WO2007099156A1

WO2007099156A1 - Binder composition comprising an aminoplast or phenoplast resin based on at least one glyoxal monoacetal, at least one polyisocyanate compound and at least one latex, and its use

Info

Publication number: WO2007099156A1
Application number: PCT/EP2007/051973
Authority: WO
Inventors: Ngoc Can Vu; Antonio Pizzi; Aurélien DESPRES
Original assignee: Clariant Speciality Fine Chemicals France
Current assignee: Clariant Speciality Fine Chemicals France
Priority date: 2006-03-02
Filing date: 2007-03-02
Publication date: 2007-09-07
Anticipated expiration: 2008-09-02
Also published as: AU2007220458A1; FR2898128A1

Abstract

The invention relates to binder compositions comprising an aminoplast or phenoplast resin based on at least one glyoxal monoacetal, at least one polyisocyanate compound and at least one latex, and also their uses as adhesives or binders.

Description

BINDER COMPOSITION COMPRISING AN AMINOPLAST OR PHENOPLAST RESIN BASED ON AT LEAST ONE GLYOXAL MONOACETAL, AT LEAST ONE POLYISOCYANATE COMPOUND AND AT LEAST ONE LATEX, AND ITS USE

The present invention relates to binder compositions comprising an aminoplast or phenoplast resin based on at least one glyoxal monoacetal, at least one polyisocyanate compound and at least one latex, and also their uses as adhesives or binders.

The change in regulations, especially as regards environmental and health protection, has led to the development of formaldehyde- free resins, with a view to limiting the release of formaldehyde into industrial effluents and the environment.

Aminoplast resins based on amine derivatives, such as urea or melamine, and on aldehydes and their uses for treating cellulose fibres are described, for example, in Patents EP 0381905 and EP 0698627.

Formaldehyde-based resins comprising isocyanate compounds and having a reduced formaldehyde emission are described, for example, in Patents EP 025245 or WO 01/38416.

The manufacture of cellulose particleboards using an aminoplast resin based on melamine-urea- formaldehyde as a binder, to which a polyisocyanate is added, is described in Patent EP 107260.

However, these resins do not satisfactorily solve the problem of formaldehyde emission.

The technical problem to be solved consists therefore in providing resin compositions which, while respecting the current regulations, behave in many applications as formaldehyde-based resins, such as melamine-formaldehyde, urea- formaldehyde or phenol- formaldehyde resins, but while not containing any formaldehyde.

In particular, it is desirable to obtain a product that has sufficient reactivity for the intended industrial application, and which especially allows the binder content and/or pressing time to be decreased during manufacture of materials, while respecting the current standards.

It has now been discovered that binder compositions comprising a formaldehyde- free aminoplast or phenoplast resin based on at least one glyoxal monoacetal, at least one polyisocyanate compound and at least one latex allow the problem of formaldehyde emission to be solved, while retaining satisfactory mechanical properties.

Advantageously, it has also been discovered that the addition of latex to a binder composition comprising an aminoplast or phenoplast resin based on at least one glyoxal monoacetal, and at least one polyisocyanate compound allows a composition to be obtained, the tensile strength properties of which are improved.

These properties are particularly advantageous for the use of these compositions for treating woven or nonwoven fabrics or in the manufacture of ligneous materials from agricultural waste and wood, such as fibreboards, particleboards and other similar boards and plywoods.

The term "glyoxal monoacetal" is understood to mean a compound of formula (I)

in which Ri and R₂, being identical or different, represent a linear or branched Ci-Cs alkyl group or else Ri and R₂ are linked to form a l,3-dioxolan-2-yl group optionally substituted at positions 4 and/or 5 by one or more C1-C4 alkyl substituents, or a 1,3- dioxan-2-yl group optionally substituted at positions 4 and/or 5 and/or 6 by one or more C1-C4 alkyl substituents.

In the rest of the description, it is understood that the glyoxal monoacetal of formula (I) above may also exist in its hydrated form with the following formula: R₁O OH

\ /

CH — CH

/ \

R₂O OH

The term "linear or branched Ci-Cs alkyl group" is understood to mean in particular a methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, heptyl or octyl group.

