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WO2024218102A1 - Modification de polymères aromatiques - Google Patents

Modification de polymères aromatiques Download PDF

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Publication number
WO2024218102A1
WO2024218102A1 PCT/EP2024/060323 EP2024060323W WO2024218102A1 WO 2024218102 A1 WO2024218102 A1 WO 2024218102A1 EP 2024060323 W EP2024060323 W EP 2024060323W WO 2024218102 A1 WO2024218102 A1 WO 2024218102A1
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Prior art keywords
groups
acid
group
aromatic
carbon atoms
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Inventor
Christopher KNIE
Johannes Georg Winter
Jan Ole STRÜVEN
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Prefere Resins Holding GmbH
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Prefere Resins Holding GmbH
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Priority claimed from EP23168152.9A external-priority patent/EP4450530A1/fr
Application filed by Prefere Resins Holding GmbH filed Critical Prefere Resins Holding GmbH
Publication of WO2024218102A1 publication Critical patent/WO2024218102A1/fr
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    • 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
    • C08G8/00—Condensation polymers of aldehydes or ketones with phenols only
    • C08G8/28—Chemically modified polycondensates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08H—DERIVATIVES OF NATURAL MACROMOLECULAR COMPOUNDS
    • C08H6/00—Macromolecular compounds derived from lignin, e.g. tannins, humic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
    • C08J7/12—Chemical modification
    • 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
    • C08L97/005—Lignin
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D197/00—Coating compositions based on lignin-containing materials
    • C09D197/005—Lignin
    • 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
    • C09J161/00—Adhesives based on condensation polymers of aldehydes or ketones; Adhesives based on derivatives of such polymers
    • C09J161/34—Condensation polymers of aldehydes or ketones with monomers covered by at least two of the groups C09J161/04, C09J161/18 and C09J161/20

Definitions

  • This invention is directed to method for modification of articles or bodies made from aromatic polymers K by treatment thereof with non-polymeric aromatic diazonium compounds B via azo coupling to obtain a modified article or body M.
  • the invention is also directed to such modified articles or bodies M. It is also directed to methods of use of modified articles or bodies M.
  • Aromatic diazonium compounds also referred to simply as “diazonium compounds” in the context of this invention, have been commercially used in the preparation of azo dyes where the so-called “azo coupling” occurs, i. e., an electrophilic substitution reaction of an aromatic diazonium compound with a nucleophilic molecule, usually an aromatic compound that preferably has an increased electron density at carbon atoms of its aromatic ring compared to an unsubstituted aromatic molecule, due to electron-donating substituents (also referred to as "activating groups”which replace a hydrogen atom connected to a carbon atom which is a part of the aromatic system, such as hydroxyl groups, amino groups, alkoxy groups, alkylamino groups, dialkylamino groups, and alkyl groups.
  • azo coupling i. e., an electrophilic substitution reaction of an aromatic diazonium compound with a nucleophilic molecule
  • an aromatic compound that preferably has an increased electron density at carbon atoms of its
  • the nucleophilic molecules are therefore preferably phenols, aminophenols, alkoxy aromatics, (di)alkylamino- aromatics, and alkylaromatics, and particularly preferred, alkyl phenols and alkoxy phenols. This effect has been described in detail, e. g., in Peter Sykes "Restrokesmechanismen in der organischen Chemie", 3rd edition, Weinheim 1967, pages 131 to 135, and Peter Sykes, "Guidebook to Mechanism in Organic Chemistry", 6th edition New York 1985.
  • Electron- withdrawing groups as substituents in an aromatic compound such as -NO 2 , -SO 3 H, -C(H)O, -COOH, -CN are also referred to as "deactivating groups", and lead to slower reaction rates, due to the lower electron density in comparison to the unsubstituted aromatic compound.
  • deactivating groups The change in electron density at the carbon atoms in ortho-, meta-, or para-position to the substituent in an aromatic compound, e.
  • a process of modifying a hydrocarbon polymer has been dis- closed which comprises heating said hydrocarbon polymer in admixture with a polymer of a poly(diazo) compound selected from the group consisting of , and where x is an integer of from 2 to 4, R is an organic group inert to -modifications, A is an aromatic group inert to modifications, R' is selected from the group consisting of H, alkyl, aryl, and C(O)OZ groups, where Z is an alkyl or aryl group, and R" is selected from the group consisting of H, alkyl and aryl radicals, said heating being at the decomposition temperature of said poly(diazo) compound whereby chemical bonding is effected between the polymer molecules.
  • a poly(diazo) compound selected from the group consisting of , and where x is an integer of from 2 to 4
  • R is an organic group inert to -modifications
  • A is an aromatic group inert to modifications
  • R'
  • poly(diazo) compounds examples include the bis(diazoacetate) ester of 1,6-hexanediol, the bis (diazoacetate) ester of 1,10-decanediol, the tetra (diazoacetate) ester of pentaerythritol, and the bis(diazoacetate) ester of diethylene glycol.
  • the poly(diazo) compounds react by eliminating nitrogen, leaving a carbene group at each end of the molecule. These free carbene groups then react with the hydrocarbon polymer and act as crosslinkers.
  • polymeric azo dyes are described which are prepared in a three- step process (see paragraphs 3 and 4 in page one, starting with the words "It has been found ", and "By the practice "), where in the first step, a novolac polymer is prepared from phenol and an aldehyde or ketone; in the second step, this novolac polymer (referred to herein as the "resin progenitor” in paragraph 3 of page one) is coupled with a diazonium salt to provide an "intermediate polymer"; and in the third step, "this intermediate polymer is then caused to crosslink with itself or other reactive polymers so that the cured polymer is itself a dye rather than a mechanical mixture with a dispersed conventional dye".
  • a novolac polymer is prepared from phenol and an aldehyde or ketone
  • this novolac polymer referred to herein as the "resin progenitor” in paragraph 3 of page one
  • this intermediate polymer is then caused to crosslink
  • coloured resinous materials [are] useful as components of inks, solid bodies and coating compositions", see paragraph 1 of page 1. No reaction of a diazonium salt with a surface of a pre-formed polymer is disclosed which does not require a subsequent crosslinking reaction.
  • the coating is prepared from a solution of the polymer together with solvents, dyes, slip and anti-crater additives, see page 43, "Preparation of the Coating", lines 7 et seq., the polymer is distributed homogeneously on the support. No reaction of a diazonium salt with a surface of a pre-formed polymer is disclosed.
  • a hydroponic growth medium which comprises a hemp fiber biocomposite comprising lignin-containing hemp fibers crosslinked by a polymer. See claim 1 on page 23 of the '483 document.
  • a diazonium salt formed in step (a) from an aromatic amine having a protected vinyl sulfone group is coupled in step (b) to a lignin molecule of a lignin-containing plant fibre, and the vinyl sulfone functionalised fibre is deprotected in step (c) under basic conditions in the presence of a polymer, thus forming a crosslinked product.
  • Biocomposites are formed, according to paragraph [0006], which comprise lignin- containing plant fibres (such as hemp fibres) which are crosslinked by one or more polymers, e. g. polyvinyl alcohol (PVA).
  • PVA polyvinyl alcohol
  • the polymers mentioned in the ’483 document additionally include pectin (see paragraph [0006] in page 1, right-hand column, fourth line from the top), and "any appropriate polymer” (paragraph [0056], lines 4 and 5), which may be "a molecule of repeating structural units ... formed via a chemical reaction, i. e.
