NON-AQUEOUS CROSSLINKABLE COMPOSITION

Abstract

The present invention relates to a crosslinkable composition comprising a polyol, a polyisocyanate crosslinker, a catalyst for catalysing the reaction between —OH groups of said polyol and —NCO groups of said crosslinker, a tertiary acid of formula RR′R″CCOOH (I), wherein each R, R′ and R″ group, independently, is an alkyl, alkenyl, aryl or aralkyl group containing at least one carbon atom, with the proviso that two or three of the R, R′ and R″ groups can be linked to form a ring structure and wherein the R, R′ and/or R″ groups can be substituted, and optionally, a complexing agent containing at least one —SH group, as well as its use for making coatings having improved application properties.

Claims

1. A crosslinkable composition comprising a) at least one polyol having free —OH groups, b) at least one polyisocyanate crosslinker having free —NCO groups, c) at least one catalyst for catalysing the reaction between —OH groups of said polyol a) and —NCO groups of said crosslinker b), d) at least one tertiary acid of formula RR′R″CCOOH (I), wherein each R, R′ and R″ group, independently, is an alkyl, alkenyl, aryl or aralkyl group containing at least one carbon atom, with the proviso that two or three of the R, R′ and R″ groups can be linked to form a ring structure and wherein the R, R′ and/or R″ groups can be substituted, and wherein the total number of carbon atoms in the R, R′ and R″ groups is the range of from 3 to 40, and e) optionally, at least one complexing agent containing at least one —SH group.

2. The crosslinkable composition according to claim 1, wherein the complexing agent e) is present and is selected from organic compounds.

3. The crosslinking composition according to claim 2, wherein the complexing agent e) is selected from those of formula R—SH (II), wherein R can be an alkyl, alkenyl, aryl or aralkyl group, optionally substituted with one or more other functional groups such as for example hydroxyl groups, primary, secondary or tertiary amine groups, silane or siloxane groups, ether groups, ester groups, carboxylic acid groups; those of formula HS—(CH.sub.2).sub.x—SH (IV) wherein x is from 1 to 20; those of formula (HSCH.sub.2).sub.4-mC(CH.sub.2SCH.sub.2CH.sub.2SH).sub.m (V) wherein m is from 1 to 4; those which are the reaction products of carboxylic acids of formula HS(CH.sub.2).sub.nCOOH (VI) wherein n is from 1 to 20 and a polyol having an OH-functionality of 2 or more; as well as mixtures thereof.

4. The crosslinkable composition according to claim 1, wherein the catalyst c) comprises a metal based catalyst, preferably a metal based catalyst wherein the metal is selected from tin, bismuth, zinc, zirconium or aluminium, or mixtures thereof.

5. The crosslinkable composition according to claim 4, wherein the catalyst c) is selected from tin(II) carboxylates, dialkyl tin (IV) carboxylates, bismuth carboxylates, zinc carboxylates, aluminium carboxylates, preferably from dialkyl tin dicarboxylates, bismuth carboxylates, zinc carboxylates, more preferably from dibutyl tin dilaurate, dioctyl tin dilaurate, zinc 2-ethylhexanoate, and mixtures thereof.

6. The crosslinkable composition according to claim 1, wherein the amount of complexing agent e) is such that the molar equivalent of —SH groups per molar equivalent of metal from the metal based catalyst c) is in the range of 1 to 20 molar equivalents of SH per equivalent of metal.

7. The crosslinkable composition according claim 1, wherein the tertiary acid d) has the general formula RR′R″CCOOH (I) wherein the total number of carbon atoms in the R, R′ and R″ groups is the range of from 3 to 30.

8. The crosslinkable composition according to claim 7, wherein the tertiary acid d) has a general formula RR′R″CCOOH (I) wherein R is a methyl or ethyl group and where the total number of carbon atoms of groups R′ and R″ is from 2 to 17 and where R′ and/or R″ is non-substituted or substituted with only one hydroxyl group.