The term "C1-C4 alkyl substituent" is understood to mean a linear or branched C1-C4 alkyl group, in particular a methyl, ethyl, propyl, isopropyl, butyl, isobutyl or tert-butyl group.

Preferably Ri and R₂ represent a linear or branched C1-C4 alkyl group, preferably the same group and in particular a methyl group.

When Ri and R₂ represent methyl, the monoacetal of formula (I) is dimethoxyethanal (DME), which is a preferred glyoxal monoacetal and is sold by Clariant (France) under the trademark HIGHLINK^® DM.

The term "aminoplast resin based on at least one glyoxal monoacetal" is understood to mean the product of the (poly)condensation of a substituted or unsubstituted amine derivative, such as urea, ethyleneurea, 1,3-dimethylurea, melamine, glycoluril, benzoguanamine or mixtures thereof with a glyoxal monoacetal of formula (I). Melamine, urea or mixtures thereof are preferred.

Preferably, the aminoplast resins based on at least one glyoxal monoacetal are chosen from urea-DME, melamine-DME or melamine-urea-DME type resins, sold by Clariant (France) in the Highlink^® range.

The term "phenoplast resin based on at least one glyoxal monoacetal" is understood to mean the product of the (poly)condensation of a substituted or unsubstituted phenol derivative, such as phenol, resorcinol, tannins, lignins or mixtures thereof with a glyoxal monoacetal of formula (I). Phenol is preferred. Preferably, the phenoplast resins based on at least one glyoxal monoacetal are chosen from phenol-DME type resins sold by Clariant (France) in the Highlink^® range.

According to one variant of the invention, the aminoplast and phenoplast resins described above may be partially or totally etherified by C1-C4 alcohols or by polyols.

The term "C1-C4 alcohol" is understood to mean, for example, methanol, ethanol, propanol or butanol, preferably methanol.

Suitable polyols comprise a dialkylene glycol, a polyalkylene glycol, glycerol, an alkoxylated glycerol, polyvinyl alcohol, dextrose (and oligomers and derivatives of dextrose), starch, derivatives of starch such as the hydrolysis products of starch, polyglycidol, polysaccharides (and their derivatives) or mixtures thereof.

Favoured polyols are triethoxylated glycerol, tripropoxylated glycerol, dipropylene glycol, diethylene glycol, polyvinyl alcohol, dextrose, maltose, maltodextrines, glucose and also mixtures thereof.

The term "polyisocyanate" is understood to mean linear or branched aliphatic compounds, cycloaliphatic compounds or aromatic compounds which include at least two isocyanate functional groups, that are possibly (self)emulsifiable in water, possibly dispersible in water and are miscible or immiscible in water.

They are, in a nonlimiting way, diisocyanates, triisocyanates, tetraisocyanates, polyisocyanates, or mixtures thereof.

As linear aliphatic compounds, mention may in particular be made of compounds such as hexamethylene diisocyanate (HDI), tetramethylene diisocyanate (TMDI) and undecane triisocyanates (UNTIs).

As branched aliphatic compounds, mention may be made of 2-methylpentane diisocyanate, 2,2,4- and 2,4,4-trimethyl-l,6-diisocyanatohexane. Among the cycloaliphatic compounds, mention may be made of, for example, isophorone diisocyanate (IPDI), norbornane diisocyanate (NBDI), 4,4'- bis(isocyanatocyclohexyl)methane (H12MDI) or l,3-bis(isocyanatomethyl)cyclohexane (hydrogenated XDI).

As aromatic compounds, mention may also be made of compounds such as 2,4- or 2,6- toluene diisocyanate (TDI), 4,4'- or 2,4'- or 2,2'-diphenylmethane diisocyanate, 1,5- naphthalene diisocyanate (NDI), /?-phenylene diisocyanate (PPDI), xylylene diisocyanate (XDI) or tetramethylxylylene diisocyanate (TMXDI).

The polyisocyanate compounds may also result from the condensation between two or more isocyanate compounds and may form homopolymers and/or oligomers and/or polymers.

As examples, mention may be made of polymeric 4,4'-diphenylmethane diisocyanate (pMDI) and the homopolymer of HDI.

