POLYISOCYANATE PREPARATIONS

Abstract

The invention relates to a polyisocyanate preparation containing at least one polyisocyanate component A) hydrophilically modified with at least one ionic emulsifier and a solvent component E) consisting of at least one organic solvent, characterized in that the solvent component E) has a content of peroxides of not more than 70 mg/l of H.sub.2O.sub.2 equivalents, wherein this value is the average peroxide content of all organic solvents present in the solvent component E) and the polyisocyanate component A) and the solvent component E) are present in amounts such that the calculated peroxide content of the polyisocyanate preparation based on the sum of A) and E) is not more than 20 mg/l of H.sub.2O.sub.2. The invention further relates to the use thereof and to coating compositions and substrates coated with these coating compositions.

Claims

1. A polyisocyanate preparation comprising at least one polyisocyanate component A) hydrophilically modified with at least one ionic emulsifier and a solvent component E) consisting of at least one organic solvent, characterized in that the solvent component E) has a peroxide content of at most 70 mg/l H.sub.2O.sub.2 equivalents, wherein this value is the average peroxide content of all organic solvents present in the solvent component E), and the polyisocyanate component A) and the solvent component E) are present in amounts such that the calculated peroxide content of the polyisocyanate preparation is at most 20 mg/l H.sub.2O.sub.2, based on the sum of A) and E).

2. The polyisocyanate preparation as claimed in claim 1, characterized in that the hydrophilically modified polyisocyanate component A) consists of a polyisocyanate component B) and at least one ionic emulsifier C).

3. The polyisocyanate preparation as claimed in claim 1, characterized in that the polyisocyanate component B) is any diisocyanates, triisocyanates and/or polyisocyanates having aliphatically, cycloaliphatically, araliphatically and/or aromatically bonded isocyanate groups.

4. The polyisocyanate preparation as claimed in claim 1, characterized in that the polyisocyanate component B) was prepared by modifying PDI, HDI, IPDI, 4,4′-diisocyanatodicyclohexylmethane, XDI, 2,4- and/or 2,6-TDI.

5. The polyisocyanate preparation as claimed in claim 1, characterized in that the polyisocyanate component B) comprises isocyanurate group-containing polyisocyanates based on PDI, HDI and/or IPDI and/or urethane group-containing TDI polyisocyanates.

6. The polyisocyanate preparation as claimed in claim 1, characterized in that the ionic emulsifiers C) are reaction products of polyisocyanate components B) with organic compounds bearing at least one isocyanate-reactive group and at least one sulfonic acid or sulfonate group.

7. The polyisocyanate preparation as claimed in claim 1, characterized in that the ionic emulsifiers C) are reaction products of polyisocyanate components B) with amino-functional sulfonic acids of the general formula (III) and/or salts thereof, ##STR00005## wherein in formula (III) R.sup.5 and R.sup.6 are each independently identical or different radicals and are hydrogen or saturated or unsaturated, linear or branched, aliphatic or cycloaliphatic or aromatic organic radicals having 1 to 18 carbon atoms, which are substituted or unsubstituted and/or comprise heteroatoms in the chain, wherein R.sup.5 and R.sup.6, in combination with each other and optionally one further nitrogen atom or one oxygen atom, may also form cycloaliphatic or heterocyclic rings having 3 to 8 carbon atoms, which may optionally be further substituted, and R.sup.7 is a linear or branched aliphatic radical having 2 to 6 carbon atoms.

8. The polyisocyanate preparation as claimed in claim 1, characterized in that the ionic emulsifiers C) are reaction products of polyisocyanate components B) with 2-isopropylaminoethane-1-sulfonic acid, 3-isopropylaminopropane-1-sulfonic acid, 4-isopropylaminobutane-1-sulfonic acid, 2-cyclohexylaminoethane-1-sulfonic acid, 3-cyclohexylaminopropane-1-sulfonic acid and/or 4-cyclohexylaminobutane-1-sulfonic acid and/or salts thereof.

9. The polyisocyanate preparation as claimed in claim 5, characterized in that the polyisocyanate component A) comprises at least 0.95% by weight, particularly preferably from 1.00 to 3.00% by weight, especially preferably from 1.10 to 1.80% by weight of sulfonate groups, calculated as SO.sub.3; molar weight=80 g/mol, in chemically bonded form.

10. The polyisocyanate preparation as claimed in claim 1, characterized in that the solvent component E) consists of at least one organic solvent and has a peroxide content of at most 60 mg/l H.sub.2O.sub.2, wherein these values are the average peroxide content of all organic solvents present in the solvent component E).

