RADIATION-CURABLE COATING COMPOUNDS CONSISTING OF A PLURALITY OF COMPONENTS, AND THE USE OF SAME IN RELEASE-COATED SUBSTRATES

Abstract

A composition contains at least one siloxane having ethylenically unsaturated, radically-polymerizable groups, and at least one hydrocarbon having 2 to 6 ethylenically-unsaturated, radically-polymerizable groups, and can be used as a release coating, said composition allowing a good degree of release behavior from adhesive compounds while at the same time also achieving a high level of adhesion of the coating to the carrier material.

Claims

1: A composition, comprising: components (I), (II) and optionally (III) (I) 1 to 90 wt %, based on the sum of all components of the composition, of one or more hydrocarbons consisting of the elements carbon, hydrogen and oxygen and having 2 to 6 ethylenically unsaturated, radically polymerizable groups and at least one oxyethylene group, (II) 10 to 99 wt %, based on the sum of all components of the composition, of one or more organo-modified silicones having 50 to 500 silicon atoms, wherein optionally 0.4% to 10% of the silicon atoms carry ethylenically unsaturated, radically polymerizable groups, and optionally one silicon atom carries one, two or three ethylenically unsaturated, radically polymerizable groups, (III) 0 to 70 wt %, based on the sum of all components of the composition, of one or more organomodified silicones having 4 to 40 silicon atoms, where 15% to 100% of the silicon atoms have ethylenically unsaturated, radically polymerizable groups, with component (I) being optionally free of silicon atoms.

2: The composition as claimed in claim 1, wherein the component (II) has, as ethylenically unsaturated, radically polymerizable groups, acrylic and/or methacrylic ester functions.

3: The composition as claimed in claim 1, wherein the component (III) comprises not only the ethylenically unsaturated, radically polymerizable groups but also ester groups which are as yet not radically polymerizable.

4: The composition as claimed in claim 2, wherein the components (II) have no ester groups which are not radically polymerizable.

5: The composition as claimed in claim 1, wherein the components (II) comprise one or more compounds of the formula (I),
M.sup.1.sub.aM.sup.2.sub.bD.sup.1.sub.cD.sup.2.sub.d  (I) where M.sup.1=[R.sup.1.sub.3SiO.sub.1/2], M.sup.2=[R.sup.1.sub.2R.sup.2SiO.sub.1/2], D.sup.1=[R.sup.1R.sup.2SiO.sub.2/2], D.sup.2=[R.sup.1R.sup.2SiO.sub.2/2], a=0 to 2, b=0 to 2, and a+b=2, c=50 to 490, d=0 to 15, and the ratio of the sum (b+d) to the sum (c+d+2) is from 0.004 up to 0.1; and the sum (c+d+2) is 50 to 500, R.sup.1 denotes identical or different aliphatic hydrocarbons having 1 to 10 carbon atoms or aromatic hydrocarbons having 6 to 12 carbon atoms, R.sup.2 denotes identical or different hydrocarbons which have 1 to 5 identical or different ester functions, the hydrocarbon being linear, cyclic, branched and/or aromatic, and the ester functions being selected from ethylenically unsaturated, radically polymerizable ester functions and from ester groups which are not radically polymerizable.

6: The composition as claimed in claim 1, wherein the component (III) comprises a compound of the formula (II)
M.sup.1.sub.eM.sup.3.sub.fD.sup.1.sub.gD.sup.3.sub.h  (II) where M.sup.1=[R.sup.1.sub.3SiO.sub.1/2], M.sup.3=[R.sup.1.sub.2R.sup.3SiO.sub.1/2], D.sup.1=[R.sup.1.sub.2SiO.sub.2/2], D.sup.3=[R.sup.1R.sup.3SiO.sub.2/2], e=0 to 2, f=0 to 2, and e+f=2, g=0 to 38, h=0 to 20, and the ratio of the sum (f+h) to the sum (g+h+2) is from 0.15 up to 1, and the sum (g+h+2) is 4 to 40, and the radicals R.sup.1 are defined as specified for formula (I), R.sup.3 denotes identical or different hydrocarbons which have 1 to 5 identical or different ester functions, the hydrocarbon being linear, cyclic, branched and/or aromatic, and the ester functions being selected from ethylenically unsaturated, radically polymerizable ester functions and from ester groups which are not radically polymerizable.

