EP2283053A1

EP2283053A1 - Polyurea composition

Info

Publication number: EP2283053A1
Application number: EP09749548A
Authority: EP
Inventors: Axel Schmidt; Malte Homann; Andreas Aus Der Wieschen
Original assignee: Bayer MaterialScience AG
Current assignee: Covestro Deutschland AG
Priority date: 2008-05-20
Filing date: 2009-05-07
Publication date: 2011-02-16
Also published as: WO2009141058A1; TW201009030A; US20110070387A1; DE102008024352A1

Abstract

The invention relates to materials having a higher flexural modulus which consist of polyurea compositions.

Description

polyurea

The present invention relates to materials with increased flexural modulus of polyurea compositions. Polyurethane or polyurea based two-component coating systems are known and used in the art. In general, they contain a liquid polyisocyanate component and a liquid isocyanate-reactive component. Reaction of polyisocyanates with amines as the isocyanate-reactive component gives rise to polyurea coatings. However, amines and isocyanates usually react very quickly with each other. Typical pot or gel times are often only a few seconds. Therefore, such polyurea coatings can not be applied manually, but only with special spray equipment.

Coatings of polyureas are of particular interest because the reaction of polyisocyanates with amines proceeds extremely fast and the coated surfaces can be (re) used very quickly. In addition, the presence of urea groups in polyurethanes results in a very favorable ratio of hardness to elasticity, which is evident in many coating applications, e.g. the coating of pipes is very desirable. Frequently used as amines certain aromatic diamines whose reaction with isocyanates to form corresponding Polyharnstoffsystemen runs relatively slow, which improves the workability and the material properties.

US Pat. No. 3,428,610 and US Pat. No. 4,463,126 disclose the preparation of polyurethane / polyurea elastomers by curing NCO-functional prepolymers with aromatic diamines. These are preferably di-primary aromatic diamines which, in the ortho position to each amino group, have at least one alkyl substituent having 2-3 carbon atoms and optionally also in further ortho positions to the amino groups methyl substituents, such as, for example, diethyltoluyldiamine (DETDA) , an isomeric mixture of the isomeric forms 2,6-diamino-3,5-diethyltoluene and 2,4-diamino-3,5-diethyltoluene. US Pat. No. 4,463,126 describes a process for the preparation of solvent-free elastic coatings in which isocyanate diisocyanate (IPDI) and polyether-based NCO prepolymers are cured at room temperature with sterically hindered di-primary aromatic diamines. To make such polyurea coatings more flexible, it is possible, for example, to add to the aromatic diamines according to EP-A 1 486 522 polyhydroxy compounds such as polyether or polyester polyols, prepolymers of hexamethylene diisocyanate (HDI) and also its di- and trimer or amine-terminated polyether. However, these possibilities for making the polyurea coatings more flexible have the following disadvantages: when using polyethers and polyesters, the curing time increases considerably, since the NCO / OH reaction is significantly slower than the NCO / NH ₂ reaction. In addition, polyesters have a high viscosity, which makes their processing in these highly reactive mixtures considerably more difficult. Even simple prepolymers of HDI or its oligomers show too high a viscosity and furthermore incompatibilities in the fully reacted polyurea (inhomogeneous coatings). Since the reactivity of amine-terminated polyethers and aromatic diamines is very different, this also results in inhomogeneous systems.

Disadvantage of such systems is also that the aromatic diamines tend to yellow much.

Polyureas can also be used for coatings in contact with drinking water, as described for example in EP-A 0 936 235. Such coatings are obtained by mixing a liquid aliphatic polyisocyanate, which may additionally contain a liquid epoxy resin, with a liquid aromatic polyamine.

For coatings in direct contact with drinking water, the use of aromatic raw materials is often considered disadvantageous. For example, aromatic isocyanates could release aromatic amines under certain conditions. For the same reason, the use of aromatic amines as chain extenders is often viewed critically, because aromatic amines are classified as unwanted by the relevant regulatory authorities, which is recognizable by very low migration thresholds. In contrast, aliphatic amines in some cases have a factor of 100 to 1000 higher permissible migration thresholds. In this respect, purely aliphatic binders are advantageous for such applications.

