Polyurethanes, dispersions thereof, their preparation and use

Abstract

The present invention relates to polyurethanes (A) being obtainable by reaction of (a) 15% to 70% by weight of di- or polyisocyanate comprising on average from 1 to 10 allophanate groups and on average from 1 to 10 CC double bonds per molecule, and optionally (b) 0% to 60% by weight of further di- or polyisocyanate, with (c) 5% to 50% by weight of compounds having at least two isocyanate-reactive groups, comprising at least one polycarbonate diol with a molecular weight from 500 to 3000 g/mol weight % ages being based on total polyurethane (A), with the proviso that the total is 100%.

Claims

1. A polyurethane obtained by reaction of (a) 30% to 60% by weight of di- or polyisocyanate comprising on average from 1 to 10 allophanate groups and on average from 1 to 10 CC double bonds per molecule, and (b) 1% to 20% by weight of further di- or polyisocyanate, with (c) 30% to 50% by weight of compounds having at least one isocyanate-reactive group, comprising at least one dihydroxy functional aliphatic polycarbonate diol (c1) with a molecular weight from 500 to 3000 g/mol, weight percentages being based on a total of the polyurethane of 100%, wherein: a weight-average molecular weight of the polyurethane ranges from 1000 to 25000 g/mol; an amount of the dihydroxy functional aliphatic polycarbonate diol (c1) is from 10% to 40% by weight; the at least one compound having at least one isocyanate-reactive group (c) further comprises at least one compound (c2) bearing at least one group reactive against isocyanate and at least one acid group selected from the group consisting of a 1,1,1-trimethylol-C.sub.1-C.sub.4-alkyl-carboxylic acid, citric acid, a 2,2-dimethylol-C.sub.1-C.sub.4-alkylcarboxylic acid, and a 2,2-dimethylol-C.sub.1-C.sub.4-alkylsulfonic acid; an amount of compound (c2) is from 2% to 20% by weight; the at least one compound having at least one isocyanate-reactive group (c) further comprises at least one compound (c3) bearing exactly two hydroxy groups and no further functional groups; an amount of compound (c3) is from 0.5% to 10% by weight; and a proportion of the at least one compound (c3) in the total amount of compounds (c1), (c2) and (c3) is not more than 5.73% by weight.

2. The polyurethane of claim 1, wherein: said di- or polyisocyanate (a) is prepared by reaction of at least one di- or polyisocyanate (a1) with at least one compound of the general formula (I): ##STR00008## R.sup.1 and R.sup.2 independently represent hydrogen or C.sub.1-C.sub.10-alkyl; X.sup.1 represents oxygen or NR.sup.3; A.sup.1 represents C.sub.1-C.sub.20-alkylene, which is unsubstituted or singly or multiply substituted by C.sub.1-C.sub.1-alkyl, phenyl or OC.sub.1-C.sub.4-alkyl, and in which one or more nonadjacent CH.sub.2 groups may be replaced by oxygen; X.sup.2 represents hydroxyl or NHR.sup.3; R.sup.3 independently represents hydrogen, C.sub.1-C.sub.10-alkyl or phenyl.

3. The polyurethane according to claim 1, wherein: the polycarbonate diol is represented by formula (II):
HOR.sup.5[O(CO)OR.sup.5].sub.xOH(II); R.sup.5 represents a divalent aliphatic or cycloaliphatic; and x represents a positive integer from 2 to 20.

4. The polyurethane according to claim 1, wherein the at least one compound having at least one isocyanate-reactive group (c) further comprises at least one poly-C.sub.2-C.sub.3-alkylene glycol having on average from 3 to 300 C.sub.2-C.sub.3-alkylene oxide units per molecule.

5. The polyurethane according to claim 4, wherein acidic groups in the polyurethane are at least partially neutralized by at least one tertiary amine bearing at least one hydroxy group or an alkali metal hydroxide.

6. An aqueous dispersion, comprising: (A) the polyurethane of claim 1; (B) a pigment; and (C) at least one polymerization inhibitor.

7. The aqueous dispersions according to claim 6, further comprising: (D) at least one resin selected from the group consisting of a styrene-acrylate copolymer and a polyurethane.

8. The aqueous dispersions according to claim 6, further comprising: (E) at least one photoinitiator (E).

9. The aqueous dispersions according to claim 6, wherein the aqueous dispersion is cured by electron radiation in the absence of a photoinitiator (E).