7: The composition as claimed in claim 1, wherein component (III) is necessarily included.

8: A radiation-curing coating material, comprising: the composition as claimed in claim 1.

9: The radiation-curing coating material as claimed in claim 8, which is a release coating material.

10: The radiation curing coating material as claimed in claim 8, further comprising an additive.

11: The radiation-curing coating materials as claimed in claim 10, wherein the additive is at least one selected from the group consisting of photoinitiators, photosensitizers, fillers, pigments, solvents, phosphorus-containing compounds which polymerize under UV light, stabilizers, anti-misting additives and amine synergists.

Description

EXAMPLES: COMPONENTS

Component I:

[0065] Not inventive: [0066] NE-I-1: Trimethylolpropane triacrylate, SR 351, Sartomer, France [0067] NE-I-2: Pentaerythritol triacrylate, Miramer M340, Rahn AG, Germany [0068] NE-I-3: Hexanediol diacrylate, Miramer M200, Rahn AG, Germany [0069] NE-I-4: Tripropylene glycol diacrylate, Miramer M220, Rahn AG, Germany [0070] Inventive: [0071] E-I-1: Ethoxylated (according to product description, 3 ethylene oxide units in total) trimethylolpropane triacrylate, Miramer 3130, Rahn AG, Germany [0072] E-I-2: Ethoxylated (according to product description, 20 ethylene oxide units in total) trimethylolpropane triacrylate, SR 415, Sartomer, France [0073] E-I-3: Polyethylene glycol 600 diacrylate (according to product description, Mw 700 g/mol; corresponds to glycol with 12 ethylene oxide units), Ebecryl® 11, Allnex, Ebecryl is a trade mark of Cytec Surface Specialties S.A. Anderlecht, Belgium [0074] E-I-4: Ethoxylated and propoxylated (according to .sup.1H-NMR 1.2 propylene oxide and 5 ethylene oxide units in total) pentaerythritol tetraacrylate, Ebecryl® 40, Allnex, Ebecryl is a trade mark of Cytec Surface Specialties S.A. Anderlecht, Belgium

Component II:

[0075] E-II-1: An exclusively terminally modified silicone with N=50, where N is the number of silicon atoms in the molecule. Prepared by process described in U.S. Pat. No. 6,211,322 via a corresponding hydrogensiloxane by hydrosilylation with trimethylolpropane monoallyl ether and subsequent esterification with acrylic acid, to give 4 acrylate groups per molecule; correspondingly, 4% of the silicon atoms are acrylated. [0076] E-II-2: An exclusively terminally modified silicone with N=100. Prepared as E-II-1; correspondingly, 2% of the silicon atoms are acrylated. [0077] E-I-3: An exclusively terminally modified silicone with N=200. Prepared as E-II-1; correspondingly 1% of the silicon atoms are acrylated. [0078] E-II-4: An exclusively terminally modified silicone with N=300. Prepared as E-II-1; correspondingly 0.67% of the silicon atoms are acrylated. [0079] E-II-5: An exclusively terminally modified silicone with N=100. Prepared by process described in U.S. Pat. No. 6,211,322 via a corresponding hydrogensiloxane by hydrosilylation with 5-hexen-1-ol and subsequent esterification with acrylic acid, to give 2 acrylate groups per molecule; correspondingly, 2% of the silicon atoms are acrylated. [0080] S-II-1: An exclusively laterally modified silicone with N=100. Prepared by process described in U.S. Pat. No. 4,978,726 via a hydrogensiloxane with 6 pendant SiH groups, by hydrosilylation with allyl glycidyl ether and subsequent ring opening with acrylic acid, to give 6 acrylate groups per molecule; correspondingly, 6% of the silicon atoms are acrylated. [0081] S-II-2: A terminally and laterally modified silicone with N=150. Prepared by process described in U.S. Pat. No. 6,211,322 via a hydrogensiloxane having 6 pendant and 2 terminal SiH groups, by hydrosilylation with 5-hexen-1ol and subsequent esterification with acrylic acid, to give 8 acrylate groups per molecule; correspondingly, 5.3% of the silicon atoms are acrylated.

