HYPERBRANCHED POLYESTER POLYOLS SUITABLE FOR USE IN ORGANIC SOLVENT-BASED TWO-COMPONENT POLYURETHANE COATING COMPOSITIONS

Abstract

The present invention relates to polyester polyols comprising units derived from a) at least one COOH group or derivative thereof carrying component or mixture of components (A) comprising at least one compound carrying two COOH groups or derivatives thereof (A1), b) at least one OH group carrying component or mixture of components (B) comprising (i) at least one compound carrying three OH groups selected from the group consisting of 1,3,5-tris(hydroxymethyl)isocyanurate, 1,3,5-tris(2-hydroxyethyl) isocyanurate, 1,3,5-tris(2-hydroxyisopropyl)isocyanurate, 1,3,5-tris(2-hydroxypropyl)isocyanurate and 1,3,5-tris(2-hydroxybutyl)isocyanurate (B1), (ii) at least one compound carrying two OH groups selected from the group consisting of 1,1-bis(hydroxymethyl)-cyclohexane, 1,2-bis(hydroxymethyl)-cyclohexane, 1,3-bis(hydroxymethyl)-cyclohexane, 1,4-bis(hydroxymethyl)-cyclohexane, 1,1-bis(hydroxyethyl)-cyclohexane, 1,2-bis(hydroxyethyl)-cyclohexane, 1,3-bis(hydroxyethyl)-cyclohexane and 1,4-bis(hydroxyethyl)cyclohexane (B2), (iii) optionally at least one compound or polymer carrying at least three OH groups, which is different from B1 (B3), and (iv) optionally at least one compound or polymer carrying two OH groups, which is different from B2 (B4), and c) optionally at least one compound carrying at least one OH group and at least one COOH group or a derivative thereof (C), and to organic-solvent based two-component coating compositions comprising a) a first component (K1) comprising (i) at least one polyester polyol of the present invention and (ii) optionally at least one polymer carrying more than one OH group, which is different from the polyester polyol of the present invention (D), and b) a second component (K2) comprising (i) at least one compound, oligomer or polymer carrying more than one N═C═O group or blocked N═C═O group (F).

Claims

1.-16. (canceled)

17. A polyester polyol comprising units derived from a) at least one COOH group or derivative thereof carrying component or mixture of components (A) comprising at least one compound carrying two COOH groups or derivatives thereof (A1), b) at least one OH group carrying component or mixture of components (B) comprising (i) at least one compound carrying three OH groups selected from the group consisting of 1,3,5-tris(hydroxymethyl)isocyanurate, 1,3,5-tris(2-hydroxyethyl) isocyanurate, 1,3,5-tris(2-hydroxyisopropyl)isocyanurate, 1,3,5-tris(2-hydroxypropyl)isocyanurate and 1,3,5-tris(2-hydroxybutyl)isocyanurate (B1), (ii) at least one compound carrying two OH groups selected from the group consisting of 1,1-bis(hydroxymethyl)-cyclohexane, 1,2-bis(hydroxymethyl)cyclohexane, 1,3-bis(hydroxymethyl)-cyclohexane, 1,4-bis(hydroxymethyl)cyclohexane, 1,1-bis(hydroxyethyl)-cyclohexane, 1,2-bis(hydroxyethyl)cyclohexane, 1,3-bis(hydroxyethyl)-cyclohexane and 1,4-bis(hydroxyethyl)cyclohexane (B2), (iii) optionally at least one compound or polymer carrying at least three OH groups, which is different from B1 (B3), and (iv) optionally at least one compound or polymer carrying two OH groups, which is different from B2 (B4), and c) optionally at least one compound carrying at least one OH group and at least one COOH group or a derivative thereof (C).

