Esterified ethanolamines for preparing isocyanurate polymers

Abstract

The present invention relates to the use of esterified ethanolamines as catalysts for the cross-linking of isocyanate groups which are aliphatically and / or cyclo-aliphatically bonded. The catalysts according to the invention have the particular advantage that they are thermally latent.

Description

[0001] Esterified ethanolamines for from

[0002] The present invention relates to the use of esterified ethanolamines as catalysts for crosslinking aliphatically and / or cycloaliphatically bound isocyanate groups. The catalysts according to the invention have the particular advantage of being thermolatent.

[0003] The production of isocyanurate plastics by crosslinking aliphatically or cycloaliphatically bound isocyanate groups with each other, i.e., without the involvement of thiol, hydroxyl, or amino groups, is generally known. It has also been described that such materials can be used as polymer matrices for composites.

[0004] WO 2019 / 197638 describes isocyanate adducts of hydroxy-functional tertiary amines and the use of these compounds as trimerization catalysts. However, the addition of these adducts to polyisocyanates causes an immediate increase in the viscosity of the reaction mixtures activated by them. This increase persists throughout the intended service life of the composition. Many manufacturing processes for composites with a polyisocyanurate matrix, such as the pultrusion process, are based on wetting a fibrous filler with the matrix material in an immersion bath. Therefore, the increase in viscosity limits the service life of the reaction mixture used to construct the matrix. This is particularly detrimental given the use of the system in the pultrusion process for composite materials, since optimal fiber bonding cannot be reliably achieved.

[0005] WO 2019 / 197639 discloses the use of hydroxy-functional tertiary amines for crosslinking aliphatic polyisocyanates in the extrusion process for producing composite materials. However, no compounds in which the OH group of these compounds is esterified are disclosed. Even with these compounds, a disturbing increase in the viscosity of the reaction mixture is observed.

[0006] The object of the present invention was to provide trimerization catalysts which lead to the lowest possible increase in viscosity of a polyisocyanate composition, enable good bonding of the polyisocyanurate matrix of a composite material to the filler and lead to polyisocyanurate matrices with reliably high glass transition temperatures.

[0007] This object is achieved by the embodiments of the present invention disclosed in the claims and in this description. In a first embodiment, the present invention relates to the use of a compound according to formula (I)

[0008] Where R 1 and R 2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl and isobutyl, branched C5 alkyl, unbranched C5 alkyl, branched C6 alkyl, unbranched C6 alkyl, branched C7 alkyl and unbranched C7 alkyl;

[0009] A is selected from the group consisting of 0, S and NR 3 , where R 3 is selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, butyl and isobutyl; and

[0010] R 4a branched or unbranched alkyl radical of up to 7 carbon atoms or hydrogen, as a catalyst for crosslinking at least two isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, araliphatically and aromatically bound isocyanate groups.

[0011] Preferred variants of the compound according to formula (I)

[0012] In a preferred embodiment of the present invention, A NR 3 , where R 3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl and isobutyl. Preferably, R 3 Methyl or ethyl. R is particularly preferably 3 Methyl.

[0013] In a further preferred embodiment of this invention, A is oxygen.

[0014] In yet another preferred embodiment of this invention, A is sulfur. In a preferred embodiment of the present invention, R 4selected from the group consisting of hydrogen, methyl and ethyl. Particularly preferred is R 4 Hydrogen or methyl.

[0015] Polyisocyanat

[0016] In the present application, a "polyisocyanate" is understood to mean any compound which has on average at least 1.8, preferably at least 2.0 and particularly preferably 2.1 isocyanate groups. In contrast, a "monoisocyanate" is understood to mean a compound having on average at most 1.6 isocyanate groups per molecule, in particular only one isocyanate group per molecule.

[0017] The term "polyisocyanates" in this application refers equally to monomeric and / or oligomeric polyisocyanates. However, for understanding many aspects of the invention, it is important to distinguish between monomeric diisocyanates and oligomeric polyisocyanates. When "oligomeric polyisocyanates" are mentioned in this application, this refers to polyisocyanates composed of at least two monomeric diisocyanate molecules, i.e., they are compounds that represent or contain a reaction product of at least two monomeric diisocyanate molecules.

[0018] Oligomeric isocyanates

[0019] Oligomeric isocyanates are obtained by "modification" of a monomeric isocyanate. "Modification" here means the reaction of monomeric isocyanates to form oligomeric isocyanates with uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione, and / or oxadiazinetrione structures. Diisocyanates are preferred starting materials for the production of oligomeric isocyanates.

[0020] For example, hexamethylene diisocyanate (HDI) is a “monomeric diisocyanate” because it contains two isocyanate groups and is not a reaction product of at least two polyisocyanate molecules:

[0021] HDI

[0022] In contrast, reaction products of at least two HDI molecules, which still have at least two isocyanate groups, are "oligomeric polyisocyanates" within the meaning of the invention. Representatives of such "oligomeric polyisocyanates" are, for example, HDI isocyanurate and HDI biuret, which are each composed of three monomeric HDI building blocks:

[0023] HDI-Isocyanurate HDI-Biuret

[0024] (idealized structural formulas)

[0025] Preparation processes for oligomeric polyisocyanates with uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure are described, for example, in J. Prakt. Chem. 336 (1994) 185 - 200, in DE-A 1 670 666, DE-A 1 954093, DE-A 2 414 413, DE-A 2 452 532, DE-A 2 641 380, DE-A 3 700 209, DE-A 3 900 053 and DE-A 3 928 503 or in EP-A 0 336 205, EP A 0 339 396 and EP-A 0 798 299.

[0026] The monomeric isocyanates defined further below in this application are particularly preferably used as starting materials for the modification.