11. The polyisocyanate preparation as claimed in claim 1, characterized in that the polyisocyanate component A) and the solvent component E) are present in amounts such that the calculated peroxide content of the polyisocyanate preparation, based on the sum of A) and E), is 1 to 20 mg/l H.sub.2O.sub.2.

12. The polyisocyanate preparation as claimed in claim 1, characterized in that the proportion of the solvent component E) is 5 to 90% by weight, of the total amount of the components A) and E).

13. (canceled)

14. A coating composition comprising at least one polyisocyanate preparation as claimed in claim 1.

15. A substrate coated with an optionally heat-cured coating composition as claimed in claim 14.

Description

EXAMPLES

[0121] All percentages are based on weight unless otherwise stated.

[0122] NCO contents were determined titrimetrically to DIN EN ISO 11909:2007-05.

[0123] All viscosity measurements were recorded using a Physica MCR 51 rheometer from Anton Paar Germany GmbH (Germany) to DIN EN ISO 3219:1994-10 at a shear rate of 250 s.sup.−1.

[0124] Residual monomer contents were measured in accordance with DIN EN ISO 10283:2007-11 by gas chromatography with internal standard.

[0125] The color indices (Hazen color index according to DIN EN ISO 6271-2:2005-03, iodine color index according to DIN 6162:2014-09) were measured spectrophotometrically using a LICO 690 spectral colorimeter from Hach Lange, Germany.

[0126] The peroxide content was determined using commercially available peroxide test strips. Suitable test strips are, for example, MQuant® Peroxide test strips from Merck KgaA, Darmstadt, Germany or Quantofix® Peroxide test strips from MACHEREY-NAGEL GmbH & Co. KG, Duren, Germany. The reaction principle underlying these test strips is that peroxide oxygen is transferred enzymatically by means of a peroxidase to an organic redox indicator in the reaction zone, resulting in a colored oxidation product. The peroxide concentration is determined semi-quantitatively by visually assessing the reaction zone of the test strip using the fields on a color scale. There are different test strips with differently graded color scales for different concentration ranges. Test strips of Merck article number 10011.0001. cover, for example, the range 0.5-2-5-10-25 mg/L peroxide, those of Merck article number 1.10081.0001. the range 1-3-10-30-100 mg/L peroxide, those of Merck article number 1.10337.0001. the range 100-200-400-600-800-1000 mg/L peroxide and test strips of Macherey-Nagel article number REF 913 33 the range 0-50-150-300-500-800-1000 mg/L peroxide, where the peroxide specification corresponds in each case to a hydrogen peroxide equivalent.

Starting Compounds

Solvent Components E)

Solvent E1)

1-Methoxy-2-propyl acetate (MPA)

[0127] 5 1 plastic container, supplier: Azelis Deutschland GmbH (formerly Kraemer & Martin GmbH), Sankt Augustin, Germany

[0128] Quality 1: Peroxide content ca. 3 mg/l H.sub.2O.sub.2 equivalents

[0129] Quality 2: Peroxide content ca. 30 mg/l H.sub.2O.sub.2 equivalents

[0130] Quality 3: Peroxide content ca. 50 mg/l H.sub.2O.sub.2 equivalents

[0131] Quality 4: Peroxide content ca. 100 mg/l H.sub.2O.sub.2 equivalents

[0132] Quality 5: Peroxide content ca. 150 mg/l H.sub.2O.sub.2 equivalents

Solvent E2)

[0133] 3-Methoxy-n-butyl acetate (Butoxyl)

[0134] 500 ml glass bottle, supplier: abcr GmbH, Karlsruhe, Germany

[0135] Quality 1: Peroxide content ca. 3 mg/l H.sub.2O.sub.2 equivalents

[0136] Quality 2: Peroxide content ca. 50 mg/l H.sub.2O.sub.2 equivalents

[0137] Quality 3: Peroxide content ca. 60 mg/l H.sub.2O.sub.2 equivalents

[0138] Quality 4: Peroxide content ca. 100 mg/l H.sub.2O.sub.2 equivalents

Solvent E3)

Solvent Light Naphtha

[0139] 5 1 plastic container, supplier: Azelis Deutschland GmbH, Sankt Augustin, Germany

