HARD RESIN SOLUTION AND WATER-BASED OVERPRINT VARNISH INCLUDING AN AMINE COMPOUND COMPRISING HYDROXYL GROUPS

Abstract

The present invention relates to an aqueous hard resin solution for the use in a water-based overprint varnish, wherein the aqueous hard resin solution contains water, at least one hard resin and at least one amine compound, wherein at least one of the at least one amine compound has one amino group, at least two hydroxyl groups and at least one C.sub.n-including group, with n being an integer of 3 or more.

Claims

1. An aqueous hard resin solution for the use in a water-based overprint varnish, wherein the aqueous hard resin solution contains water, at least one hard resin and at least one amine compound, wherein at least one of the at least one amine compound has one amino group, at least two hydroxyl groups and at least one C.sub.n-including group, with n being an integer of 3 or more.

2. The aqueous hard resin solution according to claim 1, wherein the one amino group of the amine compound is a terminal amino group.

3. The aqueous hard resin solution according to claim 1, the amine compound does not contain any nitrogen atom in addition to that of the amino group.

4. The aqueous hard resin solution according to claim 1, wherein the amine compound has at least two vicinal hydroxyl groups.

5. The aqueous hard resin solution according to claim 1, wherein the amine compound has the general formula (I):
NR.sup.1R.sup.2R.sup.3  (I), wherein R.sup.1 and R.sup.2 are independently from each other H, a linear or branched alkyl group, a cycloalkyl group, an alkyl ether group, an hydroxyl functional alkyl ether group, an alkyl thioether group, an aryl group or a linear or branched hydroxyl alkyl group and R.sup.3 is a linear or branched alkyl group, a cycloalkyl group, an alkyl ether group, an alkyl thioether group, an aryl group or a linear or branched hydroxyl alkyl group, with the provision that the residues R.sup.1, R.sup.2 and R.sup.3 comprise in total two or more hydroxyl groups and that at least one of residues R.sup.1, R.sup.2 and R.sup.3 is a C.sub.n-including group, with n being an integer of 3 or more.

6. The aqueous hard resin solution according to claim 5, wherein R.sup.1 and R.sup.2 are independently from each other H, a linear or branched C.sub.1-10alkyl group, a C.sub.6-12-cycloalkyl group, a C.sub.1-10-alkyl ether group, a C.sub.6-12-aryl group or a linear or branched C.sub.1-10-hydroxyl alkyl group, a linear or branched C.sub.1-10-hydroxyl alkyl ether group and R.sup.3 is a linear or branched C.sub.1-10-alkyl group, a C.sub.6-12-cycloalkyl group, a C.sub.1-10alkyl ether group, a C.sub.6-12-aryl group or a linear or branched C.sub.3-10-hydroxyl alkyl group.

7. The aqueous hard resin solution according to claim 5, wherein R.sup.1 is H and R.sup.2 is a linear or branched C.sub.1-6-alkyl group, or, wherein R.sup.1 and R.sup.2 are a linear or branched C.sub.1-6-alkyl group.

8. The aqueous hard resin solution according to claim 5, wherein R.sup.3 has the general formula (II):
—(CR.sup.4R.sup.5).sub.m—(CR.sup.6(OH)).sub.n—CR.sup.7R.sup.8H.sub.p(OH).sub.q  (II), wherein m is an integer of 0 to 2, o is an integer of 2 to 8, q is an integer of 0 or 1, p is an integer of 0 or 1, wherein p is 1, when q is 0, and p is 0, when q is 1, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8 are independently from each other, H, a linear or branched alkyl group or a linear or branched alkyl group with hydroxyl functionality.

9. The aqueous hard resin solution according to claim 5, wherein R.sup.3 has the general formula (III):
—(CH.sub.2).sub.m—(CH(OH)).sub.n—CH.sub.2OH  (II), wherein m is an integer of 0 to 2 and o is an integer of 2 to 8.

10. (canceled)

11. The aqueous hard resin solution according to claim 8, wherein m is an integer of 1, o is an integer of 2 to 5, R.sup.1 is H and R.sup.2 is —CH.sub.3, or, wherein m is an integer of 1, o is an integer of 2 to 5, R.sup.1 is —CH.sub.3 and R.sup.2 is —CH.sub.3.

