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WO2025131799A1 - Promoteur d'adhérence pour espèces de bois difficiles à coller pour construction en bois d'œuvre durable - Google Patents

Promoteur d'adhérence pour espèces de bois difficiles à coller pour construction en bois d'œuvre durable Download PDF

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Publication number
WO2025131799A1
WO2025131799A1 PCT/EP2024/085185 EP2024085185W WO2025131799A1 WO 2025131799 A1 WO2025131799 A1 WO 2025131799A1 EP 2024085185 W EP2024085185 W EP 2024085185W WO 2025131799 A1 WO2025131799 A1 WO 2025131799A1
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WO
WIPO (PCT)
Prior art keywords
primer
adhesive
weight
ether
alkoxylated
Prior art date
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PCT/EP2024/085185
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English (en)
Inventor
Ruben Benedikt RICHRATH
Dominik MISPELKAMP
Anke Lewin
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Evonik Operations GmbH
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Evonik Operations GmbH
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Publication of WO2025131799A1 publication Critical patent/WO2025131799A1/fr
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/72—Polyisocyanates or polyisothiocyanates
    • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
    • C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
    • C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
    • C08G18/7664—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/30—Low-molecular-weight compounds
    • C08G18/302—Water
    • C08G18/307—Atmospheric humidity
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/64—Macromolecular compounds not provided for by groups C08G18/42 - C08G18/63
    • C08G18/6492—Lignin containing materials; Wood resins; Wood tars; Derivatives thereof
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
    • C09J175/04—Polyurethanes

Definitions

  • the invention relates to adhesive systems for lignocellulosic materials consisting of an isocyanate (NCO)- containing adhesive formulation and an adhesion promoter based on alkoxylated fatty acid esters for the pretreatment of the substrate which improves the bonding of difficult-to-bond substrates.
  • NCO isocyanate
  • Prior art Concrete is the most important building material of our times. However, concrete production is an emissions-intensive industrial process that results in significant greenhouse gas emissions. Structural glued laminated timber construction is one solution for avoiding greenhouse gas emissions in the construction sector.
  • Products in structural glued laminated timber construction such as OSB (oriented strand board), CLT (cross-laminated timber), GLT (glulam, glue-laminated timber) and LVL (laminated veneer lumber) consist of wood materials (for example wood lamellas, veneer, shavings, fibres, chemically-modified or infiltrated wood) and adhesives.
  • wood materials for example wood lamellas, veneer, shavings, fibres, chemically-modified or infiltrated wood
  • adhesives are pMDI, PF and MF.
  • Adhesives approved in the EU for load-bearing applications belong to the families of emulsion polymer isocyanate (EPI) adhesives (DIN EN16254 (2016)), phenoplastic and aminoplastic resins (DIN EN 301 (2016)) or polyurethane (PUR) adhesives (DIN EN 15425 (2017)) and must meet high strength requirements.
  • EPI emulsion polymer isocyanate
  • PUR polyurethane
  • Standard 1-component polyurethane adhesives (1K-PUR) do have the advantage that they do not result in formaldehyde emissions during processing, do not require any separate resin-curing agent handling and cure at room temperature within practicable times, however on hardwoods they often do not meet the strength requirements specified in the standards, particularly with respect to the delamination test.
  • This problem with 1K-PUR adhesive formulations is known.
  • One fundamental solution is the use of adhesive systems consisting of a primer (adhesion promoter) and the 1K-PUR adhesive formulation. To this end, the primer is applied to the wood first and only after a primer-specific exposure time is the adhesive formulation applied.
  • HMR primer it is necessary for the HMR primer to be freshly produced and to react prior to application for a defined time, which must be neither undershot nor overshot. In addition, it is based on the toxicologically harmful chemicals formaldehyde and resorcinol, the processing of which requires a high level of safety measures. It is for these reasons that adhesive systems consisting of 1K-PUR and the HMR primer have not been adopted in industry.
  • a structurally similar primer is disclosed in US5888655. This primer is a carbamate-functional novolac resin for aminoplast adhesives, the application of which is however restricted to aminoplast adhesives. US 5888655 does not comprise examples for the application on wood, or in adhesive systems with 1K- PUR.
  • US2009191354 uses primer formulations consisting of a strong inorganic base and polyethylenimine (PEI) which have a pH of at least 11.5 and discloses their use for the bonding of hardwoods of various eucalyptus types.
  • PEI polyethylenimine
  • a tensile strength test that deviates from the above-described standards is described, which is used to show that the PEI primer increases the tensile strength of a 1K-PUR adhesive on various eucalyptus types. No information is however given as to whether this also applies in the wet state. Results of delamination tests, as required in the standards stated above, are not described.
