Method for reducing the polyisocyanate monomer content in a polymeric composition

Abstract

The present invention relates to a method for reducing the polyisocyanate monomer content in a polymeric composition. It also relates to a polymeric composition having a reduced polyisocyanate monomer content.

Description

Title of the invention: Method for reducing the polyisocyanate monomer content in a polymeric composition

[0001] The present invention relates to a method for reducing the polyisocyanate monomer content in a polymeric composition. It also relates to a polymeric composition having a reduced polyisocyanate monomer content.

[0002] Global consumption of polyurethanes has steadily increased in recent years. Given the strength and versatility of these polymers, they offer a wider range of applications than other products on the market. They are found, for example, in the form of flexible foams in car seats, in the form of rigid foams in ship hulls, and in the form of textile fibers, commonly known as elastane fibers. More specifically, in the construction sector, polyurethanes are used as coatings, particularly for waterproofing roofs, facades, and balconies, as adhesives, and as sealants.

[0003] Polyurethane is typically obtained by the reaction of a polyisocyanate and a polyol. However, a major problem with this type of polymer is the residual presence of polyisocyanate monomer. Polyisocyanates are indeed toxic molecules that can, in the long term, cause asthma and dermatitis. Legislation is becoming increasingly strict regarding the residual presence of these monomers in polyurethane-based products.

[0004] Various methods have been proposed to solve this problem. For example, distillation and thin-film evaporation, which are physical methods, are effective but costly, particularly because they require specialized equipment. Chemical methods generally do not require specialized equipment, but they use expensive reagents, which are used in high concentrations and / or are themselves toxic.

[0005] There therefore remains a real need to provide a method for reducing the residual polyisocyanate monomer content in a polymeric composition, in particular a polyurethane composition, which is simple and effective. Summary of the invention

[0006] In this context, the inventors demonstrated that, surprisingly, the use of a mineral filler having a certain specific surface area made it possible to significantly reduce the amount of residual polyisocyanate monomers contained in a polymeric composition. It was also found that the rate of isocyanate terminations of an isocyanate-terminated polymer were little or not affected when the method was implemented, thus demonstrating its good selectivity.

[0007] The method is inexpensive and simple, since it can be implemented at a moderate heating temperature, or even at room temperature, as well as in ambient air, and without special equipment.

[0008] Thus, the present invention relates to a method for reducing the polyisocyanate monomer content in a polymeric composition, said method comprising:

[0009] a) the supply of a polymeric composition comprising a polymer and a polyisocyanate monomer, and

[0010] b) bringing said polymeric composition into contact with a mineral filler having a specific surface area of ​​1 to 500 m2 / g and water.

[0011] In some embodiments, the mineral filler is chosen from silica, calcium silicate, calcium carbonate, perlite, clay, alumina, magnesium silicate, potassium silicate, aluminium silicate, a hydrate of these, and a mixture of at least two of these.

[0012] In some embodiments, the specific surface area of ​​the mineral charge is from 10 to 500 m2 / g, preferably from 15 to 400 m2 / g, even better from 20 to 300 m2 / g, for example from 25 to 200 m2 / g.

[0013] In some embodiments, the weight content of said mineral filler in step b) is 0.2 to 5%, preferably 0.5 to 3%, or even 0.6 to 2.5%, or even 0.7 to 2.1%, relative to the weight of said polymer.

[0014] In some embodiments, the water in step b) is supplied solely by the humidity of the ambient air.

[0015] In some embodiments, liquid water is added in step b), preferably in a weight content less than or equal to 0.5%, better still less than or equal to 0.2%, for example from 0.01 to 0.15%, relative to the weight of said polymer.

[0016] In some embodiments, step b) is carried out at a temperature between 15 and 80 °C, preferably between 20 and 75 °C, or even between 40 and 70 °C.

[0017] In some embodiments, the polymer content by weight in the composition at step a) is from 5 to 99.9%, preferably from 10 to 99%, better still from 20 to 90%, or even from 20 to 80%, for example from 25 to 65%, or even from 25 to 50%, relative to the total weight of the composition.

[0018] In some embodiments, the weight content of polyisocyanate monomer in the composition at step a) is greater than or equal to 0.1% and less than 10%, relative to the weight of the polymer.

[0019] In certain embodiments, said polyisocyanate monomer of the polymeric composition is selected from 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), methylene bis-(4-cyclohexylisocyanate) (HMDI), pentamethylene diisocyanate (PDI), 4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, dicyclohexylmethane diisocyanate, tetramethylxylene diisocyanate, norbomane diisocyanate, bis-(isocyanatomethyl)cyclohexane, tetramethylene-1,4-diisocyanate, cyclohexane-1,4-diisocyanate, 1,12-dodecane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and diphenylmethylene 2,2'-diisocyanate (2,2'-MDI), diphenylmethylene 4,4'-diisocyanate (4,4'-MDI), 4,4'-dibenzyl diisocyanate (4,4'-DBDI), toluene 2,6-diisocyanate (2,6-TDI), m-xylylene diisocyanate (m-XDI), diphenylmethylene 2,4'-diisocyanate (2,4'-MDI), 2,4'-dibenzyl diisocyanate (2,4'-DBDI), toluene 2,4-diisocyanate (2,4-TDI),and a mixture of at least two of these.

