EP2225321A1

EP2225321A1 - Polynitrons, and use thereof for cross-linking unsaturated polymers

Info

Publication number: EP2225321A1
Application number: EP08859912A
Authority: EP
Inventors: Hakan Cinar; Helmut Ritter
Original assignee: Heinrich-Heine-Universitat
Current assignee: Heinrich-Heine-Universitat
Priority date: 2007-12-12
Filing date: 2008-12-10
Publication date: 2010-09-08
Also published as: JP2011506650A; US8883931B2; MX2010006458A; DE102007059733B4; KR20100117556A; CN101932644B; JP5592798B2; US20100273910A1; DE102007059733A1; CN101932644A; AU2008334883A1; WO2009074310A1

Abstract

The invention relates to polyfunctional nitrons (optionally in the form of nitron-terminated polymers) and the use thereof as a cross-linking and dulling agent, preferably for the production of stable molding materials and fillers, and the use thereof in paints, lacquers, and adhesives. The invention is characterized by low cross-linking temperatures. Using polyfunctional nitrons allows all unsaturated polymers to be cured, solidified, or structured at low temperatures, preferably without using a catalyst. The optical and mechanical properties of the painted surfaces can be greatly influenced in accordance with the amount of nitron-terminated polymers or low-molecular polyfunctional nitron used. The optical properties include, inter alia, the gloss of the lacquer systems and the surface structure, e.g. the dull effect.

Description

Polynitrone and their use for crosslinking unsaturated polymers

The invention relates to polynitrone and its use for crosslinking unsaturated polymers, as well as a curable composition comprising (a) a polynitrone, (b) an unsaturated polymer, (c) optionally fillers and (d) optionally pigments and their use as adhesive, putty, sprayable thick-layer filling, powder coating and / or paint based on solvent systems. Furthermore, the invention relates to crosslinking products obtainable by curing the curable composition according to the invention. Finally, the invention relates to polynitrone-terminated polyurethanes and unsaturated polyester-urethane polynitrone and to processes for their preparation.

"Nitrone" are known in the field of organic chemistry. Usually, these include compounds with the structural element

to understand. Nitrone are also referred to as azomethine oxides.

The art shows various reactions of nitrones. For example, the stereospecific addition to maleic acid or fumarate dimethyl ester was known. (Huisgen et al., Chem. Ber. 102, 736-745, 1969). Little is known about the interaction of nitrone groups and polymers in the art. For example, incorporation of the nitrones to the side chains of polyacrylates has been described for use as "waveguides" in US 5,273,863. Due to the UV sensitivity of the nitrone groups, the refractive index of the material was greatly altered during UV irradiation. The use of monofunctional nitron-containing compounds to improve the storage stability of adhesives and sealants based on (meth) acrylic acid esters and organic hydroperoxide initiators is known from US Pat. No. 3,991,261. Functionalization of polydienes based rubber polymers is another example of the use of nitrones and is disclosed in EP 1 739 098. Various lithium-terminated rubber polymers, such as, for example, polybutadiene, polyisoprene, poly (styrene-butadiene) or poly (styrene-isoprene-butadiene) react with monofunctional tional nitrones to a hydroxylamine, whereby better interactions between the rubber polymers and fillers, such as carbon black or silica gels are achieved. The properties of the resulting materials, such as tires, are improved.

Polymers with unsaturated groups can generally be used for powder coating systems. Powder coatings have ecological advantages over conventional coating systems. They are applied solvent-free and thus emission-free. Overspray, which means paint particles that do not hit the substrate to be painted, is recovered and reused. This makes it possible to exploit almost 100 percent of the powder coating substance.

Important areas of application for powder coatings are household appliances such as so-called "white goods", which are understood as refrigerators, washing machines, dishwashers, freezers, etc. But also computer housing, satellite antennas, lamp housings and metal furniture are often powder-coated Other important application areas are facade elements, especially from Aluminum, garage doors, car attachments and machine housings.

The powder coating production customary in the prior art is illustrated in FIG. In Figure 1, 1 = weigh, 2 = mix, 3 = extrude, 4 = cool, 5 = pre-break, 6 = mill and 7 = sieve. The solid coating raw materials such as binders, hardeners, pigments, fillers and additives are mixed and kneaded in an extruder at 100- 140 ⁰ C in a highly viscous state to a homogeneous mass and dispersed.

Usually, the powder coatings produced according to FIG. 1 are fluidized by supplying air before the actual application of powder and conveyed to the gun in this liquid-like state. There, the charging of the powder takes place by charging at an electrode by means of high voltage. The thus conditioned powder is deposited on a suspended object.

The application of powder coating technology has hitherto been limited by the fact that the coating process with powder coatings takes place at high baking temperatures. Weather resistant as networking, thermosetting powder coatings generally at temperatures above 160 ⁰ C. At these temperatures can not wärmebe- permanent substrates such as wood and crosslinking products, but also metallic alloys with special properties are not yet coated.

UV powder coating technology is a technique whereby the powder coatings are cured at low temperatures by UV radiation. This technology makes it possible to powder coat the surfaces of thermally sensitive products such as wood surfaces, medium density fiberboard (MDF), plastic surfaces or paper. After deposition of the powder on the substrate, the applied sheets are tempered in the oven (100- 140 ⁰ C) and then cured by UV. The curing reaction in UV technology is usually a radical polymerization of acrylic ester derivatives. This reaction is initiated by a photoinitiator that is excited by the UV light and forms radicals.

The photochemically induced radical formation thus initiates a further polymerization, so that within a few seconds three-dimensional networks are formed. Raw materials used as binders are usually polyfunctional acrylic ester derivatives, epoxy resins, polyethers and polyurethanes or else a combination of an unsaturated polyester with a polyfunctional vinyl ether crosslinker.

The UV-curable powder coatings are characterized by a low load of the coating material, shorter curing times and good optical properties. On the other hand, however, there are unresolved difficulties. These include, above all, the minimization of the layer thicknesses and the difficult surface structuring. Depending on where the powder coatings are used, there are many areas, such as the furniture industry, where the gloss of the powder coating must be reduced. Due to the limited layer thicknesses in the radiation-curable powder coatings, many techniques with which the conventional, thermally curable powder coatings are normally structured and modified, for example by means of pigments, fillers or solid additives, can not be used. Furthermore, the matting of UV curable powder coatings is difficult. A complex option is the mixtures of amorphous and crystalline resins. US Pat. No. 6,777,027 B2 describes another complicated method of matting radiation-curable coatings, wherein the combination of a free-radically and cationically-curable binder resin in the powder coating described causes the matting. The - -

However, methods used are costly and require complicated operations.

