Thermosetting mixtures having an extended storage life consisting of polyisocyanate and compounds capable of reacting with isocyanate groups, process for their preparation, and their use.

The invention relates to storage-stable at room temperature, heat-curable mixtures of polyisocyanate and at least one isocyanate-reactive compound, wherein the polyisocyanate is dispersed in the form of discrete particles that are deactivated on their surface, processes for their preparation and their use.

The preparation of combinations of polyisocyanates with binders containing isocyanate-reactive groups, and their direct applicability is known.

Great difficulties, however, the fact that the isocyanate even at room temperature with the intended reactants, such as polyols or polyamides, responsive, meaning it can be formulated not storage-stable combinations.

To circumvent this difficulty, two-component systems are often used. The reactants are thereby kept in separate preparations and only mixed immediately prior to application, and the reaction then takes place spontaneously or heat and / or catalyst accelerates.

As an example of such a mass is mentioned here, US Patent No. 4,029,626. The disadvantages of this method are the need for separate preparation and storage of the two components, the difficulty in accurate dosing and good mixing before application and in the risk of blockage of the mixing and application equipment by early response.

Another known method for producing storage stable Polyisocyanatmassen proceeds from uncrosslinked so-called prepolymer, containing little free isocyanate, and is used as a crosslinking agent-humidity. This method is described for example in FR-PS 1,237,936. The disadvantage in this case that the hardening of the surface very slowly penetrates into the depth of the coating, the final properties are only achieved after weeks or months and, for example between large areas or no curing takes place in hollows.

Stable systems may be formulated even if the polyisocyanates are first reacted with a monofunctional reactant. The adducts obtained are referred to as capped or blocked isocyanates if they are less thermally stable than the products of the intended later crosslinking reaction. On heating, the capping agent is split off and the polyisocyanate is to crosslink a thermostable the bond.

This principle is as described in Vieweg / Hoechtlen, Kunststoff-Handbuch, Volume VII, Polyurethane (Carl Hanser Verlag, Munich, 1966), page 11 et seq and is also the basis of a number of patents, for example DE-AS 26 40 295, the DE-AS 26 12 638, DE-AS 26 39 491 or EPA 0000060.

Technical and economic disadvantages of such formulations are given by the breakaway capping which, if it remains in the crosslinked composition, their properties veräncert, or if esverdampft, recovered or from the exhaust entferr: must be.

In the DE-AS 15 70 548, DE-OS 28 42 805 and DE-OS 29 21 162 melting polyisocyanates in excess of 100 ° or more than 130 ° C described resulting storage-stable combinations with special polyols among themselves warming harden to form coatings for fabrics or fabric hoses.

The technical disadvantage of these references to be removed combinations is that, to achieve good storage stability, are arge had a very narrow range specially constructed polyols and therefore not suitable for example for a number of applications.

Object of the present invention is lageistabile, show thermosetting liquid to paste-like mixtures of polyisocyanate and isocyanate-reactive compounds which do not have the disadvantages listed above.

Object of the present invention are storage-stable at room temperature, heat-curable mixtures of polyisocyanate and at least one reactive with isocyanate compound, which optionally contains additives of protective colloids, solvents, plasticizers, pigments, fillers, dyes or other in deri-acktechnik customary excipients, which are characterized in that the polyisocyanate in the form of discrete particles containing with Teilchendurchessern between 0.1 to 150 .mu.m in an amino, hydrazide, mercaptan and / or carboxyl polymerization, polycondensation or polyaddition product having a functionality of greater than 1, the optionally partially may be replaced by polyols, and optionally containing the mentioned additives, is dispersed and the polyisocyanate particles are deactivated on their surface, with the proviso that from 0.01 to 20 Äquivalentpfozent the total isocyanate groups present are deactivated.

To deactivate primary or secondary amines, water or compounds are preferably used which contain carboxyl groups, phenolic hydroxyl groups, amide groups, hydrazide groups or alcoholic hydroxyl groups, with the proviso that the compounds with alcoholic hydroxyl groups have a solubility in water of below 1%.