18. The polyester polyol of claim 17 obtained by a process comprising the step of reacting a) at least one COOH group or derivative thereof carrying component or mixture of components (A) comprising (i) at least one compound carrying two COOH groups or a derivative thereof (A1), b) at least one OH group carrying component or mixture of components (B) comprising (i) at least one compound carrying three OH groups selected from the group consisting of 1,3,5-tris(hydroxymethyl)isocyanurate, 1,3,5-tris(2-hydroxyethyl)isocyanurate, 1,3,5-tris(2-hydroxyisopropyl)isocyanurate, 1,3,5-tris(2-hydroxypropyl)isocyanurate and 1,3,5-tris(2-hydroxybutyl)isocyanurate (B1), (ii) at least one compound carrying two OH groups selected from the group consisting of 1,1-bis(hydroxymethyl)-cyclohexane, 1,2-bis(hydroxymethyl)cyclohexane, 1,3-bis(hydroxymethyl)-cyclohexane, 1,4-bis(hydroxymethyl)cyclohexane, 1,1-bis(hydroxyethyl)-cyclohexane, 1,2-bis(hydroxyethyl)cyclohexane, 1,3-bis(hydroxyethyl)-cyclohexane and 1,4-bis(hydroxyethyl)cyclohexane (B2), (iii) optionally at least one compound, oligomer or polymer carrying at least three OH groups, which is different from B1 (B3), and (iv) optionally at least one compound, oligomer or polymer carrying two OH groups, which is different from B2 (B4), and c) optionally at least one compound carrying at least one OH group and at least one COOH group or a derivative thereof (C).

19. The polyester polyol of claim 17, wherein component A1 is at least one aliphatic or alicyclic compound carrying two COOH groups or a derivative thereof.

20. The polyester polyol of claim 19, wherein component A1 is cyclohexane-1,2-dicarboxylic acid or a derivative thereof.

21. The polyester polyol of claim 17, wherein component B1 is 1,3,5-tris(2-hydroxyethyl) isocyanurate.

22. The polyester polyol of claim 17, wherein component B2 is 1,4-bis(hydroxymethyl)cyclohexane.

23. The polyester polyol of claim 17, wherein the ratio of the sum of mol OH groups derived from components B1 and B2 to the sum of mol OH groups derived from all components B and C is in the range of 40% to 100%.

24. The polyester polyol of claim 17, wherein the ratio of mol OH groups derived from components B1 to the sum of mol OH groups derived from components B1 and B3 is in the range of 20% to 100%.

25. The polyester polyol of claim 17, wherein the ratio of mol OH groups derived from components B1 to mol OH groups derived from component B2 is in the range of 10% to 1000%.

26. A solution comprising at least one polyester polyol of claim 17 and at least one organic solvent.

27. An organic-solvent based two-component coating composition comprising a) a first component (K1) comprising (i) at least one polyester polyol of claim 17, and (ii) optionally at least one polymer carrying more than one OH group, which is different from the polyester polyol of claim 17 (D) and b) a second component (K2) comprising (i) at least one compound, oligomer or polymer carrying more than one N═C═O group or blocked N═C═O group (F).

28. The two-component composition of claim 27, wherein component D is present, and is at least one (meth)acrylic polymer carrying more than one OH group.

29. The two-component composition of claim 27, wherein component F is at least one oligomer or polymer carrying more than one N═C═O group or blocked N═C═O group.

30. The two-component composition of claim 29, wherein component F is at least oligomer or polymer carrying more than one N═C═O group and comprising (i) at least one unit independently derived from the group consisting of aliphatic and alicylic compounds carrying at least two N═C═O groups, and (ii) at least one isocyanurate structural unit.

31. The two-component composition of claim 29, wherein component F has an N═C=content of 5 to 40%.

32. An article coated with the composition of claim 27.

Description

EXAMPLES

Description of Test Methods

[0241] The weight average molecular weight Mw and number average molecular weight Mn were determined using gel permeation chromatography calibrated to a polystyrene standard.

[0242] The glass transition temperature (Tg) was determined using differential scanning calorimetry.