Component III:

[0082] S-III-1: An exclusively laterally modified silicone with N=40. Prepared by process described in U.S. Pat. No. 4,978,726 via a hydrogensiloxane with 6 pendant SiH groups, by hydrosilylation with allyl glycidyl ether and subsequent ring opening with acrylic acid, to give 6 acrylate groups per molecule; correspondingly, 15% of the silicon atoms are acrylated. [0083] S-III-2: An exclusively laterally modified silicone with N=10. Prepared by process described in U.S. Pat. No. 4,978,726 via a hydrogensiloxane with 5 pendant SiH groups, by hydrosilylation with allyl glycidyl ether and subsequent ring opening with acrylic acid, to give 5 acrylate groups per molecule; correspondingly, 50% of the silicon atoms are acrylated. [0084] S-III-3: An exclusively laterally modified silicone with N=20. Prepared by process described in U.S. Pat. No. 4,978,726 via a hydrogensiloxane with 6 pendant SiH groups, by hydrosilylation with allyl glycidyl ether and subsequent ring opening with a mixture of 15% acetic acid and 85% acrylic acid, to give 5.1 acrylate groups per molecule; correspondingly, 25.5% of the silicon atoms are acrylated.

Examples: Compositions

[0085]

TABLE-US-00001 TABLE 1 Inventive compositions, content figures in wt % based on the sum total of the recited components Ex- Com- Com- Com- am- ponent Content ponent Content ponent Content ple I [wt %] II [wt %] III [wt %] E-A E-I-1 10 E-II-2 70 S-III-3 20 E-B E-I-2 10 E-II-2 70 S-III-3 20 E-C E-I-3 10 E-II-2 70 S-III-3 20 E-D E-I-4 10 E-II-2 70 S-III-3 20 E-E E-I-1 10 E-II-1 70 S-III-3 20 E-F E-I-1 10 E-II-3 70 S-III-3 20 E-G E-I-1 10 E-II-4 70 S-III-3 20 E-H E-I-1 10 E-II-5 70 S-III-3 20 E-I E-I-1 10 S-II-1 70 S-III-3 20 E-J E-I-1 10 S-II-2 70 S-III-3 20 E-K E-I-1 10 E-II-2 70 S-III-1 20 E-L E-I-1 10 E-II-2 70 S-III-2 20 E-M E-I-1 5 E-II-2 95 — — E-N E-I-1 30 E-II-2 70 — — E-O E-I-1 80 E-II-2 20 — — E-P E-I-1 2 E-II-2 60 S-III-3 38

TABLE-US-00002 TABLE 2 Non-inventive compositions, content figures in wt % based on the sum total of the recited components Ex- Com- Com- Com- am- ponent Content ponent Content ponent Content ple I [wt %] II [wt %] III [wt %] N-A NE-I-1 10 E-II-2 70 S-III-3 20 N-B NE-I-2 10 E-II-2 70 S-III-3 20 N-C NE-I-3 10 E-II-2 70 S-III-3 20 N-D NE-I-4 10 E-II-2 70 S-III-3 20 N-E NE-I-1 10 E-II-1 70 S-III-3 20 N-F NE-I-1 10 E-II-3 70 S-III-3 20 N-G NE-I-1 10 E-II-4 70 S-III-3 20 N-H NE-I-1 10 E-II-5 70 S-III-3 20 N-I NE-I-1 10 S-II-1 70 S-III-3 20 N-J NE-I-1 10 S-II-2 70 S-III-3 20 N-K NE-I-1 10 E-II-2 70 S-III-1 20 N-L NE-I-1 10 E-II-2 70 S-III-2 20 N-M NE-I-1  5 E-II-2 95 — — N-N NE-I-1 30 E-II-2 70 — — N-O NE-I-1 80 E-II-2 20 — — N-P NE-I-1  2 E-II-2 60 S-III-3 38 N-Q — — E-II-1 70 S-III-3 30 N-R — — E-II-2 70 S-III-3 30 N-S — — E-II-3 70 S-III-3 30 N-T — — E-II-4 70 S-III-3 30 N-U — — E-II-5 70 S-III-3 30 N-V — — S-II-1 70 S-III-3 30 N-W — — S-II-2 70 S-III-3 30 N-X — — E-II-2 70 S-III-1 30 N-Y — — E-II-2 70 S-III-2 30 N-Z1 NE-I-1 30 S-III-3 70 N-Z2 E-I-2 30 S-III-3 70