9. The crosslinkable composition according to claim 7, wherein the tertiary acid d) is selected from the group consisting of neodecanoic acid, versatic acid, 3-hydroxy-2,2-dimethylpropionic acid, 2,2-bis(hydroxymethyl)propionic acid, abietic acid, 1-methyl cyclohexanoic acid, dimetylmalonic acid, ethylmethylmalonic acid, diethylmalonic acid, 2,2-dimethylsuccinic acid, 2,2-diethylsuccinic acid, 2,2-dimethylglutaric acid, 2,2-dimethylpropionic acid, 2,2-dimethylbutyric acid, 2-ethyl-2-methylbutyric acid, 2,2-diethylbutyric acid, 2,2-dimethylvaleric acid, 2-ethyl-2-methylvaleric acid, 2,2-diethylvaleric acid, 2,2-dimethylhexanoic acid, 2,2-diethylhexanoic acid, 2,2-dimethyloctanoic acid, 2-ethyl-2,5-dimethylhexanoic acid, 3-methylisocitric acid, 4,4-dimethylaconitic acid, 1-methylcyclopentane carboxylic acid, 1,2,2-trimethyl-1,3-cyclopentane dicarboxylic acid, 1-methylcyclohexane carboxylic acid, 2-methylbicyclo[2.2.1]-5-heptene-2-carboxylic acid, 2-methyl-7-oxabicyclo[2.2.1]-5-heptene-2-carboxylic acid, 1-adamantane carboxylic acid, bicyclo[2.2.1]heptane-1-carboxylic acid and bicyclo[2.2.2]octane-1-carboxylic acid or mixtures thereof.

10. The crosslinkable composition according to claim 1, wherein the amount of tertiary acid d) in the composition is in the range of 0.005 to 0.5 mmol of tertiary acid d) per gram of polyol a).

11. The crosslinkable composition according to claim 1, wherein the polyol a) is selected from polyester polyols, polyacrylate polyols, polycarbonate polyols, polyether polyols, polyurethane polyols, melamine polyols, and mixtures and hybrids thereof, and has a hydroxyl value in the range of 20 to 1,000 mg KOH per gram of polyol and an acid value of 15 mg KOH per gram of polyol or less.

12. The crosslinkable composition according to claim 1 comprising from 10 to 90% of weight of polyol a), from 10 to 90% of weight of polyisocyanate crosslinker b), from 0.001 to 10% of weight of catalyst c) from 0.001 to 10% of weight of tertiary acid d), and optionally, from 0.001 to 1% of weight of complexing agent e), optionally, from 0.05 to 1.5% of weight of anti-oxidant f1), optionally, from 0.05 to 1.5% of weight of radical scavenger f2), based on the total amount of polyol a), crosslinker b), catalyst c), tertiary acid d) and, if present, complexing agent e) and/or anti-oxidant f1) and/or radical scavenger f2).

13. The crosslinkable composition according to claim 1, comprising primary and/or secondary acids in addition to the tertiary acids d) in the range of 1 to 100 mol % of the quantity of tertiary acid.

14. Kit of parts for preparing a crosslinkable composition according to claim 1, comprising: i. a binder module comprising at least one polyol a) and at least one tertiary acid d), and optionally at least one catalyst c) and/or complexing agent e) and/or antioxidant f1) and/or radical scavenger f2), and ii. a crosslinker module comprising at least one polyisocyanate crosslinker b).

15. A binder module comprising at least one polyol a) and at least one tertiary acid d) and, optionally, at least one complexing agent e), at least one anti-oxidant f1) and/or at least one radical scavenger f2) according to claim 1.

16. A method of providing a coating comprising the steps of applying a crosslinkable composition according to claim 1 to at least a part of an object, preferably the surface of a transportation vehicle, and curing the applied composition, preferably in a temperature range of 5 to 180° C.

Description

EXAMPLES

[0088] A polyacrylate polyol (Resin A) was prepared from the polymerization of a mixture of hydroxy ethyl methacrylate, hydroxy ethyl acrylate, butyl acrylate, isobornyl methacrylate, and styrene. Resin A had a hydroxyl number of 135 mg KOH/g (on non volatile content), an acid number of 1 mg KOH/g (on non-volatile content), a M.sub.w 3,100 and a M.sub.n 1,650 (GPC, polystyrene standard). The polyacrylate polyol was dissolved in butyl acetate yielding a solution with a non-volatile content of 74% by weight.

