UV curable and heat sealable ink
Disclosed is an ink comprising a transparent matrix being UV curable and heat scalable, and at least one pigment component. The ink in its UV-cured state has a peel strength in the range of about 6 to 8 N/cm, wherein this adhesiveness is achievable by means of a further lamination step under the influence of pressure and heat so that the ink acts as a hot glue. Further disclosed is a safety structure comprising a semitransparent layer being formed at least partially by the UV-cured ink, and a secure article comprising the safety structure. Further disclosed is a use of the ink for silkscreen printing.
1. An ink comprising a transparent matrix being UV curable and heat sealable, and at least one pigment component, wherein the ink in a UV-cured state has a peel strength in the range of about 6 to 8 N/cm, wherein adhesiveness corresponding to the peel strength is achievable by means of a further lamination step under the influence of pressure and heat so that the ink acts as a hot glue.
2. The ink according to claim 1 , wherein the matrix is curable in a UV wavelength window of 320 to 420 nm.
3. The ink according to claim 1 , wherein the matrix is curable by a UV radiation energy density of 200 to 300 mJ/cm2, in particular 250 mJ/cm2.
4. The ink according to claim 1 , wherein the matrix comprises at least one of a polyurethane or an acrylate polymer.
5. The ink according to claim 1 , wherein the pigment component comprises goniochromatic metal particles.
6. The ink according to claim 5 , wherein the particles are platelet-shaped.
7. The ink according to claim 5 , wherein the particles comprise a metal core.
8. The ink according to claim 5 , wherein the particles are oriented substantially flat within the matrix.
9. The ink according to claim 5 , wherein the particles are present in the matrix in the form of a monolayer.
10. The ink according to claim 5 , an average size of the particles being between 10 and 50 microns.
11. The ink according to claim 5 , a concentration by dry weight of the particles within the ink being between 5 and 50%, relative to a total weight of the matrix and the particles.
12. A safety structure comprising a semitransparent layer being formed at least partially by the UV-cured ink according to claim 1 .
13. The safety structure according to claim 12 , wherein the safety structure is a passport, an identity card, a driving license, an interactive playing or collectible card, a payment card, a bank note, a voucher, a secure label, a transport card, a loyalty card, a card of delivery, a subscription card, or a token.
14. The safety structure according to claim 12 , wherein the matrix is curable in a LV wavelength window of 320 to 420 nm.
15. The safety structure according to claim 12 , wherein the pigment component comprises goniochromatic metal particles.
16. The safety structure according to claim 15 , wherein the particles are platelet-shaped.
17. The safety structure according to claim 15 , wherein the particles comprise a metal core.
18. The safety structure according to claim 15 , wherein the particles are present matrix in the form of a monolayer.
19. The safety structure according to claim 15 , the average size of the particles being between 10 and 50 microns.
20. A method for using the ink according to claim 1 , comprising silkscreen printing the ink on a surface of a polymeric material.