Examples: Performance Testing

[0086] To produce radiation-curing coating materials, 100 g of each of the compositions of Table 1 and Table 2 were combined with 2% of photoinitiator TEGO® A18 from Evonik Industries AG. The coating materials were stirred manually with a spatula until there was no longer any visible inhomogeneity. The coating materials were applied to a sheetlike carrier. In all of the examples, this carrier was a BOPP (oriented polypropylene) film 50 cm wide, subjected to corona pretreatment beforehand with a generator power of 1 kW. The coating materials were applied using a 5-roll coating unit from COATEMA® Coating Machinery GmbH, Dormagen, Germany with a weight per unit area of about 1 g/m.sup.2 and were cured by exposure to UV light from a medium-pressure mercury vapor lamp from IST® Metz GmbH, Nürtingen Germany at 60 W/cm and at a web speed of 100 m/min under a nitrogen atmosphere with a residual oxygen content of less than 50 ppm.

[0087] The coated samples were subjected to testing for rub-off, release force and release-force stability (change in release forces over time).

[0088] Rub-off: The adhesion of the cured coating to the carrier material is tested by vigorous rubbing with the thumb on the coating. In the event of deficient adhesion, rubberlike crumbs are formed. Even if intense, rubbing should not produce such crumbs. The test is carried out by a trained panel. The evaluation is categorized in school grades from 1 to 3, with 3 corresponding to inadequate.

Rating 1=very good scratch resistance and anchorage to the substrate. With linear and subsequent circular movement at the same location, no crumbs can be ascertained.
Rating 2=sufficient scratch resistance and substrate adhesion. With linear movement, no crumbs are produced, but with a subsequent circular movement at the same location, crumbs are formed.
Rating 3=insufficient scratch resistance and adhesion. Crumbs are produced even on linear movement.

[0089] Release forces: The release forces are tested according to the protocol from FINAT Handbook 8th Edition, The Hague/NL, 2009 under the designation FTM 10, with the modification that storage is under pressure at 40° C. Materials used were the adhesive tape of trade mark TESA®7476 from tesa SE, Germany, Hamburg, and also a label laminate slit to a width of 2.5 cm and coated with the hotmelt adhesive Technomelt PS 9129A from Henkel Corporation/USA on a white paper print substrate. For the test, the laminate is parted and Technomelt PS 9129A on print carrier paper is used as test adhesive.

[0090] The results of the rub-off tests, the release forces and the release-force stabilities are set out in Tables 3a (inventive examples) and 3b (non-inventive examples): Rub-off (ratings 1 to 3); release forces (TW) with two adhesives in cN/2.5 cm after 24 hours of storage at 40° C., release-force stability for adhesive PS 9129A in cN/2.5 cm after 3 months of 40° C. storage.