[0027] The polymerizable composition according to the invention can contain oligomeric and polymeric polyisocyanates in any desired mixing ratios. For reasons of occupational safety, polymerizable compositions are generally preferred whose polyisocyanate component, i.e., the totality of all polyisocyanates contained in said composition, consists of at least 90 wt.%, preferably at least 95 wt.%, and more preferably at least 98 wt.% oligomeric polyisocyanates. If desired, for example, to reduce the viscosity of the polymerizable composition, the polyisocyanate component can also contain up to 20 wt.% or preferably up to 50 wt.% monomeric polyisocyanates.

[0028] Isocyanates with aliphatically bound isocyanate groups

[0029] In an isocyanate with aliphatically bound isocyanate groups, all isocyanate groups are bonded to a carbon atom that is part of an open carbon chain. This may be unsaturated at one or more positions. The aliphatically bound isocyanate group or—in the case of polyisocyanates—the aliphatically bound isocyanate groups are preferably bonded to the terminal carbon atoms of the carbon chain. Polyisocyanates with aliphatically bound isocyanate groups that are particularly suitable according to the invention are 1,4-diisocyanatobutane (BDI), 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, and 1,10-diisocyanatodecane.

[0030] Isocyanates with cycloaliphatically bound isocyanate groups

[0031] In an isocyanate with cycloaliphatically bonded isocyanate groups, all isocyanate groups are bonded to carbon atoms that are part of a closed ring of carbon atoms. This ring can be unsaturated at one or more positions, as long as the presence of double bonds does not impart aromatic character.

[0032] Polyisocyanates with cycloaliphatically bound isocyanate groups which are particularly suitable according to the invention are 1,3- and 1,4-diisocyanatocyclohexane, l,4-diisocyanato-3,3,5-trimethylcyclohexane, l,3-diisocyanato-2-methylcyclohexane, l,3-diisocyanato-4-methylcyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane isophorone diisocyanate; (IPDI), 1-isocyanato-l-methyl-4(3)-isocyanatomethylcyclohexane, 2,4'- and 4,4'-

[0033] Diisocyanatodicyclohexylmethane (H12MDI), 1,3- and 1,4-bis(isocyanatomethyl)cyclohexane, bis-(isocyanatomethyl)-norbornane (NBDI), 4,4'-diisocyanato-3,3'-dimethyldicyclohexylmethane, 4,4'-diisocyanato-3,3',5,5'-tetramethyl-dicyclohexylmethane, 4,4'-diisocyanato-l,l'-bi(cyclohexyl), 4,4'-diisocyanato-3,3'-dimethyl-l,l'-bi(cyclohexyl), 4,4'-diisocyanato-2,2',5,5'-tetra-methyl-l,l'-bi(cyclohexyl), 1,8-diisocyanato-p-menthane, 1,3-diisocyanato-adamantane and l,3-dimethyl-5,7-diisocyanatoadamantane.

[0034] Isocyanates with araliphatically bound isocyanate groups

[0035] In an isocyanate with araliphatically bound isocyanate groups, all isocyanate groups are bound to methylene residues, which in turn are bound to an aromatic ring.

[0036] Polyisocyanates with araliphatically bound isocyanate groups which are particularly suitable according to the invention are 1,3- and l,4-bis-(isocyanatomethyl)benzene (xylylene diisocyanate; XDI), 1,3- and l,4-bis(l-isocyanato-l-methylethyl)benzene (TMXDI) and bis(4-(l-isocyanato-l-methylethyl)phenyl) carbonate.

[0037] According to the invention, the polymerizable composition may contain any mixtures of the above-mentioned isocyanates in monomeric and / or oligomeric form. Isocyanate with aromatically bound isocyanate group

[0038] In an isocyanate with an aromatically bound isocyanate group, all isocyanate groups are directly bonded to carbon atoms that are part of an aromatic ring.

[0039] Isocyanates with aromatically bound isocyanate groups which are particularly suitable according to the invention are 2,4- and 2,6-diisocyanatotoluene (TDI), 2,4'- and 4,4'-diisocyanatodiphenylmethane (MDI) and 1,5-diisocyanatonaphthalene.

[0040] Monoisocyanates

[0041] Monoisocyanates which are particularly suitable according to the invention are preferably selected from the group consisting of n-butyl isocyanate, n-amyl isocyanate, n-hexyl isocyanate, n-heptyl isocyanate, n-octyl isocyanate, undecyl isocyanate, dodecyl isocyanate, tetradecyl isocyanate, cetyl isocyanate, stearyl isocyanate, cyclopentyl isocyanate, cyclohexyl isocyanate, 3- or 4-methylcyclohexyl isocyanate, methylbenzyl isocyanate, methyl isocyanate, (trimethylsilyl) isocyanate, 1-naphthyl isocyanate, 3-methyl-2-butyl isocyanate, l-(4-methoxyphenyl)ethyl isocyanate, l-(3-methoxyphenyl)ethyl isocyanate, 1-phenylpropyl isocyanate, 2-octyl isocyanate, 2-heptyl isocyanate, 4-butyl-2-methylphenyl isocyanate, 3-(triethoxysilyl)propyl isocyanate, 2-benzyloxycyclohexyl isocyanate, l-(4-chlorophenyl)ethyl isocyanate, 2-nonyl isocyanate, l-(4-bromophenyl)ethyl isocyanate, 2,l,3-benzothiadiazol-4-yl isocyanate, p-phenylazophenyl isocyanate, phenyl isocyanate, ethyl isocyanate, chlorosulfonyl isocyanate, allyl isocyanate, benzyl isocyanate, propyl isocyanate, isopropyl isocyanate,Furfurylisocyanat, Propylisocyanat, Octadecylisocyanat, Trichloracetylisocyanat, Benzoylisocyanat, Phenethylisocyanat, p-Tolylisocyanat, o-Tolylisocyanat, m-Tolylisocyanat, 3,4-Dimethoxyphenylisocyanat, 2,4-Dimethoxyphenylisocyanat,

