MXPA99010633A - Composicions of thermo-understanding coating of a compone - Google Patents

Abstract

The present invention relates to: The present invention relates to compounds containing modified hydrazide groups and corresponds to formula I, wherein R represents the residue obtained by removing the isocyanate groups of a monomeric polyisocyanate, a polyisocyanate adduct or an NCO prepolymer , x represents OR'óNHR'y R1 represents a group that is inert to the isocyanate groups under the conditions used to form the compound of formula I and n has a value from 2 to 6. The present invention also relates to thermosetting coating compositions of a component containing the compounds of formula I and a crosslinking component reactive with these compounds. Finally, the present invention relates to coatings, sealants and adhesives prepared with these thermosetting compositions.

Description

COMPOSITION THERMO-DECOMPOSITION COMPOSITIONS OF A COMPONENT BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to resins based on polyisocyanates containing modified hydrazide groups, with one-component thermosetting compositions containing these resins and with an en-crosslinking component and their use for the production of coatings, shutters and adhesives. Description of the Prior Art One-component polyurethane coating compositions derived from blocked polyisocyanates and polyols are an important class of materials for applications such as OEM coatings. These one-component compositions are used because of the difficulties encountered when using two component coating compositions in industrial applications. In the two component compositions, the polyisocyanates are not blocked, which gives rise to various disadvantages. The two component compositions must be mixed accurately, or the properties of the resulting coating may be substantially affected. In addition, after mixing the components, they have a limited shelf life, as the components continue to react until an unusable solid is obtained. These drawbacks are not present in one-component coating compositions containing blocked polyols and polyisocyanates with reversible monofunctional blocking agents for isocyanate groups. However, there are also drawbacks with the one component coating compositions, which are primarily caused by the volatilization of the blocking agent. The release of the blocking agent can cause blistering and yellowing in thick films and incrustations in the oven. In addition, blocking agents are considered to be volatile organic compounds (VOCs), in the same way as organic solvents. Therefore, certain coating compositions may not satisfy environmental regulations solely because of the presence of blocking agents. It is an object of the present invention to overcome the known drawbacks of the one-component reverse compositions caused by the release of blocking agents during curing, without affecting the advantages of these coating compositions when compared to the coating compositions. of two com-ponents. It is a further object of the present invention to be able to obtain coatings having chemical stability, including acid corrosion resistance, which is comparable to that obtained with coatings prepared using blocked polyisocyanates as a cross-linking agent. These objects can be achieved with the compositions of a component according to the present invention. These compositions do not require blocking agents and, therefore, do not release blocking agents. When the coating compositions according to the invention are cured, the only compounds released are water or monoalcohols, which are much less toxic than conventional blocking agents. SUMMARY OF THE INVENTION The present invention relates to compounds containing modified hydrazide groups and corresponds to formula I wherein R represents the residue obtained by removing isocyanate groups from a monomeric polyisocyanate, a polyisocyanate adduct or an NCO prepolymer, X represents OR 'or NHR' and R 'represents a group that is inert to the isocyanate groups under the conditions used