However, primary, aliphatic amines have a significantly higher reactivity towards isocyanates than aromatic amines. However, the reactivity can be reduced by the conversion of a primary amine to a secondary amine. In particular, the Settling with maleic diesters in the sense of a Michael addition or the reaction with sterically hindered carbonyl compounds in the sense of a reductive amination leads to aliphatic diamine chain extenders with a reactivity that offers a good compromise of processing time and curing time. The use of such so-called aspartic acid esters as chain extenders in polyurea coatings is known in principle.

WO2004 / 033517, EP-A 0 403 921 and US Pat. No. 5,126,170 disclose the formation of polyurea coatings by reaction of polyaspartic esters with polyisocyanates. Polyaspartic esters have a low viscosity and a reduced reactivity towards polyisocyanates and can therefore be used to prepare solvent-free coating compositions with extended pot lives.

However, despite high tensile strengths and elongations at break, such compositions are only of limited suitability in many cases where mechanical stress from bending stresses is present. The resistance of a polymer to such bending stresses can be described by the flexural modulus.

It is an object of the present invention to develop a polyurea coating,

a) which is comparable in reactivity with coatings based on aromatic

Amines are based, b) for the production of which substantially aliphatic chain extenders are used and c) which has a high flexural modulus.

This problem was solved by the use of a combination of polyaspartic acid esters with special amine chain extenders, which demonstrably increase the bending modulus without adversely affecting the other mechanical properties.

The present invention therefore provides two-component coating systems, at least comprising

A) a polyisocyanate prepolymer which has ether groups attached via allophanate groups and B) a mixture of polyamines in the

Bl) at least 75 mol% of all NH groups from an amino-functional polyaspartic acid ester of the general formula (I)

in the

X is an n-valent organic radical obtained by removing the primary amino groups of an n-valent polyamine,

R ¹ and R ^{2 are} identical or different organic radicals which are inert under the reaction conditions to isocyanate groups and

n is an integer of at least 2

come and

B2) at most 25 mol% of all NH groups derived from a cycloaliphatic diamine or aromatic diamine, and

C) optionally further polyisocyanates.

The allophanates used in component A) are obtainable by:

Al) one or more aliphatic and / or cycloaliphatic polyisocyanates

A2) one or more polyhydroxy compounds, at least one being a polyether polyol,

be converted to an NCO-functional polyurethane prepolymer and then the urethane groups thus formed then with the addition of

A3) polyisocyanates, which may be different from those of Al) and

A4) catalysts

A5) optionally stabilizers partially or completely allophanatized.

Examples of suitable aliphatic and cycloaliphatic polyisocyanates Al) are di-iser triisocyanates such as butane diisocyanate, pentane diisocyanate, hexane diisocyanate (hexamethylene diisocyanate, HDI), 4-isocyanatomethyl-l, 8-octane diisocyanate (triisocyanatonanine, TIN) or cyclic systems such as 4,4 'methylenebis (cyclohexylisocyanate), 3,5,5-trimethyl-1 -isocyanato-3-isocyanatomethyl cyclohexane (isophorone diisocyanate, IPDI) and ω.ω'-diisocyanato-l, 3-dimethylcyclohexane (H _east XDI).

Hexane diisocyanate (hexamethylene diisocyanate, HDI), 4,4'-methylenebis (cyclohexyl isocyanate) and / or 3,5,5-trimethyl-1-isocyanato-3-isocyanatomethylcyclohexane (isophorone diisocyanate, JPOT ) used as polyisocyanates. A most preferred polyisocyanate is HDI.

Al) and A3) are preferably used polyisocyanates of the same type.

As polyhydroxy compounds of component A2) it is possible to use all polyhydroxy compounds known to the person skilled in the art which preferably have an average OH functionality of greater than or equal to 1.5, where at least one of the compounds contained in A2) must be a polyether polyol.

Suitable polyhydroxyl compounds which can be used in A2) are low molecular weight diols (for example 1,2-ethanediol, 1,3- or 1,2-propanediol, 1,4-butanediol), triols (for example glycerol, trimethylolpropane) and tetraols (for example pentaerythritol) , Polyether polyols, polyester polyols, polycarbonate polyols and polythioether polyols. In A2), substances of the abovementioned type based on polyethers are preferably used exclusively as polyhydroxy compounds.

