Water-emulsifiable isocyanates with improved properties

Abstract

A mixture of water-emulsifiable isocyanates is described. The mixture contains (A) at least one polyisocyanate (a), (B) at least one emulsifier obtained by reacting at least one polyisocyanate with at least one polyether alcohol having a molecular weight of less than 400 g/mol, (C) at least one emulsifier obtained by reacting at least one polyisocyanate with at least one polyether alcohol having a molecular weight of greater than 450 g/mol, and (D) optionally at least one emulsifier obtained by reacting a polyisocyanate with at least one compound (d) having at least one hydrophilic, non-isocyanate-reactive group and precisely one isocyanate-reactive group (group D2). The weight ratio of component (B) to component (C) in the mixture is from 30:70 to 70:30, preferably from 40:60 to 60:40.

Claims

1. A mixture, comprising (A) at least one polyisocyanate (a), (B) at least one emulsifier obtained by reacting at least one polyisocyanate with at least one polyether alcohol having a number average molecular weight of less than 400 g/mol, (C) at least one emulsifier obtained by reacting at least one polyisocyanate with at least one polyether alcohol having a number average molecular weight of greater than 450 g/mol, and (D) optionally at least one emulsifier obtained by reacting a polyisocyanate with at least one compound (d) having at least one hydrophilic, non-isocyanate-reactive group D1 and precisely one isocyanate-reactive group D2, where a weight ratio of component (B) to component (C) is from 40:60 to 60:40.

2. The mixture according to claim 1, wherein the at least one polyisocyanate (a) comprises at least one polyisocyanate (a1) and at least one polyisocyanate (a2), the at least one polyisocyanate (a1) is an isocyanurate and/or biuret of 1,6-diisocyanatohexane, and the at least one polyisocyanate (a2) is an isocyanurate of 1 isophorone diisocyanate.

3. The mixture according to claim 1, comprising in solvent-free form 70-95% by weight of component (A), 2.5-20% by weight of component (B), 2.5-20% by weight of component (C), and 0-15% by weight of component (D), where a sum of (A), (B), (C) and (D) is 100% by weight.

4. The mixture according to claim 2, comprising in solvent-free form 30-70% by weight of polyisocyanate (a1), 10-50% by weight of polyisocyanate (a2), 2.5-20% by weight of component (B), 2.5-20% by weight of component (C), and 0-15% by weight of component (D), where a sum of (a1), (a2), (B), (C) and (D) is 100% by weight.

5. The mixture according to claim 1, wherein the polyisocyanate in component (B) and/or component (C) comprises an isocyanurate and/or biuret of 1,6-hexamethylenediisocyanate and/or comprises an isocyanurate of isophorone diisocyanate.

6. The mixture according to claim 1, wherein the polyether alcohol in component (B) and/or component (C) is obtained by reacting at least one saturated aliphatic alcohol having 1 to 4 carbon atoms in the alkyl radical with ethylene oxide, propylene oxide or a mixture thereof.

7. The mixture according to claim 1, wherein the polyether alcohol in component (B) and/or component (C) is obtained by reacting methanol with ethylene oxide.

8. The mixture according to claim 1, wherein the polyether alcohol in component (B) has a molecular weight ranging from 200 g/mol to 400 g/mol.

9. The mixture according to claim 1, wherein the polyether alcohol in component (C) has a molecular weight ranging from 450 g/mol to 650 g/mol.

10. A polymer dispersion, comprising a mixture according to claim 1.

11. A coating material, comprising the mixture according to claim 1.

12. A process for coating a substrate, the processing comprising: coating the substrate with a coating composition comprising the mixture according to claim 1.

13. A coating material, comprising the polymer dispersion according to claim 10.

Description

EXAMPLES

Polyisocyanate Preparation

Raw Materials

Polyisocyanate a1

(1) HDI isocyanurate having an NCO content of 22.2% and a viscosity of 2800 mPa*s at 23° C. (e.g. Basonat® HI 100 from BASF SE).

Polyisocyanate a2

(2) IPDI isocyanurate having an NCO content of 17.3% (e.g. Vestanat T1890/100 from Evonik Industries).

Polyether Alcohol 1

(3) Monofunctional polyethylene oxide, prepared starting from methanol and with potassium hydroxide catalysis, having an OH number of 112 (according to DIN 53240) and a molecular weight of 500 g/mol. The basic catalyst residues still present were subsequently neutralized with acetic acid and the product was desalted. The same procedure also removes potassium acetate that has formed.