to form the compound of formula I and n has a value of 2 to 6. The present invention also relates to thermosetting compositions of a component containing the compounds of formula I and a cross-reactive component reactive with these compounds. Finally, the present invention relates to coatings, sealants and adhesives prepared with these thermosetting compositions. DETAILED DESCRIPTION OF THE INVENTION The compounds containing modified hydrazide groups according to the present invention can be prepared by several different methods. For example, a polyisocyanate can be made to react with an excess of hydrazine to form a compound containing terminal NH-NH2 groups, which can then be reacted with a chloroformic acid ester (X = OR) or a monoisocyanate (X = NHR) to form the compounds of formula I. The compounds of formula I can also be prepared by reacting a polyisocyanate, R- (NCO) n, with a compound of formula II O X-C-NH-NH2 (II) where X and R 'are as previously defined. In formulas I and II, X represents OR 'or NHR', preferably OR ', and R 'represents a group which is inert to isocyanate groups under the conditions used to form the compound of formula I, preferably an alkyl, cycloalkyl, araliphatic or aromatic group containing from 1 to 20, preferably from 1 to 10, carbon atoms , which may eventually be replaced by heteroatoms to form ether or ester groups. When X represents OR ', examples of R' include methyl, ethyl, propyl, butyl, hexyl, octyl, phenyl, cyclohexyl and benzyl. More preferably, R 'is an alkyl group having from 1 to 4 carbon atoms. When X represents NHR, R 'is more preferably an alkyl group containing at least 4 carbon atoms. Compounds corresponding to formula II where X represents NHR 'can be prepared by reaction of hydrazine with an organic monoisocyanate in a molar ratio of 1: 1. In order to increase the amount of product corresponding to formula II, it is also possible to use an excess amount of hydrazine and remove the excess, for example by precipitation, distillation or extraction. However, this is not generally necessary, since the selectivity to form the adduct-raon is very high. Examples of suitable polyisocyanates which can be used as the polyisocyanate component for preparing the compounds of formula I include monomeric polyisocyanates, polyisocyanate adducts and NCO prepolymers having an average functionality of 1.5 to 6, preferably 1.8. to 6, more preferably from 2 to 6 and, most preferably, from 2 to 4. Suitable monomeric diisocyanates can be represented by the formula R (NCO) 2 wherein R represents an organic group obtained by removing isocyanate groups from a diisocyanate organic having a molecular weight of about 112 to 1,000, preferably about 140 to 400. Preferred diisocyanates for the process according to the invention are those represented by the above formula wherein R represents a divalent aliphatic hydrocarbon group having from 4 to 40 , preferably from 4 to 18, carbon atoms; a divalent cycloaliphatic hydrocarbon group having from 5 to 15 carbon atoms; a divalent araliphatic hydrocarbon group having from 7 to 15 carbon atoms; or a divalent aromatic hydrocarbon group having from 6 to 15 carbon atoms. Examples of suitable organic diisocyanates of 1, 4 -tetrametileno diisocyanate, 1, 6-hexamethylene diisocyanate, include 2,2,4-trimethyl-1, 6-hexamethylene diisocyanate, 1,12-dodecamethylene ciciohexano- 1, 3- and -1, 4-diisocyanate, 1-isocyanato-2 -isocianatometilciclopentano, l-isocyanato-3 -isocyanatomethyl-3, 5, 5-trimethylcyclohexane (isophorone diisocyanate or DiiF), bis (4- isocyanatocyclohexyl ) -methane, 2, 4'-diciclohexilmetano, 1,3- and 1,4-bis (isocyanatomethyl) ciciohexano, bis (4-isocyanato-3-me-tilciclohexil) methane diisocyanate, a, a ', a '-tetrame-til-1,3- and / or -1, 4-xylylene, l-isocyanato-l-methyl-4 (3) -isocyanatomethylcyclohexane, 2,4- and / or 2,6-hexahidrotoluilenodiisocianato of 1,3- and / or 1,4-phenylene, 2,4- and / or 2,6-toluylene diisocyanate, 2,4- and / or 4-diisocyanate, '-diphenylmethane, 1,5-naphthalene diisocyanate and its