UV-curing primer composition for the coating of glass

Abstract

The invention relates to a UV-curing primer composition for the coating of glass, in particular glass hollow bodies, wherein the primer composition, in addition to reactive oligomers and/or reactive monomers and at least one photoinitiator, comprises at least one organosilane, which possesses at least one acetoxy radical, in particular 1 to 4 acetoxy radicals. The invention further relates to use of at least one organosilane for providing a UV-cured primer layer on glass and/or an ink layer on glass, a method for coating glass, a substrate coated with a UV-cured primer layer, an ink and a kit.

Claims

1. A UV-curing primer composition for the coating of glass, wherein the primer composition, in addition to reactive oligomers and/or reactive monomers and in addition to at least one photoinitiator, comprises at least one organosilane that possesses at least one acetoxy radical, wherein the at least one organosilane has Formula II below:
(AcO).sub.n(R).sub.2-n(R.sup.1-L)SiOSi(L-R.sup.1)(R).sub.2-n(AcO).sub.n(II) where n is 1 or 2, AcO is the acetoxy radical, R is an alkyl radical, a methyl radical, an ethyl radical, an n-propyl radical or an isopropyl radical, an alkoxy radical, a methoxy radical, an ethoxy radical or an isopropoxy radical, or an aryloxy radical, Si is silicon, L is a divalent linear or a divalent branched hydrocarbon radical, and R.sup.1 is a reactive organic group.

2. The primer composition according to claim 1, further comprising at least one organosilane of Formula I below:
(AcO).sub.n(R).sub.3-nSi-L-R.sup.1(I) where n is 1-3, AcO is the acetoxy radical, R is an alkyl radical, a methyl radical, an ethyl radical, an n-propyl radical or an isopropyl radical, an alkoxy radical, a methoxy radical, an ethoxy radical or an isopropoxy radical, or an aryloxy radical, Si is silicon, L is a divalent linear or a divalent branched hydrocarbon radical, and R.sup.1 is a reactive organic group.

3. The primer composition according to claim 2, wherein the reactive organic group R.sup.1 is an organic group, which under the action of ultraviolet radiation or in the presence of the at least one photoinitiator, can be caused to react, wherein the reactive organic group comprises a vinyl radical, an allyl radical, an acrylate radical or a methacrylate radical.

4. The primer composition according to claim 2, wherein the organo silane is 3-methacryloxypropyltriacetoxysilane.

5. Method for coating glass or glass hollow bodies, wherein a primer composition comprising at least one organosilane as defined in claim 2 is applied to at least part of an optionally pre-treated glass, the applied primer layer is partially crosslinked by UV radiation, and at least one further coating is applied to at least part of the crosslinked primer layer, wherein the at least one further coating is applied in a digital printing process or an inkjet printing process.

6. The primer composition according to claim 1, wherein the organo silane is 1,3-bis(3-methacryloxypropyl)-1,1,3,3-tetraacetoxydisiloxane.

7. The primer composition according to claim 1, further comprising at least one pigment selected from the group composed of titanium dioxide, carbon black, aluminum, inorganic pigments, organic pigments and mixtures of at least two of the aforementioned pigments.

8. A method of coating glass, in particular for or coating glass hollow bodies, comprising: applying a primer composition according to claim 1 to at least part of an optionally pre-treated glass surface, partially crosslinking the applied primer layer by UV radiation, and optionally applying at least one further coating to at least part of the crosslinked primer layer, wherein the primer composition is applied to the glass surface in a digital printing process or an inkjet printing process.

9. The method according to claim 8, wherein the primer composition and/or the further coating are applied in an air atmosphere having a water content <8.5 g/Nm.sup.3.

10. The method according to claim 8, wherein the further coating is applied in the digital printing process, or the inkjet printing process.

