NL1006251C2 - Powder paint binder composition. - Google Patents

Description

- 1 - PN 8304

5 POWDER PAINT BINDING COMPOSITION

The invention relates to a powder paint binder saraens teil ing.

10 As can be seen from the article "Rheology of

Powder Coatings "by Sunil Kadam et al. (February 1992, Paint India / 77) is looking for powder paint systems which simultaneously have good flow, good storage stability and good reactivity. In the prior art powder paint binder systems the chemical curing is achieved by by means of cross-linking the powder paint simultaneously with heating and melting of the powder applied to the substrate If such a system has a high reactivity, on the one hand, this results in a good curing of the coating at the usual stoving times and stoving temperatures, resulting in good mechanical and chemical properties, but on the other hand it is very difficult to obtain the desired storage stability and flow If, on the one hand, a system has a low reactivity, this results on the one hand in good storage stability and flow, but on the other hand longer baking times and higher baking temperatures are required to achieve of antlers nth 30 coating properties.

The binder composition according to the invention is a thermally stable, moisture-curable powder paint binder composition with a glass transition temperature> 30 ° C or a melting temperature 35> 30 ° C comprising a polymer and optionally a crosslinker wherein at least one of these components contains moisture-latent reactive groups.

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A thermally stable powder paint binder composition is a binder composition which, when exposed to temperatures <150 ° C for 15 minutes, undergoes less than 20% of the number of thermal reactions leading to chain extension or crosslinking.

The moisture-latent reactive groups are exposed to moisture after the liquid stage of the powder, after which curing takes place to a powder coating. Preferably, less than 0.1% by weight of water (relative to the powder paint composition) is or has been present in the powder paint composition for the flow phase.

By applying the composition according to the invention it is achieved that the chemical curing can be effected by means of cross-linking after heating and melting of the powder, by exposure of the coated substrate to moisture. In this way, both the desired storage stability and a very good flow are ensured as long as absorption of moisture by one of the components of the powder paint composition is avoided. After the exposure of the applied coating to moisture, sufficient reactivity can be obtained for the chemical curing by means of cross-linking, which ensures the desired coating properties. Crosslinking does not take place without moisture being absorbed by one of the components of the powder paint composition or the coating.

A moisture-latent reactive group is a reactive group that does not react with other reactive groups in the binder system at temperatures between 0 ° C and 200 ° C, but which can react with moisture at this temperature. Reaction with water changes the chemical structure of the reactive group and as a result it is possible to start reactions with other reactive groups 1006251-3 in the binder system.

A reactive group is part of a molecule that can react with another, optionally different, reactive group such that a chemical bond is formed between the two reacting groups and therefore also between the molecules, for example polymers, on which the reactive groups are located.

When exposed to moisture, the relative humidity is usually between 20% and 100% (at temperatures between 10 ° C and 150 ° C) and preferably between 50% and 100%.

A very important advantage of moisture-latent curing according to the invention is that the flow of the powder paint (by heat) is completely separated from the curing reaction, so that powder coatings with a very good flow can be obtained.

Another advantage of using the above-described heating and curing method is the relatively low temperature required for good flow. This also makes it possible to apply to heat-sensitive substrates such as wood, paper and plastic.

The moisture-latent reactive groups are located on the polymer and / or on the crosslinker.

If the use of a crosslinker is necessary or desired, the moisture-latent reactive groups may be on the crosslinker, with other, optionally also moisture-latent, or similar reactive groups on the polymer being reactive with the moisture-modified reactive groups of the crosslinker.

It is also possible that the moisture-latent reactive groups are present on one or more polymers, while the use of an additional crosslinker is not necessary or desirable. In that 1006251-A case, the same polymer or one of the polymers also contains other, optionally also moisture-latent, or equal reactive groups which are reactive with the reactive groups modified by exposure to moisture.

The number of average reactive groups per polymer chain can be varied depending on the application, but is generally between 1.5 and 10, preferably between 2 and 4 groups, per polymer chain. Preferably, the moisture-latent groups on the polymer react with other, optionally moisture-latent, reacted or not reacted with moisture, reactive groups on the polymer and no crosslinker is necessary.

If the moisture-latent groups are present on the crosslinker, after reaction with moisture they can react with, optionally moisture-latent, reacted or not reacted with moisture, reactive groups that are on the polymer.