mixtures can also be used polyisocyanates containing 3 or more isocyanate groups, such as dilsocianato of - ^ to-isocyanatomethyl-1, 8-octamethylene diisocyanate and aromatic polyisocyanates, diisocyanates such as 4, 4 ', 4"-triphenylmethane and polyphenylpolymethylene polyisocyanates obtained by fosgepación of aniline / formaldehyde. preferred organic diisocyanates include 1, 6 -hexametileño, l-isocyanato-3-isocyanatomethyl-3, 5, 5-trimethylcyclohexane (or DiiF issforona diisocyanate), bis (4- isocyanatocyclohexyl) methane, 1-isocyanato-l-methyl-4 (3) -isocyanatomethylcyclohexane, 2,4- and / or 2,6-toluylene diisocyanate and 2,4- and / or 4,4'-diphenylmethane diisocyanate. According to the present invention, the polyisocyanate component can be in the form of a polyisocyanate adduct. Suitable polyisocyanate adducts are those containing isocyanurate, uretdione, biuret, urethane, allophanate, iminooxadiazinedione, carbodiimide and / or oxadiazi-natrione groups. The polyisocyanate adducts have an average functionality of 2 to 6 and an NCO content of 5 to 30% by weight and include: 1) Polyisocyanates containing isocyanurate groups, which can be prepared as indicated in DE-PS 2,616. 416, EP-OS 3,765, EP-OS 10,589, EP-OS 47,452, US-PS 4,288,586 and US-PS 4,324,879. The isocyanato isocyanurates have, in general, an average NCO functionality of 3 to 3.5 and an NCO content of 5 to 30%, preferably 10 to 25% and, more preferably, 15 to 100%. 25% by weight. 2) uretdione diisocyanates, which can be prepared by oligomerization of a portion of the isocyanate groups of a diisocyanate in the presence of a suitable catalyst, for example a trialkylphosphine catalyst, and which can be used in admixture with other aliphatic and / or cycloaliphatic polyisocyanates , particularly the polii-socianates containing isocyanurate groups indicated above in (1). 3) Containing polyisocyanates, biuret groups, which can be prepared according to the procedures described in US Pat. Nos. 3,124,605, 3,358,010, 3,644,490, 3,862,973, 3,903,126, 3,903,127, 4,051,165, 4,147,714 or 4,220,749, using co-reactants such as water, tertiary alcohols, monoamines primary and secondary and primary and / or secondary diamines. These polyisocyanates preferably have an NCO content of 18 to 22% by weight and an average NCO functionality of 3 to 3.5. 4) Polyisocyanates containing urethane groups, which can be prepared according to the procedures described in US Pat. No. 3,183,112 by reaction of excess amounts of polyisocyanates, preferably diisocyanates, with low molecular weight glycols and polyols "having molecular weights of less than 400, such as trimethylolpropane, -leukerin, 1,2-dihydroxy-propane and mixtures Polyisocyanates containing urethane groups have a more preferred NCO content of 12 to 20% by weight and (average) NCO functionality 2.5 to 3. 5) Polyisocyanates containing alofa-nato groups, which can be prepared according to the procedures described in US Patents Nos. 3,769,318, 4,160,080 and 4,177,342 and in copending application, US Serial No. 08 / 432,285.Polyisocyanates containing allophanate groups they have a more preferred NCO content of 12 to 21% by weight and (average) NCO functionality of 2 to 4.5.Preferred catalysts for the preparation of these polyisocyanates include organic tin (II) salts, as tin octoate (II). 6) Polyisocyanates containing isocyanurate and allophanate groups, which can be prepared according to the procedures set forth in U.S. Pat. 5,124,427, 5,208,334, 5,235,018 and 5,444,146, the disclosures of which are hereby incorporated by reference, preferably polyisocyanates containing these groups in a proportion of monoisocyanurate groups to monoalphanate groups of about 10: 1 to 1:10 , preferably about 5: 1 3, 1: 7. 7) Polyisocyanates containing imino-xadiazinedione groups and, optionally, isocyanurate, which can be prepared in the presence of special fluorine-containing catalysts, as described in DE-A 19611849. These polyisocyanates have, in general, an average NCO functionality of 3. at 3.5 and an NCO content of 5 to 30%, preferably 10 to 25% and, more preferably, 15 to 25%, by weight. 