The object of the invention was to find a curable material that does not have the disadvantages of the existing systems. It should be able to cure quickly at moderate temperatures, be provided with various pigments and fillers, and satisfy the physical and chemical requirements desired by industry in a wide range. The curable material should make it possible to influence the degree of matting.

It was also an object of the invention to provide an advantageous method for curing.

In particular, it was an object of the invention to provide a curable composition which is in the form of a 1-component system (hereinafter referred to as 1K system) or a 2-component system (hereinafter referred to as 2K system).

The tasks could be solved by the use of so-called "polynitrons", in particular by the use of polynitrons together with unsaturated polymers.

The invention therefore relates to the use of polynitrons for crosslinking unsaturated polymers.

The invention further provides a curable composition comprising

(a) a polynitron,

(b) an unsaturated polymer,

(c) optionally fillers and

(d) optionally pigments. The invention further provides a process for the preparation of a crosslinking product comprising the steps

(i) providing the curable composition of the invention, and (ii) curing the composition.

The invention also relates to crosslinking products obtainable by this process and to their use for the production of glass-fiber-reinforced polyester parts, preferably in shipbuilding.

Likewise, the invention relates to specific Polynitrone as such, in particular Polynitron terminated polyurethanes, and a process for their preparation.

Finally, the invention relates to an unsaturated polyester-urethane polynetron and a process for its preparation.

The inventors of the present patent application have unexpectedly found that polynitrone can be used to advantage for crosslinking unsaturated polymers. Crosslinking is understood to mean the formation of covalent or ionic bonds between polymer chains. Crosslinking usually forms a so-called "three-dimensional structure".

In particular, it has been found that polynitrone can be used to advantageously alter the mechanical and / or optical properties of an unsaturated polymer. For example, the mechanical properties can be advantageously changed by curing the unsaturated polymer. Likewise, alternatively or additionally, the optical properties can be advantageously changed by matting.

In the context of this invention, the term "polynitrone" is understood to mean a polyfunctional nitrone, ie the term "polynitrone" describes an organic compound which has two or more nitrone groups. The polynitrone used preferably has 2 to 12, more preferably 2 to 5, in particular 3 to 4, nitrone groups. - -

In a preferred embodiment, the polynitrone used according to the invention is a compound according to the general formula I ₁

where x is a natural number from 2 to 12, more preferably from 2, 3 or 4. The radicals R ₁ , R ₂ or R ₃ may generally be any organic radicals. Preferably, R _{1 is} an optionally substituted linear, cyclic or branched, alkylene group, alkyleneoxy group, arylene group, aryleneoxy group, naphthylene group or combinations thereof. Furthermore, R ₂ and R _{3 are} independently of one another hydrogen or an optionally substituted linear or branched alkyl group, aryl group, heteroaryl group, alkylaryl group, alkoxyl group, cycloalkyl group or combination thereof.

More preferably, the group R _{1 contains} one or more of the following groups:

R ₂ and R ₃ are more preferably a hydrogen atom or a group. In particular, R _{2 is} a hydrogen atom. In particular, R _{3 is} a methyl group. In the three structural formulas shown above, the aromatic rings may optionally be substituted in one or more positions.

In a further embodiment, the radical R ₁ may be bonded to a polymer. The polymer is preferably selected from polyurethanes, polyesters, unsaturated polyesters, poly (meth) acrylates, polysaccharides or combinations thereof. As described in more detail below is in the case of the IC system R ₁ bound in particular to an unsaturated polyester urethane.

The above-mentioned polynitrone are used for crosslinking unsaturated polymers. The term "unsaturated polymer" is usually understood as meaning a polymer having one or more unsaturated carbon-carbon bonds in the polymer chain.

The degree of unsaturated carbon-carbon bonds can be determined by DIN53241 and expressed by the unit "meq / g". Usually, the unsaturated polymers have 0, 1 to 50, preferably 1 to 20 meq / g.

The unsaturated polymers are preferably selected from polyolefins, polystyrene, polyvinyl alcohol, polyvinyl acetate, polyalkylene glycol, polyethylene oxide, polypropylene oxide, polyacetals, polyurethanes, polyureas, polyamides, polycarbonates, polyketones, polysulfones, phenol-formaldehyde resins, polyesters, polyester acrylates, polyurethane acrylates, cellulose, Gelatin, starch, and mixtures thereof.

Particular preference is given to using unsaturated polyesters, unsaturated polyester urethanes and / or polyester urethane acrylates or polyester urethane methacrylates, as described, for example, in US Pat. No. 6,284,321 B1.

The preferred unsaturated polyesters to be used are as follows. Suitable unsaturated polyesters are generally polycondensation products of α, β-ethylenically unsaturated dicarboxylic acids, such as maleic acid, fumaric acid, itaconic acid, mesaconic acid and citraconic acid, with polyalcohols, such as ethylene glycol, diethylene glycol, propane, butane and hexane diols , Trimethylolpropan and pentaerythritol, which may still residues of saturated carboxylic acids, eg. As succinic acid, glutaric acid, adipic acid, phthalic acid, tetrachlorophthalic acid, further monofunctional alcohols such as butanol, tetrahydrofuyl alcohol and ethylene glycol monobutyl ether, as well as monobasic acids such as benzoic acid, oleic acid, linseed oil fatty acid and ricinoleic acid may contain.

Suitable monomeric unsaturated compounds which can be copolymerized with the unsaturated polyesters are, for example, vinyl compounds, such as styrene, vinyltoluene, and divinylbenzene, furthermore vinyl esters, such as vinyl acetate, and then unsaturated carboxylic acids and their derivatives, such as methacrylic acid, esters and nitrile, furthermore allyl esters, such as allyl acetate, allyl acrylate, diallyl phthalate. Triallyl phosphate and triallyl cyanurate.

In particular, unsaturated polyesters containing maleate and fumarate groups are used.