In the synthesis of the individual 20 components of the binder composition, in combining the different components into the final binder composition and in processing the binder into a powder paint using the usual techniques such as crushing, milling, extruding, cooling, sieving and spraying the conditions are preferably chosen such that no or virtually no moisture can be absorbed.

Preferably, the binder composition and powder paint composition 30 are processed under an inert and dry atmosphere of nitrogen or argon, or under dried air (e.g., <20% relative humidity at a temperature between 0 ° C and 130 ° C).

Depending on the composition and / or temperature, a binder or powder paint can absorb moisture more or less easily. A polymer is loop? * -; i - 5 - for example, less likely to absorb moisture at temperatures lower than the glass transition temperature. Depending on the propensity to absorb moisture, temperature and humidity can be adjusted during processing.

Suitable polymers are, for example, saturated polyester, unsaturated polyester, polyacrylate, polyurethane, polycarbonate, polystyrene, polybutadiene, polysiloxane or a copolymer thereof.

Saturated polyesters and polyacrylates are preferably used.

Examples of suitable moisture-latent reactive groups are moisture-latent amine groups, hydrolyzable silyl groups, moisture-latent alcohols, moisture-latent acids, moisture-latent aldehyde groups and moisture-latent ketone groups.

Hydrolysable silyl groups and moisture-latent amine groups are preferably used.

Examples of suitable moisture-latent amine groups are ketimine, aldimine, oxazolidine, silazanes and isocyanate groups.

Examples of suitable hydrolyzable silyl groups are silicon-containing reactive groups according to formula (1): R 1 A - Si - R 2 (1) R 3 wherein at least one of the groups R 1, R 2 or R 3 is hydrolyzable and is selected from the groups (0λ- C20) alkoxy, (C 1 -C 20) ether groups containing alkoxy or (C 1 -C 20) carboxylate and wherein A is a non-hydrolyzable (C 1 -C 20 alkyl radical or a (C 1 -C 20) alkoxy radical.

One or two of the groups R1, R2 or R3 may be a (C1-C20) alkyl group.

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The silane can be attached via side group A to one of the mentioned polymers or crosslinkers, or can be used as such as a crosslinker.

Preferably A is a (C2-C5) alkyl radical and R1, R2 and R3 are (C1-C4) alkoxy groups.

In a further preferred embodiment, A is a C3 radical and R1, R2 and R3 are (C1-C2) alkoxy groups. The C3 radical is preferably unsubstituted.

Examples of suitable moisture-latent alcohols are silyl ethers, acetals and ketals.

Examples of suitable moisture-latent acids are silyl esters, carboxyl esters and alkenyl esters.

Examples of suitable moisture-latent aldehydes or ketones are acetals, ketals, alkenyl ethers, alkenyl esters, aldemines and ketimines.

Polyesters that can be used are generally based on the residues of aliphatic polyalcohols and polycarboxylic acids.

The polycarboxylic acids are generally selected from the group consisting of aromatic and cycloaliphatic polycarboxylic acids because these acids usually have a Tg-enhancing effect on the polyester. In particular, dibasic acids are used. Examples of polycarboxylic acids are isophthalic acid, terephthalic acid, hexahydroterephthalic acid, 2,6-naphthalenedicarboxylic acid and 4,4-oxybisbenzoic acid and, where available, their anhydrides, acid chlorides or lower alkyl esters, such as, for example, the dimethyl ester of naphthalenedicarboxylic acid. Although not a requirement, the carboxylic acid component generally comprises at least about 50 mole percent, preferably at least about 70 mole percent, isophthalic acid and / or terephthalic acid.

Other suitable aromatic cycloaliphatic and / or acyclic polycarboxylic acids are, for example, 3.6-100625! - 7 - Dichlorophthalic acid, tetrachlorophthalic acid, tetrahydrophthalic acid, hexahydroterephthalic acid, hexachloroendomethylene tetrahydrophthalic acid, phthalic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, adipic acid, succinic acid and maleic acid. These other carboxylic acids can usually be used in amounts of up to 50 mol% of the total amount of carboxylic acids. These acids can be used as such or, if available, in the form of their anhydrides, acid chlorides or lower alkyl esters.