[0243] The hydroxyl number was determined according to DIN53240, 2016.

[0244] The acid number was determined according to DIN53402, 1990.

[0245] The solid content of solutions comprising polyester polyol were measured using a moisture analyzer (Mettler Toledo HB43-S Moisture Analyzer) at 160° C. until constant mass was reached. The solid content of two-component compositions comprising the polyester polyol solutions were calculated based on the measured solid content of the polyester polyol solutions.

[0246] The viscosity was determined using a cone plate viscosimeter set to a shear rate of 100 s.sup.−1 at 23° C.

[0247] Gel time: The coating composition was filled in the test tube until at least 60% filling height was reached. The test tube was covered and placed into a free slot of the gel timer. The metal spoked wheel was fixed with its bent end facing downwards in the spoked wheel holder, using the length indication on top of the gel timer. The spoked wheel holder was placed on the gel timer, so that the metal spoked wheel dipped into the coating composition. The device was switched on. The mixture of each slot was stirred up and down by the metal spoked wheel until gelling occurred. When gelling occurred, the whole test tube is lifted by the up-moving stirrer and the contact between the bottom side of the test tube and the device is broken which is noted by the apparatus. The gel timer showed the time until gelling in hours and minutes following the decimal system.

[0248] Cotton wool drying time: The coating composition was applied with a draw down bar on a glass plat yielding a wet film thickness of 150 μm. After film application, a frayed cotton wool was swept without pressure across the surface of the coating every 5 to 10 minutes. At the beginning, cotton fibers were sticking to the coating. The time when no fibers remained attached to the coating, is referred to as the cotton wool drying time.

[0249] Sand drying time: The coating composition was applied with a draw down bar on two glass plates yielding a wet film thickness of 150 μm. The glass plates with the wet film were quickly placed under a cylindrical funnel that moves at constant velocity of 1 cm per hour over the wet film. Along the way, sand trickles out of the funnel on the film. When the film is not surface-cured, the film is still tacky and the sand sticks to it. When the film is surface-cured, the sand can be wiped away with a brush. The length (1 cm length refers to 1 hour) of the sand path sticking to the coating is referred to as sand drying time.

[0250] Sand through drying time: The coating composition was applied with a draw down bar on two glass plates yielding a wet film thickness of 150 μm. A cylindrical funnel mounted on two small metal wheels, one on each side of the funnel outlet, was quickly placed on the glass plates with the wet film. The the cyclindrical funnel on wheels moves at constant velocity of 1 cm per hour over the wet film. When the film is not “through-cured”, the wheels leave marks on the film. When the film is “through-cured”, the wheels leave no marks on the film anymore. The length (1 cm length refers to 1 hour) of the marks of the wheels in the coating is referred to as sand through drying time.

[0251] Pendulum hardness [osc.]: The coating composition was applied with a draw down bar having a gap of 150 μm on a 4 mm thick glass plate, which has been cleaned with acetone before, yielding a wet film. The coated glass plates were dried at 23° C., and the pendulum hardness was measured after 1, 2, 3 and 7 days. After 7 days, the glass plass plates were additionally heated to 60° C. for 15 hours, and after cooling to 23° C., the pendulum hardness was measured again. The pendulum hardness was measured according to DIN EN ISO 1522:2006 using the König pendulum.

Example 1

Preparation of Polyester Polyols 1a, 1b, 1c and 1d, and Comparative Polyester Polyol Comp1a