The present invention also provides a process for preparing these mixtures, wherein the polyisocyanate, generally at temperatures below 40 ° C, containing in an amino, hydrazide, mercaptan and / or carboxyl polymerization, poly - condensation or polyaddition is having a functionality of greater than 1, which may optionally be partly replaced by polyols, dispersed in which the deactivating agent is included or the dispersion of the polyisocyanate is at least partly subsequently added or initially treated the polyisocyanate with the deactivating agent and then in a amino, hydrazide, Mereaptan-and / or carboxyl group-containing polymerization, polycondensation or polyaddition is having a functionality of greater than 1, which may optionally be partly replaced by polyols, dispersed.

As containing amino, hydrazide, mercaptan and / or carboxyl polymerization products having a functionality of greater than 1, which may optionally be partly replaced by polyols are conventional products in question, the production thereof, unless it is quoted hereafter, is not claimed and is not the subject of the present invention.

The present invention is also the use of the compositions according to the invention as coating compositions, and sealing compounds Verklebungsmittel on metals and non-metals and especially as underseal compositions for motor vehicles.

The present invention avoids the disadvantages of the above-identified prior art in that the polyisocyanates in the form of discrete particles in the amino, hydrazide, mercaptan, and / or carboxyl-containing polymerization, polycondensation or polyaddition products with a functionality of greater than 1, which may optionally be partly replaced by polyols, dispersed and the dispersed particles are deactivated on their surface by chemical reactions. For the deactivation of only a relatively small part of the Isocyenatgruppen is consumed, so that the particles remain reactive.

When heat curing the phase separation is removed by solvent or melting process and the crosslinking can take place.

Regarding the components of the compositions according to the invention is to carry out the following details.

Suitable polyisocyanates are the conventional aliphatic, cycloaliphatic and aromatic di- and polyisocyanates, as are obtained, for example by addition of diisocyanates to di-, tri- or polyols, or from diisocyanates by dimerization to uretdiones, trimerization to isocyanurates and with amines or water to biurets. For this uazB following diisocyanates are suitable. Diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate.

Preferred polyisocyanates are solid polyisocyanates, for example at room temperature, the addition product of toluene diisocyanate and trimethylolpropane or the cyanurate from 3 moles of tolylene diisocyanate and especially poorly soluble powdery dimerized tolylene diisocyanate with urethdione.

Suitable reactive with isocyanate compounds according to the invention come amino, hydrazide, mercaptan and / or carboxyl group-containing polymerization - polycondensation or polyaddition products with a functionality of greater than 1, preferably 2 to 4 in question, optionally partially, for example, up to 95 , preferably up to 50 weight percent, may be replaced by a polyol. Functionality of less than 2 or non-integer functionality can be provided if the reactive toward isocyanate component is not uniform, and if optionally mono-functional components are contained.

As amino group-containing addition polymerization, polycondensation or polyaddition products with a functionality of greater than 1 are suitable ₃ for example polyamines having primary and / or secondary amino groups, such as polyamide amines which are obtained by polycondensation of dimerized linseed oil fatty acid with di- and trivalent amines, the amine content can vary within a wide range by proper selection of the amines (_z,_B, (^R) _Versamide of Schering).

Hydrazide carrying polymerization products are obtained, for example by hydrazinolysis of polyacrylates, as described by M. Hartmann, R. and T. Hock Dowbenko Wender in Organic Coatings + Applied Polymer Science 46, 1982, pages 429 to 432nd

As mercaptan containing polymerization, polycondensation or polyaddition with a functionality of greater than 1 are, for example polythiols.

By the term "polythiols" always simple or complex organic compounds are referred to in the present case, that at least two branched chain or terminally disposed -SH have functional groups per average molecule.

Such polythiols are esters of Mercaptofettsäuren with polyhydroxy compounds whose preparation is given for example in DE-OS 17 20 856th

As a carboxyl group-containing polymerization, polycondensation or polyaddition product having a functionality of greater than 1 are, for example, saturated and unsaturated polyesters were prepared using an excess of acid; Homo- and copolymers of acrylic acid and / or methacrylic acid with their esters and / or other suitable unsaturated monomers; acidic polymers which are obtained by alcoholysis of the addition products of maleic acid in unsaturated compounds, for example polybutadiene or linseed oil. Likewise, i, are also suitable mixtures of these amino, hydrazide, mercaptan or carboxyl groups-containing products as well as polymerisation, polycondensation and polyaddition products, containing different these functional groups in order to adjust, for example, desired properties such as adhesion and chemical resistance.