  • a further problem is that the strongly basic nature of the solutions makes the primer unattractive for industrial application.
  • WO03093385 discloses an adhesive system consisting of a 1K-PUR and a primer, where a solution of polyvinyl alcohol, salts of dodecylbenzene sulfonic acid, copolymers based on ethene and vinyl acetate or a urea solution are possible as primer.
  • the described adhesive system however requires that the wood first be planed and then additionally treated with sandpaper so that the standard requirements in the wet state in accordance with Standard ASTM D2559 are met.
  • sandpaper is usually not used in an industrial-scale adhesion process, which is why the described primers are unsuitable for industrial production.
  • the delamination test from ASTM D2559 is also only passed with softwood of longleaf pine. Douglas fir exhibits excessive delamination.
  • Further wood types, particularly hardwoods, have not been tested, however it is to be assumed that many hardwoods cannot be bonded with these adhesive systems, since their standard-compliant 1K-PUR bonding is considered to be more difficult than the bonding of Douglas fir, which was not possible with the described primers.
  • EP2848638 describes adhesive systems containing 1K-PUR and a primer composition, where the primer composition contains polyalkylene glycols and/or the mono- and/or diethers thereof, which have an OH number (OHN) of 30 mg KOH/g or less.
  • the described primer composition may optionally also contain a solvent and/or a surfactant.
  • EP2848638 states that these adhesive systems are particularly suitable for woods with a high proportion of extractives, in particular the extractive arabinogalactan. As wood types that contain a high proportion of arabinogalactan, the patent states almost exclusively softwoods (larch, hemlock, black spruce, Douglas fir, cedar, juniper).
  • a delamination of 5% on eucalyptus, 4% on ash, 8% on beech and 0% on birch is also shown with the primer solution made of 5% Polysorbate 20 and 1% PSA-336. Delaminations of 14% on ash, 5% on beech and 0% on birch were shown with a 0.5% Polysorbate 20 primer solution. On the basis of the results shown, both primer compositions would meet the requirements in the delamination test of Method B of DIN EN 14080 (2013) of at most 4% delamination only for birch, but birch is not considered to be a good construction timber due to its low load-bearing capacity and low durability.
  • the general technical approval Z-9.1-765 of 11.8.2022 also describes the combination of the primer LOCTITE PR 3105 PURBOND ® (as described in EP2928977) with adhesives of the LOCTITE HB SX9 PURBOND ® line, which makes it possible to bond not only softwoods (spruces, fir, pines, Douglas fir) but also European beech in a standard-compliant manner.
  • the adhesive system mentioned made of HB SX9 PURBOND ® and LOCTITE PR 3105 PURBOND ® is however not suitable for the use of larch.
  • the general technical approval specifies the primer PR 7010 based on the polyethers described in EP2848638.
  • a disadvantage of Polysorbate 20-based primers (as described in EP2928977) in aqueous primer compositions is also the hydrolysis behaviour of Polysorbate 20. It is known to those skilled in the art that Polysorbate 20 is hydrolyzed in an aqueous environment (i.e. is split by water). For example, Leiss et al. (European Journal of Pharmaceutics and Biopharmaceutics, 152, 2020, 318 – 326) describe that the hydrolysis of Polysorbate 20 firstly influences the structural integrity of the respective formulation, since the emulsifying property of Polysorbate 20 is lost during hydrolysis.
  • the object is to provide a method for bonding with the adhesive systems according to the invention and the uses thereof.
  • an adhesive system for the production of lignocellulosic composite materials comprising a) a primer composition b) a moisture-curing 1-component polyurethane adhesive composition where the primer composition comprises: - 5-100% by weight of alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function - 0-15% by weight of surfactants - 0-95% by weight of solvent.
  • the object was able to be achieved by the provision of a primer composition based on alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function.
  • primer compositions containing 5-100% by weight, particularly preferably 50-100% by weight, of alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function are suitable as primer concentrate for the applications according to the invention in the adhesive system. It has also been found that in particular primer compositions containing 5-30% by weight of alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function are suitable as applicable primer solution for the applications according to the invention in the adhesive system.
  • the alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function may be produced for example by alkoxylation of castor oil or hydrogenated castor oil. It has surprisingly been found that the use of a 10% by weight aqueous primer solution made of ethoxylated castor oil makes it possible to achieve a very significant improvement of 69-94% in comparison with non-inventive primer compositions in the delamination test on oak. The longitudinal tensile shear strength and compressive shear strength of bonded oak test specimens are also significantly improved by the pretreatment with the primer according to the invention in comparison with the non-inventive examples.