  • polymerisation may, in some cases be a water-soluble polymer, a natural or synthetic polymer, a biodegradable polymer, or a biocompatible polymer, which can include one or more hydroxyl groups (see paragraph [0056], lines 7 to 12. Examples include PVA, pectin, starch, cellulose, and any combinations thereof, see lines 15 and 16 of paragraph [0056].
  • the crosslinking reaction is obviously a reaction between the vinylsulfone group bound to the aryl part of the "bifunctional linker" and the hydroxyl groups of the polymer under basic conditions which leads to the formation of a sulfonic ester group which binds to the lignin molecule via an azobenzene structure, and vinyl alcohol which is immediately converted to acetaldehyde. No reactive group is then left on the lignin part of the crosslinked plant fibre. Therefore, no functional group is left on the surface of a plant fibre after a treatment according to the '483 document.
  • non-polymeric diazonium compounds B which are free from alkyl- or arylsulfone substituents and have either no further substituents on the aromatic ring(s), or have also functional groups F which are not diazonium groups of formula bound to an aromatic carbon atom, bound to its aromatic ring(s), as reactants in an azo coupling, under incorporation of the diazo group, with aromatic polymers K to modify the reactivity, solubility, electric or dielectric properties, surface or phase interface properties of the surface of such modified aromatic polymers M.
  • An "other functional group” in the context of this invention is any atom or group which is different from a hydrogen group, H-.
  • the object of the invention is to provide a means to modify the surface of aromatic polymers K or of articles and bodies made therefrom, to obtain an object or article M having surface properties differing from those of articles made of the unmodified aromatic polymer K, with respect to mechanical or chemical properties, surface tension in contact with liquids, adhesive and electric or dielectric properties.
  • Aromatic polymers K are selected from the group consisting of resinous oligomeric or polymeric phenolic materials, including phenolic resins PF which are derived from phenols and aldehydes, preferably formaldehyde, or modified phenolic resins MPF which have been modified by incorporation of naturally occurring phenolic bodies such as lignin, and tannin, either as addition thereof to the phenol component to the resinification process, in their native form, or at least partly depolymerised by the commercial processes to isolate these materials, or as preformed condensation products with aldehydes to resins made from the commonly used starting materials, viz., phenol and derivatives thereof including alkylphenols such as cresols, xylenols, nonylphenols, and long chain-alkyl substituted phenols isolated from cashew nutshell oil.
  • phenolic resins PF which are derived from phenols and aldehydes, preferably formaldehyde, or modified phenolic resins MPF which have
  • Aromatic polymers K also include natural polymers, particularly lignocellulosic materials, such as wood, grass, plant fibers, also in particulate form, and lignin which has been obtained by separation of cellulose and hemicellulose from the lignocellulosic materials, or by fractionation of lignin isolated from natural feedstocks by any of the known processes. Further aromatic polymers include tannins.
  • the properties of these aromatic polymers K are largely determined by their composition, i. e., by the kind and the amount of starting materials (educts) used for their synthesis. It is an object of the invention to provide a possibility to modify these properties on the surface of objects, articles and bodies made therefrom, such as reactivity, solubility, interfacial properties such as surface tension, emissions of residual monomers, optical, electrical, chemical and mechanical properties, without a substantial change of the kind and the amount of starting educts. It is possible, according to the invention, to retain favourable mechanical or chemical properties of the aromatic polymers so modified by applying the modifying compound, viz., the aromatic diazonium compounds B, to the surface of ready-made aromatic resins or polymers K.
  • the modifying compound viz., the aromatic diazonium compounds B
  • the invention is therefore directed to the modification of surfaces of articles, items or bodies made from aromatic polymer materials K by treating the surface of any of these articles, items or bodies with non-polymeric aromatic diazonium compounds B, wherein aromatic diazonium compounds B having a diazonium group of formula N bound to an aromatic carbon atom are coupled to the said aromatic polymers K via an azo coupling reaction, which diazonium compounds B do not comprise vinylsulfone structures and either carry no additional substituent in their aromatic structure, or preferably carry at least one further functional group F which is capable of modifying the reactivity, solubility, interfacial properties such as surface tension, adsorption, optical, electrical, chemical and mechanical properties, of the surface of an article, object or body made from the aromatic polymers K to obtain an article, object or body M with such changed surface properties.
  • the polymeric aromatic materials K are preferably selected from the group consisting of novolaks N, resoles R, and polymers P particularly based on reaction products of aldehydes as detailed infra, with lignin L, and tannin T, which aromatic polymer materials K also include novolaks and resoles where at least a part of the phenols is replaced by lignin or tannin or other naturally occurring substituted phenols, or a mixture thereof, having aromatic moieties with increased electron density in comparison with benzene at unsubstituted carbon atoms in the said aromatic moiety.
  • the polymeric aromatic materials K also comprise natural materials such as wood, or processed wood, including logs, disks, lumber, veneer, strand, chips, wood wool (“Excelsior”), particles, fibre bundles, refined fibre and wood flour, according to the classification of Marra 1972 (cited from “Holzwerkstoffe der Modeme", M. Paulitsch 1998), and fibrous lignocellulosic materials from other plants.
  • natural materials such as wood, or processed wood, including logs, disks, lumber, veneer, strand, chips, wood wool (“Excelsior"), particles, fibre bundles, refined fibre and wood flour, according to the classification of Marra 1972 (cited from "Holzwerkstoffe der Modeme", M. Paulitsch 1998), and fibrous lignocellulosic materials from other plants.
  • the increase or decrease in electron density in any aromatic system which is due to a first substituent can be measured by the dipole moment of a singly substituted aromatic compound in comparison to the unsubstituted aromatic compound, or by comparison of the reaction rate of a singly substituted aromatic compound and that of the corresponding unsubstituted aromatic compound in an electrophilic reaction with the same electrophilic compound, such as in the nitration of an aromatic compound by a cation, see, e.
  • these groups are hydrophilic or hydrophobic, and add a further functionality to the diazonium group-containing modifiers B, and thus change the physico- chemical properties of the surface of the article, item or object M so modified, e. g., hydrophilicity or hydrophobicity, phase interface properties such as sorption, surface properties, cohesion and adhesion properties, solubility, light and chemical resistance, and chemical reactivity.
  • the simplest modifier B which has no further reactive group is made by diazotisation of aniline, under formation of a molecule of the structure , where is the anion of the acid present in the formation of a diazonium salt B derived from aniline.
  • Preferred modifiers B are made from primary aromatic monoamines having further acid functional groups, particularly, sulphonic acid groups, carboxylic acid groups, and phos- phonic acid groups which render the article, item or object M modified therewith more hydrophilic.
  • the modifiers B that increase the hydrophilicity are preferably selected from the group consisting of ortho-, meta-, and para- aminobenzene sulphonic acids, naphthalene- sulphonic acids further comprising at least one hydroxyl group and/or at least one amino group, together also known as "Buchstabensauren" which are additionally substituted amino- naphthalene sulphonic acids including Cleve ⁇ -acid (5-aminonaphthalene-2-sulphonic acid), Cleve ⁇ -acid (4-aminonaphthalene-2-sulphonic acid), naphthionic acid (1-aminonaphthalene- 4-sulphonic acid), Laurent acid, also known as purpurinic acid (l-aminonaphthal
  • modifiers B that introduce reactive sites, such as diazonium group-containing modifiers having an aromatic nucleus with addition phenolic hydroxyl groups as functional groups F, as an example, the diazonium salt derived from 3,5-dihydroxyaniline which has a reactive site that reacts easily with an aldehyde, in the para-position (carbon atom 4) to the diazonium group.