8) Polyisocyanates containing carbo-diimide groups, which can be prepared by oligomerizing di- or polyisocyanates in the presence of known carbodiimidation catalysts, as described in DE-PS 1,092,007, US-PS 3,152,162 and DE-OS 2,504 .400, 2,537,685 and 2,552,350. 9) Polyisocyanates containing oxadia-zinatrione groups and containing the reaction product of two moles of a diisocyanate and one mole of carbon dioxide. Preferred polyisocyanate adducts are the polyisocyanates containing isocyanurate, uretdione, biuret, iminooxadiazinedione and / or allophanate groups. The NCO prepolymers, which can also be used as a polyisocyanate component for preparing the compounds of formula I, are prepared from the monomeric polyisocyanates or adducts of polyisocyanates previously described, preferably monomeric diisocyanates, and organic compounds containing at least two isocyanate-reactive groups, preferably at least two hydroxy groups. These organic compounds include compounds of high molecular weight, having molecular weights of from 400 to about 6,000, preferably from 800 to about 3,000, and, optionally, compounds of low molecular weight, with molecular weights below 400. Molecular weights are weights molecular numerical means (Mn) and are determined by analysis of final groups (number of OH and / or NH). The products obtained by reacting polyisocyanates exclusively with low molecular weight compounds are adducts of polyisocyanates containing urethane groups and are not considered as NCO prepolymers. Examples of the high molecular weight compounds are polyester polyols, polyether polyols, polyhydroxypolycarbonates, polyhydroxypolycetals, polyhydroxypoly acrylates, polyhydroxypolyester amides and the polyhydroxypolythioethers. Polyester polyols, polyether polyols and polyhydroxypolycarbonates are preferred, with polyester polyols and polyhydroxypolycarbonates being more preferred. Examples of suitable high molecular weight polyhydroxy compounds include polyester polyols prepared from low molecular weight alcohols and polybasic carboxylic acids, such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, acid maleic, the anhydrides of these acids and mixtures of these acids and / or acid anhydrides. Also suitable are poly-lactones having hydroxyl groups, particularly poly-caprolactone, to produce the prepolymers. Also suitable for preparing the NCO prepolymers are polyether polyols, which can be obtained in a known manner by alkoxylation of suitable starter molecules. Examples of suitable starter molecules include polyols, water, organic polyamines having at least two N-H bonds and mixtures thereof. The alkylene oxides suitable for the alkoxylation reaction are preferably ethylene oxide and / or propylene oxide, which can be used sequentially or in admixture.

Other suitable polyols include polycarbonates having hydroxyl groups, which may be produced by the reaction of diols with phosgene or diaryl carbonates, such as diphenyl carbonate. Other details concerning low molecular weight compounds and starting materials and methods for preparing high molecular weight polyhydroxy compounds are described in US Pat. 4,701,480, incorporated herein by reference. Other examples include the well-known high molecular weight amine-functional compounds, which can be prepared by converting the terminal hydroxy groups of the previously described polyols into amino groups, and the high molecular weight polyaddimines and polyaldimines described in US Pat. 5,243,012 and 5,466,771, respectively, incorporated herein by reference. A particular advantage of the use of polyaspartates for preparing the isocyanate addition products is that, during the subsequent curing of these products, the urea groups react to form thermally stable hydantoin groups. The NCO prepolymers generally have an isocyanate content of from 0.4 to 20% by weight, preferably from 0.4 to 15% by weight and, more preferably, from 0.5 to 10.0% in weigh. The NCO prepolymers are prepared