11. The method according to claim 8, further comprising: pre-treating the glass surface by flame treatment and/or silicate treatment by flame pyrolysis, applying the UV-curing primer composition by the inkjet printing process to at least part of the pre-treated glass surface, partially crosslinking the primer composition with UV radiation, applying at least one further coating of a UV-curing ink in the inkjet printing process to at least part of the crosslinked primer layer, and curing the applied UV ink with UV radiation.

12. Method according to claim 8, wherein the primer composition is applied to the glass surface in a digital printing process or an inkjet printing process.

13. Method according to claim 8, wherein the at least one further coating is a UV-curing ink.

14. A substrate of glass, a glass container or a glass bottle, at least partially coated or printed with the UV-crosslinked primer composition according to claim 1.

15. Ink comprising at least one organosilane possessing at least one acetoxy radical, wherein the at least one organosilane is an organosilane which is defined in claim 1.

16. A kit that provides a UV-cured primer layer on glass and/or provides an ink layer or a UV-cured ink layer, on glass, wherein the kit comprises the primer composition for the coating of glass, and the primer composition, in addition to reactive oligomers and/or reactive monomers and in addition to at least one photoinitiator, comprises at least one organosilane possessing at least one acetoxy radical, wherein the at least one organosilane has Formula II below:
(AcO).sub.n(R).sub.2-n(R.sup.1-L)SiOSi(L-R.sup.1)(R).sub.2-n(AcO).sub.n(II) where n is 1 or 2, AcO is the acetoxy radical, R is an alkyl radical, a methyl radical, an ethyl radical, an n-propyl radical or an isopropyl radical, a methoxy radical, an ethoxy radical or an isopropoxy radical, an alkoxy radical, or an aryloxy radical, Si is silicon, L is a divalent linear or a divalent branched hydrocarbon radical, and R.sup.1 is a reactive organic group, or the ink according to claim 15 and at least one further component selected from the group composed of at least one further ink, a UV lamp, an LED emitter, an LED-UV drier unit, a digital printing head, a digital printing system and combinations of at least two of the aforementioned components.

17. The primer composition according to claim 15, wherein the at least one acetoxy radical comprises 2 to 4 acetoxy radicals.

18. The primer composition according to claim 1, wherein the glass is glass hollow bodies.

19. The primer composition according to claim 1, wherein the at least one acetoxy radical comprises 2 to 4 acetoxy radicals.

Description

EXAMPLE SECTION

Example 1

Printing of Glass Surfaces With Various UV-Curable Primer Compositions

(1) Glass plates (Floatglas dinA5 3 mm from Glassolutions Saint Gobain GmbH) were printed with the primer compositions shown in Tables 1-3 below:

(2) TABLE-US-00001 TABLE 1 Formulation of a primer composition according to the invention Ingredient Parts (wt %) Monomer Isobornyl acrylate 68.5 Monomer (Octahydro-4,7-methano-1H- 12.5 indendyl)bis(methylene)diacrylate Photoinitiator Diphenyl(2,4,6- 9.0 trimethylbenzoyl)phosphine oxide Organosilane 1 3-methacryloxypropyl-triacetoxysilane 8.5 Organosilane 2 1,3-bis(3-methacryloxypropyl)-1,1,3,3- 1.5 tetraacetoxydisiloxane

(3) The formulation of a primer composition according to the invention given in Table 1 above is also abbreviated below as primer 1.

(4) TABLE-US-00002 TABLE 2 Formulation of a primer composition not according to the invention Ingredient Parts (wt %) Monomer Isobornyl acrylate 68.5 Monomer (Octahydro-4,7-methano-1H- 12.5 indendyl)bis(methylene)diacrylate Photoinitiator Diphenyl(2,4,6- 9.0 trimethylbenzoyl)phosphine oxide Organosilane 3-methacryloxypropyl- 10.0 trimethoxysilane

(5) The primer composition given in Table 2 above and used for comparison purposes is also abbreviated below as primer 2.