The unsaturated polymers usually have a weight-average molecular weight of from 200 to 500,000 g / mol, preferably from 1,000 to 200,000 g / mol, more preferably from 10,000 to 100,000 g / mol.

The use according to the invention of the polynitrone described above can be carried out within the scope of a curable composition.

The invention thus provides a curable composition comprising

(a) a polynitron,

(b) an unsaturated polymer,

(c) optionally fillers and

(d) optionally pigments. In principle, two different embodiments of the curable composition according to the invention are possible.

In a first embodiment, the curable composition of the invention is a 2-component system. This means that components (a) and (b) are in the form of two compounds. Thus, components (a) and (b) are separate compounds that are not covalently linked prior to curing.

In principle, for this first embodiment of the curable composition according to the invention, the explanations of the above-mentioned preferred polynitrons apply. However, it is preferred that Polynitrone be used according to the general formula I, wherein the radical R _{1 is} not bound to a polymer, in particular not to an unsaturated polymer.

Also for this first embodiment, the explanations of the above-mentioned preferred unsaturated polymers application.

In this first embodiment of the curable composition of the invention, the polynitrone (a) is in an amount of 0.1 to 50% by weight, more preferably 1 to 20% by weight, especially 5 to 15% by weight, based on the total weight of the composition.

In a second embodiment of the curable composition of the invention, the curable composition is a 1-component system. This means that components (a) and (b) are in the form of a polynitron-terminated unsaturated polymer. Thus, components (a) and (b) are united within one compound.

In principle, for this second embodiment of the curable composition according to the invention, the explanations of the above-mentioned preferred polynitrons apply. However, it is necessary that polynitrone be used according to the general formula I, wherein the radical R ₁ is bonded to an unsaturated polymer. In the second embodiment of the curable composition of the present invention, the combined components (a) and (b) are preferably an unsaturated polyester polynitrone, more preferably an unsaturated polyester urethane polynitrone.

For both embodiments, in the curable composition, the ratio of nitrone groups (from component a) and unsaturated carbon-carbon bonds (from component b) may be 10: 1 to 1:10, preferably 5: 1 to 1: 5, especially 2: 1 to 1: 2.

In addition to components (a) and (b), the curable composition of the invention may optionally comprise components (c) fillers and (d) pigments. Further, the composition may further comprise one or more additives such as plasticizers and stabilizers. Finally, the curable composition may still comprise (f) photoinitiators. The components (a) and (b) are usually in the composition according to the invention in an amount of 30-100% by weight. preferably from 40 to 99% by weight, more preferably from 55 to 95% by weight, based on the total weight of the composition.

Suitable fillers (c) are in principle all inorganic and organic fillers, as described, for example, in Rompp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, Stuttgart, New York, 1998, "Fillers", pages 250 to 252.

Examples of suitable fillers are wood flour, saturated organic or organometallic polymers, inorganic minerals, salts or ceramic materials or organically modified ceramic materials or mixtures of these substances. Inorganic minerals are preferably used. These may be natural and synthetic minerals. Examples of suitable minerals are silicon dioxide, aluminum silicates, calcium silicates, magnesium silicates, calcium aluminum silicates, magnesium aluminum silicates, calcium magnesium silicates, beryllium aluminum silicates, aluminum phosphate or calcium phosphate, or mixtures thereof.

In the composition according to the invention, fillers (c) are generally present in an amount of from 0 to 50% by weight, preferably from 5 to 40% by weight, more preferably from 10 to 30% by weight, based on the total weight of the composition.

The composition according to the invention may further comprise as component (d) optionally at least one colorant, preferably a pigment. The colorant may be a pigment or a dye. As pigments, for example, colored pigments or effect pigments can be used.

As effect pigments, it is possible to use metal flake pigments, such as commercial aluminum bronzes, chromatized aluminum bronzes, commercially available high-grade steel bronzes and non-metallic effect pigments, for example pearlescent or interference pigments. In addition, reference is made to Rompp Lexikon Lacke and Druckfarben, Georg Thieme Verlag, 1998, pages 176, effect pigments and pages 380 and 381 metal oxide mica pigments to metal pigments.

Examples of suitable inorganic color pigments are titanium dioxide, iron oxides, and carbon black, in particular carbon black. Examples of suitable organic coloring pigments are thioindigo pigments, indanthrene blue, cromophthal red, irgazine orange and heliogen green, copper phthalocyanine. In addition, reference is made to Rompp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, 1998, pages 180 and 181, iron blue pigments to iron oxide black, pages 451 to 453, pigments to pigment volume concentration, page 563 thioindigo pigments and page 567 titanium dioxide pigments.

In the composition according to the invention, coloring agents, preferably pigments (d), are generally present in an amount of from 0 to 30% by weight, preferably from 1 to 20% by weight, more preferably from 2 to 10% by weight, based on Total weight of the composition, included.

In addition, the composition of the invention may contain at least one additive (s). Examples of suitable additives are additional oligomers and polymeric binders, UV absorbers, light stabilizers, free-radical scavengers, thermolabile free-radical initiators, deaerating agents, slip additives, polymerization inhibitors, defoamers, emulsifiers, wetting agents and dispersants, adhesion promoters, leveling agents, film-forming auxiliaries, flameproofing agents. Protective agents, corrosion inhibitors, anti-caking agents, waxes and matting agents.

In the composition according to the invention, additives (e) are generally present in an amount of from 0 to 20% by weight, preferably from 0.1 to 10% by weight, more preferably from 1 to 5% by weight, based on the total weight of the composition.

It is preferred in one embodiment that the curable composition of the invention contains no catalysts that catalyze the crosslinking of the unsaturated carbon-carbon bonds in component (b). In an alternative embodiment, the curable composition of the invention may contain one or more photoinitiators (f).

An example of a suitable photoinitiator is Irgacure®.

Photoinitiators may be used in an amount of 0-5 wt%, preferably 0.01-3 wt%, more preferably 0.4-2.0 wt%, based on the total weight of the composition.

In particular, photoinitiators (f) are used when the polynucleotides (a) are to serve as matting agents.

The curable composition according to the invention is preferably used as an adhesive, filler, sprayable thick-layer filling, powder coating and / or paint based on solvent systems. The invention therefore also an adhesive, a filler, a sprayable thick-film filling, a powder coating and / or paint based on solvent systems, comprising the composition of the invention. The composition according to the invention is preferably in the form of a powder coating.