[0140] Quality 1: Peroxide content ca. 3 mg/l H.sub.2O.sub.2 equivalents

[0141] Quality 2: Peroxide content ca. 30 mg/l H.sub.2O.sub.2 equivalents

[0142] Quality 3: Peroxide content ca. 50 mg/l H.sub.2O.sub.2 equivalents

[0143] Quality 4: Peroxide content ca. 60 mg/l H.sub.2O.sub.2 equivalents

[0144] Quality 5: Peroxide content ca. 150 mg/l H.sub.2O.sub.2 equivalents

Polyisocyanate Components B)

Polyisocyanate Component B1)

[0145] HDI polyisocyanate comprising isocyanurate groups, produced by catalytic trimerization of HDI based on Example 11 of EP-A 330 966, with the modification that the reaction was stopped by addition of dibutyl phosphate at an NCO content of the crude mixture of 40%. Subsequently, unconverted HDI was removed by thin-film distillation at a temperature of 130° C. and a pressure of 0.2 mbar.

[0146] NCO content: 21.7%

[0147] NCO functionality: 3.4

[0148] Monomeric HDI: 0.1%

[0149] Viscosity (23° C.): 3080 mPas

[0150] Color index (Hazen): 18

Polyisocyanate Component B2)

[0151] PDI polyisocyanate comprising isocyanurate groups, produced by catalytic trimerization of PDI by the method described in WO 2016/146579 for the polyisocyanate component A2). The reaction was deactivated at an NCO content of the crude mixture of 36.7% by addition of an equimolar amount of dibutyl phosphate, based on the amount of catalyst used, and further stirring for 30 minutes at 80° C. Subsequently, unconverted PDI was removed by thin-film distillation at a temperature of 140° C. and a pressure of 0.5 mbar.

[0152] NCO content: 21.8%

[0153] NCO functionality: 3.5

[0154] Monomeric PDI: 0.09%

[0155] Viscosity (23° C.): 9850 mPas

[0156] Color index (Hazen): 34

Polyisocyanate Component B3)

[0157] Urethane group-containing TDI polyisocyanate, produced based on Example 4 of EP-A 0 546 399, with the modification that a mixture of 80% 2,4-TDI and 20% 2,6-TDI is used and the resulting pale yellow resin is dissolved at 60% strength in 1-methoxy-2-propyl acetate (MPA, peroxide content 3 mg/l H.sub.2O.sub.2).

[0158] NCO content: 10.6%

[0159] NCO functionality: 3.3

[0160] Monomeric 2,4-TDI: 0.13%

[0161] Monomeric 2,6-TDI: 0.14%

[0162] Viscosity (23° C.): 370 mPas

[0163] Color index (Hazen): 34

Polyisocyanate Component A1)

[0164] (emulsifier type C1))

[0165] 943.9 g (4.88 val) of the polyisocyanate component B1) were stirred together with 36.0 g (0.16 val) of 3-(cyclohexylamino)propanesulfonic acid (CAPS), 20.1 g (0.16 mol) of dimethylcyclohexylamine and 0.05 g (50 ppm) of 2,6-di-tert-butyl-4-methylphenol under dry nitrogen at 100° C. for 4:00 hours until a substantially clear polyisocyanate mixture comprising sulfonate groups was obtained. After cooling to room temperature and filtration over a T 5500 filter layer (Seitz), the following characteristic data were determined:

[0166] NCO content: 19.8%

[0167] NCO functionality: 3.3

[0168] Color index (Hazen):

[0169] Polyisocyanate component A2)

[0170] (emulsifier type C2))

[0171] 890 g (4.60 val) of the polyisocyanate component B1) were stirred at 80° C. for 12 hours with 110 g of an emulsifier mixture consisting of 97 g of an ethoxylated tridecyl alcohol phosphate (Rhodafac® RS-710, from Solvay) and 13 g of dimethylcyclohexylamine as the neutralizing amine After cooling to room temperature, a clear polyisocyanate mixture is present having the following characteristic data:

[0172] NCO content: 19.3%

[0173] NCO functionality: 3.5

[0174] Viscosity (23° C.): 9200 mPas

[0175] Color index (Hazen): 33

Polyisocyanate component A3)

[0176] (emulsifier type C1))

[0177] 960.7 g (4.98 val) of the polyisocyanate component B2) were stirred together with 25.0 g (0.11 val) of 3-(cyclohexylamino)propanesulfonic acid (CAPS), 14.3 g (0.11 mol) of dimethylcyclohexylamine and 0.05 g (50 ppm) of 2,6-di-tert-butyl-4-methylphenol at 100° C. under dry nitrogen for 3:30 hours until a largely clear polyisocyanate mixture containing sulfonate groups was obtained. After cooling to room temperature and filtration over a T 5500 filter layer (Seitz), the following characteristic data were determined:

[0178] NCO content: 20.5%

[0179] NCO functionality: 3.3

[0180] Viscosity (23° C.): 4050 mPas

[0181] Color index (Hazen): 18

Polyisocyanate Component A4)

[0182] (emulsifier type C1))

[0183] 700 g (2.88 val) of the hydrophilic polyisocyanate component A1) were mixed with 300 g (0.76 val) of the polyisocyanate component B3) at 30° C. and homogenized by stirring for 30 minutes. A mixed aliphatic/aromatic polyisocyanate having the following characteristic data was obtained:

[0184] NCO content: 15.2%

[0185] NCO functionality: 3.2

[0186] Solids content: 88%

[0187] Viscosity (23° C.): 6800 mPas

[0188] Color index (Hazen): 29

Polyisocyanate component A5)

[0189] (emulsifier type C1) and D1))

[0190] 900.0 g (4.65 val) of the polyisocyanate component B1) were stirred together with 30.0 g (0.14 val) of 3-(cyclohexylamino)propanesulfonic acid (CAPS), 17.8 g (0.14 mol) of dimethylcyclohexylamine, 52.2 g (0.10 mol) of a methanol-initiated, monofunctional polyethylene oxide polyether of average molecular weight 500 and 0.05 g (50 ppm) of 2,6-di-tert-butyl-4-methylphenol at 100° C. under dry nitrogen for 6:00 hours until a clear polyisocyanate mixture containing sulfonate groups and polyether units was obtained. After cooling to room temperature and filtration over a T 5500 filter layer (Seitz), the following characteristic data were determined:

[0191] NCO content: 18.5%

[0192] NCO functionality: 3.2

[0193] Viscosity (23° C.): 4660 mPas

[0194] Color index (Hazen): 12

Comparative Polyisocyanate A6)

[0195] (emulsifier type D1))

[0196] 870 g (4.50 val) of the polyisocyanate component B1) were initially charged at 100° C. under dry nitrogen and stirred, and 130 g (0.37 val) of a methanol-initiated, monofunctional polyethylene oxide polyether having an average molecular weight of 350 were added over 30 minutes and stirring was continued at this temperature until the NCO content of the mixture had fallen to a value of 17.4% after about 2 hours. After cooling to room temperature, there was a colorless, clear polyisocyanate mixture having the following characteristic data:

[0197] NCO content: 17.4%

[0198] NCO functionality: 3.2

[0199] Viscosity (23° C.): 2960 mPas

[0200] Color index (Hazen): 26

Polyisocyanate Preparations 1 to 14 (Inventive and Comparative)

[0201] In each case 100 parts by weight of the polyisocyanate component A4) were mixed at room temperature with 46.7 g each of different qualities of the solvents El) to E3) and the mixtures homogenized by stirring for 30 minutes.

[0202] Tables 1 to 3 show the color indices of the 60% strength polyisocyanate preparations obtained as a function of the peroxide content of the particular solvent and that of the polyisocyanate solution after storage for 24 hours at room temperature.

TABLE-US-00001 TABLE 1 Polyisocyanate preparations with 1-methoxy- 2-propyl acetate (solvent E1)) 4 5 Polyisocyanate compar- compar- preparation 1 2 3 ative ative Polyisocyanate A4) A4) A4) A4) A4) component Solvent E1), quality 1 2 3 4 5 Peroxide content of [mg/l 3 30 50 100 150 solvent E1) H.sub.2O.sub.2] Total peroxide [mg/l 3 24 40 80 120 content of solvents*.sup.) H.sub.2O.sub.2] Peroxide content of [mg/l 1 10 16 32 48 polyisocyanate H.sub.2O.sub.2] solution*.sup.) Color index after Hazen 22 25 45 893 >1000 24 h/25° C. Iodine 0.1 0.1 0.2 5.3 9.5 *.sup.)calculated value

TABLE-US-00002 TABLE 2 Polyisocyanate preparations with 3-methoxy- n-butyl acetate (solvent E2)) 9 Polyisocyanate compar- preparation 6 7 8 ative Polyisocyanate A4) A4) A4) A4) component Solvent E2), quality 1 2 3 4 Peroxide content of [mg/l 3 50 60 100 solvent E2) H.sub.2O.sub.2] Total peroxide content [mg/l 3 40 48 80 of solvents*.sup.) H.sub.2O.sub.2] Peroxide content of [mg/l 1 16 19 32 polyisocyanate H.sub.2O.sub.2] solution*.sup.) Color index after Hazen 24 48 51 914 24 h/25° C. Iodine 0.1 0.2 0.2 5.5 *.sup.)calculated value