The polyisocyanate compounds may also result from the condensation of compounds bearing isocyanate functional groups with compounds bearing other functional groups that react with the isocyanate functional groups. Common structures in this field are, for example, urethane-type structures (also called prepolymers) obtained by reaction with polyols, biuret-type structures obtained, for example, by the reaction of three molecules of diisocyanate with one molecule of water, the isocyanurate- or uretdione-type structures obtained by trimerization or dimerization of diisocyanates or else allophanate- type structures obtained by reaction with alcohols.

The polyisocyanate compounds may also consist of a mixture of two or more compounds bearing at least two isocyanate functional groups.

According to one variant of the invention, polyisocyanate compounds, the isocyanate groups of which are totally or partially blocked and that are obtained by reaction with blocking agents, may also be used. The blocking agents are compounds having at least one hydrogen atom that reacts with the isocyanate functional group. By way of nonlimiting example, mention may be made of hydroxy lamine derivatives such as hydroxysuccinimide, oximes such as methyl ethyl ketoxime, phenol and its derivatives, amide derivatives such as imides, lactams and malonates and nitrogen heterocycles such as 3,5-dimethylpyrazole.

The polyisocyanate compounds are often commercial products or can be prepared by techniques known per se and are usually in the following forms: powder, liquid, generally as a solution in solvents or as an emulsion or a dispersion in water.

The polyisocyanate may be added to the aminoplast or phenoplast resin based on at least one glyoxal monoacetal. According to one preferred aspect, it is added just at the time of use.

The polyisocyanate compound may represent, for example, from 1 to 90% by dry weight of all the composition constituents, preferably 1 to 40%, more preferably 5 to 30% and most particularly 10 to 25%.

The term "latex" is understood to mean aqueous compositions consisting of an emulsion or a suspension of polymer particles in an aqueous medium.

The latices are well known to a person skilled in the art and are generally prepared by emulsion or suspension (co)polymerization of at least one ethylenically unsaturated monomer in an aqueous medium.

These monomers may be chosen from the group made up of: ethylenically unsaturated mono- and di-carboxylic acids such as acrylic acid, methacrylic acid, maleic acid or fumaric acid; - aromatic vinyls such as styrene, α-methylstyrene or vinyltoluene; (meth)acrylic acid esters like, for example, alkyl or hydroxyalkyl or alkoxyalkyl (meth)acrylates, such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, hydroxypropyl acrylate, ethoxyethyl methacrylate, hydroxypropyl methacrylate or ethoxyethyl methacrylate; esters of ethylenically unsaturated dicarboxylic acids such as butyl maleate; vinyl esters of linear or branched carboxylic acids such as vinyl acetate, vinyl versatates, vinyl stearate or vinyl propionate; - monoolefins such as ethylene or propylene; conjugated dienes such as butadiene or isoprene; acrylamide, methacrylamide and their derivatives such as acrylamidomethylpropanesulphonic acid or N-methylol(meth)acrylamide; acrylonitrile or methacrylonitrile; and - vinyl chloride or vinylidene chloride.

The composition of the monomer mixture to be polymerized depends on the glass transition temperature (Tg) and therefore on the character that it is desired to impart to the polymer formed ("hard" latex or "soft" latex).

These latices may be obtained according to the (co)polymerisation techniques known to a person skilled in the art, especially as an aqueous emulsion of the polymerizable monomers, in the presence of radical initiators and surfactants. The polymerization may be carried out as a continuous, batch or semi- continuous polymerization.

As examples of latices that may possibly be used in the present invention, mention may be made, for example, of: acrylate copolymers (pure acrylic latex) such as MOWILITH^® DM 777 sold by Clariant; - styrene/acrylate copolymers (styrene/acrylic latex) such as MOWILITH^®

LDM 6636 sold by Clariant; acetate/vinyl versatate copolymers (vinyl versatic latex) such as MOWILITH^®

LDM 2417 sold by Clariant; vinyl acetate homopolymers such as MOWILITH^® LD 167 sold by Celanese; styrene/butadiene copolymers; and vinyl acetate/ethylene copolymers such as MOWILITH^® LDM 1851 sold by Celanese.