10. A flexographic or gravure printing ink, comprising at least one polyurethane according to claim 1.

11. A printing process, comprising applying the aqueous dispersion of claim 6 to a substrate, wherein the printing process is selected from the group consisting of ink jet printing, flexographic printing, and gravure printing.

12. A process for printing a substrate, the process comprising printing a substrate with a printing ink comprising at least one aqueous dispersion according to claim 6, wherein the printing process is selected from the group consisting of ink jet printing, flexographic printing, and gravure printing.

13. The process according to claim 12, wherein the substrate is selected from the group consisting of a paper, a paperboard, a cardboard, a polyester sheet, a polyester film, a polyethylene sheet, a polyethylene film, and a glass.

14. The process according to claim 12, wherein the printing ink printed onto the substrate is at least partially dried before it is cured in a final step.

15. The process according to claim 14, wherein, after the at least partially drying, another printing ink is printed onto the at least partially dried ink.

16. The process according to claim 12, wherein a curing of the printing ink comprising no photoinitiator occurs by electron radiation in at least one electron flash device with an energy of 50 to 300 keV.

17. The process according to claim 12, wherein a curing of the printing ink comprising at least one photoinitiator occurs by actinic radiation having a wavelength range from 200 nm to 700 nm.

18. A polyurethane obtained by reaction of (a) 30% to 60% by weight of di- or polyisocyanate comprising on average from 1 to 10 allophanate groups and on average from 1 to 10 CC double bonds per molecule, and (b) 1% to 20% by weight of further di- or polyisocyanate, with (c) 30% to 50% by weight of compounds having at least one isocyanate-reactive group, comprising at least one dihydroxy functional aliphatic polycarbonate diol (c1) with a molecular weight from 500 to 3000 g/mol, weight percentages being based on a total of the polyurethane (A) of 100%, wherein: the compounds (c) having at least one isocyanate-reactive group do not include a polycarbonate diol derived from a cycloaliphatic polyol; an amount of the dihydroxy functional aliphatic polycarbonate diol (c1) is from 10% to 40% by weight; the at least one compound having at least one isocyanate-reactive group (c) further comprises at least one compound (c2) bearing at least one group reactive against isocyanate and at least one acid group selected from the group consisting of a 1,1,1-trimethylol-C.sub.1-C.sub.4-alkyl-carboxylic acid, citric acid, a 2,2-dimethylol-C.sub.1-C.sub.4-alkylcarboxylic acid, and a 2,2-dimethylol-C.sub.1-C.sub.4-alkylsulfonic acid; an amount of compound (c2) is from 2% to 20% by weight; the at least one compound having at least one isocyanate-reactive group (c) further comprises at least one compound (c3) bearing exactly two hydroxy groups and no further functional groups; an amount of compound (c3) is from 0.5% to 10% by weight; and a proportion of the at least one compound (c3) in the total amount of compounds (c1), (c2) and (c3) is not more than 5.73% by weight.

Description

EXAMPLES ACCORDING TO THE INVENTION

Example 1

(1) In a reaction vessel equipped with a mechanical stirrer were given 109 parts of a dihydroxy functional aliphatic polycarbonate Oxymer M112 from Perstorp, 12 parts neopentylglycole, 39 parts dimethylolpropionic acid, 0.4 parts 2,6 Di-t-butyl-p-Kresol, 0.2 parts 4-methoxyphenol, 268 parts of a polyisocyanate of formula (Ia) Laromer LR 9000 (commercially available from BASF SE, Ludwigshafen), 20 parts hexamethylene diisocyanate, 0.5 parts BorchiKat24 (Bismuth carboxylate, available from OMG Borchers GmbH, Langenfeld, Germany) and 450 parts acetone. The reaction mixture was homogenized and heated up to 80 C. The reaction was carried out for 8 hrs at 80 C. and was stopped by adding 27 parts diethanol amine in 30 parts acetone at a residual prepolymer NCO content of 1.18%. The reaction was stirred during 20 min at 80 C. For the duration of 10 min were given 30 parts triethylamine in 30 parts acetone to the reaction mixture. During additional 30 min were added 1000 parts deionized water to the polymeric solution and subsequently the acetone was stripped off under vacuum during 1.5 hrs. The viscosity of the translucent dispersion was determined to be 800 mPa s at a given solids content of 29.1% by weight.