[0042] 3,5-Dimethoxyphenylisocyanat, 2,5-Dimethoxyphenylisocyanat, tert-Butylisocyanat, 3,5- Dimethylphenylisocyanat, 2,6-Dimethylphenylisocyanat, 4-Ethylphenylisocyanat, 4- Methylbenzylisocyanat, 2-Methylbenzylisocyanat, 3-Methylbenzylisocyanat, 4- Methoxyphenylisocyanat, 4-tert-Butylphenylisocyanat, 2-Methoxyphenylisocyanat, 3,4,5-

[0043] Trimethoxyphenylisocyanat, 2,4-Dimethoxybenzylisocyanat, 4-Phenylbutylisocyanat, 4- Ethylphenethylisocyanat, 4-Methoxybenzylisocyanat, Benzenesulfonylisocyanat, 2- Methoxybenzylisocyanat, 3-Ethoxyphenylisocyanat, 3-Methoxybenzylisocyanat, 2,2- Diphenylethylisocyanat, 1,1,3,3-Tetramethylbutylisocyanat, 2-Ethylhexylisocyanat, 4- Biphenylylisocyanat, 3-Phenylpropylisocyanat, 2,3-Dimethoxyphenethylisocyanat, Decylisocyanat, Cyclohexanmethylisocyanat, 3,4-Methylendioxyphenethylisocyanat, 3,4-

[0044] Dimethoxyphenethylisocyanat, 5-lndanylisocyanat, Cycloheptylisocyanat, 2- Phenylcyclopropylisocyanat, 1-Cyclohexylethylisocyanat, 4-Nitrophenylisocyanat, 1-

[0045] Adamantylisocyanat, 2-Nitrophenylisocyanat, 3-Nitrophenylisocyanat, Pyridine-3-isocyanat, Chloracetylisocyanat, 2,6-Diisopropylphenylisocyanat, Hexadecylisocyanat, 4-Acetylphenylisocyanat, 4-Phenoxyphenylisocyanat, 4-Pentylphenylisocyanat, 3-Phenoxyphenylisocyanat, p- Toluenesulfonylisocyanat, 2-Chlorethylisocyanat, 2-Bromphenylisocyanat, 3-Chlorphenylisocyanat, 2- Chlorphenylisocyanat, 4-Bromphenylisocyanat, 4-Chlorphenylisocyanat, 2-Naphthylisocyanat, 4- Fluorophenylisocyanat, 2-Bromethylisocyanat, 4-Cyanophenylisocyanat, 3,4-Dichlorphenylisocyanat,

[0046] 2.3.4-Trifluorphenylisocyanat, 3-Cyanophenylisocyanat, 2,6-Dichlorphenylisocyanat,

[0047] Diethoxyphosphinylisocyanat, 2,4-Dichlorphenylisocyanat, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- Heptadecafluordecylisocyanat, 4-Fluorbenzylisocyanat, 2-Fluorphenylisocyanat, 3- Chlorpropylisocyanat, 3-Fluorphenylisocyanat, 4-lodphenylisocyanat, 3,5-Dichlorphenylisocyanat, 4- Chlorbenzenesulfonylisocyanat, 2,4,6-Tribromphenylisocyanat, 2-lodphenylisocyanat, 3,4- Difluorphenylisocyanat, 3-Bromphenylisocyanat, 2,4-Dichlorbenzylisocyanat, 2,5- Difluorphenylisocyanat, 2-Benzylphenylisocyanat, 2-Fluorbenzylisocyanat, 4-Fluorphenethylisocyanat, Pentafluorphenylisocyanat, 2,4-Dichlorphenethylisocyanat, 4-Chlorbenzylisocyanat, Diphenylmethylisocyanat, Tributylzinnisocyanat, 2-Chlorbenzolsulfonylisocyanat, 2- Chlorbenzylisocyanat, 3,3-Diphenylpropylisocyanat, , 3,4,5-Trimethoxybenzylisocyanat, 3- Chlorphenethylisocyanat, 3-Fluorbenzylisocyanat, 2,6-Difluorphenylisocyanat, 3-lodphenylisocyanat,

[0048] 2.4-Difluorphenylisocyanat, 2-Cyanophenylisocyanat, 2-Fluorphenethylisocyanat, 2-Thienylisocyanat,

[0049] 3.4-Dichlorbenzylisocyanat, 3,4-Dichlorphenethylisocyanat, 4-Benzylphenylisocyanat, 4-

[0050] Brombenzylisocyanat, 4-Fluorbenzopsulfonylisocyanat, mPEG5K-lsocyanat, 3,5-Dimethylisoxazol-4- ylisocyanat, 2-Methoxy-5-methylphenylisocyanat, 2-(4-Biphenyl)ethylisocyanat, 2-Ethyl-6- methylphenylisocyanat, 2-Methyl-5-phenyl-3-furylisocyanat, 1-(1-Naphthyl)ethylisocyanat, 3,4- (Methylenedioxy)phenylisocyanat, 2,3-Dihydro-l-benzofuran-5-ylisocyanat, 4-Methoxy-2- nitrophenylisocyanat, 3,5-Bis(trifluormethyl)phenylisocyanat, 4-(Maleinimido)phenylisocyanat, 4- (Dimethylamino)phenylisocyanat, 3-(Trifluormethyl)phenylisocyanat, 4-