[0020] In some embodiments, the polymer is a polymer formed from polyisocyanate(s) and compound(s) comprising several reactive functions with respect to isocyanates, preferably the polymer is a polyurethane or a polyurea, even better a polyurethane.

[0021] Preferably, the polymer is an isocyanate-terminated polymer. Advantageously, the method is selective so that at least 70%, preferably at least 75%, or even at least 80%, in particular at least 90%, for example at least 95%, of the isocyanate terminations of the isocyanate-terminated polymer are preserved.

[0022] The present invention also relates to a polymeric composition comprising:

[0023] - a polymer (preferably a polyurethane),

[0024] - a mineral filler having a specific surface area of ​​1 to 500 m² / g, and

[0025] - a polyisocyanate monomer content by weight of less than 0.5% (preferably less than 0.3%, or even less than 0.1%, relative to the weight of the polymer,

[0026] said composition preferably being in the form of a foam, a coating, an adhesive or a sealant. DETAILED DESCRIPTION

[0027] The method according to the invention is a method for reducing the polyisocyanate monomer content in a polymeric composition. The polymeric composition comprises a polymer and a polyisocyanate monomer. Although the terms "polymer" and "polyisocyanate monomer" are used in the singular in this application, they also encompass, unless otherwise specified, mixtures of polymers and mixtures of polyisocyanate monomer, respectively.

[0028] The polymer of the composition is typically a polymer formed from polyisocyanate monomer(s) and compound(s) comprising several (i.e. at least 2) reactive functions with respect to isocyanates.

[0029] Examples of reactive functions with respect to isocyanates include, in particular, a hydroxy (-OH), a mercapto (-SH), a primary amino (-NH2), a secondary amino (-NH-), a carboxylic acid (-COOH), or an amido (-C(O)-NH-, in particular -C(O)NH2).

[0030] The compound comprising several reactive functions with respect to isocyanates is preferably chosen from polyols, polyamines, amino alcohols, hydroxylated carboxylic acids, amino carboxylic acids, or a mixture thereof, even better from polyols.

[0031] The term "polyol" means any organic compound comprising at least two hydroxyl groups. In particular, the polyol may be an aliphatic or aromatic polyol, saturated or unsaturated, linear or branched, and cyclic or acyclic.

[0032] The polyol is preferably chosen from the group consisting of a polyether-polyol (e.g. polyethylene glycol, polypropylene glycol), a polyester-polyol and a polycarbonate-polyol.

[0033] Polyether-polyols can be obtained by the polymerization of a cyclic oxide, for example propylene oxide, ethylene oxide, trimethylene oxide, tetrahydrofuran, 3-methyl tetrahydrofuran or by the addition of one or more of these oxides to initiators such as water, ethylene glycol, propylene glycol, diethylene glycol, glycerol, cyclohexane-dimethanol, trimethylolpropane, pentaerytrithol, bisphenol A. Thus, examples of linear or branched polyether-polyols are polypropylene glycol, polyethylene glycol, polytetramethylene glycol or poly(ethylene / propylene) glycol.

[0034] Examples of aliphatic or aromatic polyester-polyols are glycol esters with one or more alcohol groups obtained by condensation of polycarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and phthalic anhydride with polyols. Examples of polyols for preparing polyester-polyols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, glycerol, trimethylolpropane, pentaerythritol, cyclohexane-dimethanol, and 1,8-octanediol. Polyester-polyols can also be obtained by the polymerization of lactones such as caprolactone.

[0035] Polyester-polyols can also be obtained from unsaturated fatty acids such as oleic acid, linoleic acid, licanic acid, arachidonic acid, ricinoleic acid or linoleic acid, for example from linseed, soybean, sunflower, rapeseed or herring oil.

[0036] Polycarbonate polyols can be obtained by esterification of carbonic acid with a diol or a polyol. Polycarbonate polyols can also be obtained by reacting phosgene or carbonates, such as diethyl carbonate or diphenyl carbonate, with a diol or a polyol. Examples of polyols include ethylene glycol, propylene glycol, and glycerol.

[0037] The number average molar masses of the polyols used are generally between 300 and 10000, or more particularly between 400 and 8000, or even between 500 and 5000 (number average molar masses determined by gel permeation chromatography, also called size exclusion chromatography).

[0038] Low molar mass polyols, typically between 60 and 300, can also be used in the synthesis of the carboxylated prepolymer. Examples of low molar mass polyols are ethylene glycol, propylene glycol, 1,2- and 1,3-propanediol, 1,2-, 1,3-, and 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerol, neopentyl glycol, trimethylol-propane, pentaerythritol, cyclohexane-dimethanol, 1,2- and 1,4-cyclohexanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, and tripropylene glycol.

[0039] The term “polyamine” means any organic compound comprising at least two amino groups selected from primary and secondary amino groups. The polyamine may in particular be selected from aliphatic polyamines, cycloaliphatic polyamines, arylaliphatic polyamines, aromatic polyamines, heteroaliphatic polyamines (for example, those containing at least one ether group), polyamidoamines, phenalkamines, fatty amines, and a combination thereof.