Polyether Alcohol 2

(4) Monofunctional polyethylene oxide, prepared starting from methanol and with potassium hydroxide catalysis, having an OH number of 160 (according to DIN 53240) and a molecular weight of 350 g/mol. The basic catalyst residues still present were subsequently neutralized with acetic acid and the product was desalted. The same procedure also removes potassium acetate that has formed.

Comparative Polyisocyanate 1

(5) 142.9 g of polyisocyanate a2 (70% in 3-methoxypropyl acetate) and 15.0 g of polyether alcohol 1 were reacted with addition of 0.022 g of zinc neodecanoate (50% in butyl acetate) as catalyst. After 2 hours at 90° C., the NCO content was 9.7%. Then 100.0 g of polyisocyanate a1 and 15.0 g of polyether alcohol 1 were added. After 2 hours at 90° C., the reaction was halted with addition of 0.110 g of p-toluenesulfonic acid (10% in polyether alcohol 1). The corresponding product has an NCO content of 12.8% and a viscosity of 4350 mPa.Math.s at 23° C.

Comparative Polyisocyanate 2

(6) 142.9 g of polyisocyanate a2 (70% in 3-methoxypropyl acetate) and 15.0 g of polyether alcohol 2 were reacted with addition of 0.022 g of zinc neodecanoate (50% in butyl acetate) as catalyst. After 2 hours at 90° C., the NCO content was 9.1%. Then 100.0 g of polyisocyanate a1 and 15.0 g of polyether alcohol 2 were added. After 2 hours at 90° C., the reaction was halted with addition of 0.110 g of p-toluenesulfonic acid (10% in polyether alcohol 1). The corresponding product has an NCO content of 12.9% and a viscosity of 4900 mPa.Math.s at 23° C.

Inventive Polyisocyanate 1

(7) 143.2 g of polyisocyanate a2 (70% in 3-methoxypropyl acetate) and 7.6 g of polyether alcohol 1 and 7.6 g of polyether alcohol 2 were reacted with addition of 0.022 g of zinc neodecanoate (50% in butyl acetate) as catalyst. After 2 hours at 90° C., the NCO content was 9.6%. Then 100.0 g of polyisocyanate a1 and 7.6 g of polyether alcohol 1 and 7.6 g of polyether alcohol 2 were added. After 2 hours at 90° C., the reaction was halted with addition of 0.110 g of p-toluenesulfonic acid (10% in polyether alcohol 1). The corresponding product has an NCO content of 12.7% and a viscosity of 3750 mPa.Math.s at 23° C.

Inventive Polyisocyanate 2

(8) 143.2 g of polyisocyanate a2 (70% in 3-methoxypropyl acetate) and 7.6 g of polyether alcohol 1 and 7.6 g of polyether alcohol 2 were reacted with addition of 0.022 g of zinc neodecanoate (50% in butyl acetate) as catalyst. After 2 hours at 90° C., the NCO content was 9.7%. Then 100.0 g of polyisocyanate a1 and 7.6 g of polyether alcohol 1 and 7.6 g of polyether alcohol 2 were added. After 2 hours at 90° C., the reaction was halted with addition of 0.110 g of p-toluenesulfonic acid (10% in polyether alcohol 1). The reaction product was diluted further with addition of 3-methoxypropyl acetate to a solids content of 79.5%. The corresponding product has an NCO content of 12.1% and a viscosity of 1300 mPa.Math.s at 23° C.

Comparative Polyisocyanate 3

(9) 143.2 g of polyisocyanate a2 (70% in 3-methoxypropyl acetate) and 3.8 g of polyether alcohol 1 and 11.4 g of polyether alcohol 2 were reacted with addition of 0.022 g of zinc neodecanoate (50% in butyl acetate) as catalyst. After 2 hours at 90° C., the NCO content was 9.7%. Then 100.0 g of polyisocyanate a1 and 3.8 g of polyether alcohol 1 and 11.4 g of polyether alcohol 2 were added. After 2 hours at 90° C., the reaction was halted with addition of 0.110 g of p-toluenesulfonic acid (10% in polyether alcohol 1). The reaction product was diluted further with addition of 3-methoxypropyl acetate to a solids content of 80.7%. The corresponding product has an NCO content of 11.8% and a viscosity of 1300 mPa.Math.s at 23° C.