The curable composition of the present invention may be processed by curing (ie, by crosslinking) into a crosslinked product. The curing (ie the crosslinking) is carried out by suitable temperature control of the curable composition. The invention therefore also provides a process for the preparation of a crosslinking product comprising the steps

(i) providing a curable composition of the invention, and

(Ii) curing of the composition at temperatures of 20 to 180 ⁰ C, preferably from 50 to 150 ⁰ C, in particular from 60 ⁰ C to 120 ⁰ C.

The invention likewise provides a crosslinking product obtainable by the process according to the invention.

The curing / crosslinking can be carried out by mixing and tempering the constituents of the hardenable composition. The unsaturated polymer (b) and the polynitrone (a) (or, alternatively, an unsaturated polynitrone-terminated polymer as a 1K system) may be ground to a powder and mixed, for example, in a conventional mill (optionally together with ingredients (c) - (e)) become. Another possibility of mixing is by means of a solvent system in which both the unsaturated polymer and the polyfunctional nitrones (optionally together with components (c) - (e)) are dissolved or dispersed. The ingredients are first converted to a uniform mixture, and after removal of the solvent, curing / crosslinking is accomplished by heating to the desired temperature.

In the process of the present invention, the curing time is usually 10 seconds to 2 hours, preferably 20 seconds to 60 minutes, more preferably 30 seconds to 15 minutes, more preferably 1 minute to 10 minutes.

The novel crosslinking products are usually dependent on the type of unsaturated polymer used. It is preferably elastic soft to hard crosslinking products. These are preferably inert to water and organic solvents

The novel crosslinking products are versatile. Examples are dental materials, household appliances, cake plates, general Construction industry, baths and sinks. The crosslinking products according to the invention are preferably used as a lacquer layer. Likewise, the crosslinking products according to the invention are used as (preferably glass-fiber-reinforced) polyester parts, in particular in shipbuilding.

In addition to the use according to the invention, the curable composition according to the invention and the crosslinking product according to the invention, the preferably suitable polynitrone as such are also part of the invention.

The invention therefore also relates to polynitrone selected from terephthalaldehyde bis (N-phenylnitrone), isophthalaldehyde bis (N-phenylnitrone),

Isophthalaldehyde bis (N-methylnitrone), terephthalaldehyde bis (N-butyl nitrone), isophthalaldehyde bis (N-cyclodecyl nitrone), isophthalaldehyde bis (N-cyclohexyl nitron), 4,4'-decanediyl dioxydi (N-methyl-p phenylnitrone), 4,4'-hexanediyldi- oxydi (N-methyl-p-phenylenemonoic, 4,4'-butanediyldioxydi (N-methyl-p-phenylenedi- nitrone), 4,4'-ethanediidioxydi (N-methyl- p-phenylenenitrone) and polynetron-terminated polyurethanes.

By "polynitron-terminated polyurethane" is generally meant a compound comprising two or more urethane groups and two or more nitrone groups.

In a preferred embodiment, it is a polynitrone-terminated polyurethane according to the general formula II

x in which x is a natural number from 2 to 12 and R ₁ to R _{5 is} an organic radical.

Preferably, x is a natural number from 2 to 5, more preferably 3 or 4. R ₁ and R ₃ are each independently preferably an optionally substituted a linear, cyclic or branched alkylene group, alkyleneoxy group, arylene group, aryleneoxy group, naphthylene group or combinations thereof. R ₂ , R ₄ and R ₅ are preferably a hydrogen atom or a C ₁ -C 6 -alkyl group. In particular, R ₂ and R _{4 are} a hydrogen atom and R 5 is a methyl group.

In particular, the invention provides a polynitron-terminated polyurethane according to the general formula III

X in which x is a natural number from 2 to 20 and R ₁ to R _{7 is} an organic radical.

Preferably, x is a natural number of 2 to 5, more preferably 3 to 4. R ₁ and R ₃ are preferably independently an optionally substituted linear, cyclic or branched, alkylene group, alkylenoxy, arylene group. Aryleneoxy group, naphthylene group or combinations thereof. R ₄ , R ₅ , Re and R ₇ are preferably a hydrogen atom or a C ₁ -C 6 alkyl group. In particular, R ₄ , R ₅ and R 6 are a hydrogen atom and R _{7 is} a methyl group. R ₂ is preferably a diphenylmethane radical, a tolylene radical or an isophorone radical.

In particular, the invention further provides a polynitrone-terminated polyurethane according to the general formula IV

in the R ₁ to R5 and Ry to Rs> an organic radical. R ₁ and R _{1 '} are preferably an optionally substituted linear, cyclic or branched, alkylene group, alkyleneoxy group, arylene group, aryleneoxy group, naphthylene group or combinations thereof. R ₃ , R ₃ , R ₄ , R _{4 '} , R 5 and R _6' are preferably a hydrogen atom or a C 1 -C 6 -alkyl group. In particular, R ₃ , R ₃ , R ₄ and R ^ are a hydrogen atom and R ₅ and Rs- is a methyl group. R ₂ is preferably a diphenylmethane radical, a tolylene radical or an isophorone radical.

Examples of compounds of the general formula II, III and / or IV are

wherein R is an organic radical, preferably a diphenylmethane radical, a tolylene radical or an isophorone radical, and

UN-I (6) The invention further provides a process for preparing a polynitrone-terminated polyurethane according to the invention, comprising the steps

(i) preparing a urethane-polyaldehyde by reacting a polyisocyanate with a hydroxy-aldehyde compound (otherwise in the presence of a polyfunctional starter molecule), the reaction ratio preferably being chosen so that all isocyanate groups react, and

(ii) reacting the urethane polyaldehyde with an N-alkylhydroxylamine, preferably with N-methylhydroxylamine, or alternatively

(i) reacting a hydroxy-aldehyde compound with an N-alkylhydroxylamine, preferably with N-methylhydroxylamine, to form a hydroxy-nitrone compound and

(ii) reacting the hydroxy-nitro compound resulting from step (i) with a polyisocianate, the reaction ratio preferably being chosen so that all isocyanate groups react.