[0040] Aliphatic polyamines are in particular selected from 2,2-dimethyl-1,3-propanediamine, 1,3-pentanediamine, 1,5-pentanediamine, 1,5-diamino-2-methylpentane, 2-butyl-2-ethyl-1,5-pentanediamine, 1,6-hexanediamine, 2,5-dimethyl-1,6-hexanediamine, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 3-(2-aminoethyl)-aminopropylamine, bis-(hexamethylene)-triamine, the diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and other linear polyethylene amine homologs having 5 or more ethylene amine units. Preferred examples of aliphatic polyamines include 2-methylpentane-1,5-diamine, 1,5-pentanediamine, tetraethylenepentamine, 1,8-diamino-3,6-dioxaoctane, and 1,13-diamino-4,7,10-trioxatridecane.

[0041] Cycloaliphatic polyamines are in particular selected from 1,2-, 1,3- and 1,4-diaminocyclohexane, bis-(4-aminocyclohexyl)-methane, bis-(4-amino-3-methylcyclohexyl)-methane, bis-(4-amino-3-ethylcyclohexyl)-methane, bis-(4-amino-3,5-dimethylcyclohexyl)-methane, bis-(4-amino-3-ethyl-5-methylcyclohexyl)-methane, l-amino-3-aminomethyl-3,5,5-trimethylcyclohexane(isophoronedia mine), 2- and 4-methyl-l,3-diaminocyclohexane, 1,3- and l,4-bis-(aminomethyl)-cyclohexane, l,4-diamino-2,2,6-trimethylcyclohexane.

[0042] Arylaliphatic polyamines include, in particular, 1,3- and 1,4-bis-(aminomethyl)benzene.

[0043] Polyamines containing at least one ether group are known in particular under the trade name Jeffamine® (Huntsman) or Polyetheramine (BASF) or PC Amine® (Nitroil). Examples include polyalkylene diamines such as 4,9-Dioxa-1,12-dodecanediamine, 1,13-diamino-4,7,10-trioxatridecane (Ancamine 1922A), 1,11-Diamino-3,6,9-trioxaundecane, poly(propylene glycol) bis(2-aminopropyl ether) (Jeffamine D-230®, Jeffamine® D-400, Jeffamine® D-2000), 2-aminoethyl ether (Jeffamine® EDR-104), 2,2'-(Ethylenedioxy)bis(ethylamine) (Jeffamine® EDR-148) and Ethylene Glycol Bis(3-aminopropyl) Ether (Jeffamine® EDR-176), and the corresponding polyamines from BASF and Nitroil, as well as polyalkylene triamines such as Trimethylolpropane. tris[poly(propylene glycol), amine terminated] ether (Jeffamine® T403, Jeffamine® T-3000, Jeffamine® T-5000) and the corresponding polyamines from BASF and Nitroil.

[0044] Aromatic polyamines are selected in particular from m-phenylenediamine, p-phenylenediamine, 4,4', 2,4' and 2,2'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 2,4- and 2,6-toluenediamine, mixtures of 3,5-dimethylthio-2,4- and 2,6-toluenediamine (marketed under the reference Ethacure® 300 by Albemarle), mixtures of 3,5-diethyl-2,4- and -2,6-toluenediamine, 3,3',5,5'-tetraethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetraethyl-2,2'-dichloro-4,4'-diaminodiphenylmethane, the 3,3'-diisopropyl 5,5'-dimethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetraisopropyl-4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 4-amino-N-(4-aminophenyl)-benzenesulfonamide, 5,5'-methylenedianthranilic acid, dimethyl-(5,5'-methylenedianthranilate), 1,3-propylene-bis-(4-aminobenzoate), 1,4-butylene-bis-(4-aminobenzoate),polytetramethyleneoxide-bis-(4-aminobenzoate) (marketed under the name Versalink® by Evonik), 1,2-bis(2-aminophenylthio)ethane, 2-methylpropyl-(4-chloro-3,5-diaminobenzoate) and tert-butyl-(4-chloro-3,5-diaminobenzoate).

[0045] Polyamidoamines are preferably reaction products of a monofunctional or polyfunctional carboxylic acid or of their esters or anhydrides, in particular fatty acids, with an aliphatic, cycloaliphatic, arylaliphatic or aromatic polyamine (in particular a polyalkyleneamine such as diethylenetriamine or triethylenetetramine) used in stoichiometric excess. These products are in particular commercially available under the polyamidoamine names Versamid® 100, 125, 140 and 150 (Cognis), Aradur R 223, 250 and 848 (Huntsman), Euretek® 3607 and 530 (Huntsman) and Beckopox®, EH 651, EH 654, EH 655, EH 661 and EH 663 (Cytec).

[0046] Phenalkamines, also known as Mannich bases, are the products of the reaction of phenol derivatives with aldehydes, in particular formaldehyde, and polyamines. Commercially available Mannich bases include Cardolite® NC-541, NC-557, NC-558, NC-566, Lite 2001 and Lite 2002 (Cardolite), Aradur R. 3440, 3441, 3442 and 3460 (Huntsman) and Beckopox®, EH 614, EH 621, EH 624, EH 628 and EH 629 (Cytec).

[0047] The fatty amines are preferably N-cocoalkyl-1,3-propanediamine and the products of a Michael type reaction of primary amines with acrylonitrile, maleic, fumaric, citraconic diesters, acrylic and methacrylic esters, acrylic and methacrylic amides and itaconic diesters, reacted with a molar ratio of 1:1.