in a known manner by reaction of the aforementioned starting materials at a temperature of 40 to 120 ° C, preferably 50 to 100 ° C, and at an equivalent NCO / OH (or NH) ratio of about 1, 3: 1 to 20: 1, preferably from about 1.4: 1 to 10: 1. If chain extension is desired through urethane groups during the preparation of the isocyanate prepolymers, an equivalent NCO / OH ratio of 1.3: 1 to 2: 1 is selected. If the extension of the chain is not desired, an excess of diisocyanate, corresponding to an equivalent NCO / OH ratio of 4: 1 to 20: 1, preferably 5: 1 to 10: 1, is preferably used. The excess of diisocyanate (and any volatile solvent used during the preparation) can be eventually removed by thin layer distillation when the reaction is complete. According to the present invention, the NCO prepolymers also include NCO semi-prepolymers which contain unreacted starting polyisocyanates, in addition to the prepolymers containing urethane groups. The compounds containing modified hydrazide groups can be prepared by reacting the polyisocyanate with the compound corresponding to formula II at a temperature of 20 to 150 ° C, preferably 50 to 100 ° C. The amount of the compounds corresponding to formula II must be sufficient to react with all or substantially all (ie, up to 90% equivalent), preferably all, isocyanate groups of the polyisocyanate. To prepare the one-component thermosetting compositions, the compounds of formula I are mixed with a compound that is reactive with the modified hydrazide functional groups. These reactive groups include active methylol or methylalkoxy groups on aminoplast crosslinking agents or on other compounds, such as phenol / formaldehyde adducts, siloxane or silane groups and anhydride groups. Examples include melamine formaldehyde resins (including monomeric or polymeric melamine resins and partially or fully alkylated melamine resins), urea resins (eg, methyl-lureas, such as urea resins and formaldehyde resins, and alco-xiureas, such as urea and formaldehyde butylated resins), N-methylolacrylamide emulsions, iso-butoxymethyl acrylamide emulsions, polyanhydrides (e.g., polysuccinic anhydride) and siloxanes or silanes (e.g., dimethyldimethoxysilane). Amino-plastic resins are preferred, such as melamine resins and formaldehyde resins or urea and formaldehyde resins. To control the crosslink density of the final product, it is possible to react one or more of the amino nitrogens or hydroxy groups. For example, melamine / formaldehyde resins can react or O O II II X-C-NH-NH-C-X (lli) urea / formaldehyde alkylated with a compound corresponding to formula III where X and R 'are as defined above. In the thermosetting compositions of a component according to the invention, the compounds corresponding to formula I and the co-reactants should preferably be present in an amount sufficient to obtain an equivalent ratio of modified hydrazide groups to the groups reactive with the modified hydrazide groups of 2: 1 to 1: 6, more preferably 1.5: 1 to 1: 3, more preferably 1.2: 1 to 1: 2.5. When aminoplast resins, especially melamine resins, are used, they may be present in an amount of 10 to 70%, based on the weight of the reactive components. This amount exceeds the previous equivalent ratios, since these resins can also undergo self-crosslinking. When aminoplast compounds, especially monomeric melamines are used, as the co-reactant for the compounds of formula I, strong acid catalysts are preferred. These catalysts are well known and include p-toluenesulfonic acid, dinonylnaphthalenedi-sulfonic acid, dodecylbenzenesulfonic acid, phenyl acid phosphate, monobutyl maleate, butyl phosphate and hydroxyphosphate ester. Other catalysts that may be useful include Lewis acids, zinc salts and tin salts. The one-component compositions may contain the organic solvents known from melamine chemistry. These solvents may be present in an amount of up to 95%, preferably up to 80%, based on the total weight of the thermosetting composition. Alcohols can be added to improve storage stability.

