008]
• DIN 53 183 [0028]
• EN 322 [0028]
• EN 717-3 [0042]
• EN 323 [0045]
• EN 317 [0046]
• EN 1087 [0050]
• EN 717-3 [0051]
• EN 717-3 [0052]
• EN 717-3 [0056]
• European standard 717-3 [0056]
• Sundin, B. and Roffael, E. (1992). "Determination of emissions from wood-based panels using the flask method." Wood As Raw Material 50 (10): 383-386 [0057]
• Wood As Raw Material 50 (10): 383-386 (1992) [0060]
• EN 717-3 [0060]
• EN 120 [0060]
• EN 3112: 2003 [0062]
• Sunding / Roffael (1992) [0063]
• EN 317 is described in Kloeser, L. (2008): Use of organofunctional silanes for the production of wood-based materials. Sierke-Verlag. Goettingen. ISBN: 978-3868440270 [0065]
• EN 1087 is described in Grigoriou A (1997) Bark extractives from Pinus halepensis Mill. Fortified with polymeric diisocyanates for exterior grade particleboards. European Journal of Wood and Wood Products 55 (2): 269 [0066]

Claims (15)

A process for producing a composite based on a cellulosic or lignocellulosic material, the process comprising the following steps: (a) treating the cellulosic or lignocellulosic material with a liquid containing an aminoalkylsilane compound; (b) drying the material treated in step (a) to at least 2% wood moisture content; (c) gluing the material dried in step (b) with a binder; and (d) transferring the material treated in step (c) to a desired shape and then heat-pressing it into a composite material. The method of claim 1, wherein the aminoalkylsilane compound is an aminoalkylsilane compound of the formula (I) R ¹ R ² N (CHR ⁴ ) _a Si (R ³ ) _r (OR) _3-r (I), wherein groups R ¹ and R ^{2 are the} same or different and each represents H or a linear, branched or cyclic C ₁ to C ₂₀ alkyl group or an aryl group or an aminocarbyl group, wherein groups R ¹ and R ^{2 may} optionally be substituted groups R ^{4 are the} same or different and R ^{4 is} H or methyl, a is 1 to 10, R ^{3 is} H or a linear or branched C ₁ to C ₈ alkyl group, R is the same or different and R is H or a linear or branched C ₁ to C ₈ alkyl group and r is 0 or 1 or 2; or at least one cocondensate of at least one aminoalkylsilane of the general formula (I) and at least one further functional silane of the general formula (II) R ⁷ (CHR ⁶ ) _b Si (R ⁵ ) _p (OR) _3-p (II) wherein R ^{7 is} H or a vinyl group or an amino group or a glycidoxy group or an acryloxy group or a methacryloxy group or a mercapto group or a Sulfangruppe or a linear or branched C ₁ to C ₂₀ alkyl group or an aryl group, wherein the group R ⁷ optionally substituted R ^{6 is the} same or different and R ^{6 is} H or methyl, b is 0 to 18, R ^{5 is} H or a linear or branched C ₁ to C ₈ alkyl group, Rs are the same or different and R is H or a linear or branched C ₁ to C ₈ alkyl group and p is 0 or 1 or 2, wherein the amino functions in the cocondensate may be partially or completely neutralized with an inorganic or organic acid; or an aqueous solution containing at least one aminoalkylsilane compound of the formula (I) or at least one cocondensate based on at least one aminoalkylsilane of the general formula (I) and at least one further functional silane of the general formula (II). A process according to claim 1 or 2, wherein the aminoalkylsilane compound is an aminoalkyl group selected from 3-aminopropyl, 3-amino-2-methylpropyl, N- (2-aminoethyl) -3-aminopropyl, N- (2-aminoalkyl) -3 amino-2-methylpropyl, N- [N '- (2-aminoethyl) -2-aminoethyl] -3-aminopropyl, N- [N' - (2-aminoethyl) -2-aminoethyl] -3-amino-2 -methylpropyl, N, N- [di (2-aminoethyl)] - 3-aminopropyl, N, N- [di (2-aminoethyl)] - 3-amino-2-methylpropyl, N- (n-butyl) tyl) -3-aminopropyl or N- (n-butyl) 3-amino-2-methylpropyl. The method of claim 1 or 2, wherein the aminoalkylsilane compound comprises an aqueous 3-aminopropylsilane hydrolyzate, an organo-functional siloxane oligomer in water or an amino / alkyl siloxane co-oligomer in water, or a mixture of at least two of these compounds. A method according to claim 1, wherein the aminoalkylsilane compound is an aminoalkylsilane compound of the formula (III) and / or the formula (IV)