TABLE-US-00003 TABLE 3 Polyisocyanate preparations with solvent naphtha 100 (solvent E3)) 14 Polyisocyanate compar- preparation 10 11 12 13 ative Polyisocyanate A4) A4) A4) A4) A4) component Solvent E3), quality 1 2 3 4 5 Peroxide content of [mg/l 3 30 50 60 150 solvent E1) H.sub.2O.sub.2] Total peroxide [mg/l 3 24 40 48 120 content of solvents*.sup.) H.sub.2O.sub.2] Peroxide content of [mg/l 1 10 16 19 48 polyisocyanate H.sub.2O.sub.2] solution*.sup.) Color index after Hazen 24 28 50 58 >1000 24 h/25° C. Iodine 0.1 0.1 0.2 0.3 12.1 *.sup.)calculated value

Polyisocyanate Preparations 15 to 25 (Inventive and Comparative)

[0203] In each case 100 parts by weight of the polyisocyanate components A1), A2), A3) and A5) were mixed at room temperature with 42.8 g each of different qualities of the solvents E1) to E3) and the mixtures homogenized by stirring for 30 minutes.

[0204] Table 4 shows the color indices of the 70% strength polyisocyanate preparations obtained as a function of the peroxide content of the particular solvent and that of the polyisocyanate solution after storage at 50° C. for 5 days.

Polyisocyanate Preparations 16 to 34 (Inventive and Comparative)

[0205] Polyisocyanate component A1) was mixed at room temperature with different amounts of different qualities of the solvent E1) and homogenized by stirring for 30 minutes.

[0206] Table 5 shows the compositions and solids contents of the polyisocyanate preparations obtained and their color indices as a function of the peroxide content of the solvent and that of the polyisocyanate solution after storage at 50° C. for 5 days.

TABLE-US-00004 TABLE 4 Polyisocyanate preparations 15 to 25 Polyisocyanate 16 19 21 23 25 preparation 15 comparative 17 18 comparative 20 comparative 22 comparative 24 comparative Polyisocyanate A1) A1) A1) A1) A1) A2) A2) A3) A3) A5) A5) component Solvent E1), quality 3 4 — — — — — 3 4 3 4 Solvent E2), quality — — — — — 3 4 — — — — Solvent E3), quality — — 3 4 5 — — — — — — Peroxide content [mg/l H.sub.2O.sub.2] 50 100 50 60 150 60 100 50 100 50 100 of solvent Peroxide content of [mg/l H.sub.2O.sub.2] 15 30 15 18 45 18 30 15 30 15 30 polyisocyanate solution.sup.*) Color index after Hazen 14 107 17 20 216 29 128 20 138 18 112 5 d/50° C. Iodine 0 0.5 0 0 1.2 0.1 0.7 0 0.7 0 0.6 *.sup.)calculated value

TABLE-US-00005 TABLE 5 Polyisocyanate preparations 26 to 34 31 34 Polyisocyanate preparation 26 27 28 30 comparative 32 33 comparative Polyisocyanate component A1) [parts by wt.] 70 60 50 40 30 70 60 50 Solvent E1), quality 3 [parts by wt.] — — — — — 30 40 50 Solvent E1), quality 2 [parts by wt.] 30 40 50 60 70 — — — Solids content [%] 70 60 50 40 30 70 60 50 Peroxide content of solvent [mg/l H.sub.2O.sub.2] 30 30 30 30 30 50 50 50 Peroxide content of [mg/l H.sub.2O.sub.2] 9 12 15 18 21 15 20 25 polyisocyanate solution.sup.*) Color index after 5 d/50° C. Hazen 9 12 15 28 65 14 34 83 Iodine 0 0 0 0.1 0.3 0 0.1 0.4 *.sup.)calculated value

Polyisocyanate Preparation 35 (Comparative)

[0207] 100 parts by weight of the polyisocyanate component A6) were mixed at room temperature with 42.8 g of the solvent D1), quality 4 (100 mg/l H202) and homogenized by stirring for 30 minutes. The color index of the 70% strength solution obtained was 17 Hazen immediately after mixing, and 14 Hazen after storage for 5 days at 50° C.

[0208] The comparison shows that diluting an exclusively non-ionically hydrophilized polyisocyanate with a peroxide-containing solvent does not lead to an increase in the color index over time, but rather has a brightening effect.