The preferred resins based on at least one glyoxal monoacetal are those in which: in the case of the aminoplast resins, these are based on a nitrogen-containing compound/dimethoxyethanal mixture, preferably at a ratio of about 1/1 to 1/3, especially 1/1.5 to 1/2.5, particularly 1/2. - in the case of the phenoplast resins, these are based on a phenols/ dimethoxyethanal mixture, preferably at a ratio of about 1/1 to 1/3, especially 1/1.5 to 1/2.5, particularly 1/2.

The latex may represent, for example, from 1 to 90% by dry weight of all the composition constituents, especially 10-90%, particularly 15-70%, more particularly 10 to 50%, preferably 20 to 40% and more preferably 25 to 35%.

According to one advantageous aspect, the aminoplast or phenoplast resin based on at least one glyoxal monoacetal, the polyisocyanate compound(s) and the latex (or latices) are packaged separately, and mixed at the time of use.

According to another advantageous aspect, the aminoplast or phenoplast resin based on at least one glyoxal monoacetal comprising, as a mixture, at least one latex on the one hand, the polyisocyanate compound(s) on the other hand are packaged separately and mixed at the time of use.

The invention therefore also relates to the various packagings as described above comprising the aminoplast or phenoplast resin based on at least one glyoxal monoacetal, the polyisocyanate compound(s) and at least one latex.

The composition according to the invention may be prepared according to the known mixing techniques, for example by taking an aminoplast or phenoplast resin based on at least one glyoxal monoacetal then by adding at least one latex while using gentle stirring.

The addition of the polyisocyanate to the composition may be carried out before or after addition of the latex. Advantageously, the addition of the polyisocyanate is carried out after that of the latex. Preferably, the polyisocyanate is added just at the time the composition is used.

Another subject of the invention is a method for preparing a binder composition as described above, comprising the steps that consist in bringing, at the time of use, a mixture comprising at least one aminoplast or phenoplast resin based on at least one glyoxal monoacetal and at least one latex into contact with at least one polyisocyanate compound.

The ingredients are usually added to the mixer following an addition order such as the one that is present in the lowest quantity is added to the ingredient that is present in the largest quantity.

The addition of acid or latent acid curing catalysts to the binder composition is generally desirable, preferably just before its use. Suitable catalysts are, for example, hydrochloric acid, sulphuric acid, phosphoric acid, /?-toluenesulphonic acid, methanesulphonic acid, aluminium salts such as aluminium chloride and aluminium chlorhydroxide, magnesium chloride, ammonium sulphate, zirconium sulphate, zinc chloride and mixtures thereof.

Mono-, di-, tri- and tetracarboxylic acids may also be used, such as acetic acid, glyoxylic acid, oxalic acid, citric acid and also mixtures thereof.

In a preferred embodiment glyoxylic acid is used as a catalyst, which facilitates the reaction(s) that cause crosslinking and film formation of the compositions of the present invention.

The acid catalyst is generally added in a quantity of 0.1% to 15%, preferably 1% to 10% and more preferentially 3% to 7% by weight (on a dry basis) of the composition. Also, additives may be incorporated into the composition, such as those conventionally used in the applications of formaldehyde-based aminoplast or phenoplast resins and known to a person skilled in the art.

Generally, these additives are added to the composition just before its use. Thus, the composition may comprise one or more adjuvants chosen from fillers, demoulding agents, dyes or pigments, stabilizers, thickeners, emulsifiers, surfactants, co-solvents, antifreezes, anti-foaming agents, bactericides, fungicides, pesticides, plasticizers, flame retardants, coalescing agents, tackifiers, UV stabilizers, viscosity reducers, fragrances, antioxidants, acids, bases and buffering agents.

The compositions of the invention do not contain formaldehyde, are stable over time, possess a high solids content and have good mechanical properties such as dimensional stability under heat and tensile strength.

These properties justify the use of the compositions according to the invention as a binder for natural or synthetic fibres such as, for example glass fibres, nylon, polyester fibres, nonwoven substrates and also cellulose substrates.

These properties also justify the use of the compositions described above in the manufacture of impregnable substrates including laminated papers or boards, especially sheets of decorative paper or decorative laminates.