  • reactive sites such as diazonium group-containing modifiers having an aromatic nucleus with addition phenolic hydroxyl groups as functional groups F, as an example, the diazonium salt derived from 3,5-dihydroxyaniline which has a reactive site that reacts easily with an aldehyde, in the para-position (carbon atom 4) to the diazonium group.
  • the diazonium group-containing modifiers B can be prepared by reaction of aromatic primary amines with nitrous acid in the presence of additional acid at low temperatures, i.e., under cooling with ice.
  • the aromatic primary amine which may also have further functional groups is dissolved in water, in the presence of a stoichiometric excess of acid such as hydrochloric acid, the solution is cooled to a temperature of preferably between 0 °C and 5 °C, where the amine hydrochloride usually precipitates in the form of crystals.
  • An aqueous solution of sodium nitrite is slowly added, keeping the temperature in the mentioned range, until the nitrite is no longer consumed.
  • phenolic resins such as novolaks N and resoles R are preferred which can be prepared by reaction of phenolic bodies C with aldehydes A, preferably aliphatic monoaldehydes A1A such as formaldehyde, acetaldehyde, propionaldehyde, butyric and isobutyric aldehyde; preferably formaldehyde; aliphatic dialdehydes A2A such as glyoxal, malonaldehyde (propanedial), succinaldehyde (butanedial), glutaraldehyde (pentanedial), and adipaldehyde (hexanedial), preferably glyoxal; cycloaliphatic monoaldehydes A1C, including furfural (IUPAC name: furan-2-carbaldehyde), 5-hydroxymethyl furfural (IUPAC name: 5-(hydroxymethyl)furan-2-carbaldehyde); and
  • Phenolic bodies C include aromatic compounds having at least one hydroxyl group bound to a carbon atom which is part of a mononuclear aromatic compound, and at least one unsubstituted carbon atom which carries a hydrogen atom, and is part of the same ring, which unsubstituted carbon atom is preferably in ortho position or para position, and less preferred, in meta position, with respect to the carbon atom carrying the hydroxyl group in the case of a six-membered ring, and has increased electron density in comparison with a carbon atom in benzene, via the mesomeric effect and/or the inductive effect.
  • phenolic bodies C may have linear or branched alkyl groups having up to twenty carbon atoms attached to the aromatic nuclei, where it is also possible that these alkyl substituents have the same, or different numbers of carbon atoms, or may be differently branched, or have olefinic unsaturation in their chains.
  • This definition also includes the naturally occurring phenols in the plant anacardium occidental, the main products of which are cardanol, viz., 3-[(8Z,11Z)- pentadeca-8,11,14-trienyl]phenol, cardol, viz., 5-[(9E,12E)-pentadeca-9,12-dienyl]benzene-l,3- diol, and 2-methylcardol, viz., 2-methyl-5-[(9E,12E)-pentadeca-9,12-dienyl]benzene-l,3-diol, all commercially recovered from cashew nutshell liquid.
  • cardanol viz., 3-[(8Z,11Z)- pentadeca-8,11,14-trienyl]phenol
  • cardol viz., 5-[(9E,12E)-pentadeca-9,12-dienyl]benzene-l,3- diol
  • the phenolic bodies useful for this invention are grouped into mononuclear monohydroxy aromatic compounds Cll, such as phenol itself, ortho-, meta-, and para-cresol, 2,4- and 2,6-xylenol, mononuclear aromatic compounds C12 having at least two hydroxyl groups, such as catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, and hydroxyquinol, multinuclear monohydroxy aromatic compounds CM1 having at least two aromatic rings annealed or otherwise chemically bound, such as 4-hydroxydiphenyl, alpha-naphthol, and beta-naphthol, and multinuclear aromatic compounds CM2 having at least two aromatic rings annealed or otherwise chemically bound, and at least two hydroxyl groups such as bisphenol A, IUPAC name: [2-(4-hydroxyphenyl)propan-2-yl]phenol), the mixture of isomers known as "bisphenol F", IUPAC name of
  • resoles R and novolaks N derived from phenol and formaldehyde, mixtures thereof with condensates made from lignin and formaldehyde, tannin and formaldehyde, and cocondensates from phenol and lignin, or from phenol and tannin, with formaldehyde. It is also possible, within the scope of the invention, to replace, partially or completely, formaldehyde by other aliphatic monoaldehydes and dialdehydes as detailed supra, and preferably, by aldehydes made from a natural base material, such as furfural, 5- hydroxymethylfurfural, and 2,5-furandicarbaldehyde.
  • Phenolic bodies also include lignins L which are generally classified into the groups of softwood, hardwood, and grass lignins. These native lignins are typically separated from the wood or other lignocelluloses in the form of "milled wood lignin” (MWL), "dioxane lignin”, or “enzymatically liberated lignin”.
  • MLL milled wood lignin
  • Kraft lignin or sulphate lignin
  • alkali lignin or soda lignin
  • lignosulphonates are derived from lignocellulose subjected to the Kraft, the soda-anthra- quinone, and the sulphite pulping processes, respectively.
  • a further lignin source is the so-called acid hydrolysis lignin which is still mostly converted to pellets for firing.
  • lignin grades have been made accessible by more recent processes, viz., the organosolv process which provides a sulphur-free high purity lignin grade, and the hydrolysis process which is acid-catalysed and leads to formation of the so-called Hibbert ketones and of free phenolic moieties.
  • organosolv process which provides a sulphur-free high purity lignin grade
  • hydrolysis process which is acid-catalysed and leads to formation of the so-called Hibbert ketones and of free phenolic moieties.
  • Other emerging processes are the steam-explosion process and the ammonia-fibre expansion process. Any of these lignin materials may be used in the present invention.
  • Lignin materials provided by different sources and separated from the cellulose and hemicellulose accompanying materials in lignocellulose by the different processes as detailed supra differ from each other, not only in the composition with regard to the shares of 4-hydroxyphenyl-, guaiacyl- (3-methoxy-4-hydroxyphenyl-), and syringyl- (3,5-dimethyoxy- 4-hydroxyphenyl-) units of the C 9 -building blocks in lignin, which is different for gymnosperms (predominantly guaiacyl units), angiosperms (both guaiacyl and syringyl units), and grass (predominantly 4-hydroxylphenyl emits), but also in the decomposition products obtained, as the decomposition process follows different routes depending on the kind of pulping process.
  • the lignins obtained by the processes supra have also variations in the molar mass, as reported in "Molar mass determination of lignins by size-exclusion chromatography", S. Baumberger et al., Holzaba 2007 (61), pages 459 to 468.
  • lignin fractions may be collected, e. g., in a first mixture comprising substantially lignin oligomers and polymers of a low degree of polymerisation (hereinafter each individually, and all collectively referred to as low molar mass lignins, "LML”) having from 1 to 10 monomer units, and in a second mixture comprising substantially lignin polymers (hereinafter collectively referred to as high molar mass lignins, "HML”) having from 11 to 70 monomer units.