  • the primer is also suitable for the bonding of other difficult-to-bond hardwood species, softwoods and other lignocellulosic materials.
  • the primer compositions according to the invention contain alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function and optionally additional surfactants.
  • the alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function may optionally be assigned to the surfactants; however, in the context of this invention they are intended to describe a separate group, independent of other surfactants.
  • alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-functionrefer to the products of an alkoxylation of (poly)glycerol esters, where the alkoxylated (poly)glycerol esters contain at least one fatty acid that is linked via an ester bond and that does not have a pure alkyl chain (for example stearyl) or alkenyl chain (for example oleyl) but additionally has an alcohol function.
  • fatty acids which comprise at least one OH- and/or ether-functionrefer to the products of an alkoxylation of (poly)glycerol esters, where the alkoxylated (poly)glycerol esters contain at least one fatty acid that is linked via an ester bond and that does not have a pure alkyl chain (for example stearyl) or alkenyl chain (for example oleyl) but additionally has an alcohol function.
  • Examples of such compounds are ethoxylated (poly)glycerol esters of ricinoleic acid, polyricinoleic acid, lesquerolic acid, 12-hydroxystearic acid, aleuritic acid, avenoleic acid, isanolic acid, myrmicacin or juniperic acid. Further such compounds may be obtained for example by the alkoxylation of (poly)glycerol esters of unsaturated fatty acids which have been derivatized by ozonolysis, epoxidation and/or hydroformylation and subsequent functionalization with alcohol functions.
  • each of the R 2 radicals having the formula may independently conform to either the formula or the formula
  • [CR 4 2CR 4 2O] is not selected from the group consisting of [CH2CH2O], [CH(CH3)CH2O] and [CH2CH(CH3)O]. It is thus preferable that [CR 4 2CR 4 2O] is different from [CH2CH2O], [CH(CH3)CH2O] and [CH2CH(CH3)O].
  • the number y of covalently directly bonded structural units [R 2 -R 3 ] in a chain of repeating structural units having the formula [R 2 -R 3 ]y is 1 - 10, particularly preferably 0 - 2. It is additionally preferable that the number z of covalently directly bonded structural units [R 3 -R 3 ] in a chain of repeating structural units having the formula [R 3 -R 3 ]z is 1 - 50, particularly preferably 0 - 1. It is also preferable that alkoxylated (poly)glycerol esters containing at least one OH- and/or ether- functional fatty acid component according to the invention contain 750 or fewer carbon atoms per molecule.
  • the indices indicate the amounts of the individual repeating units in the theoretical molecule number-averaged across the polymer distribution. In the individual molecules actually present, the specified repeating units may be present within the polymer distribution in blocks, in random order or in another order.
  • alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function are preferably selected from the group of the ethoxylated fatty acid glycerol esters, 202300221
  • Foreign Filings 9 particularly preferably from the group of the ethoxylated castor oils or ethoxylated hydrogenated castor oils.
  • Example structures for alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function according to the invention, which conform to the general formula (I), and possible sources for their precursors are shown below:
  • primers according to the invention based on alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function have a better hydrolysis behaviour than Polysorbate 20. Even if a part of the primers according to the invention is hydrolyzed, the resulting hydrolysis products still have surface activity and exhibit a better solubility than the alkanecarboxylic acids formed in the hydrolysis of Polysorbate 20, which means that disruptive precipitates are not formed.
  • Surfactants The primers according to the invention contain 0-15% by weight from the group of water-soluble surfactants, water-dispersible surfactants and mixtures thereof.
  • Preferred surfactants are organically modified siloxanes, acetylenediol derivatives, alkoxylated fatty alcohols, sulfosuccinates, alkylpolyglycosides and biosurfactants such as RHEANCE ® One.
  • Moisture-curing 1-component polyurethane adhesive composition The NCO-containing adhesive formulations for the bonding of lignocellulosic materials in each case have an NCO content of 1-32% by weight, which was measured in accordance with DIN EN ISO 11909 (2007).
  • the main component of the NCO-containing adhesive formulations is either polymeric methylene diphenyl diisocyanate (pMDI) or an isocyanate prepolymer consisting of at least one diisocyanate, for example one or more isomers of methylene diphenyl diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated methylene diphenyl diisocyanate and/or a higher isocyanate, for example pMDI or trimers, oligomers or homopolymers of the aforementioned diisocyanates and/or mixtures thereof comprising two or more of said isocyanates and at least one isocyanate-reactive substance used in a substoichiometric amount, usually an alcohol compound and/or amine compound, often in the form of polymers, i.e.