Example 2

(2) In a reaction vessel equipped with a mechanical stirrer were given 104 parts of a dihydroxy functional aliphatic polycarbonate Oxymer M112 from Perstorp, 9 parts neopentylglycole, 40 parts dimethylolpropionic acid, 8 parts Laromer LR 8765 (epoxy acrylate based on 1,4-Butanediylbis[oxy(2-hydroxy-3,1-propanediyl)]diacrylate, commercially available from BASF SE, Ludwigshafen), 0.4 parts 2,6 Di-t-butyl-p-Kresol, 0.2 parts 4-methoxyphenol, 268 parts of a polyisocyanate Laromer LR 9000 (commercially available from BASF SE, Ludwigshafen), 20 parts hexamethylene diisocyanate, 0.5 parts BorchiKat24 (Bismuth carboxylate, available from OMG Borchers GmbH, Langenfeld, Germany) and 450 parts acetone. The reaction mixture was homogenized and heated up to 80 C. The reaction was carried out for 8 hrs at 80 C. and was stopped by adding 27 parts diethanol amine in 30 parts acetone at a residual prepolymer NCO content of 1.24%. The reaction was stirred during 20 min at 80 C. For the duration of 10 min were given 30 parts triethylamine in 30 parts acetone to the reaction mixture. During additional 30 min were added 1000 parts deionized water to the polymeric solution and subsequently the acetone was stripped off under vacuum during 1.5 hrs. The viscosity of the translucent dispersion was determined to be 260 mPa s at a given solids content of 31.8% by weight.

Example 7

(3) In a reaction vessel equipped with a mechanical stirrer were given 150 parts of a dihydroxy functional aliphatic polycarbonate Ravecarb 107 from Enichem, 9 parts neopentylglycole, 40 parts dimethylolpropionic acid, 0.4 parts 2,6 Di-t-butyl-p-Kresol, 0.2 parts 4-methoxyphenol, 233 parts of a polyisocyanate of formula (Ia) Laromer LR 9000 (commercially available from BASF SE, Ludwigshafen), 17 parts hexamethylene diisocyanate, 0.5 parts BorchiKat24 (Bismuth carboxylate, available from OMG Borchers GmbH, Langenfeld, Germany) and 450 parts acetone. The reaction mixture was homogenized and heated up to 80 C. The reaction was carried out for 8 hrs at 80 C. and was stopped by adding 25 parts diethanol amine in 30 parts Acetone at a residual prepolymer NCO content of 1.13%. The reaction was stirred during 20 min at 80 C. For the duration of 10 min were given 30 parts Triethylamine in 30 parts Acetone to the reaction mixture. During additional 30 min were added 800 parts deionized water to the polymeric solution and subsequently the acetone was stripped off under vacuum during 1.5 hrs. The viscosity of the translucent dispersion was determined to be 1070 mPa s at a given solids content of 42.2% by weight.

Example 3

(4) In a reaction vessel equipped with a mechanical stirrer were given 138 parts of a dihydroxy functional aliphatic Polycarbonate PM2000 from UBE, 7 parts neopentylglycole, 40 parts dimethylolpropionic acid, 7 parts Laromer LR 8765 (epoxy acrylate based on 1,4-Butanediyl-bis[oxy(2-hydroxy-3,1-propanediyl)]diacrylate, commercially available from BASF SE, Ludwigshafen), 0.4 parts 2,6 Di-t-butyl-p-Kresol, 0.2 parts 4-Methoxyphenol, 239 parts of a polyisocyanate of formula (Ia) Laromer LR 9000 (commercially available from BASF SE, Ludwigshafen), 18 parts hexamethylene diisocyanate, 0.5 parts BorchiKat24 (Bismuth carboxylate, available from OMG Borchers GmbH, Langenfeld, Germany) and 450 parts acetone. The reaction mixture was homogenized and heated up to 80 C. The reaction was carried out for 8 hrs at 80 C. and was stopped by adding 16 parts monoethanol amine in 30 parts acetone at a residual pre-polymer NCO content of 1.20%. The reaction was stirred during 20 min at 80 C. For the duration of 10 min were given 30 parts Triethylamine in 30 parts acetone to the reaction mixture. During additional 30 min were added 900 parts deionized water to the polymeric solution and subsequently the acetone was stripped off under vacuum during 1.5 hrs. The viscosity of the translucent dispersion was determined to be 980 mPa s at a given solids content of 37.1% by weight.