Suitable polyols are the polyesterols usually used in polyurethane chemistry, polyetherols and hydroxyl polymers, for example copolymers of olefinically unsaturated monomers without active hydrogens and olefinically unsaturated monomers with) active hydrogen.

Suitable monomers having no active hydrogen are, for example vinyl aromatic compounds such as styrene or vinyltoluene, olefins, such as ethylene or propylene, acrylic or methacrylic esters, such as butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, vinyl esters of linear or branched carboxylic acids such as vinyl acetate, vinyl propionate or vinyl pivalate and vinyl ethers such as isobutyl.

Suitable monomers containing isocyanate-reactive hydrogen are, for example, mono (meth) acrylic esters of polyhydric, in particular dihydric, alcohols, such as butanediol monoacrylate, hydroxypropyl (meth) acrylate, other copolymerizable olefinically unsaturated compounds containing hydroxyl groups, such as vinyl glycol, and copolymerizable olefinically unsaturated compounds with amine and / or amide groups such as acrylamide and methacrylamide.

The compositions of the invention contain the polyisocyanates in the form of discrete particles having particle diameters of between 0.1 to 150, preferably 1 to 50 microns dispersed in said mt isocyanate-reactive compounds or their mixtures with polyols, of isocyanate groups with isocyanate reactive groups in general in proportions 0.5: 1 to 1: 0.5, preferably 0.9: 1 to 1: 0.9 are present.

The invention is not limited to these amounts, for certain purposes may also be deviated from. As an adhesive for wiederentfernbare metal labels such as mixtures with considerable Isocyanatunterschuß suitable.

The dispersed polyisocyanate particles are deactivated on their surface as far as that at room temperature, no reaction of the polyisocyanate with the reactive compounds occurs.

The deactivating agent is advantageously chosen such that it is bonded to the surface of the polyisocyanate by chemical or physical forces and so a phase separation between the polyisocyanate and the isocyanate-reactive compound or mixture alia with polyol is effected.

For the chemical deactivation 0.01 to 20, preferably made 0.3 to 5 equivalent percent of the total isocyanate groups present with the deactivating agent to the reaction.

To speed up and control the deactivation also suitable unc can btverzugt deactivation selectively demanding catalysts are used.

Suitable deactivating are: water, mono- and polyamines, _MONO and polyalcohols. Particularly suitable long-chain_MONO amines, for example stearylamine, the grafted into a kind of emulsifiers react. Higher molecular weight polyamines such as polyamide amines and hydroxyl-terminated polymers, such as hydroxyl-terminated polybutadiene, react to form grafted protective colloids. Particularly suitable for the deactivation of the isocyanate groups on the surface of the polyisocyanate particles, ie the stabilization of the isocyanate / polyol - dispersions are reactions leading to the isocyanates to form urea or polyurea, because they are insoluble in most polyols and organic solvents. Such ureas or polyureas forming reagents are water and primary or secondary amines, wherein short-chain diamines such as ethylenediamine or propylenediamine are preferred. The polyureas formed from these short-chain diamines are organophobic than those formed as a relatively long-diamines and therefore are more effective stabilizing. A preferred procedure is based on sparingly powdered dimerized toluene diisocyanate. Because isocyanate with primary amines react much faster than with polyols, for example, can be obtained by stirring powdered dimerized toluene diisocyanate in diaminhaltiges Polyetherol immediately a storage-stable mixture.

An advantage of this method is given by the fact that the urea structures react further at higher temperatures with further isocyanates Bil = formation of biuret, that the deactivating agent is incorporated into the crosslinked system and does not leave any inhomogeneity.

Suitable deactivating agents are also compounds which carboxyl groups I, contain phenolic hydroxyl groups, amide groups, hydrazide groups or alcoholic hydroxyl groups, the compounds with alcoholic hydroxyl groups have a solubility in water of below 1%.