  • LML low degree of polymerisation
  • HML high molar mass lignins
  • any larger number of mixtures, each comprising different groups of oligomers and polymers, may also be collected from the isolated fractions provided by controlled precipitation, or other separation processes.
  • the molar masses of lignin can be determined according to the method described in Linping Wang et al., Holzaba 2019; 73(4): 363 to 369, by size-exclusion chromatography of acetylated samples of the lignin fractions. These mixtures can be condensed individually with aldehydes, and mixed thereafter, or they can be condensed in sequence, and the addition time of phenol and aldehyde can be varied.
  • WO 2013/144453 Al the use of certain combinations of lignin fractions of different molar mass leads to different levels of the possibility of substitution of phenol by lignin.
  • lignin It is also possible to purify lignin from any of the sources mentioned, by a plethora of methods including ultrasonic extraction, solvent extraction, dialysis, and hot water treatment. It is particularly important to remove inorganic impurities such as sulphur which stems from the
  • the reactivity of lignin can be increased by various processes, including demethylation, methylolation/hydroxymethylation, phenolation/phenolysis, reduction, oxydation, hydrolysis, and alkalation. See, e.g. Hu, LiHong, et al., Bioresources 6(3), pages 3515 to 3525, and WO 2013/144454 Al.
  • lignins L All modified lignins mentioned hereinabove, as well as native lignins, and lignins obtained by the processes described in the literature can be used as lignins L, in the context of the present invention.
  • the natural aromatic polymers P other than lignin having aromatic moieties with increased electron density in comparison with benzene at unsubstituted carbon atoms in the said aromatic moiety are preferably selected from the group consisting of tannins T, particularly gallotannins, ellagitannins, complex tannins and condensed tannins.
  • tannins T particularly gallotannins, ellagitannins, complex tannins and condensed tannins.
  • aromatic polymers P based on natural polymers can be used, especially based on polysaccharides such as cellulose, amylose, amylopectin, and those based on amino polysaccharides such as chitin and chitosan; in order to be able to react with the electrophilic diazonium compound B, these saccharides and aminosaccharides may be grafted with electron-rich aromatic compounds having reactive groups, e. g., (di)methoxystyrene. Such grafting can also be applied to lignins, where an improvement of reactivity of the graft product toward electrophilic substitution in the aromatic moieties has been noted.
  • the novolaks N, resoles R, lignin L, tannin T, and also the other polymers P can each be used alone, in combination with other components of the same class, or with at least one component of at least one other class. Therefore, combinations of at least two novolaks N1 and N2 which are chemically or physically different, combinations of at least two resoles R1 and R2 which are chemically or physically different, by changing the phenol component or the aldehyde component, or the degree of polymerisation, and also combinations of a novolak N and a resole R, and combinations of either of both or a resole R and a novolak N with one or more of a lignin L, a mixture of lignin components comprising at least two fractions LI and L2 of lignin molecules having different degrees of polymerisation or different compositions in terms of the relative abundance of H, G, and S units, and a tannin T can also be used within the scope of this invention.
  • the modified surface of an article, item or object M of the present invention is preferably made in the following way: a solution of a primary aromatic amine, optionally having a functional group F as detailed supra as further substituent, in an aqueous acid is prepared, and cooled to a temperature of 25 °C or less, preferably not more than 20 °C, particularly preferred, not more than 15 °C, and especially preferred, not more than 10 °C, and most preferred, not more than 5 °C, to the solution of the first step, a solution of an alkali nitrite is added preferably in an amount such that the amount of substance of nitrite ions present in the reaction mixture is equal to the amount of substance of amino groups in the aromatic amine, and mixed at a temperature of 25 °C or less, preferably not more than 20 °C, particularly preferred, not more than 15 °C, and especially preferred, not more than 10 °C, and most preferred not more that 5 °C, (at the end of the addition of nitrite, it
  • modifiers B in the form of solid diazonium salts, which are prepared according to any of DE 25212650 Al and EP 0 125587 Al.
  • the material K is a novolak N, or a lignin L, or a resol R, or mixture of at least two of a novolak N, a resol R, and a lignin L.
  • the ratio m(B) / m(K) of the mass m(B) of aromatic diazonium compounds B to the mass m(K) of the surface layer in the materials K can be chosen between 0.1 % and 50 %, preferably between 0.5 % and 35 %, and particularly preferred, between 1 % and 25 %.
  • the low mass ratios can preferably be used for colouration (colour coding) of the modified article, item or object M so obtained, using the colour developed by the diazo coupling products, while the highest mass ratios are preferably used to modify the solubility properties and the surface properties, particularly with regard to chemical and environmental stability, of the modified article, item or object M so obtained.
  • the "mass m(B) of aromatic diazonium compounds B" refers only to the mass of the solute.
  • modified articles, items or objects M made according to the present invention can be used for a wide variety of applications, particularly in composite wood materials, in abrasive materials or in friction materials such as brake pads, in heat and sound insulation materials, as foams, as binders for coatings, or as foundry moulds. They are also particularly suited for applications in elevated temperature regimes.
  • Embodiment 2 surface modification of hydroxy-functional natural polymers N
  • This embodiment to the modification of the surface of particulate hydroxy-functional aromatic compounds by treatment with a non-polymeric aromatic diazonium compound having no vinylsulfone structural moiety in its molecule, and to polymers based on reaction of the said modified hydroxy-functional aromatic compounds with aldehydes. It also relates to a process for the preparation of modified particulate hydroxy-functional aromatic compounds by coupling of the said hydroxy-functional aromatic compounds with nonpolymeric diazonium salts having no vinylsulfone structure in its molecule, and to a process for the preparation of polymers by reaction of the said modified hydroxy-functional aromatic compounds with aldehydes.
  • binders particularly for adhesives, coatings, composites, organic and inorganic fibre products, filled and reinforced polymer composites, for friction materials, moulding powders, and abrasives, for thermal, electrical, and acoustic insulation materials, foams, refractory materials, and foundry moulds.
  • a further object was to provide a process for the production of polymers based on the polycondensation of natural polymers comprising
  • a still further object was to provide a method of used of polycondensates thus produced as binders, particularly for adhesives, coatings, composites, organic and inorganic fibre products, filled and reinforced polymer composites, for friction materials, moulding powders, and abrasives, for thermal, electrical, and acoustic insulation materials, foams, refractory materials, and foundry moulds.
  • Embodiment 1 Modification of the surface of articles, items, and objects made from aromatic natural polymers K by azo coupling of non-polymeric aromatic diazonium salts having no vinylsulfone structure element has been described in Embodiment 1 hereinbefore, as a novel route to increase their reactivity on the surface of these articles, items, and objects.
  • This embodiment is therefore directed to the modification of hydroxy-functional natural aromatic compounds N in solid particulate form by diazo coupling with a diazonium salt D which is a non-polymeric aromatic compound bearing a diazonium group having the structure , where is a monovalent anion which is preferably selected from the group consisting of the halogenide ions , tetrafluoroborate , hydrogensulphate and tosylate .
  • the diazonium salt D may also bear further substituents in the aromatic ring(s) of the aryl group Ar-, preferably, at least one substituent which increases the electron density of the aryl group Ar- vis-a-vis that of the corresponding unsubstituted aromatic ring system.