[0089] SETATHANE® D 1150 is a castor oil based polyol supplied by allnex with a hydroxyl value of 155 mg KOH/g and an acid value <2 mg KOH/g.

[0090] TINUVIN® 292 is a mixture of two active tertiary amine ingredients: bis(1,2,3,6,6-pentramethyl-4-piperidinyl)sebacate and methyl(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate. TINUVIN® 1130 is a benzotriazole-based UV absorber.

[0091] TOLONATE® HDT-LV is a hexamethylene diisocyanate based trimer.

[0092] NOURACID® LE80 is a linseed oil fatty acid.

[0093] FINMA-SORB® 430 is a molecular sieve supplied by Finma Chemie GmbH

[0094] Barytes EWO: barium sulphate extender, supplied by Sachtleben Chemie GmbH (

[0095] R-KB-2 is Sachtleben R-KB-2 pigment (titanium dioxide), supplied by Sachtleben Chemie GmbH

[0096] DBTL is a dibutyl tin dilaurate based catalyst commercialized under the name of TINSTAB® BL 277.

[0097] Dibasic ester is a mixture of dimethylsuccinate, dimethylglutarate and dimethyladipate.

[0098] SOLVESSO® 100 is a mixture of aromatic hydrocarbons, C9, purchased from ExxonMobil Chemicals.

[0099] BYK® 315N is a solution of polyester modified polymethyl alkyl siloxane in 2-phenoxyethanol and 2-methoxy-1-methylethyl acetate.

[0100] BYK® A 501 is a solution of foam-destroying polymers, silicone free

[0101] BYK® A 530 is a solution of foam-destroying polymers and polysiloxanes

[0102] LANKROMARK™ LE 527 is a tris-alkylphosphite based anti-oxidant

[0103] Tack free drying times were determined as follows: in a climatized environment (22° C., 60% relative humidity) a cotton ball was placed on the drying coating, a weight of 1 kg was placed on the cotton ball for 10 seconds, the weight was removed and the cotton ball was blown away. This procedure was repeated as function of time after applying the crosslinkable composition. The coating was said to be tack free when the cotton ball did not leave any marks. This time was recorded as the tack free time.

[0104] For determination of pot-life and working time, the viscosity of the reacting paint before spraying was measured in time with a DIN Flow Cup 4 according to DIN 53211 and is indicated in seconds. The working time (+2) is the time required until the viscosity was increased with 2 seconds relative to the initial viscosity. The working time (+4) is the time required until the viscosity was increased with 4 seconds relative to the initial viscosity. The pot-life is the time required until the viscosity was doubled relative to the initial viscosity.

[0105] Persoz hardness was measured in a climatized room at 23° C., and 55+/−5% relative humidity. Hardness was measured with a pendulum acc. Persoz as described in ASTM D 4366.

[0106] Shore D hardness was determined according to ISO 868 2003.

Examples 1 to 4 and Comparative Examples C1 and C2

[0107] Clearcoat formulations were prepared by preparing the 2 components as shown in Table 1 and then mixing them. The quantities are specified in gram. For each of the compositions, the NCO/OH ratio was kept constant at 1.1 and the level of DBTL catalyst was 0.075% on total resin solids (non-volatile part of resin A+isocyanate component) for all formulations. Four tertiary acids were tested (Examples 1-4) and compared to a primary acid and a conjugated acid (Examples C1 and C2), all at equal molar levels and at equal molar concentration.

[0108] The formulations were applied on glass by draw-down application at equal dry layer thickness and left to dry at room temperature. Tack-free time was determined; Persoz hardness after 1 day RT was measured as well as pot-life and working time.