  • pMDI polymeric methylene diphenyl diisocyanate
  • the moisture-curing 1-component polyurethane adhesive compositions are characterized in that - they contain prepolymers which are formed by reaction of polyether polyols and aromatic isocyanates having two or more NCO functionalities and - they have an NCO content of 1-28% by weight, preferably an NCO content of 1-20% by weight, particularly preferably an NCO content of 10-20% by weight.
  • 1-component polyurethane adhesive compositions are characterized in that they contain polymeric diphenylmethane diisocyanate (pMDI) as main component and have an NCO content of 28 – 32% by weight.
  • NCO-containing adhesive formulations may contain further additives or/and auxiliaries.
  • aqueous primer compositions in the application amount of 1-500 g/m 2 , preferably 5-100 g/m 2 , particularly preferably 10-50 g/m 2 , based on the surface materials and/or boards (for example lamellas) and/or finger joints to be bonded.
  • surface materials and/or boards for example lamellas
  • finger joints for example lamellas
  • lignocellulosic fibres and particles for example wood chips
  • Method steps c) and e) may optionally also be performed simultaneously by means of two separate application systems.
  • an aqueous primer composition is produced by addition of water to a primer composition according to the invention.
  • the primer composition may contain 5-100% by weight of alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether- function.
  • the content of alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function may alternatively be 50-100% by weight or 5-30% by weight. Depending on the concentration of this component, it is possible to produce an applicable primer composition by the addition of water.
  • step e it is possible to use 1-component polyurethane adhesive amounts of 90-350 g/m 2 , preferably 120-250 g/m 2 , particularly preferably 140-200 g/m 2 , based on the surface materials and/or boards (for example lamellas) and/or finger joints to be bonded.
  • surface materials and/or boards for example lamellas
  • finger joints for example lamellas
  • lignocellulosic fibres and particles for example wood chips
  • Method steps c) and e) may be performed by spraying, knife coating, dipping, brushing, passing through a primer or adhesive curtain or application using nozzles or cartridges.
  • Method steps d), g) and h) may optionally be carried out at elevated temperature, and step g) also at elevated pressure, in order to achieve a fast-curing and firm adhesive join.
  • a pressure of 0.4-2 N/mm 2 preferably 0.6-1.4 N/mm 2
  • a pressure of 5-15 N/mm 2 preferably 7.5-10 N/mm 2
  • a temperature of 0-210°C, preferably 15-40°C may be used, for example by means of a heated ambient atmosphere or temperature-controlled presses.
  • Bonded lignocellulosic materials are used in various application markets, for example in furniture construction, in structural glued laminated timber construction, in vehicles, in boat construction, in parquet and facades. It has been found that the adhesive systems according to the invention are also suitable for the bonding of lignocellulosic materials with other materials, for example metal, plastics, in particular with foam materials, ceramics and glass. Examples All stated percentages relating to the compositions or formulations refer to % by weight based on the total weight of the respective composition, unless expressly stated otherwise.
  • test specimens The bonded lignocellulosic materials made of hardwood were produced in accordance with Standards DIN EN 14080 (2013) and DIN EN 302-1 (2017). Unsteamed beech and oak wood boards were used, these having a standard-compliant bulk density, wood moisture content, length, thickness and width. Creation of the test specimens for the longitudinal tensile shear tests: The 130 x 150 x 5 mm boards were placed in a climatic chamber at a temperature of 18-22°C and a relative humidity of 60-70% for at least one week. For the production of in each case up to 5 wood test specimens, two boards were bonded.
  • the boards were first pretreated using an airbrush application system with the specified amount of the primer solution or, for the reference, with the same amount of water. In the case of non-primed references, this step was skipped.
  • the specified amount of the 1K-PUR adhesive composition was applied and the wood boards were placed one on top of the other and lightly pressed. This was followed by compression using a hydraulic press at various pressing pressures and pressing times at room temperature of 20-30°C, after which the bonded materials were stored for 7-14 days under normal climatic conditions.
  • the test specimens were cut to size using a CNC router, by making two offset cuts at right angles to the wood fibre in accordance with the standard.
  • Miscanthus giganteus The raw material used for the production of a board material and subsequent rod-shaped test specimens made of Miscanthus (Miscanthus giganteus) was Miscanthus stem pieces produced from 160 mm-long Miscanthus stems which were split into four in the longitudinal direction and from which the parenchyma was removed.
  • the Miscanthus stem pieces were placed in a climatic chamber at a temperature of 18-22°C and a relative humidity of 60-70% for at least one week.
  • 60 g of Miscanthus stem pieces was used for the production of in each case.