As polyisocyanates are generally known from the prior art aliphatic, cycloaliphatic and aromatic isocyanates in question. Examples are 2,2'-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 1, 5-naphthylene diisocyanate (NDI), 2,4- and / or 2,6-toluene diisocyanate ( TDI), diphenylmethane diisocyanate, 3,3'-dimethyl-diphenyl-diisocyanate, 1, 2-diphenylethane diisocyanate and / or phenylene diisocyanate, tri-, tetra-, penta-, hexa-, hepta- and / or octamethylene diisocyanate, 2-methylpentame - Thylene diisocyanate 1, 5, 2-ethyl-butylene-diisocyanate-1, 4, pentamethylene diisocyanate 1, 5, butylene diisocyanate 1, 4, l-isocyanato-3,3,5-trimethyl 5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 1,4- and / or 1,3-bis (isocyanatomethyl) -cyclohexane (HXDI), 1,4-cyclohexane diisocyanate, 1-methyl -2,4- and / or 2,6-cyclohexane diisocyanate and / or 4,4'-, 2,4'- and 2,2'-dicyclohexylmethane diisocyanate, preferably 2,2'-, 2, 4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 2,4- and / or 2,6-toluene diisocyanate (TDI), hexamethylene diisocyanate and / or IPDI, in particular IPDI is used. As the hydroxy-aldehyde compound, a compound having both a hydroxy function and an aldehyde function is basically suitable. Preferably, a 4-hydroxyalkyloxy-3,5-dimethyloxybenzaldehyde is used, wherein the alkyl radical comprises 1 to 12 carbon atoms. Examples of these are methyl, ethyl, propyl or hexyl. In particular, 4-hydroxyethyloxy-3,5-dimethoxybenzaldehyde (hereinafter referred to as HEBA) is used. HEBA is thus also the subject of the invention.

As the hydroxy-nitrone compound, a compound having both a hydroxy function and a nitrone function is basically suitable. Preferably, the following compound (referred to as HEBN) is used. HEBN is thus also the subject of the invention.

The process according to the invention for preparing a polynitrone-terminated polyurethane according to the invention comprises two alternatives, these are to be illustrated in the following reaction diagram.

In the above reaction scheme, R is an organic radical, R is preferably a diphenylmethane radical, a tolylene radical or an isophorone radical, so that the resulting isocyanate is preferably MDI, TDI or IPDI.

In the process of the present invention for producing a polynitron-terminated polyurethane of the present invention, a urethane polyaldehyde is used. By this is meant a compound having two or more urethane groups and two or more aldehyde groups.

The invention thus also Urethanpolyaldehyde the general formula V

in which x is a natural number from 2 to 12 and R ₁ to R _{5 is} an organic radical.

Preferably, x is a natural number of 2 to 5, more preferably 3 or 4. R ₁ and R ₃ are preferably an optionally substituted linear, cyclic or branched alkylene group, alkyleneoxy group, arylene group, aryleneoxy group, naphthylene group or combinations thereof. R4 and R5 are preferably a hydrogen atom or a Cα-Cβ-alkyl group, in particular a hydrogen atom. R ₂ is preferably a diphenylmethane radical, a tolylene radical or an isophorone radical.

The invention further Urethanpolyaldehyde the general formula VI

VI in which R ₁ to R ₄ and R ₁ 'to R ^ represent an organic radical.

R ₁ and Ry are preferably an optionally substituted linear, cyclic or branched, alkylene group, alkyleneoxy group, arylene group, aryleneoxy group, naphthylene group or combinations thereof. R ₃ , R ₃ , R ₄ and R ₄ 'are preferably a hydrogen atom or a Cα-Cβ-alkyl group, in particular a hydrogen atom. R ₂ is preferably a diphenylmethane radical, a toluene radical or an isophorone radical.

Examples of preferred urethane polyaldehydes are the following compounds:

in which R is an organic radical, preferably a diphenylmethane radical, a toluene radical or an isophorone radical, and

5th Compound 5 is a trifunctional urethane aldehyde. Three and more functional urethane aldehydes can be obtained by reacting a trihydric and polyfunctional starter molecule with the hydroxy aldehyde and the polyisocyanate. Examples of suitable starter molecules are, for example, glycerol, trimethylolpropane and pentaerythritol.

Finally, the invention relates to processes for the preparation of an unsaturated polyester urethane polynitrone comprising the steps

(i) reacting an unsaturated polyester with a hydroxy-aldehyde compound and

(ii) reaction with a polyisocyanate, followed by

(iii) reaction of the unsaturated polyester resin obtained in step (ii)

Urethane aldehyde with an N-alkylhydroxylamine, preferably with N-methylhydroxylamine.

The term "unsaturated polyester-urethane polynitron" is understood as meaning a polyester which has at least one carbon-carbon double bond in the polymer chain and which furthermore has at least two urethane groups and nitrone groups.

With respect to the terms "unsaturated polyester", "hydroxy-aldehyde compound" and "polyisocyanate", reference is made to the above explanations on preferred embodiments.

Likewise provided by the invention is the unsaturated polyester urethane polynitrone, obtainable by the process according to the invention.

In summary, it can be stated that unsaturated polymers, preferably unsaturated polyester resins, can already be cured at low temperatures by the novel crosslinking method (ie by the use according to the invention of polynitrons). This results in mechanistically stable polymer networks, usually neither harmful metal catalysts are used nor environmentally harmful cleavage products are formed. The crosslinking is fast and provides thermally and mechanistically stable products. The crosslinking products according to the invention are characterized by their extremely versatile usability at a relatively low cost in the production. They are easy to handle, can be used alone or optionally together with smaller amounts of other polymers and can be processed with a large number of fillers, since they have an excellent wetting ability.

Unsaturated polyester-urethane-polynitrates according to the invention are advantageous curable one-component systems which contain both the unsaturated functions and the nitrone groups in a polymer skeleton, so that they are preferably thermally self-crosslinkable without an additional crosslinker or catalyst

The invention will be explained in more detail by means of the following examples.

Example 1: Synthesis of terephthalaldehyde bis (nitron) (DN-O, 1)

DN-O (1)

A mixture of 2.95 g (0.022 mol) of terephthalaldehyde and 3.67 g (0.044 mol) of N-methylhydroxylamine hydrochloride dissolved in 5 ml of water is added to the NaOH solution (1.76 g, 0.044 mol in 30 ml of ethanol) Stirred for 12 hours at room temperature (RT). The precipitated product is filtered off, washed with water and then recrystallized in DMF. Melting point: 240 ^° C.