  • Preferred aldehydes are formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, furfural, 5-hydroxymethyl- furfural, glyoxal, glutaraldehyde, and mixtures of these. These alkylol compounds react in a polycondensation reaction to form resins of the novolak or resol types.
  • the additional aryl group introduced by azo coupling with the diazonium salts D into the modified hydroxy-functional natural aromatic compound NM contributes to the increased reactivity of NM compared to that of the unmodified hydroxy-functional natural aromatic compound N in reactions thereof with aldehydes by providing additional aryl groups Ar- having free reactive sites in the aryl group where reactions with aldehydes either under alkaline conditions where an aldehyde is added in ortho or para position to, e.g., a phenolate ion to form an alkylol group in the Ar part of the modified hydroxy-functional natural aromatic compound NM, or under acidic conditions where a protonated (and optionally substituted) methyleneglycol is added in ortho- or para-position to, e.g., a phenolic hydroxyl group to form an alkylol group in the Ar part of the modified hydroxy-functional natural aromatic compound NM.
  • Both lignin L and tannin T as unmodified hydroxy-functional natural aromatic compounds N have only few unsubstituted carbon atoms in their aromatic rings, the wood lignins having two or three unsubstituted carbon atoms in their benzene rings in lignin from angiosperms (three in guaiacyl-units, and two in syringyl-units), three unsubstituted carbon atoms in their benzene rings in lignin from gymnosperms (in guaiacyl-units), or even four unsubstituted carbon atoms in their benzene rings in grass lignin (in p-hydroxy phenyl units).
  • Tannins are a class of poly phenolic biomolecules, their molar mass ranging from about 500 g/mol for esters of sugars and gallic or digallic acid, to about 20 kg/mol for proanthocyanidines. They all comprise both phenolic and cycloaliphatic hydroxyl groups. Basic chemical structures are derived from gallic acid (3,4,5-trihydroxybenzoic acid), 1,3,5-trihydroxybenzene (phloroglucinol), and flavan-3-ol. Naturally occurring tannins are found in leaf, bud, seed, root, and stem tissues. A structural differentiation for tannins has been proposed by Khanbabee and van Ree in Natural Product Reports 5, 2001, vol.
  • Gallotannins are esters of gallic acid or its depsidic derivatives with (mostly sugar-based, catechin-based or terpenoid-based) polyols.
  • Ellagitannins comprise acidic components based on ellagic acid (2,3,7,8-tetrahydroxy-chromeno[5,4,3,c,d,e]chromene-5,10-dione) and do not contain glycosidically linked catechin units; the sugar-based polyols include, i.
  • Tannins are those in which a catechin unit is bound glycosidically to a gallotannin or ellagitannin unit; and Condensed Tannins, also referred to as proanthocyanidines, are flavonoid-based oligomeric and polymeric compounds formed via linkage of the C4-atom of one catechin unit with a C8- or C6-atom of the next monomeric catechin unit.
  • Naturally occurring tannins are usually mixtures of at least two of these four classes.
  • Gallotannins have two reactive unsubstituted C-H groups in a galloyl moiety, so a gallotannin which is a penta-ester of five molecules of gallic acid with one molecule of glucose has ten reactive sites; an ellagitannin which is an ester of two molecules of ellagic acid, one molecule of gallic acid, and one molecule of glucose has a total of four reactive sites in the two ellagoyl groups, and two further reactive sites in the galloyl group, leading to a total of six.
  • the catechin units In a complex tannin, the catechin units would provide a total of five reactive unsubstituted C-H groups in the two aromatic moieties of the flavanol structure, in addition to those of the moieties derived from gallo- or ellagi-tannin.
  • Condensed tannins include trimers, tetramers, or higher oligomers of catechin, epicatechin, which (with the exception of one end catechin group) have only one reactive unsubstituted C-H group in the A rings of the catechins, and related compounds having a third phenolic hydroxyl group in the B ring of the catechins, viz., gallocatechin, and epigallocatechin, exhibit further reduced reactivity.
  • Cashew nutshell liquid is isolated from the mesocarp of cashew seeds as a dark brown and viscous oily liquid which comprises mainly anacardic acid (2-hydroxy-6- pentadecylbenzoic acid, with one, two, or three double bonds in the alkyl group; in a mass fraction of about 70 %), cardanol (3-pentadecylphenol, with one, two, or three double bonds in the alkyl group; in a mass fraction of about 5 %), and cardol (5-pentadecyl-l,3- dihydroxybenzene, with one, two, or three double bonds in the alkyl group; in a mass fraction of about 18 %).
  • anacardic acid (2-hydroxy-6- pentadecylbenzoic acid, with one, two, or three double bonds in the alkyl group; in a mass fraction of about 70 %)
  • cardanol 3-pentadecylphenol, with one, two, or three double bonds
  • cardanol offers sufficient unsubstituted aromatic carbon atoms to react easily with aldehydes
  • the long chain alkyl groups present in the molecule lead to a reduction of brittleness by replacing phenol with cardanol, in comparison with phenol-formaldehyde resins, which also leads to a reduction of flexural modulus.
  • Additional aryl groups which are introduced by diazo coupling can therefore lead to a better balance between avoiding of brittleness, and keeping the desired stiffness.
  • diazo coupling on natural polymers comprising aromatic structures therefore offers a simple way to increase the reactivity of these polymers vis-a-vis aldehydes to a desired extent by adding unsubstituted or less substituted aromatic moieties, to adapt the mechanical properties by changing the balance between aromatic and aliphatic structures, and last but not least, options to replace at least partly aromatic intermediate products such as phenol by natural polymers.
  • the desired changes in the properties of the reaction products can be made for any of the intended applications where phenolic resins are used.
  • Embodiment 3 Treating the surfaces of cut wood
  • This embodiment relates to a method for treating wood, or wood-based materials, which method improves the adhesion of coatings and glues to the surface of wood, or of wood-based materials.
  • This method includes impregnation of wood, or of wood-based materials with a solution of a diazonium salt, and a subsequent drying step.
  • primer Before applying a varnish or a paint on wood parts, it has become customary to use a preparatory coating referred to as primer, which serves multiple purposes: the durability of the paint coating is improved, the wood part is protected against ambient and environmental damages, unwanted stains present inside the wood part are blocked, and impregnation of the wood part with the applied paint is reduced.
  • primers for wood are oil-based or (acrylic) latex-based. Depending on the microporosity of the wood part and the viscosity of the primer, primers can partly penetrate into the wood part, and also partly remain on its surface.
  • the solid portions of the primer which are originally present in dissolved or dispersed form, or generated in the drying or crosslinking process, or both, form a film on the surface of wooden parts, and fill at least a part of open pores inside the wood part.
  • the adhesion of coating layers or glues to a wood surface can also be improved by treating the wood surface with a primer.