Example 4

(5) In a reaction vessel equipped with a mechanical stirrer were given 74 parts of a dihydroxy functional aliphatic polycarbonate Oxymer M112 from Perstorp, 7 parts neopentylglycole, 32 parts dimethylolpropionic acid, 5 parts Laromer LR 8765 (epoxy acrylate based on 1,4-Butanediyl-bis[oxy(2-hydroxy-3,1-propanediyl)]diacrylate, commercially available from BASF SE, Ludwigshafen), 13 parts 2-hydroxyethyl acrylate, 0.4 parts 2,6 Di-t-butyl-p-Kresol, 0.2 parts 4-methoxyphenol, 203 parts of a polyisocyanate of formula (Ia) Laromer LR 9000 (commercially available from BASF SE, Ludwigshafen), 15 parts hexamethylene diisocyanate, 0.5 parts BorchiKat24 (Bismuth carboxylate, available from OMG Borchers GmbH, Langenfeld, Germany) and 350 parts acetone. The reaction mixture was homogenized and heated up to 80 C. The reaction was carried out for 8 hrs at 80 C. and was stopped by adding 17 parts Diethanol amine in 30 parts acetone at a residual prepolymer NCO content of 0.97%. The reaction was stirred during 20 min at 80 C. For the duration of 10 min were given 24 parts triethylamine in 30 parts acetone to the reaction mixture. During additional 30 min were added 700 parts deionized water to the polymeric solution and subsequently the acetone was stripped off under vacuum during 1.5 hrs. The viscosity of the translucent dispersion was determined to be 6540 mPa s at a given solids content of 38.5% by weight.

Example 5

(6) In a reaction vessel equipped with a mechanical stirrer were given 104 parts of a dihydroxy functional aliphatic polycarbonate Oxymer M112 from Perstorp, 9 parts neopentylglycole, 44 parts dimethylolpropionic acid, 7 parts Laromer LR 8765 (epoxy acrylate based on 1,4-Butanediylbis[oxy(2-hydroxy-3,1-propanediyl)]diacrylate, commercially available from BASF SE, Ludwigshafen), 19 parts 2-hydroxyethyl acrylate, 0.5 parts 2,6 Di-t-butyl-p-Kresol, 0.2 parts 4-methoxyphenol, 285 parts of a polyisocyanate of formula (Ia) Laromer LR 9000 (commercially available from BASF SE, Ludwigshafen), 21 parts hexamethylene diisocyanate and 210 parts acetone. The reaction mixture was homogenized and heated up to 80 C. and was carried out for 6 hrs at 80 C. and finally was quenched by the addition of 9 parts monoethanol amine in 30 parts acetone at a residual prepolymer NCO content of 0.91%. The reaction was stirred during 20 min at 80 C. For the duration of 10 min were given 126 parts of a 10% by weight containing aqueous sodium hydroxide solution to the reaction mixture. During additional 30 min were added 750 parts deionized water to the polymeric solution and subsequently the acetone was stripped off under vacuum during 1.5 hrs. The viscosity of the translucent dispersion was determined to be 458 mPa s at a given solids content of 36.2% by weight.

(7) A flexographic ink was made by blending 30% by weight of a pigment concentrate (42.5% Irgalith GLO (BASF SE)/34.0% Joncryl HPD96E (BASF SE)/23.0% Water/0.5% Foamex 810 (Evonik)), 65% by weight of a polymer dispersion prepared in the Examples or Comparative Examples and 5% by weight of a wax emulsion (JONWAX35, BASF SE).

(8) This mixture was diluted using a blend of pigment concentrate/water=30/70 until a viscosity of 20 sec in a DIN 4 cup was reached.

(9) The ink thus obtained was applied to LDPE, transparent LDPE and on transparent coes-OPP using a K-Bar 0 (4 micron wet) on the different films. Afterwards the print was dried in an oven at 60 C. for 30 sec.

(10) After drying the prints were electron beam-cured with an EBeam Lab unit Navarone LA100 from COMET and an EB Dose of 25 kGy. Acceleration voltage was set to 60 kV, current 10.5 mA, feed rate 3 m/min.