It is also possible according to the application in question to use water as a solvent. If the thermosetting compositions are dispersed in water, the reagents preferably have a hydrophilic character, which can be obtained in a known manner by incorporating ionic and / or nonionic hydrophilic groups to the reagents and / or by the use of external emulsifiers. The thermosetting compositions of a component of the present invention are suitable for preparing coatings, adhesives or sealants. Depending on the particular application, the compositions may also contain known additives, such as leveling agents, wetting agents, flow control agents, anti-skid agents, antifoaming agents, re-fillers (such as silica, aluminum silicates and waxes). high boiling point), viscosity regulators, plasticizers, pigments, dyes, UV absorbers and stabilizers against thermal and oxidative degradation. The one component compositions can be applied to any heat resistant substrate, preferably metals, glass and ceramic and, more preferably, metals. They can be applied by standard methods, such as spray coating, extension coating, flood coating, pouring, dip coating or roller coating. The coating compositions can be transparent or pigmented. The one-component thermosetting compositions are cured at elevated temperatures of 80 to 250 ° C, preferably 100 to 230 ° C and, more preferably, 100 to 160 ° C, for a period of 5 to 60 minutes, preferably from 10 to 50 minutes and, more preferably, 20 to 40 minutes. The invention is further illustrated, but without intending to limit it, by the following examples, wherein all parts and percentages are by weight, unless otherwise indicated. EXAMPLES The following materials were used in the examples: Polyol 1 A polyester polyol having an OH equivalent weight of 400, an OH content of 4.25% and a functionality of about 3.1 and prepared from 34.6 parts of 1,6-hexanediol, 9.8 parts of trimethylolpropane, 30.43 parts of isophthalic acid, 5.4 parts of phthalic acid anhydride and 10.7 parts of adipic acid. Polyol 2 A polyester polyol having a molecular weight of 840 and which is prepared from 1,6-hexanediol and adipic acid. Polyisocyanate 1 A polyisocyanate containing isocyanurate groups, prepared from 1,6-hexamethylene diisocyanate and having an isocyanate content of 21.6%, a monomeric diisocyanate content of <0.2% and a viscosity at 20"c of 3,000 mPa.s (which can be obtained from Bayer Corporation as Desmodur N 3300) Example 1 334 parts of isophorone diisocyanate and 2223 parts of butyl acetate were charged in a 2-liter round-bottomed flask equipped with a condenser, 566 parts of polyol 2 were weighed into a 1 liter flask and dried under vacuum at 100 ° C. 377 parts of butyl acetate were then added. A dropping funnel was added dropwise to the DIIF solution over a period of 2 hours.The temperature was maintained at 70 to 80 ° C. After all the polyol had been added, the mixture was heated to 80.degree. C for 6 hours The NCO prepolymer, having an NCO content of 5.2%, was obtained based on the solution, 423 parts of the NCO prepolymer (423 g) were stirred at 60 ° C in a flask 1 liter, 3-neck and round bottom equipped with a condenser, 47 parts of ethyl carbazate were added. followed by 31 parts of butyl acetate (31 g). The mixture was heated at 70 ° C for 4 hours and then placed in a heated oven at 70 ° C overnight. The resulting product had a solids content of 60%. Example 2 236 parts of isophorone diisocyanate and 156 parts of propylene glycol acetate monomethyl ether (MPA) were charged into a 2 liter round bottom flask equipped with a condenser. 343 parts of Polyol 1 and 157 parts of Polyol 2 (157 g) were weighed into a 1 liter flask and dried in vacuoOOO'C. 269 parts of MPA were added to the mixture of polyols. The resulting solution was placed in a dropping funnel and added dropwise to the DIIF solution over a period of 2 hours. The temperature was maintained at 70 to 80 ° C. After all the polyol had been added, the mixture was heated at 80 ° C for 3 hours. An NCO pre-limero was obtained, which stained an NCO content of 4.1%, based on the solution. 428 parts of the NCO prepolymer were stirred at 60 ° C in a 1 liter, 3-necked, round bottom flask equipped with a condenser. Then 43 parts of ethyl carbazate (43 g) were added, followed by 29 parts of MPA. The mixture was heated at 70 ° C for 4 hours and then placed in an oven heated at 70 ° C overnight. The resulting product had a solids content of 60%. Example 3 293 parts of isophorone diisocyanate, 57 parts of polyisocyanate 1 and 234 parts of MPA were charged into a 2 liter round bottom flask equipped with a condenser. 540 parts of polyol 1 and 117 parts of polyol 2 were weighed into a 1 liter flask and dried under vacuum at 100 ° C. Then 258 parts of MPA were added to the mixture.