  • the Miscanthus stem pieces were first sprayed using an airbrush application system with 0.5 g of the primer solution. In the case of the production of test specimens for the non-inventive reference without primer, this step was skipped.
  • the press mask needed for the pressing and the press punch were treated before the pressing with a suitable release agent in order to prevent adhesion thereto. After an exposure time of the primer of 10 min, the Miscanthus stem pieces were placed parallel to one another in the press mask and 6.6 g of the pMDI adhesive was applied between the layers. The press punch was applied at the end.
  • the samples were first boiled in water for 6 hours and then, in a departure from the standard, immersed in cold water overnight instead of just for two hours, and measured wet in the longitudinal tensile shear test.
  • Procedure for the longitudinal tensile shear test The test specimens were clamped parallel to the direction of stress in the clamping jaws of the tensile testing machine at a distance of 90 mm and tested with the increase in load of 2.0 [ ⁇ 0.5] kN/min specified in Standard DIN 302-1 (2017). The test was judged to have ended when the test specimen 202300221 Foreign Filings 17 fractured.
  • the specified longitudinal tensile shear strength is the mean value of the determined longitudinal tensile shear strengths of the tested test specimens.
  • Test specimens that were significantly twisted and were not able to be clamped in the jaws without generating a substantial stress in the adhesive join at right angles to the fibre direction were not included in the calculation of the mean value. Such test specimens often already delaminate before the longitudinal tensile shear test while being clamped in the clamping jaws.
  • Determination of wood tear-out After carrying out the longitudinal tensile shear test, the wood tear-out is determined in each case by analysing the two test specimen fragments using a Keyence VR-5000 optical 3D profilometer. In this test, raised areas or depressions respectively higher or deeper than 0.1 mm are considered to be wood tear- out. The wood tear-out after carrying out the compressive strength test is determined using microscopy.
  • the specified wood tear-outs are each mean values of all wood tear-outs of the respective test specimens.
  • Procedure for the compressive shear tests For the compressive shear tests, in each case five test specimens with a width of 50 mm and a thickness of 40 mm of both sides were taken from the glue-laminated timber in accordance with the description in DIN EN 14080 (2013) Appendix D. The compressive shear tests were then carried out according to the method described in DIN 52187 (1979). The specified compressive shear strength is the mean value of the 10 test specimens. Determination of bending modulus of elasticity: The Miscanthus material test specimens were placed on the support rollers of the test machine with a spacing of 100 mm and were tested in accordance with Standard DIN EN 310 (1993).
  • test was ended after at the latest 6% deformation or after the sample had fractured.
  • the specified modulus of elasticity is the mean value of the determined moduli of elasticity of the tested test specimens.
  • Procedure for the delamination tests For the delamination tests, in each case three test specimens were sawn from the glue-laminated timber (left, middle and right) and subjected to one or two (Example 10) test cycles in accordance with DIN EN 14080 (2013) Annex C Method B. These consist of a watering phase (30 min, 15-30 kPa reduced pressure, 120 min 600 – 700 kPa elevated pressure) and a drying phase (several hours at 70 ⁇ 5°C and a relative humidity of 9 ⁇ 1% with an air flow of 2.5 ⁇ 0.5 m/s).
  • Beech wood conditioned to a wood moisture content of 12% was placed into a climatic chamber and a droplet of 10 ⁇ l of the primer solution or water (reference) was applied using a cannula. The time needed for the droplet to completely infiltrate into the wood was then measured. The specified measured values are average values of in each case 3 contact angle measurements.
  • Materials The 1-component polyurethane adhesive compositions used are commercially available. LOCTITE ® HB S309 PURBOND from Henkel AG & Co.
  • the prior art includes various documents in which alcohols, carboxylic acids or esters are used as starter compounds for the alkoxylation reaction.
  • a good overview of polyoxyalkylenes and processes for preparing polyoxyalkylenes is given for example by "N. Schönfeldt, Surface Active Ethylene Oxide Adducts, Pergamon Press, 1969".
  • the alkoxylated compounds used in the context of this invention if they were not acquired commercially, were prepared according to the following method: In the first step, a starter compound is reacted using a catalyst with epoxides, for example ethylene oxide or propylene oxide or any desired mixtures of these epoxides.
  • the reaction temperature in the first step is preferably 80°C to 220°C, particularly preferably 100°C to 180°C.
  • the pressure in the first step is preferably 0.5 bar to 20 bar, preferably 1.0 bar to 12 bar (absolute).
  • the epoxy monomers may be used in pure or mixed form, such that homopolymers or random copolymers are obtained.
  • further monomer may be metered in, such that block structures are obtained.