  • (a) impregnation of wood, wood-based materials, or wood materials for the production of wood-based materials with a curable aqueous composition which comprises at least one crosslinkable compound selected from low molar mass compounds V having at least two N- bonded groups of the formula CH 2 -OR, where R is hydrogen or C 1 - to C 4 -alkyl, and/or a 1,2- bis-hydroxyethane-l,2-diyl group bridging two nitrogen atoms, or mixtures of compound V with at least one alcohol which is selected from C 1 - to C 6 -alkanols, C 2 - to C 6 -polyols, and oliogoalkylene glycols, the conditions of the impregnation being chosen so that the mass of curable constituents of the aqueous composition which is absorbed is at least 5 % of the dry mass of the untreated wood or woodbase material; and
  • step (b) treatment of the material obtained in step (a) at elevated temperature and optionally further processing to give a woodbase material
  • the surface treatment composition mentioned hereinbefore comprises, according to claim 2, a polymeric binder and/or a prepolymer curing in the form of a polymeric binder.
  • the crosslinkable compound is preferably selected from l,3-bis(hydroxymethyl)-4,5-dihydroxyimidazolidin-2-one and a l,3-bis(hydroxymethyl)-4, 5-dihydroxyimidazolidin-2-one modified with a C 1 - to C 6 -alkanol, a C 2 - to C 6 -polyol, and/or a polyalkylene glycol.
  • Suitable polyols are ethylene glycol, diethylene glycol, 1,2- and 1,3-propylene glycol, 1,2-, 1,3- and 1,4-butylene glycol and glycerol.
  • Suitable oligo- and polyalkylene glycols are in particular oligo- and poly-C 2 - to C 4 - alkylene glycols, especially homo- and co-oligomers of ethylene oxide and/or of propylene oxide, which, if appropriate, are obtainable in the presence of low molar mass initiators, e.g., aliphatic or cycloaliphatic polyols having at least two hydroxyl groups, such as 1,3-propane- diol, 1,3- and 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerol, trimethylolethane, trimethylolpropane, erythritol and pentaerythritol, and pentitols and hexitols, such as ribitol, arabitol, xylitol, dulcitol, mannitol and sorbito
  • the curing reaction of the curable aqueous composition which comprises at least one crosslinkable compound sets in, and "it is assumed that, owing to these properties, the compounds can penetrate into the cell walls of the wood and, on curing, improve the mechanical stability of the cell walls and reduce their swelling caused by water.” See paragraph [0013], last sentence.
  • a further object was to provide an adapted process for the treatment of wood and wood materials with solutions of a diazonium salt, followed by a drying step of the impregnates which leads to an optimum performance.
  • This embodiment is directed to the modification of wood or wood materials by impregnation thereof with a solution of a non-polymeric diazonium salt D having no vinylsulfone group in its molecule, which is an aromatic compound bearing a diazonium group having the structure where is a monovalent anion which is preferably selected from the group consisting of the halogenide ions , tetrafluoroborate hexafluorophosphate hydrogensulphate and tosylate . It is also possible to use a diazonium salt comprising two molecules of a diazonium cation together with a bivalent anion such as hexafluorosilicate .
  • the diazonium salt D may also bear further substituents in the aromatic ring(s) of the aryl group Ar-, preferably, at least one hydroxyl group, or at least one alkoxy group, or a mixture of both hydroxyl groups and alkoxy groups.
  • wood materials and “wood-based materials” shall relate not only to solid wood, but also to finely divided wood materials which include veneers, coarse shavings, chips, shreds, shavings, wood wool, strands, fine shavings, fibre bundles, fibres, flour, dust, and the like, basically according to the classification of G. G. Marra in Forest Products Journal, 22 (1972), pages 43 to 51. These materials are usually bonded using ad- hesives at elevated temperature and pressure to engineered wood products or composites, commercially most important of which are laminated veneer lumber (LVL), particle boards, medium density fibre boards, oriented strand boards (OSB), and plywood.
  • LDL laminated veneer lumber
  • OSB oriented strand boards
  • all wood types are suitable for the invention, in particular those which can absorb a mass of water corresponding to at least 30 %, in particular at least 50 %, of their dry mass, and particularly preferably those which are classified under impregnability classes 1 and 2 in accordance with DIN-EN 350-2.
  • These include, for example, timbers of conifers, such as pine of several species, spruce, Douglas fir, larch, Italian stone pine, fir, coastal fir, cedar and Swiss stone pine, and timbers of broad-leaved trees, e.g.
  • the diazonium salts D have preferably the structure where is a monovalent or divalent anion which is preferably selected from the group consisting of the halogenide ions , tetrafluoroborate hexafluorophosphate hydrogensulphate and tosylate . .
  • a monovalent or divalent anion which is preferably selected from the group consisting of the halogenide ions , tetrafluoroborate hexafluorophosphate hydrogensulphate and tosylate .
  • tetrafluoroborate is tetrafluoroborate .
  • diazonium tetrafluoroborates are relatively stable in solid state. In solution they slowly decompose under elimination of nitrogen.
  • a diazonium salt comprising two molecules of a diazonium cation together with a bivalent anion such as hexafluorosilicate They are usually used to form azo compounds but also form reactive aromatic cations and radicals. Especially radicals might react with many chemical species that are exposed on wood surfaces. Therefore, not only azo coupling to aromatic moieties may occur, but also, a radical coupling to carbohydrates such as cellulose or hemicellulose which are present in the wood materials.
  • Other Ar- groups such as 4-phenoxyphenyl, stilbene-4-yl, 3,5-dihydroxystilbene-4'-yl, and 4-phenylbenzene-l-yl can also be used.
  • diazonium salts D having phenolic hydroxy groups, or alkoxy groups in the Ar- group have been found to improve the bonding between the wood parts and the adhesive if adhesives based on phenolic resins are used, only small improvement has been realised when using other adhesives, particularly, isocyanate-based adhesives such as MDI (diphenyl- methylene diisocyanate) and oligomeric or polymeric MDI.
  • diazonium salts D based on 3-aminobenzylalcohol (IUPAC name: benzenemethanol, -3-amino) or 3-( ⁇ - hydroxyethyl)-aniline are preferred as these have aliphatic hydroxyl groups which react easily with diisocyanates.
  • Solutions of the diazonium salt D in water have preferably a concentration of from 0.01 mol/L to 0.5 mol/L, particularly preferred, from 0.02 mol/L to 0.25 mol/L.
  • the solid wood part is usually sprayed with aqueous solutions of the diazonium salt D, while it is preferred for veneers or particulate wood materials to be used for the preparation of wood composite parts (engineered wood parts) to submerge or soak the these in the aqueous solutions of the diazonium salt D.
  • Solid wood parts are free from adhering drops of solution with cloth or paper, and dried in an air stream at room temperature (22 °C) for about 24 hours.
  • Particulate wood materials are washed with deionised water or acetone, and dried in an air stream at room temperature (22 °C) for about 24 hours. A slight discolouration of the wood material indicates successful azo coupling.
  • ABS Automated Bonding Evaluation System
  • Adhesives Evaluation Systems Inc. Corvallis, Oregon, USA.
  • Veneers to be tested are cut, a pair of veneers of the same wood type was coated with adhesive binder in the overlapping binding area.
  • the pair of veneers is inserted into the pair of clutches at the opposite free end of the veneers, and the binder is cured in the press (which is in the central part of the measuring system) in the joint region.
  • the veneer modification targets an improved bonding between veneer and binder. It was found in all tests performed, either one of the veneers breaks, or the joint breaks, but never the bond between veneer and binder.
  • a method for treating wood, or wood-based materials which method improves the adhesion of coatings and glues to the surface of wood, or of wood-based materials, wherein the method includes impregnation of wood, or of wood-based materials with a solution of a diazonium salt D, and a subsequent drying step.