[0048] By "hydroxylated carboxylic acid" is meant any organic compound comprising at least one carboxylic acid function and at least one hydroxy.

[0049] Examples of hydroxylated carboxylic acids are 2,2-bis(hydroxymethyl)-propionic acid (DMPA), 2,2-bis(hydroxymethyl)-butyric acid (DMBA), tartaric acid, 2-(bis(2-hydroxyethyl)amino)acetic acid, 3-[bis(2-hydroxyethyl)amino]propanoic acid or N,N-Bis(2-hydroxyethyl)alanine.

[0050] By "amino carboxylic acid" is meant any organic compound comprising at least one carboxylic acid function and at least one amino (primary or secondary).

[0051] Examples of amino carboxylic acids are ethylenediamine-N,N'-diacetic acid, alanine or glycine.

[0052] Examples of amino and hydroxylated carboxylic acids are N-(2-hydroxyethyl)-[3-alanine, threonine or serine.

[0053] The term "amino alcohol" means any organic compound comprising at least one hydroxyl group and at least one amino group. Examples of amino alcohols include propanolamine, ethanolamine, dimethylethanolamine, and N-methylethanolamine.

[0054] By "polyisocyanate monomer" is meant any monomeric (i.e. non-polymeric) organic compound comprising at least two isocyanate (-NCO) functions. Preferably, the polyisocyanate monomer is a diisocyanate. The polyisocyanate monomer can be aliphatic or aromatic, preferably aromatic.

[0055] The polyisocyanate monomer generally has a molar mass between 80 and 700 g / mol, preferably between 100 and 500 g / mol, or even between 120 and 350 g / mol.

[0056] Said polyisocyanate monomer is advantageously selected from 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), methylene bis-(4-cyclohexylisocyanate) (HMDI), pentamethylene diisocyanate (PDI), 4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, dicyclohexylmethane diisocyanate, tetramethylxylene diisocyanate, norbornane diisocyanate, bis-(isocyanatomethyl)cyclohexane, tetramethylene-1,4-diisocyanate, cyclohexane-1,4-diisocyanate, 1,12-dodecane diisocyanate, 2,2,4-trimethylhexamethyllene diisocyanate, diphenylmethylene 2,2'-diisocyanate (2,2'-MDI), the 4,4'-diphenylmethylene diisocyanate (4,4'-MDI), 4,4'-dibenzyl diisocyanate (4,4'-DBDI), 2,6-toluene diisocyanate (2,6-TDI), m-xylylene diisocyanate (m-XDI), 2,4'-diphenylmethylene diisocyanate (2,4'-MDI), 2,4'-dibenzyl diisocyanate (2,4'-DBDI), 2,4-toluene diisocyanate (2,4-TDI), and a mixture of at least two of these.

[0057] Preferably, said polyisocyanate monomer is toluene 2,6-diisocyanate (2,6-TDI), toluene 2,4-diisocyanate (2,4-TDI), or a mixture of these.

[0058] In particular, the polymer of the polymeric composition may be a polyurethane or a polyurea, preferably a polyurethane. The polymer of the polymeric composition may include isocyanate terminations. Preferably, the polymer of the polymeric composition is an isocyanate-terminated polymer, for example, an isocyanate-terminated polyurethane or an isocyanate-terminated polyurea, more particularly an isocyanate-terminated polyurethane. The method according to the invention is advantageously selective. Advantageously, the method is such that at least 70%, preferably at least 75%, or even at least 80%, particularly at least 90%, for example at least 95%, of the isocyanate terminations of the isocyanate-terminated polymer are preserved.

[0059] The molar mass of the polymer in the polymeric composition is typically between 200 and 500,000 g / mol, for example between 500 and 300,000 g / mol, between 800 and 100,000 g / mol, between 2,000 and 60,000 g / mol, between 5,000 and 50,000 g / mol, between 10,000 and 40,000 g / mol, or between 12,000 and 30,000 g / mol (number-average molar masses determined by size-exclusion chromatography).

[0060] Preferably, the molar mass of the polymer in the polymeric composition is between 200 and 40,000 g / mol, better still between 500 and 20,000 g / mol, or even between 800 and 15,000 g / mol.

[0061] The polymer weight content in the polymeric composition is generally from 5 to 99.9%, preferably from 10 to 99%, better still from 20 to 90%, or even from 20 to 80%, for example from 25 to 65%, or even from 25 to 50%, relative to the total weight of the polymeric composition.

[0062] The polyisocyanate monomer of the polymeric composition is as defined above. It is understood that the "polyisocyanate monomer of the polymeric composition" refers to the "free" polyisocyanate monomer present in the polymeric composition and not to any polyisocyanate monomeric unit forming part of the polymer backbone.

[0063] Preferably, the polyisocyanate monomer of the polymeric composition is a diisocyanate. The polyisocyanate monomer of the polymeric composition may be aliphatic or aromatic, preferably aromatic.

[0064] The polyisocyanate monomer of the polymeric composition generally has a molar mass between 80 and 700 g / mol, preferably between 100 and 500 g / mol, or even between 120 and 350 g / mol.