[0051] (Chlorsulfonyl)phenylisocyanat, 3-lsopropenyl-a,a-dimethylbenzylisocyanat, 3-Chlor-4- methylphenylisocyanat, 4-(Trifluormethyl)phenylisocyanat, 2-(Trifluormethyl)phenylisocyanat, 4,4'- Oxybis(phenylisocyanat), 4-(Chlormethyl)phenylisocyanat, 4-Chlor-3-(trifluormethyl)phenylisocyanat, 9H-Fluoren-2-ylisocyanat, 2-(Chlormethyl)phenylisocyanat, 2-Fluor-5-(trifluormethyl)phenylisocyanat,

[0052] 2-Fluor-3-(trifluormethyl)phenylisocyanat, 4-(Benzyloxy)phenylisocyanat, 4-Fluor-3-

[0053] (trifluormethyl)phenylisocyanat, 4-Fluor-3-methylphenylisocyanat, 3-Fluor-5-

[0054] (trifluormethyl)phenylisocyanat, 4-Chlor-2-fluorphenylisocyanat, 5-Fluor-2-methylphenylisocyanat, 2,3-Dimethyl-6-nitrophenylisocyanat, 2-(Trifluormethoxy)phenylisocyanat, 2-Fluor-5- methylphenylisocyanat, 4-(Difluormethoxy)phenylisocyanat, 4-Methyl-2-nitrophenylisocyanat, 3- Fluor-2-methylphenylisocyanat, 4-(Trifluormethylthio)phenylisocyanat, 4-Fluor-2-

[0055] (trifluormethyl)phenylisocyanat, l-(4-Fluorphenyl)ethylisocyanat, l-Benzothiophen-5-ylisocyanat, 2- (Difluormethoxy)phenylisocyanat, 2-(Thien-2-yl)ethylisocyanat, 2-Brom-4,6-difluorphenylisocyanat, 2- Chlor-4,6-dimethylphenylisocyanat, 2-Chlor-4-(trifluoromethyl)phenylisocyanat, 2-Chlor-4- (trifluormethylthio)phenylisocyanat, 2-Chlor-5-methylphenylisocyanat, 2-Fluor-4-iodphenylisocyanat,

[0056] 3-Bromo-2,4,6-trimethylphenylisocyanat, 3-Chlor-2-fluorphenylisocyanat, 3-Chlor-2- methylphenylisocyanat, 4-(Trifluormethyl)benzylisocyanat, 4-Brom-2,6-difluorphenylisQcyanat, 4- Brom-2,6-dimethylphenylisocyariat, 4-Brom-2-(trifluormethyl)phenylisocyanat, 4-Brom-2-chlor-6- methylphenylisocyanat, 4-Brom-2-chlor-6-methylphenylisocyanat, 4-BrQm-2-ethylphenylisocyanat, 4- Chlor-2-phenoxyphenylisocyanat, 4-Ethoxy-2-nitrophenylisocyanat, 4-Fluor-2-nitrophenylisocyanat, 5-Chlor-2-methylphenylisocyanat, 5-Chlor-2-phenoxyphenylisocyanat, 5-Methyl-2- nitrophenylisocyanat, 5-Phenyl-2-thienylisocyanat, 6-Fluor-4H-l,3-benzodioxin-8-ylisocyanat, 9H- Fluoren-9-ylisocyanat, Benzylisocyanat, Ethylisocyanat, Trichloracetylisocyanat, 1- Phenylethylisocyanat, Ethylisocyanatformat, Isocyanatphosphonicdichlorid, 2- Isocyanatthylmethacrylat, 3-lsocyanat-4-methoxybiphenyl, 2,4,6-Trichlorphenylisocyanat, Triphenylsilyl isocyanat, 2,6-Dibrom-4-ethylphenylisocyanat, 2-Chlor-4-nitrophenylisocyanat,2-tert- Butyl-6-methylphenylisocyanat, 4,4'-Methylenebis(2-chlorphenylisocyanat), 4,5-Dimethyl-2- nitrophenylisocyanat, 4-Chlor-2-(trifluormethyl)phenylisocyanat, 4-Chloro-2-nitrophenylisocyanat, 1- lsocyanat-2,3-dimethoxybenzol, 3-lsocyanatopentan, Isocyanatocyclobutan, lsocyanato(methoxy)methan, Ethyl(4-isocyanatophenyl)acetat, Ethyl4-,

[0057] (isocyanatomethyl)cyclohexanecarboxylate, l,l-dimethoxy-2-isocyanatoethane, l-chloro-3-fluoro-2-isocyanatobenzene, 2-chloro-3-fluorophenyl isocyanate, 2-isocyanato-3-methylbutyric acid methyl ester, 2-isocyanato-5-methylbenzonitrile, 5-chloro-2-isocyanatobenzonitrile, 5-ethyl-2-isocyanatobenzonitrile, 6-isocyanatohexanoic acid methyl ester, dimethyl 2-isocyanatoterephthalate, ethyl 2-isocyanate-4-methylvalerate, methyl 2-isocyanate-4-(methylsulfanyl)butanoate, methyl 2-isocyanate-4-methylpentanoate, ethyl isocyanatoacetate, phenyl isocyanatoformate, methyl 4-isocyanatobenzoate, methyl 3-isocyanatobenzoate, methyl isocyanatoformate, dimethyl 5-isocyanatoisophthalate and any mixtures of such Monoisocyanates.

[0058] Thioisocyanates are also suitable. Preferred thioisocyanates are selected from the group consisting of 4-fluorobenzyl isothiocyanate, dibutyltin diisothiocyanate, 2,6-difluorophenyl isothiocyanate, 3-cyanophenyl isothiocyanate, 3-nitrophenyl isothiocyanate, and phenyl isocyanate.

[0059] Particularly preferred is a monoisocyanate selected from the group consisting of cyclohexyl isocyanate, phenyl isocyanate, octadecyl isocyanate and hexyl isocyanate.

[0060] Also suitable are mono- or polyisocyanates obtained by modifying monomeric isocyanates as described above in this application.