wherein R is a divalent Si-C and Si-N bonded, optionally cyano- or halogen-substituted C ₃ -C ₁₅ -hydrocarbon radical in which one or more, non-adjacent methylene units represented by -O-, -CO-, -COO-, -OCO-, or -OCOO-, -S-, or -NR ^x - may be replaced and in which one or more mutually non-adjacent methine units by -N =, -N = N-, or -P = may be replaced , R ^{x is} hydrogen or an optionally halogen-substituted C ₁ -C ₁₀ -hydrocarbon radical, and R ^{2 is} a hydrogen atom or a monovalent, optionally cyano- or halogen-substituted Si-C bonded C ₁ -C ₂₀ -hydrocarbon radical or C ₁ -C ₂₀ -hydrocarbonoxy radical in which in each case one or more, non-adjacent methylene units by -O-, -CO-, -COO-, -OCO-, or -OCOO-, -S-, or -NR ^x - may be replaced and in the one or more, mutually non-adjacent methine units can be replaced by -N =, -N = N-, or -P =, and R ³ is a monovalent C ₁ -C ₂₀ -hydrocarbon radical in which in each case one or more, mutually non-adjacent methylene units by -O-, -CO-, -COO-, -OCO-, or -OCOO-, -S-, or - NR ^x - can be replaced and in which one or more mutually non-adjacent methine units can be replaced by -N =, -N = N-, or -P =. A process according to any one of claims 1-5, wherein the binder is a formaldehyde-containing binder or an isocyanate (pMDI), preferably wherein the formaldehyde-containing binder comprises an organic resin selected from the group consisting of phenol-formaldehyde resin (PFM). Resin), melamine-urea-phenol-formaldehyde resin (MUPF resin), urea-formaldehyde resin (UF resin), tannin-formaldehyde resin (TF resin), melamine-formaldehyde resin (MF resin) and melamine-urea-formaldehyde resin (MUF resin), resorcinol-formaldehyde resin (RF), and phenol-resorcinol-formaldehyde resin (PRF). Process according to any one of claims 1-6, wherein in step (a) 0.05-8% by weight of solid-aminoalkylsilane compound, preferably 0.5-5% by weight based on atrocellulose or lignocellulose-containing material become. The method of any one of claims 1-7, wherein step (a) and / or step (c) comprises treating the material in a tumbler mixer. The method of any one of claims 1-8, wherein the method further comprises adding at least one further ingredient in step (c), wherein the ingredient is selected from the group consisting of a hardener, a wax-based or water-based hydrophobing agent Flame retardant, a curing agent, a biocidal substance, dye and / or a fragrance. The method of claim 9, wherein the method comprises adding a wax in an amount of up to 4% by weight, preferably 0.25-1% by weight, based on atrocellulose or lignocellulose-containing material, in step (c). The method of any one of claims 1-10, wherein step (b) comprises incrementally raising the temperature to a maximum temperature of 100-150 ° C such that condensation of the aminoalkyl silane occurs A method according to any one of claims 1-11, wherein the cellulose or lignocellulosic material is a natural or semi-natural material selected from the group consisting of industrial wood, forest industry wood, recycled wood, wood shavings, wood chips, wood fibers, wood wool, wood dust, shavings, wood pellets, Wood bark, rind, veneer waste, chip, chipboard of annual plants and a mixture of at least two materials thereof. The method of any one of claims 1-12, wherein the cellulosic or lignocellulosic material is derived from hardwood, softwood, palm, perennial, coconut, cotton, flax, hemp, barley, jute, sisal, reed, rice straw, bamboo or cereal straw. A method according to any one of claims 1-13, wherein the composite material. a wood material is, preferably a chipboard, fiberboard, ultra light fiberboard, light fiberboard, medium density fiberboard, high density fiberboard, OSB board, veneer board, plywood board, an engineered wood product, a press molding, especially for automotive interior lining, a technical wood building material, an insulating material Wood pellet, a wood briquette or a plant pot is; in particular wherein the composite material does not contain a thermoplastic material. A composite prepared according to a method of any one of claims 1-14, wherein the formaldehyde release after 24 hours of incubation, determined according to the WKI bottle method, EN 717-3, is at least 15% less than that of a comparable composite thereof before gluing with a formaldehyde-containing binder was treated with an aminoalkylsilane is reduced.

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