Indeed, conventionally the manufacture of laminates using thermosetting resins is carried out by impregnation of a paper support with various resins, for example phenolic or melamine-based resins, then drying and trimming. After drying and trimming, the coated (pre-impregnated) papers are stacked up and stored. The laminating phase makes it possible, by stacking of these sheets and hot pressing, to stop the reaction of the resins and thus to produce the final product. There are also methods combining, after impregnation, drying and laminating.

Another subject of the invention is the use of the compositions described above in the manufacture of ligneous materials from agricultural waste and wood, such as fibreboards, particleboards, oriented strand boards (OSB), medium and high density fibreboards (MDF), and other types of similar boards and plywoods.

The manufacture of the boards generally combines mechanical mixing of the particles or fibres with the composition of the present invention followed by hot pressing in order to cure the resin and form the board. Typically, the pressing temperatures are in the range of 110⁰C to 240⁰C. Generally, the boards contain 3 to 40% by weight of the composition, preferentially 5 to 20% by weight of the composition.

The particles or fibres may be mixed with the composition of the invention either when the aminoplast or phenoplast resin based on at least one glyoxal monoacetal is premixed with one or some polyisocyanate compound(s) and with one or some latex or latices, or else when the various components are simply added simultaneously.

Alternatively, one or more components of the composition may be premixed with the particles or fibres, and the remainder of the components added afterwards. For example, the aminoplast or phenoplast resin based on at least one glyoxal monoacetal comprising, as a mixture, at least one latex, may be mixed with the particles or fibres, then the polyisocyanate compound(s) is (are) incorporated.

The use of the binder composition as described above for manufacturing fibreboards, particleboards, oriented strand boards or medium and high density fibreboards represents subsequent aspects of the invention.

In particular, the invention relates to such a use, comprising a step of mixing the particles or fibres with an aminoplast or phenoplast resin based on at least one glyoxal monoacetal, at least one polyisocyanate compound, and at least one latex, said resin, said polyisocyanate compound and said latex being either mixed together first or added simultaneously to said particles or fibres.

Alternatively, the invention relates to such a use, comprising a step that consists in mixing the particles or fibres with a mixture previously made from an aminoplast or phenoplast resin based on at least one glyoxal monoacetal and from at least one latex, and a step of adding at least one polyisocyanate compound.

Advantageously, the use of the compositions according to the invention enables the pressing time and/or the binder content to be decreased during the manufacture of said materials.

Another subject of the invention is the use of the compositions described above as an adhesive intended to bond the materials, together or to a support, and in all their forms.

The material to be bonded may be chosen from the list comprising paper, board, plastics and wood.

Preferably, said material is wood. This material may be made from a plurality of flat layers of wood, such as the thin sheets of wood used in veneering.

The adhesive may be applied to the substrate, such as a sheet of paper, then dried according to normal procedures.

The invention is illustrated, in a nonlimiting way, by the examples below.

Example 1

65.48 g of 67.7% melamine/DME (1/2) resin were mixed with 45.47 g of an aqueous dispersion of APPRET AN^® N 9213 acrylic ester copolymers (acrylic-type latex having a T_g of 25°C, a solids content of about 45% and a pH of 6; sold by Clariant), then 12.94 g of MONDUR^® 1441 (sold by Bayer; water-dispersible polyisocyanate derived from MDI) were added. A homogenous composition was obtained.

Application example 2: bonding of particleboards Particleboards were manufactured from various mixtures of adhesive, dry wood chips and catalysts (see Table 1). The quantities in Table 1 are given in g and expressed as dry weights. The wood chips, then the aminoplast resin based on at least one glyoxal monoacetal comprising, as a mixture, the latex and the catalyst, and lastly the polyisocyanate compound were successively introduced into a mixer, which allowed a good distribution of the adhesive around the wood chips. Next, the wood chips were spread homogeneously in a mould and pressed at a surface temperature of 192°C with a pressing cycle of 2 min 30 s at 28 kg/cm , 3 min at 13 kg/cm and 4 min 30 s at 8 kg/cm , to give a final board thickness of 14 mm (pressing time: 42.8 s/mm).

Tensile strength measurements were carried out on the boards obtained, using the method described in European standard EN 319.

The binder content represents the mass of dry composition divided by the mass of dry wood. The binder content was 12%.

The urea/DME resin used was a HIGHLINK^® DU resin concentrated to 67.7% and sold by Clariant (France).