Example 2: Synthesis of 1, 10-di (4-formylphenoxy) -decane (DA-10, 2)

24.4 g (0.2 mol) of p-hydroxybenzaldehyde, 30 g (0.1 mol) of 1, 10-dibromodecane and 11.2 g (0.2 mol) of KOH (85%) are refluxed in 200 ml of DMF for 30 min. Then the solution is allowed to cool to room temperature and poured onto water / ice. The resulting solid is filtered off with suction. For purification, crystallizing the still moist product from ethanol / water and dried at about 70 to 80 ⁰ C.

Example 3: Synthesis of 4,4 ^V -Decandiyldioxydi (N-methyl-p-phenylenenitrone) (DN-10, 3)

A mixture of 6.7 g (0.022 mol) of terephthalic aldehyde and 3.67 g (0.044 mol) of iV-methylhydroxylamine hydrochloride dissolved in 5 ml of water is added to the NaOH solution (1.76 g, 0.044 mol in 30 ml of ethanol) Stirred for 12 hours at room temperature. The precipitated product is filtered off, washed with water and then recrystallized in DMF. Melting point: 134 ^° C.

Example 4: Synthesis of 4-hydroxyethyloxy-3,5-dimethoxybenzaldehyde (HEBA, 4)

4-Hydroxy-3,5-dimethoxybenzaldehyde (4.99 g, 27.4 mmol), 2-iodoethanol (9.43 g, 54.8 mmol) and potassium carbonate (7.56 g, 27.4 mmol) become 50 Add DMF and stir under nitrogen flow at 80 ⁰ C for 24 h. After cooling to RT, about 200 ml of water are added to the solution, acidified with 10% HCl and then extracted with chloroform. After drying with magnesium sulfate, the solvent is distilled off and the solid - -

Fabric isolated. For further purification, the solid is purified by column chromatography (flash: ethyl acetate / n-hexane (1: 1)).

Example 5 Synthesis Example of Urethane Aldehyde (UA-I, 5)

A mixture of 1.61 g (0.012 mol) of trimethylolpropane (TMP) and 4.44 g (0.02 mol of isophorone diisocyanate) IPDI and 2.53 g (0.02 mol) of HEBA (4) is introduced into 20 ml of ethyl acetate, To this is added dropwise 1-2 drops of dibutyltin laurate (DBTL). Thereafter, the reaction mixture is heated under nitrogen flow to 65 ° C. The reaction mixture is cooled to RT if the samples taken from the reaction solution show no isocyanate band at about 2200 cm ^-1 . To isolate urethane-aldehyde (UA-I, 5), about 30 ml of n-hexane are added to the reaction solution After removal of the solvent, the resulting viscous polymer composition is reacted without further purification steps in the next step (see Example 6).

Example 6 Synthesis Example of Urethane Nitron (UA-I, 6)

The urethane-aldehyde (5) isolated in Example 5 is suspended in 25 ml of 2 N NaOH solution (in ethanol). 2.24 g (25.9 mmol) of N-methylhydroxylamine hydrochloride dissolved in 5 ml of water are then added to the suspension for 12 hours at RT. The precipitated product is filtered off, washed with water and dried in a drying oven under vacuum at 40 °.

IR (diamond): 331 1 (-NH-), 2948 (CH), 1695 (O-CO-NH), 1576 (C = N), 1 152 (N-O) Maldi-TOF: 1564, 1700, 1860 , 2020, 2141 (m / z)

Example 7: Characterization of a commercially available unsaturated polyester UP-I (7)

UP-I (7) is the commercial product of the company DSM (Uracross P 3125), with the building blocks terephthalate / fumarate / neopentyl glycol.

Acid value: <5 mg KOH / g Viscosity: 30 -50 Pas Glass transition temperature: 45 ^° C. Example 8: Synthesis of an unsaturated polyester UP-2 (8)

A mixture of 1, 96 g (0.02 mol) of maleic anhydride (MA), 2.36 g (0.02 mol) of hexanediol (hex), 0, 1 wt .-% toluenesulfonic hydrate and 1 wt .-% BHT Stabilizer are heated for 30 min in the microwave (CEM) at 200 ⁰ C at a microwave power of 300 watts under reflux. For purification of low molecular weight starting components, the reaction product is dissolved in acetone and then precipitated by the addition of petroleum ether (60/80). After the solvent has been decanted, the unsaturated polyester is dried under vacuum

Acid number: 74.06 mg KOH / g GPC: Mn: 750; M _w : 1500; PD: 2 glass temperature T _g : -47 ⁰ C (DSC9

Example 9: Preparation of a hydroxy-terminated unsaturated polyester (UP-3, 9)

A mixture of 32.8 g (0.42 mol) of diethylene glycol, 38.2 g (0.23 mol) of terephthalic acid and 0.05 g (26.3 mmol) of p-toluenesulfonic acid monohydrate was added to a flask equipped with a water separator Stirring heated to 190 - 200 ⁰ C. Once the terephthalic acid was completely dissolved, the mixture was cooled to 160 ⁰ C and 0.05 g BHT stabilizer and 1 1, 8 g (0 1 mol) of maleic anhydride added. The mixture was slowly heated again to 180-190 ° C and kept under stirring until the specific acid number is about 20 mg KOH / g. After another hour of heating at 180-190 ⁰ C under vacuum and subsequent cooling to RT a transparent unsaturated polyester was obtained, showing the following property.

Acid value: 16.2 mg KOH / g T _g : 38 ^° C. (DSC) - -

Example 10 Preparation of an Unsaturated Polyester Urethane Aldehyde (UP-UA-2, 10)

51 g (0.017 mol) of prepared in Example 9, unsaturated polyester (UP-3, 9), and 10.86 g (0.05 mol) of 4- (2-hydroxyethyloxy) benzaldehyde were heated to 120 ⁰ C. While stirring, 2-3 drops of dibutyltin laurate were added and then added dropwise at 120 ⁰ C slowly 18 g of IPDI (isophorone diisocyanate). The mixture was further stirred at 120 ⁰ C until the withdrawn samples have an NCO content below 0, 1 wt .-%.