TABLE-US-00001 TABLE 1* Example 1 2 3 4 C1 C2 Component 1 Resin A 89.3 89.3 89.3 89.3 89.3 89.3 Dibasic ester 0.9 0.9 0.9 0.9 0.9 0.9 Butyl acetate 10.9 11.1 14.3 8.7 11.4 7.4 Solvesso 100 5.8 5.8 5.8 5.8 5.8 5.8 Tinuvin 1130 1.5 1.5 1.5 1.5 1.5 1.5 Tinuvin 292 0.5 0.5 0.5 0.5 0.5 0.5 BYK-315N 0.5 0.5 0.5 0.5 0.5 0.5 DBTL** 7.5 7.5 7.5 7.5 7.5 7.5 Abietic acid.sup.a 6.61 2,2-dimethylbutyric acid.sup.# 8.37 1-methyl-1- 2.05 cyclohexanecarboxylic acid.sup.b 2,2-dimethylpropionic acid.sup.# 7.36 Acetic acid.sup.# 4.33 Benzoic acid.sup.# 8.80 Component 2 Tolonate HDT-LV 32.6 32.6 32.6 32.6 32.6 32.6 Butyl acetate 7.7 7.7 7.7 7.7 7.7 7.7 Xylene 15.4 15.4 15.4 15.4 15.4 15.4 *all values are in grams/ **1% solution by weight in butyl acetate/ .sup.#10% solution by weight in butyl acetate/ .sup.a33% solution by weight in butyl acetate/ .sup.b50% solution by weight in butyl acetate.

[0109] The results are displayed in Table 2. The pot-life-drying ratio is the ratio between the pot-life and the tack-free time measured as specified here above.

[0110] The data clearly show that the compositions according to the invention show much improved pot-life-drying ratio, working time and early hardness compared to the compositions of comparative example C1. Furthermore, the compositions according to the invention show very much improved pot-life-drying ratio with a similar or improved working time and similar or improved early hardness compared to the composition of comparative example C2. In conclusion, the data in Table 2 show that the compositions according to the invention are a significant improvement and result in better-balanced coatings.

TABLE-US-00002 TABLE 2 1 2 3 4 C1 C2 Pot-life - 0.77 0.85 0.81 0.68 0.51 0.43 drying ratio Working time 43 40 28 18 12 18 (+2) (min) Persoz 206 213 231 205 189 216 hardness* *hardness after 1 day; curing at ambient temperature

Examples 5 and 6 and Comparative Examples C3 and C4

[0111] Similarly to the examples here above, compositions were prepared which included besides tertiary acids also C—(CH.sub.2OC(═O)CH.sub.2CH.sub.2SH).sub.4 as complexing agent e). Clearcoat formulations were prepared as shown in Table 3. The NCO/OH ratio was kept constant at 1.1 and the level of DBTL catalyst was 0.15% on total resin solids (resin A+isocyanate component) for all formulations. Four tertiary acids were tested (Examples 5-6) and compared to a primary acid and a conjugated acid (Examples C3 and C4), all at equal molar levels and at equal molar concentration. The formulations were applied on glass by draw-down application at equal dry layer thickness and left to dry at room temperature. Tack-free time was determined and Persoz hardness 1 hour after 30 min 60° C. curing was measured. Furthermore, working time (+2) and working time (+4) were determined.

TABLE-US-00003 TABLE 3* 5 6 C3 C4 Component 1 Resin A 89.3 89.3 89.3 89.3 Dibasic ester 0.9 0.9 0.9 0.9 Butyl acetate 15.3 15.2 15.6 8.2 Solvesso 100 5.8 5.8 5.8 5.8 Tinuvin 1130 1.5 1.5 1.5 1.5 Tinuvin 292 0.5 0.5 0.5 0.5 BYK-315N 0.5 0.5 0.5 0.5 DBTL** 1.5 1.5 1.5 1.5 C—(CH.sub.2OC(═O)CH.sub.2CH.sub.2SH).sub.4** 0.6 0.6 0.6 0.6 Acetic acid.sup.a 0.86 Benzoic acid* 8.71 2,2-dimethylpropionic acid.sup.a 1.46 2,2-dimethylbutyric acid.sup.a 1.66 Component 2 Tolonate HDT-LV 32.6 32.6 32.6 32.6 Butyl acetate 7.7 7.7 7.7 7.7 Xylene 15.4 15.4 15.4 15.4 *all values are in grams/ **10% solution by weight in butyl acetate/ .sup.a50% solution by weight in butyl acetate

[0112] The results are displayed in Table 4. The working time (+4)/drying time ratio is the ratio between the working time (+4) and the tack-free time measured as specified here above.