As carboxyl-containing deactivating agents are, for example question: homopolymers and copolymers of acrylic acid, methacrylic acid, maleic acid and other polymerizable acids, acidic polycondensation products, such as prepared with an excess of acid polyester, acidic polymers obtained by alcoholysis of the adducts of Maleinsäureannydrid of unsaturated polymers, such as linseed oil or polybutadiene, are obtained.

Suitable deactivating suitable compounds which contain phenolic hydroxyl groups, are, for example phenol, cresol, cardanol, p-tert-butylphenol, 2,2-bis [4-hydroxy-phenyl] -propane and the uncross-linked condensation products of these phenol body with aldehydes, for example formaldehyde , which are also known as resols.

Suitable deactivating appropriate amide group-containing compounds are, for example soluble polyamides and polymers of acrylamide and methacrylamide or copolymers of acrylamide and / or methacrylamide with acrylic acid and / or methacrylic acid esters.

Also suitable are polyhydrazides obtained by hydrazinolysis of polyacrylates and their preparation is described, for example by M Hartmann, R. Dowbenko, UT Hock Wender in Organie Coatings + Applied Polymer Science 46, 1982, pages 429 to 432nd

In a particular embodiment, the compositions can additionally contain 0.5 to 60% of conventional plasticizers, such as esters of phthalic, adipic, sebacic acid or phosphoric acid, high-boiling hydrocarbons, chlorinated hydrocarbons, epoxidized natural oils or low molecular weight polyester.

Detailed explanations of the term plasticizer are in D. Weinmann, coatings paints and plastics, Verlag WA Colomb, Stuttgart, 1967, page 103 ff, if.

For adjustment to special processing conditions or to achieve special effects, can compositions according to the invention, generally in the reactive with isocyanate compounds, addition of protective colloids, for example in amounts of 0.1 to 15 X, solvents, such as benzene, esters, ketones, ethers, glycol ethers and pigments, such as carbon black, titanium dioxide, organic and inorganic color pigments, fillers, such as talc, clay, chalk and silica flour, coloring agents or other conventional auxiliary substances.

The preparation of the compositions according to the invention is generally carried out using conventional dispersion and mixing units. The polyisocyanate is added conveniently at temperatures below 40 ° C, preferably at temperatures between 0 and 25 ° C, dispersed in said reactive with isocyanate compound, wherein either the latter already contains the entire quantity of the deactivating agent, or the deactivating agent shortly after the dispersing of the mixture becomes. The presence of catalysts selectively promote the reaction between the polyisocyanate and the deactivating agent is added if appropriate.

Another possibility for preparing the compositions of the invention is the polyisocyanate is first generally carried out at temperatures of below 40 ° C, preferably between 0 and 25 ° C and, optionally, be treated in the presence of suitable catalysts, with the deactivating agent and then into the reactive with isocyanate compound or things, to disperse mixture with polyol.

The compositions of the invention are at 25 ° C good storage stability of at least 3 months without a the designated correct use of the material mixture affecting change in the mass were observed.

The curing of the compositions according to the invention is generally conducted at 70 to 180 ° C.

The compositions according to the invention can be used in liquid or paste form and are suitable as coating agents, Verklebungsmittel and sealants. As substrates while metals such as steel, aluminum, copper, magnesium, which may be i coated with a primer and non metals such as glass, ceramics, heat-resistant plastics and textile substrates are suitable.

Particularly advantageous compositions according to the invention can be used as underbody protection for motor vehicles.

The following examples serve to illustrate the invention, but without restricting it to these examples.

The parts and percentages in the following examples are,), unless otherwise indicated, parts by weight and percentages by weight.

example 1

A) Preparation of hydrazide polymer 5

In a glass polymerization reactor with a reflux condenser, 2 feed vessels, a stirrer and a thermometer 430 parts of butyl glycol are heated under a slight stream of nitrogen to 130 ° C, feed 1, consisting of 225 parts of ethylhexyl acrylate, 225 parts Methylmeth-3 acrylate, 50 parts of ethyl acrylate, 5 Share dodecylmercaptan is added over 3 hours and feed 2, consisting of 70 parts of butyl glycol and 5 parts of t-butyl perbenzoate in 4 hours.

