Method for protecting glass surface using long-chain organic material
A method for protecting a sheet surface by forming a discontinuous layer of a long-chain organic material having a main carbon chain comprising at least 12 carbon atoms and a hydrophilic group at one end of the main chain on the sheet surface. The protective layer is easy to remove using standard cleaning method, while providing satisfactory surface protection against particle contamination and scratches, at a very low coating thickness. The invention is particularly useful for protecting glass sheet surfaces during glass sheet finishing such as edge grinding and polishing. The invention is especially useful for the finishing and packaging of LCD glass substrates.
1. A method of handling a glass sheet material having a sheet surface comprising the following steps:
(I) forming a discontinuous layer of a long-chain organic material having a main carbon chain comprising at least 12 carbon atoms and a hydrophilic group and
(II) exposing the sheet surface bearing the long-chain organic material to a plurality of traveling particles;
wherein in step (I), the organic material has a main carbon chain comprising a hydrophilic group selected from a hydroxyl and a carboxyl group.
2. A method according to claim 1 , wherein the sheet surface of the glass sheet material is hydrophilic.
3. A method according to claim 1 , wherein in step (I), the organic material has a main carbon chain comprising at most 40 carbon atoms.
4. A method according to claim 1 , wherein in step (I), the organic material is selected from C18-OH and mixtures of C18-OH and C18-acid.
5. A method according to claim 1 , wherein the density of the long-chain organic material at the end of step (I) is from 20 ng·cm −2 to 160 ng·cm —2 .
6. A method according to claim 1 , wherein the average thickness of the layer of the long-chain organic material at the end of step (I) is at most 10 nm.
7. A method according to claim 1 , wherein the average thickness of the layer of the long-chain organic material on the sheet surface is at most three times of the length of the main carbon chain.
8. A method according to claim 1 , wherein the molecules of the long-chain organic material form a plurality of discontinuous islets on the sheet surface.
9. A method according to claim 1 , wherein the islets are separated by non-coated bare surface area of the sheet surface.
10. A method according to claim 1 , wherein the average distance between adjacent islets on the sheet surface is from 0.1 μm to 3 μm.
11. A method according to claim 1 , wherein step (II) comprises:
(II.1) grinding an edge of the glass sheet material.
12. A method according to claim 1 , wherein step (II) further comprises:
(II.2) applying water to the edge of the glass sheet material.
13. A method according to claim 1 , wherein step (II) comprises:
(II.3) scribing part of the sheet surface of the glass sheet material to form a score-line; and
(II.4) separating a part of the glass sheet material along the score-line from the glass sheet material.
14. A method according to claim 1 , wherein at the end of step (I), the sheet surface bearing the long-chain organic material exhibits a water contact angle of from 12° to 50°.
15. A method according to claim 1 , wherein at the end of step (I), the sheet surface bearing the long-chain organic material exhibits a reduction of adhesion force as measured by AFM of from 20% to 70%.
16. A method according to claim 1 , wherein in step (I), the temperature of the glass sheet material is maintained below the melting point of the long-chain organic material.
17. A method of handling a glass sheet material having a sheet surface comprising the following steps:
(I) forming a discontinuous layer of a long-chain organic material having a main carbon chain comprising at least 12 carbon atoms and a hydrophilic group and
(II) exposing the sheet surface bearing the long-chain organic material to a plurality of traveling particles, wherein step (I) comprises:
(I.1) providing a gas stream comprising the long-chain organic material; and
(I.2) contacting the gas stream with the sheet surface for a sufficient period of time to effect the forming of the layer of the long-chain organic material.
18. A method according to claim 17 , wherein in step (I.2), the gas stream has a temperature higher than the melting point of the long-chain organic material, but below the flash point of the long-chain organic material.
19. A method of handling a glass sheet material having a sheet surface comprising the following steps:
(I) forming a discontinuous layer of a long-chain organic material having a main carbon chain comprising at least 12 carbon atoms and a hydrophilic group and
(II) exposing the sheet surface bearing the long-chain organic material to a plurality of traveling particles, wherein step (I.1) comprises:
(I.1.1) forming a liquid comprising the long-chain organic material; and
(I.1.2) passing a carrier gas stream through the liquid or in the vicinity of the surface of the liquid to load the gas stream with the long-chain organic material.