Useful polyalcohols, especially diols, which can be reacted with the carboxylic acids to obtain the polyester include aliphatic diols such as, for example, ethylene glycol, propane-1,2-diol, propane-1,3-diol, butane-1 , 2-diol, butane-1,4-diol, butane-1,3-diol, 2,2-dimethylpropanediol-1,3 (= neopentyl glycol), hexane-2,5-diol, hexane-1,6-diol , 2,2-bis- (4-hydroxy-20-cyclohexyl) -propane (hydrogenated bisphenol-A), 1,4-dimethylolcyclohexane, diethylene glycol, dipropylene glycol and 2,2-bis [4-2-hydroxylethoxy) -phenyl] propane , the hydroxypivalin ester of neopentyl glycol.

Small amounts, such as less than about 4 wt%, but preferably less than 2 wt%, of triols or triacids can be used to obtain branched polyesters. Examples of useful polyols and polyacids are glycerol, hexanetriol, trimethylolethane, trimethylolpropane, tris- (2-hydroxyethyl) isocyanurate and trimellitic acid.

The polyesters are prepared by conventional esterification or transesterification, optionally in the presence of conventional esterification catalysts such as, for example, dibutyl tin oxide or tetrabutyl titanate. The 7006251-8 preparation conditions and the COOH / OH ratio can be selected to provide end products that have an acid number or hydroxyl number within the intended range of values.

The polyester can be either crystalline or amorphous. Preferably, the polyester is amorphous. Mixtures of crystalline and amorphous polyesters can also be used. Amorphous polyesters usually have a viscosity between 100 and 8000 dPas (measured at 10 158 ° C, Emila). Crystalline polyesters usually have a viscosity between about 2 and about 200 dPas.

Polyacrylates, such as epoxy, carboxy and hydroxy-reactive polyacrylates, are described in patents US-A-3,752,870, US-A-3,787,340 and US-A-3,758,334 and in British patent 1,333,361, and by reference disclosed in said patents is incorporated herein.

The polymer Tg is generally between about 30 ° C and about 120 ° C. In order to obtain an optimal storage stability, the Tg is preferably higher than 50 ° C. For the processing of the polymer, the Tg is preferably less than 100 ° C.

In the preparation of a hydrolyzable silyl groups containing polyester or polyacrylate, a hydroxyl or acid functional polyester or polyacrylate which can react with a hydrolysable silyl group-containing compound according to formula (2) can be used: 30 R1 XA-Si - R2 (2) R3 35 wherein X is a reactive group capable of reacting with hydroxyl, acid or ester groups, 1006251 - 9 - - wherein A is an optionally substituted organic radical containing (1-20) carbon atoms and - wherein at least one of the groups R1, R2 or R3 is hydrolyzable and is selected from the groups 5 (C 1 -C 8) alkoxy, (C 1 -C 7) ether groups containing alkoxy or (C 1 C 20) carboxylate.

Suitable examples of hydrolyzable silyl groups containing compounds that can react with acid groups are: 3-glycidoxypropyltrite-oxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltri (2-methoxyethoxy) silane, beta- (3,4-epoxycyclohexyl-methyltrimethoxysyl) epoxycyclohexyl) ethyl triethoxysilane.

15 Suitable examples of hydrolyzable silyl groups-containing compounds that can react with ester groups are: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 20 bis (3-trimethoxysilylpropyl) amine, bis (3-triethoxysilylpropyl) amine, β-β-mercaptopropyltriethoxysilane and mercaptopropyltrimethoxysilane.

Suitable examples of hydrolyzable silyl groups containing compounds which can react with hydroxyl groups are 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane.

It is also possible to start from a polyester containing hydroxyl groups which reacts successively with a diisocyanate and with an isocyanate-reactable silyl compound.

Examples of suitable diisocyanates are 1,4-diisocyanato-4-methyl-pentane, 1,5-diisocyanato-5-35 methylhexane, 3 (4) -isocyanatomethyl-1-methylcyclohexylisocyanate, 1,6-diisocyanato-6-methyl-1006251 - 10 - heptane, 1,5-diisocyanato-2,2,5-trimethylhexane and 1,7-diisocyanato-3,7-dimethyloctane, respectively 1-isocyanato-1-methyl-4- (4-isocyanatobut-2-yl ) -cyclohexane, 1-isocyanato-1,2,2-trimethyl-3- (2-5 isocyanatoethyl) -cyclopentane, 1-isocyanato-1,4-dimethyl-4-isocyanatomethyl-cyclohexane, 1-isocyanato- 1 , 3-dimethyl-3-isocyanatomethyl-cyclohexane, 1-isocyanatol-n-butyl-3- (4-isocyanatobut-1-yl) -cyclopentane, 1-isocyanato-1,2-dimethyl-3-ethyl-3-10 isocyanatomethylcyclopentane.