(6) TABLE-US-00003 TABLE 3 Formulation of a further primer composition not according to the invention Ingredient Parts (wt %) Monomer Isobornyl acrylate 68.5 Monomer (Octahydro-4,7-methano-1H- 12.5 indendyl)bis(methylene)diacrylate Photoinitiator Diphenyl(2,4,6- 9.0 trimethylbenzoyl)phosphine oxide Organosilane (3-Acryloxypropyl)tri-methoxysilane 10.0

(7) The primer composition given in Table 3 above and also used for comparison purposes is also abbreviated below as primer 3.

(8) The glass plates were printed with the primer compositions shown in the above table with and without prior silicate pre-treatment. Printing was carried out by manual pressure using a no. 2 spiral doctor blade. For this purpose, the glass plates were first printed with the primer by manual pressure. After this, intermediate curing was carried out using a mercury drier from the firm IST (two 120 W/cm lamps, tape speed 20 m/min). After this, overprinting was carried out using White 7100/82464170Z or White 7100/79095170 (manufacturer: Marabu GmbH & Co. KG). This was followed by post-curing with the mercury drier from the firm IST (two 120 W/cm lamps, tape speed 10 m/min).

(9) Adhesion Tests:

(10) The adhesion of the printed primer composition was validated by means of the cross-cut test (according to DIN EN ISO 2409). The cross-cut was carried out immediately after immersion in water on the still-wet substrate. An adhesive tape (Tesa 4101) was applied to the substrate immediately after it was wiped dry. After this, the adhesive tape was pulled off. The adhesion results are shown in Tables 4 to 6 below:

(11) With pre-treatment of the glass surfaces and immersion in water at room temperature:

(12) TABLE-US-00004 TABLE 4 Cross-cut parameters after pre-treatment of the glass surfaces and/or after immersion in water at room temperature Cross-cut before After 3 h After 24 h White immersion immersion immersion Test Primer overprinting in water in water in water Test 1 Primer 1 7100/82464170 CP0 CP0 CP0 Test 2 Primer 1 7100/79095170 CP0 CP0 CP0 Test 3 Primer 2 7100/82464170 CP0 CP5 CP5 Test 4 Primer 2 7100/79095170 CP0 CP3-4 CP3 Test 5 Primer 3 7100/82464170 CP1-2 CP5 CP5 Test 6 Primer 3 7100/79095170 CP0 CP5 CP3-4

(13) With pre-treatment of the glass surfaces and after immersion in water at elevated temperature:

(14) TABLE-US-00005 TABLE 5 Cross-cut parameters after pre-treatment and/or after immersion in water at elevated temperature Test Primer White overprinting Water bath Cross-cut Test 7 Primer 1 7100/82464170 0.5 h 60 C. CP0 Test 8 Primer 1 7100/79095170 0.5 h 60 C. CP0 Test 9 Primer 1 7100/82464170 0.5 h 60 C. + CP0 1 h 70 C. Test 10 Primer 1 7100/79095170 0.5 h 60 C. + CP0 1 h 70 C.

(15) Without pre-treatment of the glass surface and immersion in water at room temperature:

(16) TABLE-US-00006 TABLE 6 Determined cross-cut parameters without pre-treatment Cross-cut Cross-cut before after 24 h immersion immersion Test Primer White overprinting in water in water Test 11 Primer 1 7100/82464170 CP0 CP0 Test 12 Primer 1 7100/79095170 CP0 CP0

(17) The adhesion test confirmed the superiority of the primer composition according to the invention (primer 1) under the effect of water compared to the primer compositions primer 2 and primer 3 used for comparison purposes and showed that in this case, is it possible that pre-treatment can be dispensed with.