Preparation of Polyester Polyol 1a

[0252] Cyclohexane-1,2-dicarboxylic acid anhydride (mixture of isomers) (HHPA) (556.0 g, 3.606 mol, 2 equivalents), 1,4-bis(hydroxymethyl)-cyclohexane (CHDM) (195.1 g, 1.353 mol, 0.75 mol equivalents), 1,3,5-tris(2-hydroxyethyl) isocyanurate (THEIC) (176.7 g, 0.674 mol, 0.375 mol equivalents), 1,1,1-trimethylolpropane (TMP) (272.2 g, 2.028 mol, 1.125 mol equivalents) were added into a 4 L round bottom flask equipped with a mechanical stirrer, digital thermometer, distilling trap, reflux cooler and nitrogen-inlet. The reaction was carried out under a steady flow of nitrogen. The reaction mixture was slowly heated to 160° C. When the reaction mixture reached 135° C., an exothermic reaction was observed. The reaction mixture was kept at 160° C. for 30 min, and then heated to 180° C. The reaction was monitored by the titration of hydroxyl number and acid number until the acid number reached a value of 7.7 mg KOH/g. The melt was cooled to 80° C. and butyl acetate was added until a solid content of 68.1% was reached. The hydroxyl number, the acid number, the molecular weight and the Tg of polyester polyol 1a, as well as the solid content and the viscosity of the solution of polyester polyol 1a in butyl acetate were determined according to the methods described in the section above titled “Description of test methods” and is shown in table 1.

[0253] Preparation of polyester polyols 1b, 1c and 1d and comparative polyester polyol comp1a Polyester polyols 1b, 1c, 1d and comparative polyester polyol comp1a were prepared in analogy to polyester polyol 1a but using the molar monomer ratios shown in table 1 and keeping the reaction mixture at 180° C. until the hydroxyl number as indicated in table 1 is reached. Butyl acetate was added until the solid content as indicated in table 2 was reached. The hydroxyl numbers, the acid numbers, the molecular weights and the Tgs of polyester polyols 1b, 1c, 1d and comp1a, as well as the solid contents and the viscosities of the solutions of polyester polyols 1b, 1c, 1d and comp1a in butyl acetate were determined according to the methods described in the section above titled “Description of test methods” and are shown in table 1.

TABLE-US-00001 TABLE 1 polyester polyol comp1a 1a 1b 1c 1d monomers HHPA 2 2 2 2 2 CHDM 0.75 0.75 0.75 0.75 0.75 THEIC 0 0.375 0.75 1.125 1.5 TMP 1.5 1.125 0.75 0.375 0 properties Hydroxyl number 183.2 172.8 171.8 169.0 171.1 [mg KOH/g] acid number 3.3 7.7 16.3 24.9 39.9 [mg KOH/g] Mn [g/mol] 2921 2096 1438 1146 873 Mw [g/mol] 18039 9218 4088 2586 1537 Tg [° C.] 40.4 47 46.4 43.8 45.6 solid content [%] 68.1 68.1 68.2 68.1 68.0 viscosity 5980 4459 3808 3033 4081 [mPa × s]

Example 2

[0254] Preparation and application of “clear coat” coating compositions comprising the polyester polyols 1a, 1b, 1c and 1d and comparative polyester polyol comp1a, respectively, of example 1

[0255] 4.8 g of a 1 wt % solution of dibutyltin dilaurate in butylacetate was added in a 250 mL glass jar. Afterwards 45 g Joncryl® 507 (80 wt % solution of a hydroxyl-functional acrylic polymer in butyl acetate) was combined with 17.6 g of a 68 wt % solution of the polyester polyols 1a, 1b, 1c, 1d and comparative polyester polyol comp1a, respectively, of example 1 in butyl acetate and added to the dibutyltin dilaurate solution. The mixture was stored for 16 h. Basonat® HI 2000 NG (solvent-free, aliphatic polyisocyanate) at an index of 100 was added to the mixture, followed by addition of butyl acetate to adjust the solid content to approximately 63 wt %. After stirring the mixture for 10 to 15 min at 750 rpm with a lab stirrer using a 40 mm disc the flow time was measured. Subsequently, butyl acetate was added in an amount that the flow time according to DIN EN 53211:1987 using a flow cup having a 4 mm hole diameter corresponds to 20 sec. After waiting for 10 min, the “clear coat” coating composition was ready to use. After cleaning the substrates properly with acetone (glass plates) the “clear coat” coating compositions were applied with a draw down bar with a wet film thickness of 150 μm. The dry film thickness was approximately 45 μm.