The polyether polyols used in A2) preferably have number-average molecular weights M _{n of} from 300 to 20 000 g / mol, particularly preferably from 1000 to 12 000 g / mol, very particularly preferably from 2000 to 6000 g / mol.

Furthermore, they preferably have an average OH functionality of> 1, 9, particularly preferably> 1.95.

Such polyether polyols are accessible in a conventional manner by alkoxylation of suitable starter molecules under base catalysis or use of double metal cyanide compounds (DMC compounds). Particularly suitable polyether polyols of component A2) are those of the abovementioned type having an unsaturated end group content of less than or equal to 0.02 meq / gram of polyol (meq / g), preferably less than or equal to 0.015 meq / g, more preferably less than or equal to 0.01 meq / g (method of determination ASTM D2849-69).

Such polyether polyols can be prepared in a manner known per se by alkoxylation of suitable starter molecules, in particular using double metal cyanide catalysts (DMC catalysis). This is e.g. in US-A 5,158,922 (e.g., Example 30) and EP-A-0654302 (page 5, lines 26 to 6, Z. 32).

Suitable starter molecules for the preparation of polyether polyols are, for example, simple, low molecular weight polyols, water, organic polyamines having at least two N-H bonds or any mixtures of such starter molecules. Alkylene oxides which are suitable for the alkoxylation are, in particular, ethylene oxide and / or propylene oxide, which can be used in any order or also in a mixture in the alkoxylation.

Preferred starter molecules for the preparation of polyether polyols by alkoxylation, in particular by the DMC process, are in particular simple polyols such as ethylene glycol, 1,3-propylene glycol and 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 2-ethylhexanediol l, 3, glycerol, trimethylolpropane, pentaerythritol and low molecular weight, hydroxyl-containing esters of such polyols with dicarboxylic acids of the exemplary type mentioned below or low molecular weight ethoxylation or Pro poxylierungsprodukte such simple polyols or any mixtures of such modified or unmodified alcohols.

The polyurethane prepolymers containing isocyanate groups as intermediates are prepared by reacting the polyhydroxy compounds of component A2) with excess amounts of the polyisocyanates from Al). The reaction is generally carried out at temperatures of 20 to 14O ⁰ C, preferably at 40 to 100 ⁰ C, optionally with the use of known from polyurethane chemistry catalysts such as tin soaps, eg dibutyltin dilaurate, or tertiary amines, eg triethylamine or diazabicyclooctane. The allophanatization is then carried out subsequently by reacting the isocyanate group-containing polyurethane prepolymers with polyisocyanates A3), which may be identical or different to those of component A1), suitable catalysts A4) being added for allophanatization. Typically, the acidic additives of component A5) is subsequently added for stabilization and excess polyisocyanate, for example by thin film distillation or extraction, is removed from the product.

The molar ratio of the OH groups of the compounds of component A2) to the NCO groups of the polyisocyanates of Al) and A3) is preferably 1: 1.5 to 1:20, particularly preferably 1: 2 to 1:15, very particularly preferably 1: 2 to 1:10.

Zinc (II) compounds are preferably used as catalysts in A4), these being particularly preferably zinc soaps of longer-chain, branched or unbranched, aliphatic carboxylic acids. Preferred zinc (II) soaps are those based on 2-ethylhexanoic acid and the linear, aliphatic C ₄ - to C ₃ o-carboxylic acids. Very particularly preferred compounds of component A4) are Zn (II) bis (2-ethylhexanoate), Zn (II) bis (n-octoate), Zn (II) bis (stearate) or mixtures thereof.

These allophanatization catalysts are typically used in amounts of from 5 ppm up to 5% by weight, based on the total reaction mixture. Preference is given to using 5 to 500 ppm of the catalyst, particularly preferably 20 to 200 ppm.

Optionally, stabilizing additives may also be used before or after allophanatization. These may be acidic additives such as Lewis acids (electron deficient compounds) or Broensted acids (protic acids) or compounds which release such acids upon reaction with water

These are, for example, inorganic or organic acids or else neutral compounds such as acid halides or esters which react with water to give the corresponding acids. Hydrochloric acid, phosphoric acid, phosphoric acid esters, benzoyl chloride, isophthalic acid dichloride, p-toluenesulfonic acid, formic acid, acetic acid, dichloroacetic acid and 2-chloropropionic acid may be mentioned here in particular.