Comparative Polyisocyanate 4

(10) 143.2 g of polyisocyanate a2 (70% in 3-methoxypropyl acetate) and 11.4 g of polyether alcohol 1 and 3.8 g of polyether alcohol 2 were reacted with addition of 0.022 g of zinc neodecanoate (50% in butyl acetate) as catalyst. After 2 hours at 90° C., the NCO content was 9.7%. Then 100.0 g of polyisocyanate a1 and 11.4 g of polyether alcohol 1 and 3.8 g of polyether alcohol 2 were added. After 2 hours at 90° C., the reaction was halted with addition of 0.110 g of p-toluenesulfonic acid (10% in polyether alcohol 1). The reaction product was diluted further with addition of 3-methoxypropyl acetate to a solids content of 80.3%. The corresponding product has an NCO content of 12.1% and a viscosity of 1450 mPa.Math.s at 23° C.

Results in Technical Application

Formulation

Comparative 1—Comparative 2—Example 1

(11) Coating component I: 400.0 g of Liocryl AM 920 (acrylate-based aqueous polyol from Synthopol, OH number 60 mg KOH/g, 40% in water) were adjusted to a pH of 8.1 at room temperature by addition of dimethylethanolamine/water (1/1 mixture) with stirring (600 rpm) and then admixed with 16.0 g of butyl diglycol and 16.0 g of Solvesso as film-forming assistants. Lastly, 1.2 g of Hydropalat® WE3240 (from BASF SE) were added as wetting additive and the solids content was adjusted to 35.0% by weight with DI water.

(12) The various polyisocyanates were added to dispersion (coating component I) and incorporated by hand with a wooden spatula for 30 seconds. Lastly the viscosity was adjusted using DI water to 30 sec from the DIN 4 cup.

Comparative 3—Comparative 4—Example 2

(13) Coating component II: 200.0 g of Joncryl 8312 (acrylate-based aqueous polyol from BASF, OH number 100 mg KOH/g, 45% in water) were adjusted to a pH of 8.1 at room temperature by addition of dimethylethanolamine/water (1/1 mixture) with stirring (600 rpm) and then admixed with 5.0 g of butyl diglycol acetate and 14.0 g of butyl glycol acetate as film-forming assistants. Lastly, 1.2 g of Hydropalat® WE3240 (from BASF SE) were added as wetting additive and the solids content was adjusted to 38.0% by weight with DI water.

(14) The various polyisocyanates were added to dispersion (coating component II) and incorporated by hand with a wooden spatula for 30 seconds. Lastly the viscosity was adjusted using DI water to 30 sec from the DIN 4 cup.

(15) Immediately after their preparation, the formulations and comparative formulations obtained were drawn down using a 200 μm doctor onto a precoated white aluminum panel (30×10 cm) and stored under standard conditions (23° C., relative atmospheric humidity 50%) for 15 minutes. After that time, the coated aluminum panels obtained were dried in a drying cabinet at 60° C. for 30 minutes. After cooling, determinations were made of the gloss and turbidity (haze) of the resulting coatings in accordance with DIN 2813 and DIN 13803. A total of 5 measurements at different locations were carried out on each of the coated aluminum panels. The average values obtained from these measurements are listed in the tables below. Higher values denote better gloss values, whereas lower values denote better haze values.

Tests in Technical Application

Results

(16) TABLE-US-00001 Formulation Comparative 1 Comparative 2 Example 1 Coating component I [g] 120.0 120.0 120 Comparative polyisocyanate 1 [g] 28.6 Comparative polyisocyanate 2 [g] 28.4 Inventive polyisocyanate 1 [g] 27.5 Dist. water [g] 33.8 33.3 32.0 Incorporability by stirring (manual): (−) (+) (+) (+): very good (−): poor Appearance clear matt clear Gloss 20° 79 28 78 Gloss 60° 89 64 88 Haze 41 207 44 Formulation Comparative 3 Comparative 4 Example 2 Coating component II [g] 100 100 100 Comparative polyisocyanate 3 27.3 Comparative polyisocyanate 4 26.5 Inventive polyisocyanate 2 26.3 Dist. water 4 6 5 Incorporability by stirring (manual) (+) (−) (+) (+): very good (−): poor Appearance matt clear clear Gloss 20° 2 75 49 Gloss 60° 14 88 76 Haze 62 44 129