[0113] The data clearly show that the compositions according to the invention show much improved working time and early hardness compared to comparative example C3. Furthermore, the compositions according to the invention show very much improved working time (+4)-drying time ratio, improved working time and similar early hardness compared to comparative example C4. In conclusion, the data in Table 4 show that the examples according to the invention are a significant improvement and result in better-balanced coatings.

TABLE-US-00004 TABLE 4 5 6 C3 C4 Working time (+4)/ 0.51 0.51 0.49 0.40 drying time ratio Working time (+2) (min) 29 36 25 29 Persoz hardness* 161 158 149 164 *hardness 1 hour after 30 min 60° C.

Examples 7 and 8 and Comparative Examples C5-C7

[0114] Comparative examples C5-C7 and Examples 7-8 demonstrate that the composition according to the present invention is also beneficial in pigmented systems as well as in other applications. All ingredients from Component 1 in Table 5 were added together and milled until the particle size was <10 μm. The mixture was left under vacuum to deaerate. Component 2 was added, mixed and the curable mixture was poured and levelled. Shore hardness was determined and appearance was judged visually.

TABLE-US-00005 TABLE 5* 7 8 C5 C6 C7 Component 1 Setathane D 1150 127.06 126.25 125.63 125.53 124.75 2,2-dimethylpropionic 2.28 acid 3-Hydroxy-2,2- 2.63 dimethylpropionic acid 2-Ethylhexanoic acid 3.19 Isononanoic acid 3.5 Nouracid LE80 6.12 Finmasorb 430 24.84 24.96 25.02 25.00 24.82 Barytes EWO 133.83 134.47 134.78 134.67 133.71 R-KB-2 20.49 20.59 20.64 20.62 20.48 BYK A 501 1.05 1.05 1.05 1.05 1.04 BYK A 530 0.63 0.63 0.63 0.63 0.63 n-C.sub.12H.sub.25SH 0.24 0.24 0.24 0.24 0.24 2% DBTL solution 7.62 7.58 7.53 7.53 7.48 in Castor Oil Component 2 Tolonate HDT-LV2 81.95 82.19 101.34 81.01 81.60 *all values are in grams

[0115] In some application such as flooring applications, use of lower molecular weight acids such as acetic acid is undesired because of the relatively high vapour pressure, requirement of near-zero VOC and smell. Therefore, other acids were tested as comparative example with much higher boiling point. Again, the data in Table 6 show that use of the tertiary acids of the present invention resulted in much better balanced coatings, i.e. a higher Shore D hardness and better appearance compared to the Comparative examples containing primary or secondary acids.

TABLE-US-00006 TABLE 6 7 8 C5 C6 C7 Shore D hardness after 48 h 40 42 35 35 36 Appearance + ++ −− − +/−

Example 9

[0116] A composition (Resin B) was prepared by mixing 410.3 g of Resin A, 6.14 g of a 10 wt % solution of C—(CH.sub.2OC(═O)CH.sub.2CH.sub.2SH).sub.4 in butyl acetate, 28.01 g of a 10 wt % solution of 2,2-dimethylpropionic acid by weight in butyl acetate and 1.97 g of anti-oxidant LANKROMARK™ LE 527.

[0117] 50% by weight of this Resin B was then further mixed with the other ingredients of Component 1 as mentioned in Table 7 and then mixed with Component 2 and tested in the same way as Example 5. Results for t=0 are shown in Table 8.

[0118] The other 50% by weight of Resin B was stored in a closed container at 50° C. for 1 month and then mixed with the other ingredients of Component 1 (Table 7) and then mixed with Component 2 (Table 7) and tested in the same way. Results were obtained which were similar compared to the results obtained for Resin B at t=0.

[0119] This Example 9 shows that the binders according to the invention are stable and maintain their properties even after long time storage.

TABLE-US-00007 TABLE 7 9 Component 1 Resin B 223.2 Tinuvin 1130 3.8 Tinuvin 292 1.3 Byk-315N 1.2 DBTL (10% in butyl acetate) 3.8 Dibasic ester 2.2 Xylene 25.7 Butyle acetate 19.9 Component 2 Tolonate HDT-LV 88.3 Xylene 37.8

TABLE-US-00008 TABLE 8 9 (t = 0) 9 (after 1 month 50° C.) Pot-life - drying ratio 1.5 1.5 Working time (+2) (min) 61 62