The abovementioned acidic additives can also be used for deactivating the allophanatization catalyst. They also improve the stability of the Allophanates prepared according to the invention, for example under thermal stress during thin-film distillation or after preparation during storage of the products.

The acidic additives are usually added at least in such an amount that the molar ratio of acidic centers of the acidic additive and the catalyst is at least 1: 1. Preferably, however, an excess of the acidic additive is added.

If acidic additives are used at all, these are preferably organic acids, such as carboxylic acids or acid halides, such as benzoyl chloride or isophtalyldichloride.

If excess diisocyanate to be separated, the thin film distillation is the preferred method and is usually carried out at temperatures of 100 to 160 ° C and a pressure of 0.01 to 3 mbar. The residual monomer content is then preferably less than 1 wt .-%, more preferably less than 0.5 wt .-% (diisocyanate).

The entire process steps can optionally be carried out in the presence of inert solvents. Inert solvents are to be understood as those which do not react with the educts under the given reaction conditions. Examples are ethyl acetate, butyl acetate, methoxypropyl acetate, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, aromatic or (cyclo) aliphatic hydrocarbon mixtures or any desired mixtures of such solvents. However, the reactions according to the invention are preferably carried out solvent-free.

The addition of the components involved can be carried out either in the preparation of the isocyanate-containing prepolymers or in allophanatization in any order. However, preference is given to adding the polyether polyol A2) to the prepolymeric polyisocyanate of the components A1) and A3) and finally adding the allophanatization catalyst A4).

In a preferred embodiment of the invention, the polyisocyanates of components Al) and A3) are initially charged in a suitable reaction vessel and, if appropriate with stirring, heated to 40 to 100 ° C. After reaching the desired temperature, the polyhydroxy compounds of component A2) are then added with stirring and stirred until the theoretical NCO content of selected stoichiometry was expected or slightly undercut polyurethane prepolymer expected. Now, the allophanatization catalyst A4) is added and the reaction mixture is heated to 50 and 100 ° C until the desired NCO content is reached or slightly below. After addition of acidic additives as stabilizers, the reaction mixture is cooled or fed directly to the thin-film distillation. In this case, the excess polyisocyanate at temperatures of 100 to 160 ° C and a pressure of 0.01 to 3 mbar to a residual monomer content of less than 1%, preferably less than 0.5%, separated. After the thin-film distillation, further stabilizer may optionally be added.

Such allophanates used in the claimed two-component coating systems typically correspond to the general formula (II)

embedded image in which

Q ¹ and Q ² independently of one another are the radical of a linear and / or cyclic aliphatic diisocyanate of the type mentioned, preferably - (CH ₂ ) O-,

R ³ and R ⁴ independently of one another are hydrogen or a C 1 -C ₄ -alkyl radical, where R ³ and R ^{4 are} preferably hydrogen and / or methyl groups and in each repeat unit k the meaning of R ³ and R ⁴ may be different,

the rest of a starter molecule of the type mentioned having a functionality of 2 to 6, and thus

is a number from 2 to 6, which must of course not be an integer by using different starter molecules, as well preferably corresponds to as many monomer units that the number average molecular weight of the structure of the underlying polyether is from 300 to 20,000 g / mol, and

m is 1 or 3.

Preferably allophanates are obtained, which correspond to the general formula (IH),

embedded image in which

Q is the radical of a linear and / or cyclic aliphatic diisocyanate of the type mentioned, preferably - (CH ₂ ) ₆ -,

R ³ and R ⁴ independently of one another are hydrogen or a C ₁ -C ₄ -alkyl radical, where R ³ and R ^{4 are} preferably hydrogen and / or methyl groups, where in each repeat unit m the meaning of R ³ and R ⁴ may be different .

stands for the rest of a difunctional starter molecule of the type mentioned and

corresponds to the number of monomer units that the number average molecular weight of the underlying polyether is 300 to 20,000 g / mol, and

m is 1 or 3.