TABLE-US-00003 TABLE 3a Results of example 3, inventive coating materials according to example 1. TW (PS 9129A) TW (PS 9129A) TW (TESA 7476) Exam- Rub- 24 h 3 months 24 h ple off [cN/2.5 cm] [cN/2.5 cm] [cN/2.5 cm] E-A 1 11 14 36 E-B 1 10 11 34 E-C 1 10 12 35 E-D 1 11 13 36 E-E 1 23 25 71 E-F 1 7 8 29 E-G 2 4 4 30 E-H 1 4 6 31 E-I 1 17 19 49 E-J 1 16 16 40 E-K 1 10 11 32 E-L 1 13 13 41 E-M 1 8 9 34 E-N 1 12 15 42 E-O 1 16 23 48 E-P 1 10 11 36

[0091] The release forces of inventive examples E-A, E-E to E-L (Table 3a) are comparable to the non-inventive, comparative examples N-Q to N-Y (Table 3b). On comparison of the rub-off values, the disadvantage of the absence of component I is evident in the non-inventive examples N-Q to N-Y; the values for the inventive examples E-A, E-E to E-L show an improved, lower rub-off.

[0092] It is possible likewise to compare non-inventive example N-R with inventive examples E-A to E-D. The release forces are comparable; the rub-off of the inventive compositions is improved. In the non-inventive examples N-A to N-D as well, the rub-off is improved relative to the figure for N-R, but the release forces are increased. Particularly noteworthy here is the particularly degraded release-force stability of the non-inventive examples N-A to N-D relative to the inventive examples E-A to E-D.

[0093] Even a small fraction of inventive component I may already bring about an improvement in the rub-off, as shown by example E-P. Again, in comparison to the non-inventive components, a better release force is observed; example N-P.

[0094] It is also apparent from Tables 3a and 3b that mixtures without component III are also able to achieve good rub-off. Inventive examples E-M to E-O achieve a lower release force again than the non-inventive mixtures N-M to N-O.

TABLE-US-00004 TABLE 3b Results of example 3, non-inventive coating materials according to example 1. TW (PS 9129A) TW (PS 9129A) TW (TESA 7476) Exam- Rub- 24 h 3 months 24 h ple off [cN/2.5 cm] [cN/2.5 cm] [cN/2.5 cm] N-A 1 16 28 51 N-B 1 17 29 48 N-C 1 18 32 46 N-D 1 18 35 46 N-E 1 31 48 86 N-F 1 15 29 42 N-G 2 12 26 38 N-H 1 11 23 40 N-I 1 25 38 55 N-J 1 21 36 48 N-K 1 15 28 41 N-L 1 17 35 52 N-M 1 14 27 43 N-N 1 19 39 56 N-O 1 29 56 76 N-P 1 15 31 46 N-Q 2 22 26 72 N-R 2 10 13 35 N-S 3 6 8 30 N-T 3 4 5 28 N-U 3 6 6 33 N-V 2 18 20 48 N-W 3 15 16 38 N-X 3 9 11 33 N-Y 2 12 13 40 N-Z1 1 159 296 563 N-Z2 1 162 312 620

[0095] From table 3b it is apparent that non-inventive compositions consisting only of components II and III, corresponding to examples N-Q to N-Y, do not exhibit very good substrate adhesion as expressed via rub-off (all values above 1). Some of the comparative examples achieve sufficient adhesion, especially those mixtures with a relativeliy high release force. The adhesion of mixtures with particularly low release forces (N-S to N-U and also N-X) is insufficient.

[0096] This shows that with mixtures consisting only of components II and III, it is not possible to obtain a coating combining good adhesion with low release force.

[0097] It is apparent, moreover, that using only component I and component III, as in examples N-Z1 and N-Z2, does not give coatings with low release forces. It is irrelevant in this case whether component III is mixed with inventive component I or non-inventive component I. Mixtures without component II are therefore not purposive and not inventive. Component II must, instead, be added in order for the required low release forces to be achieved.

[0098] It is apparent, moreover, that by adding non-inventive components I (N-A to N-P) it is possible to improve the rub-off, but the release force is increased. In this regard, a comparison ought to be made between the figures for N-A and N-E to N-L and the figures for N-Q to N-Y.

[0099] By using the compositions of the invention, accordingly, success is achieved in simultaneously obtaining good rub-off, low release force and good release-force stability.