[0065] Said polyisocyanate monomer of the polymeric composition is advantageously selected from 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), methylene bis-(4-cyclohexylisocyanate) (HMDI), pentamethylene diisocyanate (PDI), 4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, dicyclohexylmethane diisocyanate, tetramethylxylene diisocyanate, norbornane diisocyanate, bis-(isocyanatomethyl)cyclohexane, tetramethylene-1,4-diisocyanate, cyclohexane-1,4-diisocyanate, 1,12-dodecane diisocyanate, 2,2,4-trimethylhexamethyllene diisocyanate, diphenylmethylene 2,2'-diisocyanate (2,2'-MDI), 4,4'-diphenylmethylene diisocyanate (4,4'-MDI), 4,4'-dibenzyl diisocyanate (4,4'-DBDI), 2,6-toluene diisocyanate (2,6-TDI), m-xylylene diisocyanate (m-XDI), 2,4'-diphenylmethylene diisocyanate (2,4'-MDI), 2,4'-dibenzyl diisocyanate (2,4'-DBDI), 2,4-toluene diisocyanate (2,4-TDI), and a mixture of at least two of these.

[0066] Preferably, said polyisocyanate monomer of the polymeric composition is toluene 2,6-diisocyanate (2,6-TDI), toluene 2,4-diisocyanate (2,4-TDI), or a mixture thereof.

[0067] When the polymer of the polymeric composition according to the invention is formed from a polyisocyanate monomer and a compound comprising several reactive functions with respect to isocyanates, said polyisocyanate monomer of the polymeric composition is typically identical to that which was used to form the polymer.

[0068] The weight content of polyisocyanate monomer in the polymeric composition at step a) is advantageously greater than or equal to 0.05%, in particular greater than or equal to 0.1%, preferably greater than or equal to 0.2%, better still greater than or equal to 0.3%, for example greater than or equal to 0.5%, relative to the weight of the polymer.

[0069] The weight content of polyisocyanate monomer in the polymer composition at step a) is advantageously less than 10%, preferably less than 7%, better still less than 5%, or even less than 3%, for example less than 1%, relative to the weight of the polymer.

[0070] It is understood that this weight content of polyisocyanate monomer is based on the quantity of "free" polyisocyanate monomer present in the polymer composition, and does not take into account the possible polyisocyanate monomer unit forming part of the polymer skeleton.

[0071] The total content of NCO terminations in the polymer composition at step a) is advantageously between 0.05 and 50 mol%, preferably between 0.1 and 40 mol%, better still between 0.5 and 30 mol%, or even between 1 and 20 mol%, for example between 2 and 10 mol%, in particular between 3 and 5 mol%, relative to the weight of the polymer.

[0072] The quantity of NCO groups can be measured by potentiometric titration (for example using a dibutylamine solution) according to ISO14869.

[0073] The polymer composition may further comprise:

[0074] - one or more mineral fillers, distinct from said mineral filler having a specific surface area of ​​1 to 500 m² / g; and / or

[0075] - one or more additives, in particular selected from: dispersing agents, surfactants (including non-ionic surfactants), defoaming agents, or thickening agents (preferably water-soluble organic polymers), rheological agents (including thickening or thixotropic agents), dispersing agents, leveling agents, wetting agents, expanding agents, adhesion promoters, stabilizing agents against oxidation, heat or UV radiation, flame retardants (including halogenated or phosphorus derivatives), colorants, pigments, or a mixture thereof; and / or

[0076] - one or more polymerization catalysts; and / or

[0077] - one or more solvents (e.g. hydrocarbon solvents such as xylene).

[0078] The weight content of mineral fillers (distinct from said mineral filler having a specific surface area of ​​1 to 500 m2 / g) in the polymeric composition is generally between 0 and 95%, preferably between 1 and 85%, or even between 5 and 75%, for example between 20 and 60%, relative to the total weight of the polymeric composition.

[0079] The weight content of additives in the polymeric composition is generally between 0 and 50%, preferably between 0.1 and 30%, or even between 0.5 and 20%, for example between 1 and 10%, relative to the total weight of the polymeric composition.

[0080] The weight content of solvents in the polymeric composition is generally between 0 and 65%, preferably between 0.5 and 50%, or even between 1 and 40%, for example between 5 and 25%, relative to the total weight of the polymeric composition.

[0081] The weight content of catalysts in the polymeric composition is generally between 0 and 10%, for example between 0.1 and 5% or between 0.2 and 2%, relative to the total weight of the polymeric composition.

[0082] Preferably, the weight content of catalysts in the polymeric composition is less than 2%, or even less than 1%, or even less than 0.5%, for example less than 0.2%, relative to the total weight of the polymeric composition.

[0083] In step b) of the method according to the invention, said polymeric composition is brought into contact with a mineral filler having a specific surface area of ​​1 to 500 m2 / g and water.

[0084] In the present invention, the specific surface area of ​​said mineral filler in step b) is a BET type specific surface area (BET for "Brunauer, Emmet and Teller"). The measurement of the specific surface area by the BET method can be carried out according to ISO 9277, using nitrogen as the adsorption gas.

[0085] Preferably, the specific surface area of ​​the mineral charge is 10 to 500 m2 / g, or even 15 to 400 m2 / g, better still 20 to 300 m2 / g, for example 25 to 200 m2 / g.