[0061] Polymerizable composition

[0062] In a further embodiment, the present invention relates to a polymerizable composition comprising a) at least one polyisocyanate having isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, araliphatically, and aromatically bound isocyanate groups; and b) at least one compound according to formula (I);

[0063] Where R 1 and R 2are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5 alkyl, unbranched C5 alkyl, branched C6 alkyl, unbranched C6 alkyl, branched C7 alkyl and unbranched C7 alkyl;

[0064] A is selected from the group consisting of 0, S and NR 3 , where R 3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl and isobutyl; and

[0065] R 4 a branched or unbranched alkyl radical of up to 7 carbon atoms or hydrogen; and wherein the ratio of isocyanate groups to isocyanate-reactive groups in the polymerizable composition is at least 2:1.

[0066] All definitions given above in this application for the compound according to the invention also apply to this embodiment.

[0067] The totality of all monomeric and oligomeric polyisocyanates contained in the polymerizable composition is also referred to in this application as the "polyisocyanate component" of the polymerizable composition. A "polymerizable composition" is a composition which contains at least the components defined above and can be cured to form a polymer by crosslinking the free isocyanate groups contained in the composition. The compound of formula (I) acts as a catalyst, causing the crosslinking of the isocyanate groups.

[0068] This crosslinking of at least two isocyanate groups preferably occurs with the formation of isocyanurate and / or uretdione groups. Isocyanurate groups are predominantly formed, and uretdione groups are only a by-product. If isocyanurate groups are formed, preferably three isocyanate groups are crosslinked per isocyanurate group formed.

[0069] The quantitative ratio between the compound according to formula (I) on the one hand to the at least one polyisocyanate having isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, araliphatically and aromatically bound isocyanate groups on the other hand is chosen such that at temperatures between 80°C and 250°C at least 80% of the free isocyanate groups present can be crosslinked within a maximum of one hour. This condition is preferably met when the weight ratio between the compound according to formula (I) and the totality of the polyisocyanates present in the polymerizable composition is between 1:1000 and 1:20, more preferably between 1:500 and 1:20, even more preferably between 1:400 and 1:20 and most preferably between 1:300 and 1:20.

[0070] Preferably, at least 80%, more preferably at least 90%, even more preferably at least 95% and particularly preferably at least 98% of the isocyanate groups contained in the polymerizable composition are aliphatically and / or cycloaliphatically bound.

[0071] It is particularly preferred that the polyisocyanate component of the polymerizable composition consists of at least 80 wt. % of at least one polyisocyanate selected from the group consisting of monomeric HDI, oligomeric HDI, monomeric PDI, oligomeric PDI, monomeric IPDI, and oligomeric IPDI. Most preferably, it consists of at least 90 wt. % of at least one of the aforementioned polyisocyanates.

[0072] Preferably, the molar ratio of isocyanate groups to isocyanate-reactive groups in the polymerizable composition is at least 5:1 and more preferably at least 10:1. "Isocyanate-reactive groups" are understood to mean hydroxyl, thiol, and amino groups. Use of a kit

[0073] In yet another embodiment, the present invention relates to the use of a kit comprising a) at least one polyisocyanate having isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, araliphatically, and aromatically bound isocyanate groups; and b) at least one compound according to formula (I), for producing a polymer in which at least 30 mol% of the free isocyanate groups present in the polyisocyanate are crosslinked with one another.

[0074] The compound of formula (I) was defined earlier in this application.

[0075] The presence of the two components as a kit means that both components are present together but in separate containers. In a preferred embodiment, the kit further contains instructions for use describing the use according to the invention. Preferably, the kit contains component b) in an amount suitable for crosslinking at least 80% of the isocyanate groups present in component a) contained in the kit at a temperature between 80°C and 250°C in a maximum of 10 minutes.

[0076] The polyisocyanate contained in the kit according to the invention corresponds to the "polyisocyanate component" of the polymerizable composition defined above. All definitions given there therefore also apply to the polyisocyanate contained in the kit. Use

[0077] Preferably, the crosslinking of the at least two isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, araliphatically and aromatically bound isocyanate groups takes place with formation of an isocyanurate group.

[0078] In a particularly preferred embodiment, the compound according to formula (I) is used as a thermolatent catalyst.

[0079] Particularly preferred is the use for crosslinking at least two aliphatically and / or cycloaliphatically bound isocyanate groups. Most preferably, isocyanate groups contained in at least one compound selected from the group consisting of HDI, PDI, IPDI, oligomeric HDI, oligomeric PDI, and oligomeric IPDI are crosslinked with one another.

[0080] The use according to the invention preferably results in a highly crosslinked polymer. For the purposes of the invention, chemically highly crosslinked polymers are understood to mean those having an average chemical network length Mc of at most 1000 g / mol, preferably at most 500 g / mol, particularly preferably at most 400 g / mol, and most preferably at most 300 g / mol. The average network length is defined as the number-average molar mass between the network nodes in a polymer network.

[0081] The mean network arch length, as well as the crosslink density, can be calculated by swelling measurements according to the HERMANS-FLORY-WALL method in suitable solvents or by measuring the elastic modulus in the melt in the linear elastic range at low frequencies, see also John d. Ferry: Viscoelastic properties of polymers 3rd Edition, 1980.

[0082] The net arch length is preferably determined using a rheological measurement.

[0083] For the purposes of the invention, highly cross-linked materials are also understood to mean those which have a storage shear modulus in the melt, measured in the linear range, of at least 3 xlO 6 Pa preferably at least 5 xlO 6 Pa and most preferably at least 8 x 10 6 Pa have.