Since polyols based on polymerized ethylene oxide, propylene oxide or tetrahydrofuran are generally used for the preparation of the allophanates of the formula (H) and (HI), in the case of m = 1, particular preference is given in the formulas (D) and (HI) WE at least one radical of R ³ and R ^{4 is} hydrogen, in the case of m = 3, R ³ and R ^{4 are} hydrogen.

The allophanates used according to the invention in A) typically have number-average molecular weights of 700 to 50,000 g / mol, preferably 1,500 to 8,000 g / mol and more preferably 1,500 to 4,000 g / mol.

The allophanates used in accordance with the invention in A) typically have viscosities at 23 ° C. of 500 to 100,000 mPas, preferably 500 to 50,000 mPas and particularly preferably from 1,000 to 7,500 mPas, very particularly preferably from 1,000 to 3,500 mPas.

The group X in formula (I) of the polyaspartic acid esters of component B1) is preferably based on an n-valent polyamine selected from the group consisting of

Ethylenediamine, 1, 2-diaminopropane, 1, 4-diaminobutane, 1,6-diaminohexane, 2-methyl-

1,5-diaminopentane, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and / or 2,4,4-trimethyl-

1, 6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, and polyether polyamines having aliphatically bonded primary amino groups with a number average molecular weight Mn of 148 to 6000 g / mol.

More preferably, the group X is based on 1, 4-diaminobutane, 1, 6-diaminohexane, 2-methyl-1,5-diaminopentane, 2,2,4- and / or 2,4,4-trirnethyl-l, 6- diaminohexane, and most preferably 2-methyl-1,5-diaminopentane.

With respect to the radicals R ¹ and R ² , "inert under the reaction conditions with respect to isocyanate groups" means that these radicals do not contain groups with Zerewitinoff-active hydrogen (CH-acidic compounds, see Römpp Chemie Lexikon, Georg Thieme Verlag Stuttgart), such as OH, NH or SH have.

Preferably, R and R independently of one another are C ₁ - to Q o -alkyl radicals, particularly preferably methyl or ethyl radicals.

Preferably, n in formula (I) is an integer from 2 to 6, more preferably 2 to 4.

The amino-functional polyaspartic esters B) are prepared in a manner known per se by reacting the corresponding primary polyamines of the formula

X- [NH ₂ J _n

with maleic or fumaric acid esters of the general formula R ¹ OOC-CH = CH-COOR ²

Suitable polyamines are the diamines mentioned above as the basis for the group X.

Examples of suitable maleic or fumaric acid esters are dimethyl maleate, diethyl maleate, dibutyl maleate and the corresponding fumaric acid esters.

The preparation of the amino-functional polyaspartic esters B) from the starting materials mentioned is preferably carried out within the temperature range from 0 to 100 ° C, the starting materials are used in proportions such that each primary amino group at least one, preferably exactly one ole- finische double bond is omitted following the reaction optionally in excess used starting materials can be separated by distillation. The reaction can be carried out in bulk or in the presence of suitable solvents such as methanol, ethanol, propanol or dioxane or mixtures of such solvents.