Preferably, the reaction between the hydroxyl groups containing polyester or polyacrylate and the diisocyanate takes place in the presence of a catalyst.

Preferably, an ionic metal complex based on a metallic element of groups III, IV or VII of the Periodic Table with exchangeable counterions is used as catalyst.

Suitable metallic elements in the suitable valence are aluminum (III), tin (IV), manganese (III), titanium (III), titanium (IV) and zirconium (IV).

Tin (IV), titanium (IV), manganese (III) and zirconium (IV) are preferably used.

Examples of suitable counterions are halides, preferably chloride, (C 1 -C 8) alkoxides, preferably (C 1 -Ce) alkoxide, (C 2 -C 20) carboxylates, preferably (C 2 -C 8) carboxylates, enolates, especially preferably 2,4-pentanedione (acetylacetonates) and alkyl esters of malonic acid and acetylacetic acid, phenolates, naphthenates, cresylates and mixtures of said counterions.

Suitable catalysts are, for example, aluminum (III) acetate, aluminum (III) acetylacetonate, aluminum (III) 2,2,6,6-tetramethyl-3,5-heptanedionate, aluminum (III) ethoxide, aluminum (III) isopropoxide, 1006251 - 11 - aluminum (III) sec-butoxide, aluminum (III) tert-butoxide, tin (IV) chloride, tin (IV) bromide, tin (IV) iodide, tin (IV) acetate, tin (IV) bis (acetylacetonate) ) dichloride, tin (IV) 5 bis (acetylacetonate) dibromide, manganese (III) acetate, manganese (III) acetylacetonate, manganese (III) fluoride, titanium (IV) chloride, titanium (IV) bromide, titanium (IV) methoxide, titanium (IV) ethoxide, titanium (IV) isopropoxide (eg TYZOR TPT ™), 10 titanium (IV) propoxide, titanium (IV) butoxide (eg TYZOR TBT ™), titanium (IV) 2-ethylhexoxide (eg TYZOR TOT ™) , titanium (IV) acetylacetonate, titanium (IV) bis (acetylacetonate) diisopropoxide (eg TYZOR AA ™), titanium (IV) 15 bis (ethyl acetoacetato) diisopropoxide, titanium (IV) (triethanolaminato) isopropoxide ( eg TYZOR TE ™), zirconium (IV) chloride, zirconium (IV) bromide, zirconium (IV) acetate, zirconium (IV) 2-ethylhexanoate, zirconium (IV) ethoxide, zirconium (IV) butoxide 20 (eg TYZOR / NBZ ™ ), zirconium (IV) tert-butoxide, zirconium (IV) citrate ammonium complex, zirconium (IV) isopropoxide, zirconium (IV) propoxide, zirconium (IV) acetylacetonate and zirconium (IV) tr ifluoroacetylacetonate.

Another method of preparing a hydrolyzable silyl group-containing polyacrylate is by starting from a copolymer of polymerizable ethylenically unsaturated monomers such as, for example, alkyl acrylates with a compound of formula (3): 30 R1 Y- (A) n-Si-R2 ( 3) R3 35 wherein y is an ethylenically unsaturated polymerizable group or a chain transfer group whereby the silyl group is located after synthesis at 1008251-12 - either end of the polymer chain, wherein A is an optionally substituted organic radical that (1 -20) contains carbon atoms and wherein at least one of the groups R 1, R 2 or R 3 is hydrolyzable and is selected from the groups (C 1 -C 20) alkoxy, (C 1 -C 20) ether groups containing alkoxy or (C 1 -C 20) carboxylate.

One or two of the groups R1, R2 or R3 may be a (Cx-10 C20) alkyl group

Examples of suitable compounds according to formula (3) are: vinyltrethoxysilane, vinyltrimethoxysilane, vinyltri (2-methoxyethoxy) silane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxylethyl-methyloxyethyl-methyloxy-oxy-methyl-3-acryloxy-propyltrimethylsilane, 3-acryloxypropyltrimethoxysilane, 3-acrylic methacryloxypropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane and 3-mercaptopropyltriethoxysilane.