[0086] The mineral charge in step b) is typically in particulate form. In such a case, the d50 of the particles is generally from 1 to 600 pm, advantageously from 2 to 500 pm, preferably from 2 to 400 pm, or even from 2 to 300 pm, for example from 5 to 300 pm or even from 50 to 300 pm. The d50 indicates the value for which 50% of the particles—by number—have a size less than or equal to this value, and 50% of the particles—by number—have a size greater than this value. The d50 of the particles can be determined by laser granulometry.

[0087] Advantageously, the mineral charge of step b) comprises (preferably, is made up of):

[0088] - an oxide (or a mixture of oxides) of one or more metals selected from the alkali metals (e.g. Li, Na, K), alkaline earth metals (e.g. Ca, Mg), transition metals (e.g. Fe, Zr, Ni, Mn), and metalloids (e.g. Si, Al);

[0089] - a carbonate (or a mixture of carbonates) of one or more selected metals among the alkali metals (e.g., Li, Na, K), alkaline earth metals (e.g., Ca, Mg), transition metals (e.g., Fe, Ni, Mn), and metalloids (e.g., Si, Al); or

[0090] - a mixture of these.

[0091] In particular, the mineral charge of step b) can be a silicate of one or more metals selected from alkali metals (e.g. Li, Na, K), alkaline earth metals (e.g. Ca, Mg), transition metals (e.g. Fe, Ni, Mn), and metalloids (e.g. Si, Al).

[0092] The mineral charge of step b) can be in the form of a hydrate.

[0093] Preferably, the mineral charge of step b) is chosen from a silica, a calcium silicate, perlite, clay (e.g. sepiolite, attapulgite, kaolin), alumina, magnesium silicate (e.g. talc), potassium silicate, aluminium silicate, calcium carbonate, a hydrate of these, and a mixture of at least two of these.

[0094] More preferably, the mineral charge of step b) is chosen from a silica, a calcium silicate, a calcium carbonate, a hydrate of these, and a mixture of at least two of these.

[0095] Better still, the mineral charge in step b) is a calcium silicate or a hydrate thereof.

[0096] The weight content of said mineral filler in step b) is advantageously greater than or equal to 0.2%, for example from 0.2 to 8%, preferably from 0.2 to 5%, better still from 0.5 to 3%, or even from 0.6 to 2.5%, or even from 0.7 to 2.1%, relative to the weight of the polymer.

[0097] It may be advantageous to first dry the mineral filler used in step b) to remove any traces of water. Typically, drying is carried out at a temperature between 40 and 200°C, for example between 45°C and 150°C, more particularly between 50 and 90°C.

[0098] The contacting in step b) is advantageously carried out in ambient air or under an inert atmosphere (e.g. under an atmosphere of nitrogen or argon), preferably in ambient air.

[0099] The relative humidity at step b) can be between 30 and 70%, typically between 40 and 60%, or even between 45 and 55%. The relative humidity can be measured with a hygrometer.

[0100] In a first embodiment of the invention, in step b), liquid water is added to the polymer composition, advantageously in a weight content less than or equal to 0.5% (for example from 0.01 to 0.5%), better still less than or equal to 0.2% (for example from 0.01 to 0.15%), relative to the weight of said polymer.

[0101] In a second embodiment of the invention, the water in step b) is supplied solely by the humidity of the ambient air.

[0102] The contact in step b) is advantageously carried out at a temperature between 15 and 80 °C, preferably between 20 and 75 °C (for example between 25 °C and 40 °C), or even between 40 and 70 °C. The duration of contact in step b) can vary depending on the conditions under which the method is carried out. Advantageously, this duration is between 30 minutes and 8 days, preferably between 40 minutes and 24 hours, or even between 45 minutes and 12 hours, or even between 1 hour and 3 hours.

[0103] The present invention also relates to a polymeric composition (hereinafter "PC") comprising:

[0104] - a polymer (said polymer preferably being a polyurethane, a polymer with isocyanate terminations, or a polyurethane with isocyanate terminations),

[0105] - a mineral filler having a specific surface area (i.e., which is a specific surface area BET) from 1 to 500 m2 / g (preferably from 10 to 500 m2 / g, or even from 15 to 400 m2 / g, better still from 20 to 300 m2 / g, for example from 25 to 200 m2 / g), and

[0106] - a polyisocyanate monomer content by weight of less than 0.5%, relative to the polymer weight.

[0107] Such a CP polymeric composition according to the invention can be obtained by the method according to the invention.

[0108] The polymer of the CP polymeric composition according to the invention is as defined above in the method according to the invention. The particular and preferred modes described above for the polymer of the method according to the invention therefore apply to the polymer of the CP polymeric composition according to the invention.

[0109] Said mineral filler having a specific surface area of ​​1 to 500 m² / g of the CP polymeric composition according to the invention is as defined above in the method according to the invention. The particular and preferred modes described above for such a filler in the method according to the invention therefore apply to that of the CP polymeric composition according to the invention.

[0110] The polyisocyanate monomer of the CP polymeric composition according to the invention is as defined above in the method according to the invention. The weight content of polyisocyanate monomer in the CP polymeric composition according to the invention is less than 0.5%, preferably less than 0.4%, or even less than 0.3%, better still less than 0.2%, for example less than 0.1%, or even less than 0.05%, relative to the weight of the polymer.