12. The aqueous hard resin solution according to claim 1, wherein the aqueous hard resin solution additionally contains ammonia.

13. The aqueous hard resin solution according to claim 12, wherein the ratio of the amine compound is 0.1 to 99% by weight of the sum of the content of the amine compound and ammonia in the hard resin solution.

14. The aqueous hard resin solution according to claim 1, wherein the at least one hard resin has a weight average molecular weight of at least 800 g/mol, a glass transition temperature of more than 40° C. and a solubility in water at 23° C. of at least 100 g/l, wherein the at least one hard resin is selected from the group consisting of styrene acrylate copolymers, styrene maleic acid copolymers, maleic resins, polyester resins, fumaric resins, shellac and arbitrary combinations of two or more thereof.

15. The aqueous hard resin solution according to claim 1, wherein the content of the hard resin is 22 to 45% by weight based on the total weight of the aqueous hard resin solution, and/or, wherein the sum of the amine numbers of the ammonia and the amine compound is 80 to 120% of the sum of the carboxyl number and the OH-number of the hard resin.

16. A water-based overprint varnish containing the aqueous hard resin solution according to claim 1.

17. The water-based overprint varnish according to claim 15, which further comprises at least one additional polymer solution or dispersion, which is an emulsion or a dispersion of a another polymer being selected from the group consisting of styrene acrylate copolymers, styrene maleic acid acrylic acid copolymers, polystyrene homopolymers, vinylacetate polymers, vinylacetate ethylene copolymers, polyurethanes, polyurethane acrylate copolymers, vinylacetate acrylic acid copolymers, sulfopolyesters, lignin derivatives, cellulose derivatives, starch, chitin, casein, gelatin, polylactides, polyhydroxybutyrates and arbitrary combinations of two or more of the aforementioned polymers.

18. The water-based overprint varnish according to claim 16, which comprises: a) 10 to 30% by weight of hard resin, b) 1 to 30% by weight of the amine compound, c) 0.1 to 10% by weight of ammonia and d) 1 to 40% by weight of polymer in the polymer emulsion or dispersion.

19. An article comprising a substrate with at least one surface, wherein at least a part of at least one surface of the substrate is coated with a water-based overprint varnish according to claim 16.

20. (canceled)

21. A method of preparing a coated article comprising the steps of applying a water-based overprint varnish according to claim 16 onto at least a part of at least one surface of a substrate and drying the water-based overprint varnish.

22. The method according to claim 21 wherein the substrate is a food packing, a folding box made of board, a label made of paper, a food-tray made of paper and/or board, a composite material with paper and/or board on the printed side.

Description

EXAMPLES

[0119] The following commercial products were used as raw materials:

[0120] Joncryl 682: Acrylic resin distritbuted by BASF SE, Ludwigshafen, Germany.

[0121] Xiran 1000: Styrene maleic acid copolymer distritbuted by Polyscope Polymers BV, Geleen, The Netherlands

[0122] Erkamar 3269: Maleic resin distritbuted by Robert Kraemer GmbH, Rastede, Germany

[0123] Induprint SE 91: Acrylic dispersion distritbuted by Indulor Chemie GmbH, Ankum, Germany

[0124] Ultralube MD-2100: Wax distritbuted by keim additec surface GmbH, Kirchberg (Hunsrueck), Germany

[0125] Tego Foamex 1488: Defoamer distritbuted by Evonik Tego Chemie GmbH, Essen, Germany

[0126] Byk 019: Defoamer distritbuted by Byk Additives & Instruments GmbH, Wesel, Germany

[0127] First, as “part 1” a hard resin solution was prepared. In “part 1”, the components mentioned in the below tables for “part 1” were mixed as follows: Water was poured in a beaker, then during continuous stirring resin was added, then amine was added and the reaction mixture heated to 70 to 80° C. The reaction mixture was stirred for about one to three hours until a clear solution was obtained. The solution was allowed to cool down to room temperature. Then, all compounds mentioned in the below tables for “part 2” were added and the mixture stirred for another five minutes so as to obtain a water-based overprint varnish. Finally, water has been added to the water-based overprint varnish so as to adjust the viscosity thereof for the printing to a final draining viscosity of 40 to 55 s in a Din 4 Cup.