The blocked amine groups containing compounds are preferably used as a crosslinker in combination with a polymer containing amine-reactive reactive groups. The blocked amines are preferably derived from aliphatic amines with a functionality> 2. It is also possible to start from a block containing polyacrylate containing amine groups, using as crosslinker a compound containing two or more reactive groups containing amine groups can respond.

Preferably, the amine-reactable reactive group is a cyclic carbonate, 100625-1-13 - as described, for example, in BE-A-1009543, an α, β-unsaturated ester or ketone, or an isocyanate.

The preparation of a blocked amine group containing polyester or polyacrylate can be based on a hydroxyl group-containing polyester or polyacrylate which reacts successively with a diisocyanate and a blocked dialkylene triamine or a blocked N-alkylalkylenediamine.

Another way to prepare a blocked amine-containing polyacrylate group is by using an isocyanate group-containing ethylenically unsaturated polymerizable compound as a comonomer, after which the resulting acrylate polymer reacts with blocked dialkylene triamines or blocked N-alkylalkylenediamines.

An example of a suitable isocyanate group-containing compound is 3-isopropenyl- (a, a) -dimethylbenzyl isocyanate.

Suitable examples of a blocked dialkyl triamine are bis-ketimines and bis-aldimines of diethylene triamine and bis (hexa) methylene triamine. Suitable examples of blocked N-alkyl-alkylenediamines are the aldimines of N-ethyl-ethylenediamine, N-methyl-ethylenediamine, N- (m) ethyl-1,3-propanediamine and N- (m) ethyl-1,6- hexanediamine.

The preparation of powder paints and the chemical curing reactions of these powder paints to cured coatings are generally described in, for example, Powder Coatings (Wiley and Son, 1991) 30 by Misev (pages 44-54, 148 and 225-226) and what is contained therein disclosed is incorporated herein by reference.

Of course, if desired, use can be made in the powder coating systems according to the invention of all conventional additives. The additives are preferably non-water-containing.

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Examples of additives are pigments, fillers, degassing agents, flow agents and stabilizers. Pigments include inorganic pigments such as titanium dioxide, zinc sulfide, iron oxide and chromium oxide, as well as organic pigments such as azo compounds. Fillers include, for example, metal oxides, silicates, carbonates and sulfates.

As additives use can be made of stabilizers such as primary and / or secondary antioxidants and UV stabilizers such as, for example, quinones, (sterically hindered) phenolic compounds, phosphonites, phosphites, thioethers and HALS compounds (hindered amine light stabilizers).

Examples of degassing agents are benzoxne and cyclohexane dimethanol bisbenzoate. The fluxes include polyalkyl acrylates, hydrofluorocarbons and silicone oils. Other additives include additives to improve tribo chargeability, such as, for example, sterically hindered tertiary amines.

Powder paints according to the invention can be applied in the usual manner, for example by electrostatic spraying of the powder on a grounded substrate and curing of the coating by exposure to heat at a suitable temperature for a sufficiently long period of time. The applied powder can for instance be heated in a gas oven, an electric oven or with the aid of infrared radiation. Preferably, the powder or coating 30 absorbs as little moisture as possible during the liquid stage.

Thermosetting coatings of powder paint (coating) compositions intended for industrial applications are further generally described in Misev, p. 141-173 (1991).

Compositions of the present invention can be used in powder coatings 1006251-15 for application to metal, wood and plastic substrates. Examples include general purpose industrial coatings, machinery coatings, as well as cans, household and other small equipment. The 5 coatings are also very suitable in the car industry for coating external and / or internal parts of vehicles such as cars.

The invention is illustrated by the following non-limiting examples.

10

Example 1

Moisture-curing powder coatino based on a cyclic carbonate functional resin and a blocked amine crosslinker 15

Step 1: Preparation of MiBK blocked DAB-fPA) 1 52 g N, N, N ', N'-tetrakis (3-aminopropyl) -1,4-diaminobutane (DAB- (PA) 4 from DSM) were added with 150 g methyl isobutyl ketone (MiBK) and 200 ml of toluene into a 500 ml 20 ml round bottom flask equipped with a stirrer, thermometer and Dean-Stark distillation set-up. After 4 hours of reaction at 120 ° C (boiling point azeotrope water / toluene), 12 ml of water was collected. The reaction was stopped at this point and the excess toluene and MiBK were removed on a rotary evaporator. 58.5 g of pure product were obtained.