Example 2

Printing on a Glass Surface Using a Further UV-Curable Primer Composition According to the Invention

(18) Glass plates (Floatglas dinA5 3 mm from the firm Glassolutions Saint Gobain GmbH) and shaped bottles (Braunglas HKL III, manufacturer: Stlzle-Oberglas GmbH) were printed using a UV-curable primer composition with the following formulation:

(19) TABLE-US-00007 TABLE 7 Formulation of a further primer composition according to the invention Ingredient Content (wt %) Monomer Isobornyl acrylate 68.5 Monomer (Octahydro-4,7-methano-1H- 12.5 indendiyl)bis(methylene)diacrylate Photoinitiator Diphenyl(2,4,6- 9.0 trimethylbenzoyl)phosphine oxide Organosilane 1 3-methacryloxypropyl-triacetoxysilane 7.0 Organosilane 2 1,3-bis(3-methacryloxypropyl)-1,1,3,3- 2.0 tetraacetoxydisiloxane Additive Stabilizer 1.0

(20) The above primer composition had a viscosity of 10.0 mPas and a surface tension of 31.2 mN/m at 40 C.

(21) The above-mentioned glass plates and the shaped bottles were printed as follows:

(22) The glass plates and shaped bottles were first subjected to flame treatment and/or silicate treatment. The glass surfaces treated in this manner were then printed with the primer composition given in Table 7 above. Printing was carried out by means of an inkjet printing system (model XY300 from the firm Industrial Inkjet Ltd.). The printing heads used were model KM1024iM from the manufacturer Konica-Minolta Business Solutions Deutschland GmbH. Printing was carried out using single pass technology with a resolution of 360360 dpi. The printing speed was 200 mm/s.

(23) After application of the primer composition (with a delay of 12 s), intermediate curing, i.e. partial crosslinking, was carried out using an LED emitter (Pinning-Lampe LED 395 nm 8 W from Dr. Hnle AG). After this, overprinting was carried out with White 7100/82464170Z (manufacturer: Marabu GmbH & Co. KG), followed without delay by intermediate curing using the above-mentioned LED emitter. Post-curing was carried out without delay using a model VZERO2 085 mercury lamp (manufacturer: Integration Technology Ltd.).

(24) The primer composition used could be processed in the inkjet printing system without difficulty, particularly without clogging of the printing heads and/or corrosive damage.

(25) Adhesion Tests:

(26) The adhesion of the printed primer composition was validated by means of the cross-cut test (according to DIN EN ISO 2409). Cross-cutting was carried out directly on the still-wet substrate after immersion in water. An adhesive tape (Tesa 4101) was applied to the substrate immediately after it was wiped dry. After this, the adhesive tape was pulled off. The cross-cut parameters (CP) are given in Table 8 below:

(27) TABLE-US-00008 TABLE 8 Determined cross-cut parameters Cross-cut Glass plate Bottle Drying CP1 CP1-2 After 1 h water bath at room CP1 CP1-2 temperature After 24 h water bath at room CP1 CP 1-2 temperature

(28) The tests carried out confirmed the outstanding printability and the outstanding adhesive strength of the primer composition on glass surfaces. The adhesion tests also showed that the adhesive strength of the applied primer composition was not impaired or at least not significantly impaired even after immersion in water for several hours. The validated primer composition was thus characterized by outstanding resistance to water.

(29) 3. Analysis of the effect of air moisture on the open condition of a printing head:

(30) In a test stand for inkjet printing heads (XY300 by Industrial Inkjet, UK) a printing head of Konica Minolta (Type KM1024MHE-D) was filled with a primer via an injector with hose and subjected to printing once a week and checked for failed nozzles thereby. During the test period, the printing head was not capped so that a nozzle plate was always exposed to environmental air.

(31) Test 1:

(32) The air moisture was 40% (rel.). The air temperature was 25 C. After a test period of 6 weeks, the first nozzles failed. The failed nozzles could not be regenerated by cleaning.

(33) Test 2:

(34) The air moisture in the environment of the printing head was lowered to 0.5% (rel.) by supplying dried air. Even after 6 months, there was no change detectable on the printing head.