[0128] The amine numbers of ammonia and the respective amines have been calculated using the following equation:

1000×56.1/molecular weight of material=Amine Number (mg KOH/g)

TABLE-US-00001 Molecular weight Amine number Amine [g/mol] [mg KOH/g] Ammonia, 25% in water DEA 105.14 533.57 MDEA 119.16 470.80 TEA 149.188 376.06 MG 209.24 267.11 * MG is methyl meglumine, which is also designated as dimethylglucosamine

[0129] Acid numbers are a measure for the content of COOH groups in organic materials, e.g. polymers or resins. The following table shows the numbers for the investigated binders:

TABLE-US-00002 Acid number Hard resin [mg KOH/g] Joncryl 682 230-245 Xiran 1000 P 475 Erkamar 3269 190-210

[0130] In “part 1” of the recipes the amount of amine/ammonia to hard resin was calculated to be slightly above a 1:1 equivalent ratio of combined amine values and acid numbers.

TABLE-US-00003 TABLE 1 Compar- Compar- Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative ative ative Joncryl 682 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 1 Example 2 Example 3 Example 7 Part 1 Water 16.75 18.36 19.17 10.23 15.10 17.54 0.12 10.05 15.01 19.97 Joncryl 682 21.72 21.97 22.09 21.72 21.97 22.09 16.91 19.57 20.89 22.22 ammonia 25% 3.08 4.62 0.00 3.08 4.62 0.00 3.08 4.62 6.16 solution in water Diethanolamine 9.89 4.95 2.47 (DEA) 100% Triethanolamine 16.41 8.20 4.10 (TEA) 85% Methylmeglumine 31.32 15.66 7.83 (MG) 50% Part 2 Induprint SE 91 42.87 42.87 42.87 42.87 42.87 42.87 42.87 42.87 42.87 42.87 Ultralube MD-2100 3.22 3.22 3.22 3.22 3.22 3.22 3.22 3.22 3.22 3.22 Dioctylsulfosuccinate, 5.36 5.36 5.36 5.36 5.36 5.36 5.36 5.36 5.36 5.36 70% in water Tego Foamex 1488 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 Sum 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 added water to adjust 20.54 18.31 18.13 21.44 20.54 18.76 13.13 13.49 15.36 18.49 print viscosity draining time Din 4 52 55 55 55 44 46 54 55 55 46 Cup

TABLE-US-00004 TABLE 2 Compar- Compar- Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative ative ative Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple 8 ple 9 ple 10 ple 11 ple 12 ple 13 ple 4 ple 5 ple 6 ple 14 Part 1 Water 29.14 23.66 20.92 21.53 18.17 18.17 0.12 9.15 13.66 18.18 XIRAN 1000 10.11 14.71 17.01 13.29 15.69 17.50 10.52 14.92 17.11 19.31 ammonia 25% solution 5.43 8.15 5.43 8.15 5.43 8.15 10.86 in water Diethanolamine (DEA) 9.10 4.55 2.28 100% Triethanolamine (TEA) 13.53 9.06 4.53 85% Methylmeglumine 37.71 18.86 9.43 (MG) 50% Part 2 Induprint SE 91 42.87 42.87 42.87 42.87 42.87 42.87 42.87 42.87 42.87 42.87 Ultralube MD-2100 3.22 3.22 3.22 3.22 3.22 3.22 3.22 3.22 3.22 3.22 Dioctylsulfosuccinate. 5.36 5.36 5.36 5.36 5.36 5.36 5.36 5.36 5.36 5.36 70% in water Defoamer Byk 019 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 Sum 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 added water for 7.15 10.72 12.50 16.08 16.08 15.18 14.29 10.72 13.40 17.86 adjusting print viscosity draining time Din 4 50 53 52 50 46 51 38 53 49 54 Cup