  • wood or the wood-based materials comprise solid wood, and also finely divided wood materials which include coarse shavings, chips, shreds, shavings, wood wool, strands, fine shavings, fibre bundles, fibres, flour, and dust.
  • wood or the wood- based materials include those from conifers, viz., pine of several species, spruce, Douglas fir, larch, Italian stone pine, fir, coastal fir, cedar and Swiss stone pine, and those from broad-leaved trees, viz., maple, hard maple, acacia, birch, pear, beech, oak, alder, aspen, ash, serviceberry (amelanchier), hazel, hornbeam, cherry, chestnut, lime, American walnut, poplar, olive, elm, walnut, robinia, rubber tree, willow, and Turkey oak.
  • conifers viz., pine of several species, spruce, Douglas fir, larch, Italian stone pine, fir, coastal fir, cedar and Swiss stone pine
  • broad-leaved trees viz., maple, hard maple, acacia, birch, pear, beech, oak, alder, aspen, ash, serviceberry (amelanchier),
  • a method of bonding wood parts wherein at least one surface of at least one of the wood parts is treated with a solution of a diazonium salt D according to at least one of the embodiments 3-1 to 3-10, rinsing the wood part with water or a solvent, or a mixture of water or a solvent, drying the coated surface, applying a an adhesive to the treated surface of the wood part, and curing the applied coating.
  • a method of coating wood parts comprising treating at least one surface of at least one of the wood parts with a solution of a diazonium salt D according to at least one of the claims 1 to 10, rinsing the wood part with water or a solvent, or a mixture of water or a solvent, drying the coated surface, and then, applying a decorative or protective coating to the treated surface of the wood part, and curing the applied coating.
  • Fig-1 shows the high performance liquid chromatograms (HPLC) of the modified novolak N2 obtained in Example 2 (solid line) and of the unmodified Novolak N0 (dotted line),
  • Fig. 2 shows the UV-Vis spectra of the modified novolak N2 obtained in Example 2 (solid line) with the characteristic azobenzene absorption bands ⁇ * and n ⁇ * transition, and of the unmodified Novolak N0 (dashed line),
  • Fig. 3 shows the high performance liquid chromatograms of the modified novolak N5 obtained in Example 5 (solid line) and of the unmodified Novolak N0 (dotted line),
  • Fig. 4 shows the UV-Vis spectra of the modified novolak N5 obtained in Example 5 (solid line) and of the unmodified Novolak N0 (dashed line),
  • Fig. 5 shows the high performance liquid chromatograms of the modified novolak N8 obtained in Example 8 (solid line) and of the unmodified Novolak N0 (dotted line),
  • Fig. 6 shows the UV-Vis spectra of the modified novolak N8 obtained in Example 8 (solid line) with the characteristic azobenzene absorption bands ⁇ * and n ⁇ * transition, compared to the unmodified Novolak N0 (dashed line),
  • Fig. 7 shows the UV-Vis spectra of seven different reaction products of the Novolak Nil separated in the HPLC, corresponding to individual peaks in the chromatogram differing in their retention times; the different heights of the additional characteristic azobenzene absorption bands ( ⁇ * and n ⁇ * transition) in the UV-Vis spectra for the individual peaks in the chromatogram show that the different peaks correspond to species with different degrees of modification which have been separated in the chromatographic process, these species having different mass ratios of the mass m B of modifier B to the mass m N0 of the novolak substrate N0 in the separated species of N11; the different mass ratio being the cause for the difference in absorbance, Fig. 8 shows the high performance liquid chromatograms of the modified novolak N12 obtained in Example 12 (solid line) and of the unmodified Novolak N0 (dotted line),
  • Fig. 9 shows the UV-Vis spectra of two different reaction products of modified lignin separated in the HPLC, corresponding to individual retention times (72.5 min and 101.9 min in the chromatogram of the modified lignin) differing in their heights of the additional characteristic azobenzene absorption bands ( ⁇ * and n ⁇ * transition) in the UV-vis, the different mass ratio being the cause for the difference in absorbance, compared to the UV-vis absorption spectrum of unmodified lignin taken at a retention time of 70.3 min, and
  • Fig. 10 shows the UV-vis spectra of 3,4,5-trimethoxytoluene modified with the diazonium salt obtained in Example 1 (solid line) and that of the unmodified 3,4,5-trimethoxytoluene, as a model compound for sinapyl alcohol which is the precursor for syringyl groups in lignin; it is shown by the strong signal due to the characteristic azobenzene absorption bands ( ⁇ * and n ⁇ * transition) that even this highly substituted aromatic ring can be successfully modified in an azo coupling reaction.
  • the abscissa is the retention time, measured in the unit “min” (minutes), and the signal shown in the ordinate is the light absorption as recorded by the UV- vis detector, in arbitrary units.
  • the measured light absorption (arbitrary units, denoted as “mAU” in the ordinate) is recorded as a function of the wavelength of the incident light of the spectrophotometer, indicated in the unit “nm” (nanometre).
  • This novolak is referred to as "N0" in the following examples.
  • HPLC high pressure liquid chromatography
  • Example 2 A sample of 50 mg of the modified novolak N2 obtained in Example 2 was suspended in a mixture of water and tetrahydrofuran (in a mass ratio of 3:7), the suspension was homogenised during ten minutes in an ultrasonic bath at ambient temperature (20 °C).
  • the HPLC chromatograms are shown in Fig. 1; as can be seen, the retention times of novolak N2 obtained in example 2 (solid line) modified by additional phenyl groups from the diazonium salt derived from aniline (prepared in Example 1) are shifted towards longer retention times with regard to the unmodified novolak N0 (dotted line).
  • the individual peaks shown in the left part of the chromatogram correspond to oligomers having different degrees of polymerisation.
  • Example 5 A sample of 50 mg of the modified novolak N5 obtained in Example 5 was suspended in a mixture of water and tetrahydrofuran (in a mass ratio of 3:7), the suspension was homogenised during ten minutes in an ultrasonic bath at ambient temperature (20 °C).
  • a sample of the unmodified novolak N0 was prepared in the same way as detailed above, and also subjected to HPLC analysis.
  • the chromatograms are shown in Fig. 3; as can be seen, the retention times of novolak N5 obtained in example 5 modified by additional phenyl-4-sulphonic acid groups from the diazonium salt derived from sulfanilic acid (prepared in Example 4) are shifted towards shorter retention times with regard to the unmodified novolak N0, meaning that the modified novolak N5 is more hydrophilic than the unmodified novolak N0.
  • the individual peaks shown in the left part of the chromatogram correspond to oligomers having different degrees of polymerisation.
  • Example 8 A sample of 50 mg of the modified novolak N8 obtained in Example 8 was suspended in a mixture of water and tetrahydrofuran (in a mass ratio of 3:7), the suspension was homogenised during ten minutes in an ultrasonic bath at ambient temperature (20 °C).
  • a sample of the unmodified novolak N0 was prepared in the same way as detailed above, and also subjected to HPLC analysis.