[0256] The solid content, the gel time, the cotton wool drying time, the sand drying time, the sand through drying time and the pendulum hardness [osc.] of the “clear coat” coating compositions comprising polyester polyols 1b, 1c, 1d and comp1a were determined as described above in the section titled “Description of Test Methods” and are shown in table 2.

TABLE-US-00002 TABLE 2 “clear coat” coating compositions comprising polyester polyols Comp1a 1a 1b 1c 1d monomers HHPA 2 2 2 2 2 CHDM 0.75 0.75 0.75 0.75 0.75 THEIC 0 0.375 0.75 1.125 1.5 TMP 1.5 1.125 0.75 0.375 0 properties solid content [%] 58.3 59.2 59.7 60.1 60.1 gel time 7 h 11 h 18 h 19 h 19 h 50 min 42 min 34 min 32 min 09 min cotton wool drying >720 >720 580 >540 450 time [min] sand drying time 19.5 19.5 18.5 14.5 11 [h] sand through drying 24 24 24 24 19 time [h] pendulum hardness 9 9 12 19 27 [osc.] after 1 d pendulum hardness 44 50 59 70 81 [osc.] after 2 d pendulum hardness 73 80 91 100 106 [osc.] after 3 d pendulum hardness 126 130 131 130 129 [osc.] after 7 d pendulum hardness 133 133 132 128 127 [osc.] after 7 d + 15 h (the last 15 h at 60° C.)

[0257] Table 2 shows that the replacement of 1,1,1-trimethylolpropane (TMP) with 1,3,5-tris(2-hydroxyethyl) isocyanurate (THEIC) leads to “clear coat” coating compositions of higher solid content and longer gel time. With increasing amount of TMP, the “clear coat” coating compositions also show a shorter cotton wool drying time and a shorter sand drying time, and an increased pendulum hardness [osc.] after 1, 2, 3 and 7 days.

Example 3

Preparation of Comparative Polyester Polyols Comp1b, Comp1c, Comp1d and Comp1e

[0258] Comparative polyester polyol comp1b, comp1c, comp1d and comp1e were prepared in analogy to polyester polyol 1a but using the monomer ratios shown in table 3 and keeping the reaction mixture at 180° C. until the acid number indicated in table 3 is reached. Butyl acetate was added until the solid content as indicated in table 3 is reached. The hydroxyl numbers, the acid numbers, the molecular weights and the Tgs of comparative polyester polyols comp1b, comp1c, comp1d and comp1e, as well as the solid contents and the viscosities of the solutions of polyester polyols 1b, 1c, comparative polyester polyols comp1b, comp1c, comp1d and comp1e in butyl acetate were determined according to the methods described in the section above titled “Description of test methods” and are shown in table 3.

TABLE-US-00003 TABLE 3 Polyester Polyol comp1b comp1c comp1d comp1e Monomer HHPA 2 2 2 2 CHDM 0 0 0 0 THEIC 0 0.393 0.785 1.178 TMP 1.571 1.178 0.785 0.393 Property hydroxyl number 156 172 174 151 [mg KOH/g] acid number 88 115 119 104 [mg KOH/g] Mn [g/mol] 1924 1015 821 823 Mw [g/mol] 6146 1571 1183 1251 Tg [° C.] 21.4 22.2 23.3 23.0 solid content [%] 66.0 67.4 67.3 67.2 viscosity 4177 1921 2752 4751 [mPa × s]

Example 4

Preparation and Application of “Clear Coat” Coating Compositions Comprising the Comparative Polyester Polyols Comp1b, Comp1c, Comp1d and Comp1e of Example 3