Step 2: Conversion of alkydyl methacrylate to the cyclic carbonate (GMACC) 93 g of glycidyl methacrylate and 2 g of potassium iodide were dissolved in 100 g of methoxypropanol. CO2 was passed through a gas passage pipe at a temperature of 120 ° C. The reaction was monitored titrimetrically by amount of epoxide end groups. The reaction was terminated after 15 hours of reaction, when the epoxy number dropped from 3.5 meq / g to 0.06 meq / g.

1006251 - 16 -

After work-up via extraction, 120 g of product with a purity> 98% were obtained.

Step 3: Preparation of a cyclic carbonate 5 functional polycarbonate sheet

In a 2 liter reactor, 3.26 parts of toluene were heated to 110 ° C. To this was added a mixture of 4.15 parts of methyl methacrylate, 0.47 parts of butyl acrylate, 0.88 parts of GMACC obtained according to Step 2 and 0.22 parts of Luperox 575 ™ over a period of 3 hours. After all monomers were added, it was re-initiated with 0.04 parts of Luperox 575 ™. After 2 hours of reaction at 130 ° C, of which half an hour under vacuum (removing toluene), the product was poured out. The product was yellow in color, had a Tg of 68 ° C (determined by method TM 2076 from DSM-Resins) and a viscosity (E / 165, determined by method TM2005, DSM-Resins) of 350-400P.

20

Step 4: Preparation of clear coat binder composition using: the products obtained in steps 1 and 3 350 g of cyclic carbonate functional polyacrylate 25 (obtained according to Step 3) was blocked with 2.3 g of flux (BYK 361), 3 g of benzoin and 56 g of MiBK DAB (PA) 4 (obtained according to Step 1) mixed on a Buss kneader at 100 ° C, extruded on a PRISM twin screw extruder at 110 ° C, milled and sieved at <90 µm. The powder was electrostatically sprayed. Good flow was obtained after melting the powder at 110 ° C for 10 minutes (visual evaluation). No curing had taken place after melting, acetone resistance 12 ADR determined by acetone test, where an acetone resistance> 100 ADR was assessed as complete curing, 25-100 ADR as partial curing and <25 ADR no curing). After a 4 hour stay of the coated test panels in a climate oven at 90 ° C and 90% relative humidity for 4 hours, the coating was fully cured (acetone resistance> 100 ADR).

Example 2: Moisture-curing powder coatina based on an alkoxysilane functional resin 10 Step 1: Drying polyester powder coatina resin An isophthalic acid and neopentyl glycol-based polyester resin with a hydroxyl number of 30 mg KOH / g resin, an acid number <1 mg KOH / g resin, a functionality 2, Tg 53 ° C (method TM 2076, DSM-15 Resins), Mn 4500, Mw / Mn 2.3 and a water content of 3 mg / g resin was melted in a heated glass reactor and heated to 160 ° C. 1 ml of p-xylene was added, which was then evaporated again under vacuum until the resin no longer contained any volatile compounds. This procedure was repeated four times.

After this treatment, the resin contained <0.2 mg water / g resin; other properties were similar to the base resin.

Step 2: Preparation of triethoxysilane functional polyester powder coatina resin

To the polyester resin (500 g) dried in step 1, 1.0 g of dibutyltin diacetate as catalyst was added in molten state in the reactor (160 ° C) under an inert atmosphere, followed by 68 g of 3-isocyanatopropyltriethoxysilane. After 30 minutes of reaction at 160 ° C, the resin was poured under an inert atmosphere and cooled to the exclusion of moist air.

35 The characteristics of the resin:

Tg: 38 ° C (method TM 2076, DSM-Resins), 10Ü62 51 - 18 -

Mn: 5600, Mw / Mn: 2.7 and - viscosity (E / 165, method TM2005, DSM-Resins): 150-180P.