  • a further epoxide can also be metered continuously over time into an epoxide already present in the reaction mixture, so as to give rise 202300221 Foreign Filings 19 to an increasing concentration gradient of the epoxide added continuously.
  • the correlations between metered addition and product structure are known to those skilled in the art.
  • the end of the epoxide addition is typically followed by a period of further reaction to allow the reaction to proceed to completion.
  • the further reaction can for example be carried out by continued reaction under reaction conditions (i.e. maintenance for example of the temperature and of the pressure) without addition of reactants.
  • the further reaction is effected with mixing of the reaction mixture, especially with stirring.
  • residual monomers are removed in a vacuum distillation and, if required, the reaction product is neutralized with an acid such as lactic acid, acetic acid, propionic acid or phosphoric acid, and the salts formed are optionally removed by filtration.
  • Example 2 shows that, in comparison to the use of water as primer, the primers according to the invention accelerate the curing reaction in such a way that the press bonding can be carried out at low pressing pressures in only 75 min.
  • the tests that follow are carried out at an increased pressing pressure of 1.28 N/mm2.
  • Example 3 Penetration time Substrate: Beech wood (Fagus sylvatica) Primer Penetration time [min:s] Only water 1:55 Primer A 0:27 An important property of a primer is to penetrate into the wood within a short time in order to not delay the subsequent adhesive application and further subsequent steps for long. A short penetration time ensures that the wood workpieces require only brief intermediate storage, if any.
  • Example 3 shows that primers according to the invention, such as Primer A, significantly reduce the penetration time in comparison with the exclusive use of water as primer.
  • Example 4 shows that such a broad substance class definition primarily includes compounds that are only poorly suitable, if at all, as primers, and that primers according to the invention are superior to the structures from the broad substance class definition in their effect as primers in terms of the adhesive join strength. It is also shown that primers according to the invention are superior to polyethers with OHN ⁇ 30 from EP2848638B1 and salts of dodecylbenzene sulfonic acid from WO03093385A2.
  • Example 5 Longitudinal tensile shear test in accordance with DIN EN 302-1 (2017) A4 of non-inventive primers in comparison with Primers B and C according to the invention
  • Substrate Beech wood (Fagus sylvatica) Primer: 20 g/m 2
  • Adhesive 200 g/m 2
  • Primer Compound class Longitudinal Wood tear- Number of composition tensile shear out test strength [N/mm 2 ] specimens
  • Primer B According to the 7.5 38% 5 invention: alkoxylated (poly)glycerol ester containing at least one OH- and/or ether- functional fatty acid component
  • Primer C According to the 7.0 57% 5 invention: alkoxylated (poly)glycerol ester containing at least one OH- and/or ether- functional fatty acid component POE(34)
  • a non-inventive primer based on an alkoxylated glycerol ester which prepared from fatty acids which does not comprise an OH- and/or ether- function gives worse longitudinal tensile shear results.
  • Example 6 Compatibility of alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function with other surfactants as primer Substrate: Beech wood (Fagus sylvatica) Primer: 20 g/m 2 Adhesive: 200 g/m 2 LOCTITE PURBOND ® HB S309 Pressing pressure: 1.28 N/mm2 Pressing time: 75 min Primer Longitudinal tensile shear Wood tear-out Number of composition strength [N/mm 2 ] test specimens Primer D 8.1 71% 10 Primer E 8.1 60% 10
  • Example Table 6 shows that alkoxylated (poly)glycerol esters prepared from fatty acids which comprise at least one OH- and/or ether-function according to the invention can be combined with further surfactants in order to additionally increase the tensile strength.
  • Example 7 Longitudinal tensile shear test in accordance with DIN EN 302-1 (2017) A4 on difficult-to-bond oak wood Substrate: Oak wood (Quercus robur) Primer: 20 g/m 2 Adhesive: 200 g/m 2 LOCTITE PURBOND ® HB S309 Pressing pressure: 1.28 N/mm2 Pressing time: 75 min Primer composition Longitudinal tensile shear Number of strength [N/mm 2 ] test specimens Primer A 7.2 10 LOCTITE PR 3105 5.7 10 PURBOND ® (as a 10% aqueous solution) In comparison with LOCTITE PR 3105 PURBOND ® (10% aqueous solution), which is suitable according to the general technical approval No.
  • Primer A according to invention has the advantage that it produces good 202300221 Foreign Filings 25 longitudinal tensile shear strengths not only on beech, but also on other difficult-to-bond hardwood species, such as the ring-porous species oak.