Example 11 Preparation of an Unsaturated Polyester Urethane Nitrone (UP-UN-I, 11)

10 g of the UP-UA-I (10) finely ground in Example 10 were dispersed in 30 ml in ethanol to this was dissolved in 10 ml of water 0.30 g (7.5 mmol) of NaOH and 0.62 g (7, 5 mmol) of N-methylhydroxylamine hydrochloride is slowly added dropwise and allowed to stir overnight at RT. The precipitated solid was filtered and washed with water and dried under vacuum.

The resulting unsaturated polyester urethane nitrone is a 1K system that is crosslinked in Example 15.

Example 12 Crosslinking of Unsaturated Polyester UP-I (7) with Polynitrone DN-O (1)

9 g of UP-I (7) (DSM, Uracross P 3125) and 1 g of DN-O (1) are ground to a fine powder in a hand mill and then placed between two metal plates in a four-cornered Teflon mold. After 1 h at 120 ⁰ C storage in the oven, a very hard, white and opaque molding composition was obtained. The resulting molding material is solvent resistant to chloroform, THF and acetone.

Example 13: Crosslinking of UP-2 (8) with DN-O (1)

0.92 g of UP-2 (8) and 0.08 g of DN-O (1) were mixed to form a dispersion and then stored in a prefabricated Teflon mold at 80 ^° C. for 5 hours. From the teflon mold, an elastic film could be peeled off. The film was solvent resistant.

Example 14: Crosslinking of UP-2 (8) with DN-IO (2)

0.9 g UP-2 (8) and 0, 1 g DN IO (2) were mixed to form a dispersion and then stored in a Teflon mold vorfertigten 6h at 80 ⁰ C. From the teflon mold, an elastic film could be peeled off. The film was solvent resistant.

Example 15: Self-crosslinking of UP-UN-I (11)

5 g of the unsaturated polyester urethane nitrone UP-UN-I (I l) prepared in Example 11 were ground to a fine powder in a hand mill and then placed between two metal plates in a quadrangular Teflon mold. After storage for ² hours at 120 ^° C., a transparent, solvent-resistant molding composition was obtained.

Discussion of the results:

Crosslinking of the mixture of UP-2 (8.90% by weight) and DN-10 (2.10% by weight) (Example 13) was measured by DSC measurement at a heating rate of 10 ° C / min between -60 and 200 ⁰ C tracked. The resulting DSC curves are shown in FIG.

A: dissolution process

B: Tg = -34 ° C (cross-linked)

C: Tg = -47 ° C (not crosslinked)

D: exothermic crosslinking

The first DSC heating curve in Figure 2 shows that UP-2 (8) has a T _g of -47 ⁰ C prior to crosslinking. Immediately after the Homogenisierungspro- process the cross-linking of the mixture occurs at about 80 ⁰ C, which is easily recognized in the first heating curve by the exothermic peak. The second heating curve shows no exothermic peak due to the complete crosslinking process and as a consequence of the restricted chain mobility. By networking, a Ty value shifted by about 13 ⁰ C (-34 ⁰ C) compared to the first heating curve.

Supporting the above DSC study, the kinetics of cycloaddition of DN-IO (2) to UP-2 (8) was also monitored by IR spectroscopy. The IR spectra in Figure 3 show a continuous decrease in the absorption band at 1600 cm ¹ , which can be assigned to the C = N group of DN-IO (2).

The IR spectra clearly show the fast course of the crosslinking reaction. FIG. 4 depicts the crosslinking of the unsaturated polyester UP-2 (8) with DN-IO (2) (Example 13).

The results can be summarized as follows:

The crosslinking method according to the invention provides new possibilities for the development of new materials according to an environmentally friendly variant. The combination of e.g. unsaturated polyesters and polyfunctional nitrones (= polynitrons) can be exploited in the following areas to develop new products.

• development of new adhesives (e.g., hot melt adhesives);

• In the furniture sector. Fast curing and virtually 100% solids make it possible to apply very thick layers in one operation;

Production of fast-hardening and easily sandable fillers (car repair, woodworking and metalworking industry);

• production of sprayable thick-film fillers (car repair, metalworking and metalworking industry);

Production of glass fiber reinforced polyester parts (GRP polyester) z. In shipbuilding; Development of thermosetting paints, in particular water-based paints;

Development of self-curing powder coatings, e.g. Nitron-terminated urethane-unsaturated polyester.

The invention is in addition to the above areas an optimal solution for the matting of curable powder coatings. This is about the inventive use of polynitrates as Mattier ungsmittel. It has unexpectedly been found that the curable powder coatings, in particular UV-curable powder coatings, show very good matting properties by the addition of polynitrons.

Due to the small addition of different polynitrones to the UP powder coating (P-UP, 9), surfaces were produced after the UV curing, the gloss of the surface being greatly reduced in addition to the good surface profile.

The use of polynitrons as matting agent is again exemplified in the following examples.

Comparative Example 16 Production of the UP Powder Coating (P-UP, 12)

Tab. 1: Formulation of the UP powder coating (P-UP, 12)

The mixture of composition listed in the table is processed according to the process described in Figure 1 for powder coating P-UP (12).

Comparative Example 17 P-UP (12) powder coating without addition of polynitrone

Powder coating P-UP (12) is applied to various surfaces (glass, PET foils, phosphated steel). After 15 minutes tempering in an oven at 140 ⁰ C and subsequent UV curing all surface-applied chenzeigen show very high gloss (60 degree gloss> 90%).

Example 18: P-UP (12) powder coating with addition of Polynitron DN-10 (2)

Polynitron DN-10 (2), in dry form, was added to the finished powder coating P-UP (12), the finely ground polynitrone having an average particle size of about 40-50 μm. After physical homogenization, the application was carried out on various surfaces (glass, PET films, phosphated steel sheet). The sheets thus applied are tempered in the oven for 15 min at 140 ⁰ C and then cured by UV radiation. Here, the weight content of Polynitron 1- 1% of the total powder coating amount. All applied surfaces show a strong gloss reduction (60 ° gloss: <50%).

Discussion of the matting process

Due to the small addition of polynitron (DN-10, 2) to the UP powder coating (P-UP, 12), surfaces were produced after UV curing, whereby the gloss of the surface is greatly reduced in addition to the good surface profile. FIG. 5 shows powder-coated glass surfaces with and without the addition of Polynitron DN-10 (2). Figure 5 is a photomicrograph of the coated glass surface once without (left) and once with (right) addition of Polynitron DN-10 (2).