TABLE-US-00005 TABLE 3 Compar- Compar- Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative ative ative Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple 15 ple 16 ple 17 ple 18 ple 19 ple 20 ple 7 ple 8 ple 9 ple 21 Part 1 Water 24.91 25.63 25.98 22.74 24.52 25.44 13.96 20.15 23.24 26.34 Erkamar 3269 16.91 17.29 17.48 15.71 16.69 17.18 13.68 15.68 16.67 17.67 ammonia 25% 2.17 3.26 2.17 3.26 2.17 3.26 4.35 solution in water Diethanolamine 6.52 3.26 1.63 (DEA) 100% Triethanolamine 9.91 4.95 2.48 (TEA) 85% Methylmeglumine 20.72 10.36 5.18 (MG) 50% Part 2 Induprint SE 91 42.87 42.87 42.87 42.87 42.87 42.87 42.87 42.87 42.87 42.87 Ultralube MD-2100 3.22 3.22 3.22 3.22 3.22 3.22 3.22 3.22 3.22 3.22 Dioctylsulfosuccinate, 5.36 5.36 5.36 5.36 5.36 5.36 5.36 5.36 5.36 5.36 70% in water Tego Foamex 1488 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 Sum 100.00 100.00 100.00 100.00 99.98 100.00 100.00 100.00 100.00 100.00 added water for 14.29 16.97 19.65 8.04 13.40 16.08 4.47 9.82 17.86 5.36 adjusting print viscosity draining time Din 4 50 53 46 49 47 53 49 53 43 46 Cup

[0131] The water-based overprint varnishes of all examples and comparative examples were evaluated concerning their gloss and blocking resistance as follows:

[0132] Application of the Overprint Varnishes:

[0133] The overprint varnishes were applied with a K control coater 623 and a 6 μm K bar, both from Erichsen GmbH & Co. KG, Herner, Germany, on Invercote T from Iggesund Paperboard, Iggesund, Sweden, 220 g/m.sup.2.

[0134] Gloss Measurement:

[0135] The gloss was measured after the varnish had been coated on Invercote T as substrate with a micro tri-gloss instrument from Byk Gardner GmbH, Geretsried, Germany. The coated substrates were allowed to dry for 24 hours in a climate controlled room at 21-23° C. and 55-65% humidity, before the gloss was measured. The gloss was measured at two different viewing angles, namely at 20° and at 60°. An average of five measurement results was calculated, respectively.

[0136] The higher the value of the gloss units, the more glossy the surface.

[0137] Blocking Resistance:

[0138] Wet blocking was tested with a Prufbau blocking test device from pruefbau Dr.-Ing. H. Duerner GmbH, Peissenberg, Germany, to identify the blocking behavior in a humid or even wet environment. The substrates coated as described above were allowed to dry for 24 hours in a climate controlled room at 21-23° C. and 55-65% humidity, before wet blocking behavior was measured. 10 small round samples of 2 cm.sup.2 were cut out with a cutting device. Five samples were placed printed side up into the block testing device. The coated sample was covered with another coated sample, whereas the coating was facing the coated side. The sample “sandwich” in the block testing device was pressed between two precision plates for three hours at 50° C. At the five measuring points different pressures were applied: 0.25 kg/cm.sup.2, 0.5 kg/cm.sup.2, 1.0 kg/cm.sup.2, 2.0 kg/cm.sup.2, 5.0 kg/cm.sup.2. After three hours the samples were removed from the block testing device and the coated test samples were separated. Samples did block together or not. An average of two measurement results at each pressure was calculated, respectively.

[0139] The following scale for the determined blocking resistance was used:

[0140] 3: no adherence

[0141] 2: slight adherence

[0142] 1: slight destruction of the printed surface

[0143] 0: extended destruction of the printed surface

[0144] The obtained results are summarized in Tables 4 to 6.