[0084] The use as a thermolatent catalyst is characterized in that the catalyst is mixed with the isocyanate to be crosslinked, and the resulting reaction mixture is initially stored at a temperature at which the catalyst displays no significant catalytic activity. The temperature is then raised to a value at which the catalyst is active, thus initiating the crosslinking reaction. Storage is preferably carried out at temperatures of at most 40°C, more preferably at most 30°C. The storage time is such that the viscosity of the reaction mixture increases by at most 200% during this time. At storage temperatures of 30°C, this is preferably a period of 30 minutes to 5 days, more preferably 30 minutes to 24 hours. In particular, at a storage temperature of at most 30°C, the viscosity increases by at most 20% within 4 hours.To activate the catalyst, the temperature is increased to 50 °C to 250 °C, preferably to 80 °C to 250 °C and more preferably to 120 °C to 250 °C.

[0085] The present invention further relates to the use of a polymerizable composition as defined above or of a kit as defined above for producing a polymer. The polymer is a polymer in which at least 30 mol%, preferably at least 50 mol%, of the free isocyanate groups present in the polymerizable composition are crosslinked with one another, i.e., without the involvement of isocyanate-reactive groups, in particular hydroxyl, amino, or thiol groups. Particularly preferably, the aforementioned proportions of the free isocyanate groups are crosslinked to form isocyanurate groups.

[0086] Said polymer is preferably the matrix material of a composite material. It is particularly preferably the matrix material of a highly filled composite material.

[0087] The term "composite material" is well known to those skilled in the art; it basically refers to materials in which a filler is embedded in a matrix. According to the invention, this matrix is ​​a polymer formed by crosslinking the isocyanate groups contained in the polyisocyanate component a).

[0088] The filler can be any suitable organic or inorganic filler known to those skilled in the art. It can have any desired geometry. However, it is preferably a fibrous organic or inorganic filler.

[0089] The aspect ratio of a fibrous filler is greater than 1000, preferably greater than 5000, more preferably greater than 10,000, and most preferably greater than 50,000. The aspect ratio is defined as the length of the fiber divided by the diameter.

[0090] When maintaining the aspect ratio defined above, the fibrous fillers preferably have a minimum length of 2 mm, more preferably 5 mm, even more preferably 20 mm, even more preferably 100 mm, most preferably 1000 mm, particularly preferably 50 mm and most preferably 100 mm.

[0091] Preferred inorganic fibers are glass fibers, basalt fibers, boron fibers, ceramic fibers, whiskers, silica fibers, and metallic reinforcing fibers. Preferred organic fibers are aramid fibers, carbon fibers, carbon nanotubes, polyester fibers, nylon fibers, and Plexiglas fibers. Preferred natural fibers are flax fibers, hemp fibers, wood fibers, cellulose fibers, and sisal fibers.

[0092] The ratio of the proportions of filler to polymer matrix in the composite material is referred to as the filler ratio. Highly filled systems are characterized by a filler weight fraction between 50 wt.% and 90 wt.%, preferably between 60 wt.% and 85 wt.%, and even more preferably between 70 and 85 wt.%, always based on the total mass of polyisocyanate component a) and filler.

[0093] Proceedings

[0094] In yet another embodiment, the present invention relates to a process for producing a polymer comprising the steps of a) mixing at least one polyisocyanate having isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, aromatically and araliphatically bound isocyanate groups with at least one compound according to formula (I); b) curing the polymerizable composition obtained in process step a) by increasing the temperature to at least 50 °C, wherein at the beginning of process step b) the ratio of isocyanate groups to isocyanate-reactive groups in the polymerizable composition is at least 2:1.

[0095] All definitions of the polyisocyanates and the compound of formula (I) usable according to the invention, which were given earlier in this application, also apply to this embodiment. The mixing of the components in process step a) can be carried out using any suitable method known to the person skilled in the art. Process step a) is preferably carried out at temperatures of at most 40°C. At the end of process step a), a reaction mixture is present which corresponds to the polymerizable composition disclosed at the beginning of this patent application. In this respect, process step a) considered on its own discloses a method for preparing the polymerizable composition according to the invention.

[0096] Suitable proportions of the components are described above in connection with the polymerizable composition. In particular, the ratio of isocyanate groups to isocyanate-reactive groups in the polymerizable composition is at least 5:1, and more preferably at least 10:1. "Isocyanate-reactive groups" are understood to mean hydroxyl, thiol, and amino groups.

[0097] Since the compound according to formula (I) is a thermolatent catalyst, process step b) is preferably initiated by raising the temperature of the polymerizable composition. The elevated temperature is preferably also maintained throughout process step b). It is preferred that a temperature of at least 50°C is maintained throughout process step b). More preferably, the temperature during process step b) is between 50°C and 250°C, even more preferably between 80°C and 250°C, and most preferably between 120°C and 250°C.

[0098] Since the compound according to formula (I) does not show any significant catalytic activity at temperatures up to 30 °C, the polymerizable composition obtained in process step a) can be stored for 30 to 360, preferably 30 to 249 minutes, before starting process step b) and while maintaining this temperature limit, without its viscosity increasing by more than 20%.

[0099] The "curing" of the polymerizable composition occurs through the crosslinking of the isocyanate groups contained in the polyisocyanate. This creates a solid polymer network. Since the compound according to formula (I) primarily catalyzes the formation of isocyanurate groups, at least 80 mol% of isocyanurate groups are preferably formed, while the sum of uretdione, urethane, allophanate, urea, biuret, iminooxadiazinedione, and oxadiazinetrione structures formed during curing is less than 20 mol%.

[0100] Process step b) is complete when the liquid polymerizable composition has transformed into a solid that retains its shape without external supports such as molds. This is preferably the case when at least 75%, more preferably at least 80%, even more preferably at least 85%, and most preferably at least 90% of the isocyanate groups present in the polymerizable composition at the beginning of process step b) have been consumed. At temperatures between 80°C and 250°C, this state is preferably reached after a maximum of 20 minutes.