5

Step 3: Preparation of clear coat binder composition using: products from steps 1 and 2

To 569 grams of the triethoxysilane functional resin obtained in Step 2 were added in the reactor in molten state at 160 ° C under an inert atmosphere 3 g BYK 361 (flux enhancer) and 1.5 g benzoin (degassing agent). The resin was poured under an inert atmosphere and cooled to the exclusion of moist air. After breaking the resin, the resin was milled and sieved (<90 μ) with the exclusion of moist air. After exposure of the powder to a controlled climate of 23 ° C and 50% relative humidity for 2 weeks, no significant increase in melt viscosity at 165 ° 20 C was found to have occurred: 150-210P (E / 165 method TM2005, DSM-Resins ).

The powder was electrostatically sprayed on aluminum test panels. Very good flow was obtained after melting the powder at 120 ° C for 15 minutes (visual evaluation). No curing had taken place after melting (acetone resistance 14 ADR). After a 4 hour stay of the coated test panels in a climate oven at 90 ° C and 90% relative humidity, the coating was fully cured (acetone resistance> 100 ADR), the impact resistance was 60 inchpound (reverse impact resistance) and the König hardness 255 seconds. The coating had a very good appearance, a high brightness and a good gloss.

1006251

Claims (10)

1. Thermally stable, moisture-curable powder paint binder composition with a glass transition temperature> 30 ° C or a melting temperature> 30 ° C comprising a polymer and optionally a crosslinker wherein at least one of these components contains moisture-latent reactive groups. 2. A composition according to claim 1, characterized in that the polymer is a saturated polyester, unsaturated polyester, polyacrylate, polyurethane, polycarbonate, polybutadiene, polystyrene, polysiloxane or a copolymer thereof. Composition according to claim 2, characterized in that the polymer is a saturated polyester or a polyacrylate. 4. A composition according to any one of claims 1-3, characterized in that the moisture-latent reactive group is a moisture-latent amine group, a hydrolysable silyl group, a moisture-latent alcohol, a moisture-latent acid, a moisture-latent aldehyde group or a moisture-latent ketone group. R3 where at least one of the groups R1, R2 or R3 is hydrolyzable and is selected from the groups (C1-C20) alkoxy, (C1-C20) ether groups containing alkoxy or (C1-C20) carboxylate and 10 where A is a -hydrolyzable (Cx-C10) alkyl radical or an ((- - € 20) alkoxy radical. Composition according to claim 4, characterized in that the moisture-latent reactive group is a moisture-latent amine group or a hydrolyzable silyl group. 6. A composition according to claim 5, characterized in that the moisture-latent amine group is a ketimine, aldimine, oxazolidine, silazanes or isocyanate group. Composition according to claim 5, characterized in that the hydrolyzable silyl group is a silicon-containing reactive group according to formula (1): 10 0 32 51 - 20 - R1 A - Si - R2 (1) 8. Method for obtaining a fully or partly coated substrate by applying a powder paint composition containing a composition according to any one of claims 1-7 to a substrate in which the moisture-latent groups are exposed to moisture after the liquid stage. Powder paint containing a binder composition according to any one of claims 1-7. Fully or partially coated substrate in which the coating is obtained from a powder paint according to claim 9 or obtained by the method according to claim 8. 100625 1 COOPERATION TREATY (PCT) REPORT ON NEWNESS RESEARCH OF INTERNATIONAL TYPE IDENTIFICATION OF OE NATIONAL APPLICATION Characteristic of the applicant ol of the submitted 8304NL Dutch application no. indtenngsdaaim 1006251 June 6, 1997 Priority invoked Applicant (Name) DSM NV Date of the request for an investigation of mtematanal type Granted to the request for an investigation of international type by the msante for Intemaeonaal Onderzoek (ISA) No. SN 29565 EN I. CLASSIFICATION OF THE SUBJECT (when using different classifications. Provide all symbols of the assessment) According to the Donation Classification (IPC) Int. Cl. 6: C 09 D 5/03 II. FIELDS OF TECHNIQUE EXAMINED Minimum Documentation Examined Classification System Classification Symbols Int. Cl.6 C 09 D, C 08 G Examined other than minimum documentary insofar as such documents are included in the areas under investigation III. i: NO RESEARCH POSSIBLE FOR CERTAIN CONCLUSIONS (remarks on supplementolad)! IV. " 1 LACK OF UNIT OF INVENTION (ODmerfcmqen on supplementolad) i_______I___ -orm PCTlSA. 31 la) CE I99J