  • the chromatograms are shown in Fig. 5; as can be seen, the retention times of novolak N8 obtained in example 8 modified by additional naphthalyl-sulphonic acid groups from the diazonium salt derived from Cleve's acid 1,6 (prepared in Example 7) show only a little shifted of the retention times with regard to the unmodified novolak N0, meaning that the modified novolak N8 has approximately the same hydrophilicity as the unmodified novolak N0, due to the contrary effects of the naphthalene group (shift to less hydrophilic) and of the sulphonic acid group (shift to more hydrophilic).
  • the different heights of the additional characteristic azobenzene absorption bands ( ⁇ * and n ⁇ * transition) in the UV-Vis spectra for the individual peaks in the chromatogram show that the different peaks correspond to species with different degrees of modification which have been separated in the chromatographic process, which have different mass ratios of the mass m B of modifier B to the mass m N0 of the novolak substrate N0 in the separated species.
  • the different mass ratio is the cause for the difference in absorbance.
  • Example 12 A sample of 50 mg of the modified lignin obtained in Example 12 was suspended in a mixture of water and tetrahydrofuran (in a mass ratio of 3 : 7), the suspension was homogenised during ten minutes in an ultrasonic bath at ambient temperature (20 °C).
  • chromatograms are shown in Fig. 8 ; as can be seen, the retention times of the modified lignin of example 12 which was modified by additional phenyl groups from the diazonium salt derived from aniline (prepared in Example 1) are shifted towards longer retention times with regard to the unmodified lignin.
  • siloxane groups it has shown to be preferable to introduce phenolic hydroxyl groups or (aromatic) amino groups by the azo-coupling step, and react these intermediates in a second step with reactive siloxane reagents such as epoxy-functional or anhydride-functional silicones, or to introduce epoxy groups or anhydride groups by the azo-coupling step, and react these intermediates with reactive siloxane reagents such as mercapto -functional silicones or amino-functional silicones.
  • these groups are hydrophilic or hydrophobic, and add a further functionality to the diazonium group- containing modifiers B, and thus change the physicochemical properties of the resins M so modified, e. g., hydrophilicity or hydrophobicity, cohesion and adhesion properties, solubility, light and chemical resistance, and chemical reactivity.
  • Products L1 through L4 each comprise approximately 10 mmol of monolignol units.
  • a further product L0 was also taken from the unmodified lignin that was also used as educt in examples 2 to 5.
  • Resoles were made from products L0, LI, L2, L3, and L4, each in a 50 mL vessel under stirring and heating to 70 °C, 0.82 g of aqueous formaldehyde solution was added, together with 0.05 g of bariumhydroxide. After two hours, stirring was stopped, and dilute sulphuric acid was added to bring the pH to about 6.5. While the formaldehyde had been completely consumed in L4, only approximately 10 % of the formaldehyde added was consumed in L0.
  • the size of spruce veneers was approximately 120 mm x 21 mm x 3.5 nun (length, width and thickness). Veneers were submerged to cover about one quarter of the veneer length in the diluted solution of Example 3-1 for ten minutes. The impregnated veneers were then washed with deionised water or acetone, and dried in an air stream at room temperature (22 °C) for about 24 hours. A slight discolouration of the veneers indicates successful azo coupling. 27 mg each of a phenolic resin binder was applied with a spatula on one side of the impregnated zone of two identical veneers, and each two coated veneers were positioned in the measuring device so that the coated areas overlapped to obtain a binding area of approximately 21 mm x 15 mm. Curing conditions in the testing instrument were set to 110 °C and 270 s. After curing and subsequent cooling of the joint to room temperature (21 °C), the tensile testing to obtain the shear strength was started.
  • beech veneers was approximately 117 mm x 20 mm x 0.6 mm (length, width and thickness). Veneers were submerged to cover about one quarter of the veneer length in the diluted solution of Example 3-1 for ten minutes. The impregnated veneers were then washed with deionised water or acetone, or a mixture of both, and dried in an air stream at room temperature (22 °C) for about 24 hours. A slight discolouration of the veneers indicates successful azo coupling.
  • Three sets with different mass of phenolic resin binder were prepared by applying the binder with a spatula on one side of the impregnated zone of two identical veneers, and each two coated veneers were positioned in the measuring device so that the coated areas overlapped to form a binding area of 20 mm x 5 mm.
  • the mass of binder in the binding area for each of the three pairs was 9 mg on each of the two coated veneers
  • the mass of binder for each of the three pairs was 7.5 mg each of the two coated veneers
  • the mass of binder for each of the three pairs was 5 mg on each of the two coated veneers.
  • a further control set was prepared based on veneers that had not been impregnated, and where the same mass of binder was applied as in sets 3a to 3 c. These control sets are referred to as 3a', 3b', and 3c'. Curing conditions in the testing instrument were set to 110 °C and 120 s. After curing and subsequent cooling of the joint to room temperature (21 °C) of each veneer pair, the tensile testing to obtain the shear strength was started, by gripping the free ends of the veneer pair, and continually increasing the elongation under recording of the pulling force measured until breaking of the adhesive bond. The recorded pulling forces were averaged over the set with identical basic data (type of wood, amount of adhesive applied, joint area) and compared for the examples according to the invention, and the control examples with non-modified wood.
  • Ar- groups such as 4-phenoxyphenyl, stilbene-4-yl, 3,5-dihydroxystilbene-4'-yl, and 4-phenylbenzene-l-yl can also be used. It is also possible to use a diazonium salt comprising two molecules of a diazonium cation together with a bivalent anion such as hexafluorosilicate

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  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

L'invention concerne des articles, des objets ou des corps modifiés M à base de matériaux phénoliques oligomères ou polymères K, un diazonium, des composés B portant au moins un autre groupe fonctionnel qui est hydrophile ou hydrophobe ou qui modifie la tension de surface des résines ainsi modifiées, sont couplés auxdits matériaux phénoliques K par l'intermédiaire d'une réaction de couplage azoïque. Les matériaux phénoliques oligomères ou polymères K sont choisis dans le groupe constitué par les novolaques N, les résols R et les polymères P comprenant en particulier la lignine L et le tanin T, présentant des fragments aromatiques présentant une densité d'électrons accrue par rapport au benzène au niveau des atomes de carbone non substitués dans ledit fragment aromatique. Les modificateurs B contenant un groupe diazonium sont des composés aromatiques présentant un groupe diazonium de formule - (I) et au moins un autre groupe fonctionnel qui est hydrophile ou hydrophobe ou qui influence d'une autre manière les propriétés de cohésion et d'adhérence des résines ainsi modifiées, tels que des groupes perfluoroalkyle ou des groupes oligosiloxane et polysiloxane.
PCT/EP2024/060323 2023-04-16 2024-04-16 Modification de polymères aromatiques Pending WO2024218102A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
EP23168152.9A EP4450530A1 (fr) 2023-04-16 2023-04-16 Résines modifiées à base de matériaux phénoliques oligomères ou polymères résineux
EP23168152.9 2023-04-16
EP23179648.3 2023-06-16
EP23179649 2023-06-16
EP23179648 2023-06-16
EP23179649.1 2023-06-16

Publications (1)

Publication Number Publication Date
WO2024218102A1 true WO2024218102A1 (fr) 2024-10-24

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Application Number Title Priority Date Filing Date
PCT/EP2024/060323 Pending WO2024218102A1 (fr) 2023-04-16 2024-04-16 Modification de polymères aromatiques

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Country Link
WO (1) WO2024218102A1 (fr)

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