[0101] If the production of a composite material is intended, the polymerizable composition must contain a filler at the beginning of process step b). This filler can be introduced into the polymerizable composition in various ways. The polymerizable composition, as it exists at the end of process step a), can be mixed with the filler. However, it is also possible to first mix a polyisocyanate containing isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, araliphatically, and aromatically bound isocyanate groups with the filler before it is used in process step a). Suitable fillers are described earlier in this application. In process step b), a composite material is thus created in which the cured reaction mixture forms a polymer matrix in which the filler is embedded.

[0102] According to a preferred embodiment of the invention, the filler is a fibrous filler selected from the group consisting of glass fibers, basalt fibers, carbon fibers, cellulose fibers, and mixtures thereof. The term "cellulose fiber" preferably refers to fibers that contain cellulose. It is not excluded that they contain other compounds such as pectins. Since preferred cellulose fibers according to the invention are of plant origin, the exact chemical structure of the fibers depends on the plant in question. Preferred cellulose fibers are fibers from jute, flax, hemp, and cotton. The fibers can be present individually, but they can also be woven or knitted into mats or tiles in any form known to those skilled in the art. Preferably, less than 50% by weight, more preferably less than 35% by weight, even more preferably less than 20% by weight, and most preferably less than 10% by weight.-% of the fibers used are in the form of mats or tiles.

[0103] In a particularly preferred embodiment of the present invention, the process according to the invention for producing a composite material is a pultrusion process, also known as a pultrusion process.

[0104] Pulp drawing is a continuous manufacturing process for fiber-reinforced plastic profiles. The basic structure of a pulp drawing system consists of the fiber rack, fiber guidance devices, an impregnation device, a curing tool, reciprocating drawing devices, and a cutting unit.

[0105] The roving spools are stored in the fiber rack. From there, the fiber rovings are guided via fiber guides to the impregnation device, where the fibers are wetted with the reaction mixture from process step a). The fibers are usually aligned or pre-sorted to the desired profile shape via the fiber guides or the impregnation device. Fibers with a minimum length of 50 m while maintaining the aspect ratio defined above are particularly suitable.

[0106] In addition, mats, woven fabrics, scrims, or nonwovens can be integrated into the process if necessary to optimize the mechanical properties for the desired application. The impregnation of the fibers with the reaction mixture can be carried out using any method known to those skilled in the art in the context of the pultrusion process.

[0107] The resin-impregnated fibers then pass through the shaping curing tool, where the reactive groups in the reaction mixture are cross-linked to form the polymer (matrix) at elevated temperature. This is step b) of the process. This is often followed by a cooling section, e.g. air cooling, before the now finished semi-finished product is passed through the alternating pulling devices (pullers). These ensure continuous transport of the material throughout the entire pultrusion process. The final process step is for the material to be cut to the required length. A flying saw is often used here, i.e. the saw moves at the same speed as the material while making the cut. This produces a straight cut edge and prevents the profile from building up or the process from stopping during the sawing step.

[0108] Furthermore, the present patent application relates to a polymer obtainable by the process described above.

[0109] Compared to the catalysts described in the prior art, in particular in WO 2019 / 197638 and WO 2019 / 197639, the use of the catalysts according to the invention offers several advantages. When the catalysts according to the invention are added to a polyisocyanate composition, the viscosity of the resulting reaction mixture is lower, both immediately after addition and several hours thereafter, than when using the catalysts known from the prior art.

[0110] The following embodiments serve only to illustrate the invention. They are not intended to limit the scope of the patent claims in any way.

[0111] Notes:

[0112] Unless otherwise stated, all percentages are by weight (%).

[0113] The ambient temperature of 23°C at the time the experiments were conducted is referred to as RT (room temperature).

[0114] The methods described below for determining the relevant parameters were used to carry out / evaluate the examples and are also generally the methods for determining the parameters relevant to the invention.

[0115] Polyisocyanate, Desmocomp Ultra AP 200 (NCO functionality > 3) with an NCO content of 23.0 wt.% from Covestro AG. The viscosity is approximately 1200 mPa s at 23°C (DIN EN ISO 3219 / A.3).

[0116] Catalyst 1: N,N,N'-Trimethylaminoethylethanolamine with an OH number of 384 mg KOH / g was obtained from Huntsman Corporation under the trade name Jeffcat-Z11O.

[0117] Catalyst 2: Catalyst adduct as described in WO 2019 / 197638 as catalyst KAI

[0118] Additives: The demoulding agent Desmorapid AP 300 from Covestro AG consists of organic fatty acids and esters.

[0119] Experimental procedure for the synthesis of catalyst 3:

[0120] After cooling a solution of 10.0 g of 2-[2-(dimethylamino)ethyl]methylaminoethanol and 9.53 ml of triethylamine in 100 ml of ethyl acetate, 5.35 ml of acetyl chloride was slowly added while maintaining the temperature between 0°C and 50°C, thereby inducing the precipitation of triethylamine hydrochloride. The reaction mixture was allowed to stir for 15 minutes at 0°C and 24 hours at room temperature. The reaction mixture was filtered, and the precipitate was washed with ethyl acetate. The solvent was evaporated in vacuo, and vacuum distillation of the crude product afforded the product as a colorless liquid (10.30 g, 80% yield) (>95% purity).

[0121] Unless otherwise stated, the reaction mixture was prepared by mixing the polyisocyanate (Desmocomp Ultra AP 200) with an appropriate amount of catalyst and additive at 23°C in a Speedmixer DAC 150.1 FVZ from Hauschild at 2750 RPM.

[0122] Comparison example 1

[0123] 0.5 wt.% of catalyst 1 was added to 99.5 wt.% polyisocyanate and prepared according to the procedure described above.