The melamine/DME resin used was a HIGHLINK^® DMM resin concentrated to 71% and sold by Clariant (France).

The DESMODUR^® VKS 20 was a mixture of 4,4'-diphenylmethane diisocyanate (MDI) with functionalized isomers and homologues, sold by Bayer.

Table 1

The results of the tensile strength measurements are given in Table 2 below.

Table 2

The current standard relating to the tensile test results (EN 312) prescribes a minimum internal bond strength (IB) value of 0.35 MPa. The results show that the resins C, D, F and G that contain both a polyisocyanate and a latex have improved particleboard internal bond strengths, allowing boards to be obtained that meet the demands of the current standards.

In addition, this great improvement in the strengths may make it possible to decrease the pressing time and/or the binder content, while satisfying the demands of standard EN 312.

Application example 3: bonding of particleboards a) preparation of boards using a melamine/DME (1/2) resin

Particleboards were manufactured from various mixtures of adhesive, dry wood chips and hardeners (see Table 3 below). The quantities in Table 3 are given in g and expressed as dry weights.

The method for preparing the boards was identical to that in example 2 above.

The binder contents (weight of dry resin divided by the weight of dry wood) were 12%.

Table 3

b) Tensile test results

Tensile strength measurements perpendicular to the surface, were carried out on the boards obtained using the methods described in European standards

EN 300, EN 313 and EN 319. The results obtained are given in Table 4 below.

Table 4

The current standard relating to the tensile test results (EN 312) prescribes a minimum internal bond strength value of 0.35 MPa for 14mm panels.

The results clearly show an improvement in the perpendicular tensile strength of the particle boards made by substituting part of the melamine/DME resin with a latex (composition I) or with a polyisocyanate (composition J). They also show an even greater strength when both additives are incorporated into the resin (composition K).

Claims

1. Binder composition, characterized in that it comprises an aminoplast or phenoplast resin based on at least one glyoxal monoacetal, at least one polyisocyanate compound and at least one latex.

2. Composition according to Claim 1, characterized in that said glyoxal monoacetal is a compound of formula (I)

in which Ri and R₂, being identical or different, represent a linear or branched Ci- Cs alkyl group or else Ri and R₂ are linked to form a l,3-dioxolan-2-yl group optionally substituted at positions 4 and/or 5 by one or more C1-C4 alkyl substituents, or a l,3-dioxan-2-yl group optionally substituted at positions 4 and/or 5 and/or 6 by one or more C1-C4 alkyl substituents.

3. Composition according to Claim 2, characterized in that in formula (I), Ri and R₂, being identical or different, represent a group chosen from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, heptyl and octyl groups.

4. Composition according to either one of Claims 2 and 3, characterized in that Ri and R₂, being identical or different, represent a linear or branched C₁-C₄ alkyl group

5. Composition according to any one of Claims 2 to 4, characterized in that Ri and R₂, being identical, represent a methyl group.

6. Composition according to any one of Claims 1 to 5, characterized in that the aminoplast resin based on at least one glyoxal monoacetal results from the (poly)condensation of a substituted or unsubstituted amine derivative, chosen from urea, ethyleneurea, 1,3-dimethylurea, melamine, glycoluril, benzoguanamine and mixtures thereof with a glyoxal monoacetal of formula (I).

7. Composition according to Claim 6, characterized in that the aminoplast resin based on at least one glyoxal monoacetal is chosen from urea-DME, melamine- DME or melamine-urea-DME type resins.

8. Composition according to any one of Claims 1 to 5, characterized in that the phenoplast resin based on at least one glyoxal monoacetal results from the

(poly)condensation of a substituted or unsubstituted phenol derivative, chosen from phenol, resorcinol, tannins, lignins and mixtures thereof with a glyoxal monoacetal of formula (I).

9. Composition according to Claim 8, characterized in that the phenoplast resin based on at least one glyoxal monoacetal is chosen from phenol-DME type resins.

10. Composition according to any one of Claims 1 to 9, characterized in that said aminoplast or phenoplast resin is partially or totally etherified by a C₁-C₄ alcohol or a polyol.

11. Composition according to any one of Claims 1 to 10, characterized in that the polyisocyanate compound is chosen from diisocyanates, triisocyanates, tetraisocyanates and mixtures thereof.