[0111] The CP polymeric composition according to the invention may further comprise:

[0112] - one or more mineral fillers, distinct from said mineral filler having a specific surface area of ​​1 to 500 m² / g; and / or

[0113] - one or more additives, in particular selected from those mentioned above in the method according to the invention; and / or

[0114] - one or more polymerization catalysts; and / or

[0115] - one or more solvents (e.g. hydrocarbon solvents such as xylene).

[0116] The weight contents of mineral fillers (distinct from said mineral filler having a specific surface area of ​​1 to 500 m2 / g), additives, polymerization catalysts, solvents described above in the method according to the invention apply to the CP polymeric composition according to the invention.

[0117] Preferably, the CP polymeric composition according to the invention is in the form of (or is intended to be used to form): a foam, a coating (in particular a sealing membrane), an adhesive or a sealant.

[0118] In the present application, a range defined with the expression "between (X) and (Y)" includes the lower bound (X) and upper bound (Y), and is therefore equivalent to "from (X) to (Y)".

[0119] The examples described below illustrate the present invention in a non-limiting manner. EXAMPLES

[0120] Measurement of the quantity of residual polyisocyanate monomer:

[0121] The measurement of the residual polyisocyanate monomer level is carried out by gas chromatography coupled with mass spectrometry, according to ISO 10283. The solvent used for sample preparation is anhydrous ethyl acetate.

[0122] Measurement of the NCO level:

[0123] The total quantity of NCO groups is measured by potentiometric titration using a dibutylamine solution according to ISO 14869.

[0124] Tensile test:

[0125] A polymeric film is drawn using a film puller and left to dry for 7 days. Test specimens are cut using a die and are used to perform tensile tests. These are carried out at 100 mm / min.

[0126] Specific surface area measurement B AND:

[0127] The specific surface area of ​​the tested mineral fillers was measured by the BET method according to ISO 9277 (degassing time: 2h, degassing temperature: 50°C, gas: nitrogen).

[0128] 1 / A first series of tests was carried out by mixing a composition of isocyanate-terminated polyurethane containing a residual TDI monomer content (mixture of 2,4-TDI and 2,6-TDI), with 2% by weight (relative to the weight of polyurethane) of precipitated silica (Sipemat 22®) having a specific surface area BET of 156 m2 / g, at 50°C or 70°C.

[0129] The precipitated silica was previously dried for 24 hours at 60°C.

[0130] Table 1: T = 50°C; 1000 ppm of water were added (under an N2 atmosphere).

[0131] Table 2: T = 50°C; the water comes solely from the humidity of the ambient air.

[0132] Table 3: T = 70°C; 2000 ppm of water were added (to ambient air).

[0133] [Tables 1] Contact time (min) tO 60 120 360 % NCO terminations ( / polymer weight) 4.7 4.6 4.5 3.5 % TDI ( / polymer weight) 0.29 0.27 0.23 0.17

[0134] [Tables2] Contact time (min) tO 60 120 180 240 360 % NCO terminations ( / polymer weight) 4.3 4.3 4.3 4.2 4.1 4.1 % TDI ( / polymer weight) 0.36 0.34 0.3 0.28 0.26 0.22

[0135] [Tables3] Contact time (min) tO 30 60 120 % NCO terminations ( / polymer weight) 3.4 3.4 3.0 3.0 % TDI ( / polymer weight) 0.35 0.27 0.22 0.14 Tensile strength (MPa) 2.6 - - 2.7 Elongation (%) 1420 - - 1360

[0136] Tables 1 to 3 show that a significant decrease in the TDI monomer content is achieved by adding precipitated silica Sipemat 22® and water under the various tested conditions (Table 1: -41%; Table 2: -39%; Table 3: -60%). These tables also demonstrate the selectivity of the reaction, given the moderate decrease in the NCO termination content of the polyurethane (Table 1: -25%; Table 2: -5%; Table 3: -12%). Table 3 also shows that the addition of this filler has little effect on the mechanical properties of the polymer.

[0137] 2 / A second series of tests by mixing a polyurethane composition with isocyanate terminations containing a residual content of TDI monomer, with 2% by weight (relative to the weight of polyurethane) of a calcium silicate hydrate (Circosil 0.1®) having a specific surface area BET of 32 m2 / g, at 25°C or 50°C.

[0138] The calcium silicate hydrate was previously dried for 24 hours at 60°C.

[0139] Table 4: Conditions of Table 2

[0140] Table 5: T = 25°C; the water comes solely from the humidity of the ambient air.

[0141] [Tables4] Contact time (min) tO 60 120 240 360 % NCO terminations ( / polymer weight) 4.5 4.2 4.6 3.7 3.7 %TDI (by polymer weight) 0.33 0.29 0.26 0.18 0.14 Tensile strength (MPa) 2.4 - - - 2.3 Elongation (%) 600 - - - 660

[0142] [Tables5] Contact time (min) tO 120 240 360 % NCO terminations ( / polymer weight) 3.3 3.2 3.2 3.2 % TDI ( / polymer weight) 0.30 0.30 0.27 0.24

[0143] Tables 4 and 5 show that a significant decrease in the TDI monomer content is achieved by adding Circosil 0.1® calcium silicate hydrate under the various tested conditions (Table 4: -58%; Table 5: -20%). These tables also demonstrate the selectivity of the reaction, given the moderate decrease in the NCO termination content of the polyurethane (Table 4: -18%; Table 5: -3%). Table 4 also shows that the addition of this filler has little effect on the mechanical properties of the polymer.