The solution was placed in a dropping funnel and added dropwise to the isocyanate mixture over a period of 2 hours. The temperature was maintained at 70 to 80 ° C. After all the polyol had been added, the mixture was heated at 80 ° C for 6 h. An NCO prepolymer having an NCO content of -4.2% was obtained, based on the solution. 424 parts of the NCO prepolymer (424 g) were stirred at 60 ° C in a 1 liter, 3-necked, round bottom flask equipped with a condenser. Then 46 parts of ethyl carbazate were added, followed by 31 parts of MPA. The mixture was heated at 70 ° C for 4 hours and then placed in an oven heated at 70 ° C overnight. The resulting product had a solids content of 60%. Example 4 A coating composition was prepared from 10 g of the product of Example 1, 0.6 g of methoxylated hexamethylmelamine (Resimene 747, Solutia) and 0.3 g of a 10% solution of p-toluenesulfonic acid in isopropa-nol. The composition was deposited on a rolled steel panel with a 5 mil stretch bar and baked at 130 ° C for 30 min. The resulting coating was clear and insoluble in acetone. EXAMPLE 5 A coating composition was prepared with 8.3 g of the product of Example 2, 0.6 g of methoxylated hexamethylolmelamide (Resimene 747, Solutia) and 0.3 g of a 10% solution of p-toluenesulfonic acid in isopropanol. The composition was deposited on a rolled steel panel with a 5 mil stretch bar and baked at 130 ° C for 30 min. The resulting coating was clear and insoluble in acetone. EXAMPLE 6 A coating composition was prepared with 8.5 g of the product of Example 3, 0.6 g of methoxylated hexamethylmethylmetal (Resimene 747, Solutia) and 0.3 g of a 10% solution of p-acid. -Toluenesulfonic in isopropanol. The composition was deposited on a rolled steel panel with a 5 mil stretch bar and baked at 130 ° C for 30 min. The resulting coating was clear and insoluble in acetone. Although the invention has been described in detail in the foregoing for illustrative purposes, it is to be understood that said detail has only such purposes and that those skilled in the art can make variations therein without departing from the spirit and scope of the invention, except in what may be limited by the claims.

Claims (6)

1. CLAIMS 1. A compound containing modified hydrazide groups and corresponding to formula I where R represents the residue obtained by removing the isocyanate groups from a monomeric polyisocyanate, a polyisocyanate adduct or an NCO prepolymer, X represents OR 'or NHR' and R 'represents a group which is inert to the isocyanate groups under the conditions used for forming the compound of formula I and n has a value of 2 to 6. 2. The compound of claim 1, wherein
2. R 'represents an alkyl group containing from 1 to 10 carbon atoms. 3. The compound of Claim 1, wherein
3. X represents OR '.
4. 4. The compound of Claim 2, wherein X represents OR '.
5. 5. The compound of Claim 1, wherein R represents the residue obtained by removing the isocyanate groups from an NCO prepolymer. 6. The compound of Claim 2, wherein R represents the residue obtained by removing the isocyanate groups from a prepolymer of_NCO. 7. The compound of Claim 3, wherein R - represents the residue obtained by removing isocyanate groups from an NCO prepolymer. 8. The compound of Claim 4, wherein R represents the residue obtained by eliminating the isocyanate groups of an NCO prepolymer. 9. A thermosetting composition of a component containing the compound of Claim 1 and a melamine and formaldehyde resin, a urea resin, an N-methylol acrylamide emulsion, an isobu-toxymethylacrylamide emulsion, a polyanhydride, a siloxane or a silane. 10. A one component thermosetting composition containing the compound of Claim 1, an acid catalyst and a melamine and formaldehyde resin or a urea resin. 11. A heat-resistant substrate coated with the thermosetting composition of Claim 9. 12. A heat-resistant substrate coated with the thermosetting composition of Claim 10. SUMMARY OF THE INVENTION The present invention relates to compounds containing modified hydrazide groups and corresponding (I) give the formula I where R represents the residue obtained by removing the isocyanate groups of a monomeric polyisocyanate, a polyisocyanate adduct or an NCO prepolymer, X represents OR 'or NHR' and R 'represents a group which is inert to the isocyanate groups under the conditions used to form the compound of formula I and n - - has a value of 2 to
6. 6. The present invention also relates to one component thermosetting coating compositions containing the compounds of formula I and a crosslinking component reactive with these compounds. Finally, the present invention relates to coatings, sealants and adhesives prepared with these thermosetting compositions.