(11) The prints were tested as follows:

(12) TABLE-US-00001 Examples: E1 E2 E3 E4 E5 Before EB Tape adhesion (airdrying) .sup.(a) 4 4-5 4-5 3 4 Before EB Tape adhesion (1 min, 60 C.) .sup.(b) 5 5 4-5 3 4 Before EB Scratch resistance .sup.(c) 3 2 3-4 3 3 Before EB Wrinkle (dry) .sup.(d) 5 5 5 5 5 Before EB Blocking (5T/30 C./24 hrs) (R/D) .sup.(e) 5/5 5/5 4-5/5 5/5 5/5 Before EB Drying speed .sup.(f) slow fast ok ok ok Before EB Ink transfer (K-lox 400lpi) .sup.(g) ++ ok ok After EB Tape adhesion (airdrying) 5 5 5 5 5 After EB Scratch resistance 2-3 4-5 3 4 4 After EB Wrinkle (wet) running tap .sup.(h) 5 4 5 5 5 After EB HSR (160 C./400N/1 sec) (R/D) .sup.(i) 4/4-5 3/3 5/5 5/5 5/5 After EB HSR (180 C./400N/1 sec) (R/D) .sup.(j) 5/5 5/5 After EB Wet satra (2 h stored in water) .sup.(k) 200/90 200/75 200/100 Comparative CE1 CE2 Before EB Tape adhesion (airdrying) .sup.(a) 1-2 4 Before EB Tape adhesion (1 min, 60 C.) .sup.(b) 1-2 4-5 Before EB Scratch resistance .sup.(c) 3 3 Before EB Wrinkle (dry) .sup.(d) 5 5 Before EB Blocking (5T/30 C./24 hrs) (R/D) .sup.(e) 5/5 5/5 Before EB Drying speed .sup.(f) slow fast Before EB Ink transfer (K-lox 400lpi) .sup.(g) ++ ++ After EB Tape adhesion (airdrying) 5 After EB Scratch resistance 4 After EB Wrinkle wet running tap .sup.(h) 4-5 After EB HSR (160 C./400N/1 sec) (R/D) .sup.(i) 3/2 After EB HSR (180 C./400N/1 sec) (R/D) .sup.(j) After EB Wet satra (2 h stored in water) .sup.(k) EB: Electron Beam curing, HSR: Heat Seal Resistance .sup.(a) Tape adhesion, before oven. Pressure-sensitive adhesive tape is applied to an area of the coating. Adhesion is considered to be adequate if no coating is pulled off by the tape when it is removed. .sup.(b) Tape adhesion, after 1 minute at 60 C. Pressure-sensitive adhesive tape is applied to an area of the coating. Adhesion is considered to be adequate if no coating is pulled off by the tape when it is removed. .sup.(c) Scratch/Scuff resistance after 1 minute at 60 C. Explanation scratch: scratch 5x with the top of a fingernail over the foil. Explanation scuff: scuff 5x with a flat fingernail over the foil. .sup.(d) Wrinkle (dry). Wrinkle 10 times the foil between the hands and observe on damage .sup.(e) Blocking. Place on top of the dried draw-down another foil with the non treated side on the ink side. Place the draw-down in the laboratory press (Specac) for 24 hours at 30 C. and 5T pressure. .sup.(f) Drying speed: Inks are applied side-by-side to OPP film, using K-bar 1 (6 m wet). After application the (difference in) dryingspeed is judged by putting the fingertip to the printed surface and record time until touch-dry. .sup.(g) Ink transfer: Inks are applied side-by-side to OPP, using a K-lox anilox proofer (400lpi anilox). Difference in colourstrength between the different inks is judged and is a measure for inktransfer. .sup.(h) Wrinkle (wet). Wrinkle 10 times the foil between the hands under a running water tap and observe on damage .sup.(i) HSR (160 C.): The draw downs are put with the coated side to the mat side of aluminium foil. Than the aluminium foil is fold up. The strokes are placed on the crimp seal machine and heated two sides (160 C.) for 1 second with a pressure of 400N. The strokes are observed on damage and release. .sup.(j) HSR (180 C.): The draw downs are put with the coated side to the mat side of aluminium foil. Than the aluminium foil is fold up. The strokes are placed on the crimp seal machine and heated two sides (180 C.) for 1 second with a pressure of 400N. The strokes are observed on damage and release. .sup.(k) Wet Satra (2 hr stored in water): Printed material will be stored in water (20 C.) for 2 hours. Prints will be removed from the water and immediately tested for wet rub resistance, using Satra rub tester. Prints will be tested up to 200rubs. After 200 rubs, the amount of inkremoval will be judged and recorded.