The cycloaliphatic or aromatic Aminkettenverlängerer from B2) are selected from the group 1, 2-diaminocyclohexane, 1, 4-diaminocyclohexane, 1, 4-di (amino methyl) cyclohexane, 1-amino-S ^ S-trimethyl-S-aminomethyl cyclohexane, 2,4- and / or 2,6-hexahydrotoluenediamine, 2,4'- and / or 4,4'-diamino-dicyclohexylmethane, 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane, 3 , 3 ', 5,5'-tetramethyl-4,4'-diamino-dicyclohexylmethane, 2,4,4'-triamino-5-methyl-dicyclohexylmethane, 1,3-bis (aminomethyl) benzene and their ( Partial) reaction products with Michael acceptors selected from the group of diethyl maleate, dimethyl maleate, acrylonitrile and mixtures thereof or their (partial) reaction products with dialkyl ketones or aldehydes selected from the group acetone, methyl ethyl ketone, diethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl tert. Butyl ketone, cyclohexanone, tert-butylaldehyde, isopropyl aldehyde in the sense of a reductive amination. In addition, substituted toluenediamines or methylenebis (anilines) can be used as amine chain extenders in B2). Specific examples are diethyltoluylenediamines, dimethylthiotoluylenediamines, in particular their isomers with amino groups in the 2,4- and 2,6-positions, and mixtures thereof, 4,4'-methylenebis (2-isopropyl-6-methylaniline), 4 , 4'-methylenebis (2,6-diisopropylaniline), 4,4'-methylenebis (2-ethyl-6-methylaniline), and 4,4'-methylenebis (3-chloro-2,6-diethylaniline), 4, 4'-methylene-bis (2-chloroaniline). However, the preferred is Use of the (partial) reaction products of 1-amino-3,3,5-trimethyl-5-aminomethyl cyclohexane, 2,4- and / or 2,6-hexahydrotoluenediamine or 2,4'- and / or 4 , 4'-Di- amino-dicyclohexylmethane with acrylonitrile or diethyl maleate, or the (partial) reaction products of 1-amino-3,3,5-trimethyl-5-aminomethyl-cyclohexane, 2,4-and / or 2,6 Hexahydrotoluenediamine or 2,4'- and / or 4,4'-diaminodicyclohexylmethane with acetone, methyl isobutyl ketone, methyl tert-butyl ketone or cyclohexanone in the sense of a reductive amination or the use of diethyltoluenediamine, dimethylthiotoluylenediamine, in particular their isomers with 2,4- and 2,6-position amino groups as well as 4,4'-methylenebis (2,6-diisopropylaniline), 4,4'-methylenebis (3-chloro-2,6-diethylaniline).

Very particular preference is given to the use of the reaction product of 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane with acrylonitrile, diethyl maleate or acetone, and of the reaction product of 2,4'- and / or 4,4'- Diamino-dicyclohexyl methane with diethyl maleate or methyl isobutyl ketone; or the use of diethyltoluylenediamine, 4,4'-methylenebis (2,6-diisopropylaniline) and 4,4'-methylbenzine (3-chloro-2,6-diethylaniline) as such.

As further polyisocyanates C), it is possible in principle to use all known by-products of aliphatic or cycloaliphatic polyisocyanates having a uretdione, biuret and / or isocyanurate structure which are modified by modification of monomeric diisocyanates known per se, such as butane diisocyanate, pentane diisocyanate, hexane diisocyanate (hexamethylene diisocyanate, HDI ), 4-isocyanatomethyl-l, 8-octane diisocyanate (triisocyanonatononane, TIN) or cyclic systems such as 4,4'-methylenebis (cyclohexyl isocyanate), 3,5,5-trimethyl-1-isocyanato-3-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI) and ω, ω'-diisocyanato-1,3-dimethylcyclohexane (H ₆ XDI) can be obtained.

The compositions according to the invention preferably contain polyisocyanates C) having a uretdione structure or isocyanurate structure, more preferably uretdiones or isocyanurates based on hexamethylene diisocyanate (HDI) and very particularly preferably isocyanurates based on hexamethylene diisocyanate (HDI).

Of course, the customary auxiliaries and additives such as pigments, (paint) additives, thixotropic agents, leveling agents, emulsifiers and stabilizers can be added to the compositions according to the invention. The addition of catalysts for curing is typically not necessary, but in principle possible.

The compositions of the invention are prepared by mixing the components A), B) and optionally C) in any order before or during the application, for example as a coating. If a component C) is used, it is preferably first mixed with component A) and the resulting mixture is then cured with component B).

In the two-component coating systems according to the invention, the ratio of free or blocked amino groups to free NCO groups is 0.5: 1 to 2: 1, preferably 0.5: 1 to 1.5: 1, particularly preferably 1: 1 to 1, 5: 1.

To produce the two-component coating systems according to the invention, the individual components are mixed together.

The coating compositions mentioned can be applied to surfaces by known techniques such as spraying, dipping, flooding, rolling, brushing or pouring. After the solvent has been flashed off, if necessary, the coatings then cure under ambient conditions or even at elevated temperatures of, for example, 40 to 200.degree.