[0124] Comparison example 2

[0125] 1.2 wt.% of catalyst 2 was added to 98.8 wt.% polyisocyanates and prepared according to the procedure described above.

[0126] Inventive example

[0127] 2.5 wt% of catalyst 3 was added to 97.5 wt% polyisocyanate and prepared according to the procedure outlined above.

[0128] Measurement methods:

[0129] Phase transition using DSC:

[0130] Determination of phase transitions using DSC: The phase transitions were determined using DSC (Differential Scanning Calorimetry) with a Mettler DSC 12E (Mettler Toledo GmbH, Gießen, Germany) in accordance with DIN EN 61006. Calibration was performed using the melting onset temperature of indium and lead. 5 mg of substance were weighed into standard capsules. The measurement was performed by heating twice from -20 °C to +200 °C at a heating rate of 20 K / min, followed by cooling at a cooling rate of 320 K / min. Cooling was performed using liquid nitrogen. Nitrogen was used as the purge gas. The values ​​given are based on the evaluation of the second heating curve. The melting temperatures Tm were obtained from the temperatures at the maxima of the heat flow curves. The glass transition temperature Tg was obtained from the temperature at half the height of a glass transition step.

[0131] 4 hours viscosity:

[0132] The viscosity of a small amount of the reactive resin was measured at 23 °C using a Physia MCR 51 from Anton Paar (plate / plate; shear rate 1 s-1) over 4 hours. As described in WO2019121349A1 and based on ISO 6721-10. Table 1: Viscosity development of the activated matrix systems over 4 hours.

[0133] Table 1 shows the viscosity development of the comparative examples and the inventive example in direct comparison over a period of 240 minutes. It is clearly evident that the activated matrix of the inventive example exhibits a stable and lower viscosity throughout the entire measurement period, which is below the initial viscosity of the polyisocyanate Desmocomp AP 200 used.

[0134] Table 2: Glass transition temperatures of the cured matrix systems

[0135] Table 2 summarizes the measured glass transition temperatures (Tg) after the second heating of both Comparative Examples 1 and 2, as well as that of the inventive example. All Tg values ​​were determined from samples cured for 10 minutes at 160°C.

[0136] The studies presented here show that by ester functionalization of tertiary amines it has been possible to produce thermosetting composites by pultrusion which exhibit a high glass transition temperature in combination with good fiber bonding.

Claims

Patent claims 1. Use of a compound according to formula (I) Where R 1 and R 2 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, branched C5 alkyl, unbranched C5 alkyl, branched C6 alkyl, unbranched C6 alkyl, branched C7 alkyl and unbranched C7 alkyl; A is selected from the group consisting of 0, S and NR 3 , where R 3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl and isobutyl; and R 4 a branched or unbranched alkyl radical of up to 7 carbon atoms or hydrogen is selected as a catalyst for crosslinking at least two isocyanate groups from the group consisting of aliphatically, cycloaliphatically, araliphatically and aromatically bound isocyanate groups.

2. The use according to claim 1, wherein in formula (I) A NR 3 is, and R 3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, isopropyl, butyl and isobutyl.

3. The use according to claim 1, wherein in formula (I) A is oxygen.

4. The use according to any one of claims 1 to 3, wherein R 4 is selected from the group consisting of hydrogen, methyl and ethyl, 5. The use according to any one of claims 1 to 4, wherein the use results in a highly cross-linked polymer.

6. A polymerizable composition comprising a) at least one polyisocyanate having isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, araliphatically, and aromatically bound isocyanate groups; and b) at least one compound as defined in any one of claims 1 to 3; wherein the molar ratio of isocyanate groups to isocyanate-reactive groups in the polymerizable composition is at least 2:

1.

7. The polymerizable composition according to claim 6, wherein the polyisocyanate component of the polymerizable composition consists of at least 80% by weight of at least one polyisocyanate selected from the group consisting of monomeric HDI, oligomeric HDI, monomeric PDI, oligomeric PDI, monomeric H12MDI, oligomeric H12MDI, monomeric IPDI and oligomeric IPDI.

8. Use of a kit containing a) at least one polyisocyanate having isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, araliphatically and aromatically bound isocyanate groups and b) at least one compound as defined in any one of claims 1 to 3 for producing a polymer in which at least 30 mol% of the free isocyanate groups present in the polyisocyanate are crosslinked with one another.

9. The use of the polymerizable composition according to claim 6 or 7 or of the kit according to claim 8 for producing a polymer in which at least 30 mol% of the free isocyanate groups present in the polyisocyanate have been crosslinked to form isocyanurate groups.

10. A process for producing a polymer comprising the steps of a) mixing at least one polyisocyanate having isocyanate groups selected from the group consisting of aliphatically, cycloaliphatically, araliphatically, and aromatically bound isocyanate groups with a compound as defined in any one of claims 1 to 3; and b) curing the polymerizable composition obtained in process step a) by raising the temperature to at least 50°C, wherein at the start of process step b) the ratio of isocyanate groups to isocyanate-reactive groups in the polymerizable composition is at least 2:

1.

11. The method according to claim 10, wherein between the end of method step a) and the beginning of method step b) there is a period of between 30 minutes and 360 minutes.

12. The process according to claim 10 or 11, characterized in that the reaction mixture obtained in process step a) is mixed with an organic or inorganic filler before carrying out process step b).

13. The method according to claim 12, characterized in that the organic or inorganic filler consists of fibers with a minimum length of 2 mm and the curing in process step b) takes place in a heated tool which imparts a profile to the fiber bundle wetted with the reaction mixture and stabilizes this profile by the curing of the reaction mixture.

14. A polymer obtainable by the process according to claim 10 or 11 or a composite material obtainable by the process according to claim 12 or 13.

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