  • Example 8 Delamination test in accordance with DIN EN 14080 (2013) Method B with oak and beech Substrate: Oak wood (Quercus robur) and beech wood (Fagus sylvatica) Primer: 20 g/m 2 Adhesive: 200 g/m 2 LOCTITE PURBOND ® HB S309 Pressing pressure: 1.2 N/mm2 Pressing time: 150 min Primer composition Mean value of the delaminations of all adhesive joins Oak wood Beech wood Non-inventive: 99% 78% 0% primer, only water Non-inventive: 99% 59% SURFYNOL ® AS 5040 Non-inventive: 74% 0.1% LOCTITE PR 3105 PURBOND ® (as a 10% aqueous solution) Inventive: 4.8% 0.0% Primer A Example Table 8 shows that Primer A according to the invention, unlike the non-inventive primer compositions, is capable of bonding oak without most of the adhesive joins coming apart in the delamination test
  • Example 9 Delamination test in accordance with DIN EN 14080 (2013) Method B with oak Substrate: Oak wood (Quercus robur) Primer: 20 g/m 2 Adhesive: 200 g/m 2 LOCTITE PURBOND ® HB S309 Pressing time: 150 min Primer composition Pressing Mean value of the Delamination in pressure delaminations of all the adhesive adhesive joins join with the greatest extent of delamination Primer A 1.0 N/mm2 3.7% 22% Primer F 1.2 N/mm2 0% 0% 202300221 Foreign Filings 26 Primer G 1.2 N/mm2 1.9% 16% Primer H 1.2 N/mm2 0.9% 11% Example Table 9 shows that with the primers according to the invention, it was possible for the first time to achieve the maximum delamination value specified in DIN EN 14080 (2013) for Method B of 4% (mean value of the delamination of all adhesive joins) and the maximum delamination value of a single adhesive join of 30% for the bonding of oak with a 1-com
  • the adhesive system according to the invention thus also satisfies the requirements of the American standard for glue- laminated timber ANSI/APA PRG 320-2019, which specifies 5% as the maximum delamination. Since oak is considered to be one of the most difficult-to-bond hardwoods, it can be assumed that the adhesive systems according to the invention containing 1-component polyurethane adhesive compositions, unlike other 1-component polyurethane adhesive systems, are also suitable for most other hardwoods in addition to oak and beech.
  • Example 10 Delamination test with two test cycles in accordance with DIN EN 14080 (2013) Method B with oak Substrate: Oak wood (Quercus robur) Primer: 20 g/m 2 Adhesive: 200 g/m 2 LOCTITE PURBOND ® HB S309 Pressing time: 150 min Primer composition Mean value of the Delamination in the delaminations of all adhesive join with adhesive joins the greatest extent after two test cycles of delamination after two test cycles Primer F 0.1% 2% In accordance with DIN EN 14080 (2013), two of the three Primer F-treated test specimens from the delamination test from Example Table 9 were sent to a second test cycle, in which the delamination barely increased and standard-compliant results were still obtained.
  • Example 11 Compressive shear test in accordance with DIN EN 14080 (2013) on bonded oak and beech test specimens Substrate: Oak wood (Quercus robur) and beech wood (Fagus sylvatica) Primer: 20 g/m 2 Adhesive: 200 g/m 2 LOCTITE PURBOND ® HB S309 Pressing pressure: 1.2 N/mm2 Pressing time: 150 min 202300221 Foreign Filings 27 Primer composition Compressive shear strength [N/mm 2 ] Oak wood Beech wood Non-inventive: 12.6 15.3 0% primer, only water Non-inventive: 12.4 17.3 LOCTITE PR 3105 PURBOND ® (10% aqueous solution) Non-inventive: 12.1 16.8 SURFYNOL ® AS 5040 (1% aqueous solution) Inventive: 14.8 18.0 Primer A Inventive: 16.4 not measured Primer F Inventive: 16.3 not measured Primer G Inventive: 17.2 not
  • Example 12 Longitudinal tensile shear test in accordance with DIN EN 302-1 (2017) A4 with oak wood test specimens with a further 1K-PUR adhesive in conjunction with Primer A according to the invention
  • the longitudinal tensile shear tests of a further commercially available 1K-PUR adhesive in combination with Primer A according to the invention show that the primer compositions according to the invention are suitable not only for a specific adhesive quality, but in general for moisture-curing 1K-PUR adhesives.