The compositions mentioned can be applied, for example, to metals such as iron, steel, aluminum, bronze, brass, copper, plastics, ceramic materials such as glass, concrete, stone and natural substances, wherein said substrates may have previously been subjected to an optionally necessary pretreatment. The compositions are preferably applied to iron or steel, wherein the surfaces and / or the materials as a whole may be damaged by corrosion. Due to their rapid curing and material properties as a whole, the compositions according to the invention are in particular also suitable for (inner) coating of structures containing or carrying liquids or gases, eg mineral oil, water, in particular drinking water or chemicals. The compositions according to the invention can also be used to coat roofs, parking areas, ballast tanks in ships, cargo holds in ships or vehicles, floors, swimming pools, manholes, aquariums, tunnels. The compositions mentioned can also be used in combination with glass fibers or so-called geotextiles as composite resin.

Examples:

Polyisocyanate 1: Desmodur ^® N3600, Bayer MaterialScience AG, Germany. Polyisocyanate 2 Desmodur ^® XP2599, Bayer MaterialScience AG, Germany. Amine 1: Desmophen ^® NH1220, Bayer MaterialScience AG, Germany. Amine 2: s. below

Amine 3: Ethacure ^® 100 (DETDA), Albemarle, USA. Amine 4: Jeff Link ^® 754, Huntsman, USA.

Amine 5: Desmophen ^® NH 1420, Bayer MaterialScience AG, Germany. Amine 6: 4,4'-methylenebis (2-chloroaniline) (M-BOCA), Sigma-Aldrich, Germany. Amine 7: Polyclear ^® 136, Hansson Group LLC, USA.

Preparation of amine 2:

4462 g of diethyl maleate are dissolved in 6650 g of methanol at 40 ° C. 2207 g of isophoronediamine are added dropwise within 90 minutes. The mixture is stirred for 20 h at 40 ° C and the solvent is distilled off in vacuo. 6669 g of amine 2 are obtained.

Example 1 contains as chain extender exclusively a non-cyclic diamine. The addition of different cyclic diamine chain extenders increases the flexural modulus by up to 492% of the initial value. The other material properties, such as tensile strength, elongation at break and notched impact strength remain virtually unchanged (deviations from the initial value <20%).

Claims

claims:

1. Two-component coating systems, at least containing

A) a polyisocyanate prepolymer having polyether groups bonded via allophanate groups, and

B) a mixture of polyamines in the

in the

n is an integer of at least 2

come and

B2) at most 25 mol% of all NH groups derived from a cycloaliphatic diamine or aromatic diamine and

C) optionally further polyisocyanates. Two-component coating systems according to claim 1, characterized in that the lophanates used for the synthesis of the polyisocyanate prepolymer A correspond to the general formula (II),

embedded image in which

Q ¹ and Q ² independently of one another are the radical of a linear and / or cyclic aliphatic diisocyanate, preferably - (CH ₂ ) ₆ -,

the rest of a starter molecule having a functionality of 2 to 6, and thus

is a number from 2 to 6, which must not be an integer by using different starter molecules, as well

corresponds to the number of monomer units that the number average molecular weight of the underlying PoIy ethers the structure is from 300 to 20,000 g / mol, and

m is 1 or 3.

Two-component coating systems according to claim 1, characterized in that the allophanates used to form the polyisocyanate prepolymer A correspond to the general formula (ffl),

embedded image in which

Q is the radical of a linear and / or cyclic aliphatic diisocyanate, preferably - (CH ₂ ) ₆ -,

R and R independently of one another represent hydrogen or a C 1 -C ₄ -

Wherein R ₃ and R _{4 are} preferably hydrogen and / or methyl groups, where in each repeat unit m the meaning of R ₃ and R ₄ may be different,

Y stands for the rest of a difunctional starter molecule and

k equals the number of monomer units that the number average

The molecular weight of the polymer underlying the structure is from 300 to 20 000 g / mol, and

m is 1 or 3.

4. Use of the two-component coating systems according to claims 1 to 3 for coating the substrates containing liquids or gases or conveyed by structures.

Use according to claim 4, characterized in that the substrates are pipelines.

6. Use according to claim 5, characterized in that it is internal pipe coatings.

7. Use according to claims 5 and 6, characterized in that it is drinking water pipes.

8. Use according to claim 4, characterized in that it is the water storage containers in the substrates.

9. Use according to claim 4, characterized in that it is the building roofs in the substrates.

Use according to claim 4, characterized in that the substrates are ballast tanks of ships.