[0144] 3 / A test was carried out under the conditions of Table 2, using a carbonate of calcium (Imerseal 36S®) having a specific surface area BET of 4 m2 / g as a mineral filler.

[0145] [Tableauxô] Contact time (min) tO 60 120 240 360 % NCO terminations ( / polymer weight) 4.3 4.3 4.3 4.3 4.3 % TDI ( / polymer weight) 0.28 0.26 0.25 0.24 0.21

[0146] Table 6 shows that a significant decrease in the TDI monomer content is achieved by adding calcium carbonate (-25%). This table also demonstrates the selectivity of the reaction, given the absence of any change in the NCO termination rate of the polyurethane.

[0147] 4 / A test was carried out under the conditions of Table 2, in the absence of a load mineral (comparative). After 360 minutes, the NCO termination rate decreased from 4.4% to 4.0% (a decrease of 9%) and the residual TDI rate decreased from 0.35% to 0.31% (a decrease of 11%).

Claims

Demands

1. A method for reducing the polyisocyanate monomer content in a polymeric composition, said method comprising: a) providing a polymeric composition comprising a polymer and a polyisocyanate monomer, and b) contacting said polymeric composition with a mineral filler having a specific surface area of ​​1 to 500 m2 / g and water.

2. Method according to claim 1, characterized in that the mineral filler is selected from silica, calcium silicate, calcium carbonate, perlite, clay, alumina, magnesium silicate, potassium silicate, aluminium silicate, a hydrate thereof, and a mixture of at least two of these.

3. Method according to claim 1 or 2, characterized in that the specific surface area of ​​the mineral charge is 10 to 500 m2 / g, preferably 15 to 400 m2 / g, even better 20 to 300 m2 / g, for example 25 to 200 m2 / g.

4. Method according to any one of claims 1 to 3, characterized in that the weight content of said mineral filler in step b) is 0.2 to 5%, preferably 0.5 to 3%, or even 0.6 to 2.5%, or even 0.7 to 2.1%, relative to the weight of said polymer.

5. Method according to any one of claims 1 to 4, characterized in that the water in step b) is supplied solely by the humidity of the ambient air.

6. A method according to any one of claims 1 to 4, characterized in that liquid water is added in step b), preferably in a weight content less than or equal to 0.5%, more preferably less than or equal to 0.2%, for example from 0.01 to 0.15%, relative to the weight of said polymer.

7. Method according to any one of claims 1 to 6, characterized in that step b) is carried out at a temperature between 15 and 80 °C, preferably between 20 and 75 °C, or even between 40 and 70 °C.

8. A method according to any one of claims 1 to 7, characterized in that the polymer content by weight in the composition at step a) is from 5 to 99.9%, preferably from 10 to 99% %, better still from 20 to 90%, or even from 20 to 80%, for example from 25 to 65%, or even from 25 to 50%, relative to the total weight of the composition.

9. Method according to any one of claims 1 to 8, characterized in that the weight content of polyisocyanate monomer in the composition at step a) is greater than or equal to 0.1% and less than 10%, relative to the weight of the polymer.

10. A method according to any one of claims 1 to 9, characterized in that said polyisocyanate monomer of the polymeric composition is selected from 1,6-hexamethylene diisocyanate, isophorone diisocyanate, methylene bis-(4-cyclohexylisocyanate), pentamethylene diisocyanate, 4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, dicyclohexylmethane diisocyanate, tetramethylxylene diisocyanate, norbornane diisocyanate, bis-(isocyanatomethyl)cyclohexane, tetra-methylene-1,4-diisocyanate, cyclohexane-1,4-diisocyanate, 1,12-dodecane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, diphenylmethylene 2,2'-diisocyanate, the 4,4'-diphenylmethylene diisocyanate, 4,4'-dibenzyl diisocyanate, 2,6-toluene diisocyanate, m-xylylene diisocyanate, 2,4'-diphenylmethylene diisocyanate, 2,4'-dibenzyl diisocyanate, 2,4-toluene diisocyanate, and a mixture of at least two of these.

11. A method according to any one of claims 1 to 10, characterized in that the polymer is formed from polyisocyanate(s) and compound(s) comprising several reactive functions with respect to isocyanates, preferably the polymer is a polyurethane or a polyurea, better still a polyurethane.

12. Method according to any one of claims 1 to 11, characterized in that the polymer is an isocyanate-terminated polymer.

13. Method according to claim 12, wherein the method is selective such that at least 70%, preferably at least 75%, or even at least 80%, in particular at least 90%, for example at least 95%, of the isocyanate terminations of the isocyanate-terminated polymer are preserved.

14. Polymeric composition comprising: - a polymer, preferably a polyurethane,

15. - a mineral filler having a specific surface area of ​​1 to 500 m² / g, and - a polyisocyanate monomer content of less than 0.5%, preferably less than 0.3%, or even less than 0.1%, relative to the weight of the polymer. Polymeric composition according to claim 14, characterized in that it is in the form of a foam, a coating, an adhesive or a sealant.