  • Example 13 Three-point bending test for determining the bending modulus of elasticity on test specimens made of a Miscanthus material in accordance with DIN EN 310 (1993) in conjunction with Primer A according to the invention
  • Substrate Miscanthus (Miscanthus giganteus)
  • Primer 0.5 g on 60 g of Miscanthus stem pieces
  • Adhesive 6.6 g of pMDI on 60 g of Miscanthus stem pieces
  • Pressing pressure 1.2 N/mm2 Pressing time and temperature: 120 min at 90°C
  • Primer composition Mean value of the modulus of Number of test elasticity [N/mm 2 ] specimens

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Adhesives Or Adhesive Processes (AREA)

Abstract

L'invention concerne des systèmes adhésifs pour matériaux lignocellulosiques comprenant a) une composition d'apprêt b) une composition adhésive de polyuréthane à 1 composant.
PCT/EP2024/085185 2023-12-19 2024-12-09 Promoteur d'adhérence pour espèces de bois difficiles à coller pour construction en bois d'œuvre durable Pending WO2025131799A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP23217813 2023-12-19
EP23217813.7 2023-12-19

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WO2025131799A1 true WO2025131799A1 (fr) 2025-06-26

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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5543487A (en) 1994-01-19 1996-08-06 The United States Of America As Represented By The Secretary Of Agriculture Hydroxymethylated resorcinol coupling agent and method for bonding wood
US5888655A (en) 1997-06-30 1999-03-30 Basf Corporation Primer coating compositions containing carbamate-functional novolac resins
US6133398A (en) 1996-01-11 2000-10-17 The Dow Chemical Company One-part curable polyurethane adhesive
WO2002048232A1 (fr) 2000-12-14 2002-06-20 Bayer Aktiengesellschaft Adhesifs pour bois a base de prepolymeres a terminaison isocyanate
WO2003093385A2 (fr) 2002-05-03 2003-11-13 Huntsman International Llc Composites lignocellulosiques, systemes adhesifs et procede associe
EP1425328A1 (fr) 2001-08-16 2004-06-09 Henkel Kommanditgesellschaft auf Aktien Colle polyurethane 1 k a prise rapide
US20090191354A1 (en) 2006-02-20 2009-07-30 Commonwealth Scientific And Industrial Research Organisation Method and Composition for Priming Wood and Natural Fibres
EP2848638A1 (fr) 2013-09-11 2015-03-18 Purbond AG Système adhésif pour substrats lignocellulosiques présentant des niveaux élevés de matières extractives
EP2928977A1 (fr) 2012-12-04 2015-10-14 Henkel AG & Co. KGaA Système adhésif permettant de préparer des composites lignocellulosiques
WO2023069254A1 (fr) * 2021-10-21 2023-04-27 Arkema France Composition adhésives durcissables à l'humidité

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5543487A (en) 1994-01-19 1996-08-06 The United States Of America As Represented By The Secretary Of Agriculture Hydroxymethylated resorcinol coupling agent and method for bonding wood
US6133398A (en) 1996-01-11 2000-10-17 The Dow Chemical Company One-part curable polyurethane adhesive
US5888655A (en) 1997-06-30 1999-03-30 Basf Corporation Primer coating compositions containing carbamate-functional novolac resins
WO2002048232A1 (fr) 2000-12-14 2002-06-20 Bayer Aktiengesellschaft Adhesifs pour bois a base de prepolymeres a terminaison isocyanate
EP1425328A1 (fr) 2001-08-16 2004-06-09 Henkel Kommanditgesellschaft auf Aktien Colle polyurethane 1 k a prise rapide
WO2003093385A2 (fr) 2002-05-03 2003-11-13 Huntsman International Llc Composites lignocellulosiques, systemes adhesifs et procede associe
US20090191354A1 (en) 2006-02-20 2009-07-30 Commonwealth Scientific And Industrial Research Organisation Method and Composition for Priming Wood and Natural Fibres
EP2928977A1 (fr) 2012-12-04 2015-10-14 Henkel AG & Co. KGaA Système adhésif permettant de préparer des composites lignocellulosiques
EP2848638A1 (fr) 2013-09-11 2015-03-18 Purbond AG Système adhésif pour substrats lignocellulosiques présentant des niveaux élevés de matières extractives
EP2848638B1 (fr) 2013-09-11 2020-04-08 Henkel AG & Co. KGaA Système adhésif pour substrats lignocellulosiques présentant des niveaux élevés de matières extractives
WO2023069254A1 (fr) * 2021-10-21 2023-04-27 Arkema France Composition adhésives durcissables à l'humidité

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
LEISS, EUROPEAN JOURNAL OF PHARMACEUTICS AND BIOPHARMACEUTICS, vol. 152, 2020, pages 318 - 326
N. SCHÖNFELDT: "Surface Active Ethylene Oxide Adducts", 1969, PERGAMON PRESS
RICHTER ET AL., INTERNATIONAL JOURNAL OF ADHESION AND ADHESIVES, vol. 113, 2022, pages 103070

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