TABLE-US-00006 TABLE 4 6 μm on Invercote T, Compar- Compar- Compar- Compar- Compar- Compar- Compar- formulations with ative ative ative ative ative ative ative Joncryl 682 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 1 Example 2 Example 3 Example 7 Gloss 20° average of 2 39 29 26 57 31 28 36 30 27 24 samples Gloss 60° average of 2 85 78 76 94 80 78 83 80 77 74 samples Blocktest Invercote T/ 1.5 3 3 1 2 3 2 3 3 3 25 kP (0.25 kg/cm.sup.2) Blocktest Invercote T/ 0.5 2 2 0 1 3 1 3 3 3 50 kP (0.5 kg/cm.sup.2) Blocktest Invercote T/ 0 1.5 2 0 1 2.5 0 3 3 3 100 kP (1.0 kg/cm.sup.2) Blocktest Invercote T/ 0 1 2 0 0 2 0 3 3 3 200 kP (2.0 kg/cm.sup.2) Blocktest Invercote T/ 0 0.5 2 0 0 2 0 2 3 3 500 kP (5.0 kg/cm.sup.2) Blocktest average 0.4 1.6 2.2 0.2 0.8 2.5 0.6 2.8 3 3

TABLE-US-00007 TABLE 5 Compar- Compar- Compar- Compar- Compar- Compar- Compar- 6 μm on Invercote T, ative ative ative ative ative ative ative formulations with Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Xiran 1000P ple 8 ple 9 ple 10 ple 11 ple 12 ple 13 ple 4 ple 5 ple 6 ple 14 Gloss 20° average of 2 22.5 22.7 20.55 32.1 25.45 23.95 29.55 26.25 23.8 19.35 samples Gloss 60° average of 2 72.5 72.65 69.85 80.65 75.6 73.9 79.1 76 73.55 67.4 samples Block test Invercote T/ 3 3 3 2 3 3 3 3 3 3 25 kP (0.25 kg/cm.sup.2) Block test Invercote T/ 3 3 3 1 3 3 3 3 3 3 50 kP (0.5 kg/cm.sup.2) Block test Invercote T/ 3 3 3 0 3 3 3 3 3 3 100 kP (1.0 kg/cm.sup.2) Block test Invercote T/ 2.5 3 3 0 3 3 2.5 3 3 3 200 kP (2.0 kg/cm.sup.2) Block test Invercote T/ 2.5 3 3 0 3 3 2.5 3 3 3 500 kP (5.0 kg/cm.sup.2) Blocktest average 2.8 3 3 0.6 3 3 2.8 3 3 3

TABLE-US-00008 TABLE 6 Compar- Compar- Compar- Compar- Compar- Compar- Compar- 6 μm on Invercote T, ative ative ative ative ative ative ative formulations with Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Erkamar 3269 ple 15 ple 16 ple 17 ple 18 ple 19 ple 20 ple 7 ple 8 ple 9 ple 21 Gloss 20° average of 2 24 21 19 30 23 20 29 23 18 19 samples Gloss 60° average of 2 73 70 67 78 73 69 78 72 66 67 samples Block test Invercote T/ 2 3 3 2 3 3 3 3 3 3 25 kP (0.25 kg/cm.sup.2) Block test Invercote T/ 2 3 3 1 3 3 3 3 3 3 50 kP (0.5 kg/cm.sup.2) Block test Invercote T/ 1 2 3 0 3 3 3 3 3 3 100 kP (1.0 kg/cm.sup.2) Block test Invercote T/ 1 2 3 0 3 3 2 3 3 3 200 kP (2.0 kg/cm.sup.2) Block test Invercote T/ 0 1 3 0 3 3 2 3 3 3 500 kP (5.0 kg/cm.sup.2) Blocktest average 1.2 2.2 3 0.6 3 3 2.6 3 3 3

[0145] The results show that the water-based overprint varnishes of the examples containing an amine compound in accordance with the present invention had an excellent gloss of at least 70 at a viewing angle of 60°. The water-based overprint varnishes of the examples had an improved blocking resistance in comparison to the water-based overprint varnish of the comparative examples including diethanol amine or triethanol amine and an improved gloss in comparison to the water-based overprint varnish of the comparative examples including only ammonia. An especially good combination of gloss and blocking resistance was obtained in examples 2, 5 and 8, in which the water-based overprint varnishes included a mixture of an amine compound in accordance with the present invention and ammonia.