[0259] 4.8 g of a 1 wt % solution of dibutyltin dilaurate in butylacetate was added in a 250 mL glass jar. Afterwards 45 g of Joncryl® 507 (80 wt % solution of a hydroxyl-functional acrylic polymer in butyl acetate) was combined with 18.18 g of a 66 wt % solution of the polyester polyols comp1b, comp1c, comp1d and comp1e of example 3 in butyl acetate and added to the dibutyltin dilaurate solution. The mixture was stored for 16 h. Basonat® HI 2000 NG (solvent-free, aliphatic polyisocyanate) at an index of 100 was added to the mixture, followed by addition of butyl acetate to adjust the solid content to approximately 63 wt %. After stirring the mixture for 10 to 15 min at 750 rpm with a lab stirrer using a 40 mm disc the flow time was measured. Subsequently, butyl acetate was added in an amount that the flow time according to DIN EN 53211:1987 using a flow cup having a 4 mm hole diameter corresponds to 20 sec. After waiting for 10 min, the “clear coat” coating composition was ready to use. After cleaning the substrates properly with acetone (glass plates) the “clear coat” coating compositions were applied with a draw down bar with a wet film thickness of 150 μm. The dry film thickness was approximately 45 μm.

[0260] The solid content, the gel time, the cotton wool drying time, the sand drying time, the sand through drying time and the pendulum hardness [osc.] of the “clear coat” coating compositions comprising polyester polyols comp1b, comp1c, comp1d and comp1e were determined as described above in the section titled “Description of Test Methods” and are shown in table 4.

TABLE-US-00004 TABLE 4 “clear coat” coating compositions comprising polyester polyols comp1b comp1c comp1d comp1e monomers HHPA 2 2 2 2 CHDM 0 0 0 0 THEIC 0 0.393 0.785 1.178 TMP 1.571 1.178 0.785 0.393 properties Tg [° C.] 21.4 22.2 23.3 23.0 solid content [%] 56.8 56.7 57.7 57.8 gel time 15 h 13 h 13 h 14 h 54 min 12 min 53 min 47 min cotton wool drying 200 100 130 100 time [min] sand drying time [h] 7 5 6 6 sand through drying 12 9 11 11 time [h] pendulum hardness 56 62 62 54 [osc.] after 1 d pendulum hardness 110 90 100 97 [osc.] after 2 d pendulum hardness 123 98 110 112 [osc.] after 3 d pendulum hardness 123 100 115 119 [osc.] after 7 d pendulum hardness 111 109 118 118 [osc.] after 7 d plus 15 h at 60° C.

[0261] Table 4 shows that the replacement of 1,1,1-trimethylolpropane (TMP) with 1,3,5-tris(2-hydroxyethyl) isocyanurate (THEIC) does not lead to “clear coat” coating compositions of high solid content when 1,4-bis(hydroxymethyl)-cyclohexane (CHDM) is not present in the composition. In addition, the replacement of 1,1,1-trimethylolpropane (TMP) with 1,3,5-tris(2-hydroxyethyl) isocyanurate (THEIC) does not lead to “clear coat” coating compositions of longer gel time when 1,4-bis(hydroxymethyl)-cyclohexane (CHDM) is not present in the composition.

[0262] When comparing the properties of “clear coat” coating compositions comprising polyester polyols comp1c, comp1d and comp1e shown in table 4 with the properties of “clear coat” coating compositions comprising polyester polyols 1a, 1b and 1c shown in table 2, it can be seen that “clear coat” coating compositions comprising 1,4-bis(hydroxymethyl)cyclohexane (CHDM) are of higher solid content and higher pendulum hardness [osc.] after 7 days as well as after 7 days plus 15 h at 60° C. compared to “clear coat” compositions not comprising CHDM. With increasing amount of TMP, “clear coat” coating compositions comprising 1,4-bis(hydroxymethyl)cyclohexane (CHDM) are also of longer gel time compared to “clear coat” compositions not comprising CHDM.