Here, the principle of so-called "double curing" is applied, wherein the powder coating initially by the cycloaddition of Polynitrons to the double bonds of the binder at low temperatures (50- 140 ⁰ C) pre-fixed or structured and then crosslinked by UV radiation becomes. The locally generated microstructures lead to a rough surface profile, which greatly reduces the gloss of the surface due to the diffuse light reflection at the surface. In Figure 6, the mechanism of matting in the examined UP powder coating (P-UP, 12) was schematically shown, the composition of which is given in the table of Comparative Example 16.

Thus, the invention also relates to the use of polynitrons as matting agent. In addition to the described Urethanpolynitron powder coatings also powder coating systems based on the following systems can be frosted by the addition of polynitrons.

• Acrylate / methacrylate-functionalized polyesters

Acrylate / methacrylate-functionalized unsaturated polyester

Unsaturated polyester - urethane (meth) acrylates, e.g. described under US Patent 006284321B 1.

All described powder coating classes are preferably prepared according to the process shown in FIG. 1 and subsequently mixed with the appropriate amounts of polynitrons and then physically homogenized and then applied to the various surfaces.

In summary, it can be said that the invention is a new (environmentally friendly) crosslinking method, whereby the use of polynitrons makes the industrially important resins, e.g. unsaturated polyesters and (meth) acrylates can be cured or patterned at low temperatures. The invention solves above all the problems of the paint manufacturer in the conversion from conventional to environmentally friendly painting methods.

Claims

claims

1. Use of polynitrons for crosslinking unsaturated polymers.

2. Use according to claim 1, characterized in that the crosslinking leads to a change in the mechanical and / or optical properties of the polymer, in particular for curing and / or matting of the polymer.

3. Use according to claim 1 or 2, characterized in that the polynitrone is a compound according to the general formula I,

in which x is a natural number from 2 to 12, R _{1 is} an optionally substituted linear, cyclic or branched, alkylene group, alkyleneoxy group, arylene group, aryleneoxy group, naphthylene group or combinations thereof, and R ₂ and R _{3 are} independently hydrogen or a optionally substituted linear or branched alkyl group, aryl group, heteroaryl group, alkylaryl group, alkoxyl group and / or cycloalkyl group.

4. Use according to claim 3, characterized in that in formula I, the radical R ₁ is bonded to a polymer.

5. Use according to any one of claims 1 to 4, characterized in that the unsaturated polymer has at least one unsaturated carbon-carbon bond in the polymer chain and is preferably selected from polyolefins, polystyrene, polyvinyl alcohol, polyvinyl acetate, polyalkylene glycol, polyethylene oxide, polypropylene oxide, polyacetals , Polyurethanes, polyureas, polyamides, polycarbonates, polyketones, polysulfones, phenol-formaldehyde resins, polyesters, polyester acrylates, polyurethane acrylates, cellulose, gelatin, starch, and mixtures thereof.

6. A curable composition comprising

(a) a polynitron,

(b) an unsaturated polymer,

(c) optionally fillers and

(d) optionally pigments.

7. A composition according to claim 6, characterized in that it is a 2-component system, wherein the components (a) and (b) are in the form of two compounds.

8. A composition according to claim 6, characterized in that it is a 1-component system, wherein the components (a) and (b) are in the form of a polynitron-terminated unsaturated polymer.

9. The composition according to claim 8, characterized in that it is the polynitron-terminated unsaturated polymer is an unsaturated polyester urethane polynitrone.

10. A composition according to any one of claims 6 to 7, characterized in that the polynitrone (a) in an amount of 1 to 20 wt .-%, based on the total weight of the composition, is included.

1 1. Use of a composition according to any one of claims 6 to 10 as an adhesive, filler, sprayable thick-film filling, powder coating and / or paint based on solvent systems.

12. A process for producing a crosslinked product comprising the steps

(i) providing a curable composition according to any one of claims 6 to 10,

(Ii) curing of the composition at temperatures of 20 to 180 ⁰ C, preferably from 50 to 150 ⁰ C.

13. Crosslinking product obtainable by a process according to claim 12.

14. Use of a crosslinking product according to claim 13 for the production of dental materials, household appliances, kitchen plates, bathtubs, sinks and glass fiber-reinforced polyester parts, preferably in shipbuilding.

15. Polynitron selected from terephthalaldehyde bis (N-phenylnitrone), isophthalaldehyde bis (N-phenylnitrone), isophthalaldehyde bis (N-methylnitrone), terephthalaldehyde bis (N-butyl nitrone), isophthalaldehyde bis (N-cyclodecylnitron). tron), isophthalaldehyde-bis (N-cyclohexylnitrone), 4,4'-decanediyldioxydi (N-methyl-p-phenylenemononite), 4,4'-hexanediyldioxydi (N-methyl-p-phenylenenitrone, 4,4'- Butanediyldioxydi (N-methyl-p-phenylenenitrone), 4,4'-ethanediyldioxydi (N-methyl-p-phenylenenitrone) and polynitron-terminated polyurethanes.

16. Polynitron according to claim 15, wherein it is a polynitrone-terminated polyurethane according to the general formula II

x in which x is a natural number from 2 to 12 and R ₁ to R _{5 is} an organic radical, wherein R ₂ , R ₄ and R _{5 are} preferably a hydrogen atom or a Ci-Ce-alkyl group.

17. A process for producing a polynitron-terminated polyurethane comprising the steps

(i) preparing a urethane-polyaldehyde by reacting a polyisocyanate with a hydroxy-aldehyde compound, and

(ii) reacting the urethane-polyaldehyde with an N-alkylhydroxylamine or (i) reacting a hydroxy-aldehyde compound with an N-alkylhydroxylamine, and

(ii) reaction of the reaction product resulting from step (i) with a polyisocyanate.

18. A process for preparing an unsaturated polyester urethane polynetron comprising the steps

(i) reacting an unsaturated polyester with a hydroxy-aldehyde compound and

(ii) reaction with a polyisocyanate, followed by

(iii) reaction of the unsaturated polyester resin obtained in step (ii)

Urethane aldehyde with N-alkylhydroxylamine.

19. An unsaturated polyester urethane polynitrone obtainable by a process according to claim 18.