12. Composition according to Claim 11, characterized in that the polyisocyanate compound is chosen from: homopolymers and/or oligomers and/or polymers resulting from the condensation of two or more isocyanate compounds; - compounds resulting from the condensation of compounds bearing isocyanate functional groups with compounds bearing other functional groups that react with the isocyanate functional groups; and polyisocyanate compounds, the isocyanate groups of which are totally or partially blocked and that are obtained by reaction with blocking agents.

13. Composition according to Claim 11, characterized in that the polyisocyanate compound is chosen from hexamethylene diisocyanate (HDI), hexamethylene diisocyanate homopolymer, tetramethylene diisocyanate (TMDI) and polymeric 4,4'-diphenylmethane diisocyanate (pMDI).

14. Composition according to any one of Claims 1 to 13, characterized in that the polyisocyanate compound is present at a ratio of 1 to 90% by dry weight of all the composition constituents.

15. Composition according to Claim 14, characterized in that the polyisocyanate compound is present at a ratio of 1 to 40% by dry weight of all the composition constituents.

16. Composition according to any one of Claims 1 to 15, characterized in that the latex is chosen from acrylate copolymers, styrene/acrylate copolymers, acetate/ vinyl versatate copolymers, vinyl acetate homopolymers, styrene/butadiene copolymers and vinyl acetate/ethylene copolymers.

17. Composition according to Claim 16, characterized in that the latex is present at a ratio of 1 to 90% by dry weight of all the composition constituents.

18. Composition according to Claim 17, characterized in that the latex is present at a ratio of 10 to 90% by dry weight of all the composition constituents.

19. Composition according to any one of Claims 1 to 18, characterized in that it comprises, in addition, at least one catalyst chosen from hydrochloric acid, sulphuric acid, phosphoric acid, /?-toluenesulphonic acid, methanesulphonic acid, aluminium salts, magnesium chloride, ammonium sulphate, zirconium sulphate, zinc chloride, acetic acid, glyoxylic acid, oxalic acid and citric acid.

20. Composition according to any one of Claims 1 to 19, characterized in that it comprises, in addition, one or more adjuvants chosen from fillers, demoulding agents, dyes or pigments, stabilizers, thickeners, emulsifiers, surfactants, co- solvents, antifreezes, anti-foaming agents, bactericides, fungicides, pesticides, plasticizers, flame retardants, coalescing agents, tackifiers, UV stabilizers, viscosity reducers, fragrances, antioxidants, acids, bases and buffering agents.

21. Packaging comprising a binder composition according to any one of Claims 1 to 20, characterized in that the aminoplast or phenoplast resin based on at least one glyoxal monoacetal, the polyisocyanate compound(s) and the latex or latices are in separate forms.

22. Packaging comprising a binder composition according to any one of Claims 1 to 20, characterized in that the aminoplast or phenoplast resin based on at least one glyoxal monoacetal, as a mixture with at least one latex on the one hand, and the polyisocyanate compound(s) on the other hand are in separate forms.

23. Use of a composition according to any one of Claims 1 to 20 as a binder for natural or synthetic fibres.

24. Use of a composition according to any one of Claims 1 to 20 in the manufacture of impregnable substrates including laminated papers or boards.

25. Use of a composition according to any one of Claims 1 to 20 in the manufacture of fibreboards, particleboards, oriented strand boards or high and medium density fibreboards.

26. Use of a composition according to any one of Claims 1 to 20 as an adhesive for bonding materials together or to a support.

27. Use according to Claim 26, characterized in that said material to be bonded is chosen from paper, board, plastics and wood.

28. Use according to Claim 25, characterized in that it comprises a step of mixing the particles or fibres with an aminoplast or phenoplast resin based on at least one glyoxal monoacetal, at least one polyisocyanate compound, and at least one latex, said resin, said polyisocyanate compound and said latex being either mixed together first or added simultaneously to said particles or fibres.

29. Use according to Claim 25, characterized in that it comprises a step that consists in mixing the particles or fibres with a mixture previously made from an aminoplast or phenoplast resin based on at least one glyoxal monoacetal and from at least one latex, and a step of adding at least one polyisocyanate compound.