It is cooled to 60 ° C and 25 parts of hydrazine hydroxide added. The temperature is raised in an hour to 130 ° C and kept at this temperature, then the reflux condenser is replaced by a descending cooler and the temperature increased to 160 ° C. There are obtained 75 g of distillate. It is then cooled and the polymer solution adjusted with butylglycol to a solids content of 50%. The resin solution obtained has an amine number of 29.3.

B) preparing a hitzehärtbren, storage-stable mixture with a hydrazide polymer and a polyether polyol:

70 parts of polyether polyol based on glycerine and propylene oxide having an OH number of about 400 and a molecular weight of about 420, 150 parts of a polyether diol having a molecular weight of about 200 and a viscosity of 320 mPas, the prepared based on propylene oxide was and 105 parts finely divided, via uretdione dimerized 2,4-toluene diisocyanate, are at a temperature of max. 35 ° C processed under a high-speed stirrer to a flowable paste.

It is then cooled to 20 ° C and stirred in succession: 0.5 parts of a polyamide amine with an amine number of about 400, 1 part of a 25 Xigen butylglykolischen solution of phenylmercury and 100 parts of the polymer A.

This gives a flowable paste, which solidifies at 140 ° C in 20 minutes to a soft viscous mass, the good water resistance and good adhesion to bare zinc phosphated or grundierlackiertem steel sheet shows. Due to these properties the paste can be used as Nahtabdichtmasse in automotive engineering.

After storage for 3 months at 30 ° C, neither the paste nor the quality of the seal made of the stored paste have changed.

example 2

Heat cross-linkable blend with a carboxyl group-containing polymer and a polyether polyol

A polymerization reactor with stirrer, two feed vessels and a thermometer, 450 parts of a polyether are heated to 140 ° C with a molecular weight of about 1060 and 450 parts of a polyether based on propylene oxide having a molecular weight of about 2000th Feed 1, consisting of 50 parts hydroxypropyl acrylate, 5_{0 T}rush acrylic acid, 400 parts of ethylhexyl acrylate, 400 parts of styrene and 9 parts of 2-hydroxyethyl mercaptan is added in 3 hours and feed 2, consisting of 45 parts of t-butyl perbenzoate in 4 hours: Then for 2 hours, polymerization is continued at 140 ° C and then cooled.

The resulting mass is transferred to a planetary. These 170 parts finely powdered, dimiersiertes by uretdione of 2,4-toluene diisocyanate are mixed. The temperature is maintained at about 20 ° C by cooling. After a smooth homogeneous paste is formed, 8 parts of a polyamide amine resin with an amine value of about 200, 5 parts of dibutyltin dilaurate, and 700 parts of 5 parts Diazabiscyclooctan are successively pulverulent, dry chalk mixed until a smooth homogeneous paste.

This paste can be crosslinked to a foamed-pliable mass that can be used as carpet backing coating or as Schalldämpfmasse in automobile at temperatures of 110 to 150 ° C in a layer thickness of approximately 10 mm.

The paste is at room temperature at least 3 months stably. If a same paste_`prepared without the stabilizing additive of the polyamidoamine resin, so the shelf life is less than 1 week.

example 3

A) Preparation of a polythiol

159 parts of β-mercaptopropionic acid, 650 parts of a polyether triol based on glycerol and propylene oxide having a molecular weight of about 2000, 0.5 parts of p-toluenesulfonic acid and 100 parts of benzene was boiled in a stirred container with water. The azeotropic benzene / water mixture was removed. Here, 25 parts of water were obtained. The reaction mixture was kept under vacuum for several hours at 70 ° C. The Polythiopolymerisat had a molecular weight of about 2210-2230 and an average functionality of third

B) Preparation of a storage-stable, heat-curable composition having a polythiol

750 parts of polythiol A are in a cooled laboratory kneader with 90 parts finely powdered dimerized via uretdione of 2,4-toluene diisocyanate kneaded homogeneously. There are 1.8 parts polyamidoamine resin added with an amine number of about 400 and further mixed for 20 minutes at about 20 ° C. Then 7.5 parts of a 33 Xigen solution of Diazabiscyclooctan in butyl glycol are mixed. This gives a good flowable paste which is> 3 months shelf life and can be converted by heating to 110 to 140 ° C in an elastomeric composition.