METHOD OF MOLDING ULTRAVIOLET CURED MICROSTRUCTURES AND MOLDS

• US 20080093776A1
• Filed: 10/05/2006
• Published: 04/24/2008
• Est. Priority Date: 10/05/2006
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Williams, Todd R.
• Application Number:
  US11/538,933
• Publication Number:
  US 20080093776A1
• Time in Patent Office: Days
• US Class Current: 264/496
• CPC Class Codes: B29C 2033/0005 with transparent parts, e.g. permitting visual inspection of the interior of the cavity
• CPC Class Codes: B29C 2035/0827 using UV radiation
• CPC Class Codes: B29C 33/405 Elastomers, e.g. rubber B29C33/50 takes precedence
• CPC Class Codes: B29C 33/424 Moulding surfaces provided with means for marking or patterning for injection moulding B29C45/372
• CPC Class Codes: B29C 35/0888 using transparant moulds
• CPC Class Codes: B29C 37/0053 Moulding articles characterised by the shape of the surface, e.g. ribs, high polish mould construction therefor B29C33/42; surface shaping of articles B29C59/00; by incorporating filler in or near the surface B29C70/64
• CPC Class Codes: B29L 2031/3475 Displays, monitors, TV-sets, computer screens

Abstract

Presently described is a microstructured mold prepared from a photocured polymeric material that comprises at least one (i.e. first) photoinitiator having certain absorption characteristics. The mold is suitable for use in methods of molding a (e.g. barrier rib) microstructure precursor composition that comprises at least one (i.e. second) photoinitiator. The second photoinitiator of the microstructure precursor preferably has similar absorptions characteristics as the first photoinitiator. Thus, the polymeric material of the mold the microstructure precursor can be cured with the same wavelength range of light.

Claims

1. A method of making barrier ribs comprising:

providing a mold having a microstructured surface comprising recesses suitable for making barrier ribs wherein at least the microstructured surface comprises a photocured polymeric material comprising a first photoinitiator having an absorption coefficient of at least 100 at a wavelength ranging from about 385 nm to about 465 nm;

filling the recesses of the mold with a photocurable rib precursor comprising an oligomer, a diluent, an inorganic particulate, and a second photoinitiator;

photocuring the rib precursor; and

removing the mold from the cured barrier ribs.

2. The method of claim 1 wherein prior to curing the rib precursor is contacted with a substrate.

3. The method of claim 2 wherein the substrate is a glass substrate having an electrode pattern and the microstructured surface of the mold is aligned with the electrode pattern.

4. The method of claim 2 wherein rib precursor is photocured through the mold, through the substrate, or a combination thereof.

5. The method of claim 1 wherein the second photoinitiator has an absorption coefficient of at least 100 at a wavelength ranging from about 385 nm to about 465 nm.

6. The method of claim 1 wherein the first photoinitiator is selected from acyl phosphine oxide, α

-aminoketone, and mixtures thereof.

7. The method of claim 1 wherein the rib precursor comprises a second photoinitiator selected from acyl phosphine oxide, α

-aminoketone, and mixtures thereof.

8. The method of claim 1 wherein the first and second photoinitiator are selected from acyl phosphine oxide, α

-aminoketone, and mixtures thereof.

9. The method of claim 1 wherein the photocuring light is provided by super actinic bulbs.

10. The method of claim 1 wherein the mold further comprises a light transmissible support.

11. The method of claim 10 wherein the support is a polyester film.

12. A mold having a microstructured surface comprising recesses wherein the microstructured surface comprises a photocured polymeric material comprising a photoinitiator having an absorption coefficient of at least 100 at a wavelength ranging from about 385 nm to about 465 nm.

13. An intermediate assembly prepared during a method of making a microstructured article comprising:

the mold of claim 12; and

a photocurable microstructure precursor composition comprising a second photoinitiator provided in at least the recesses of the microstructured surface.

14. The intermediate assembly of claim 13 wherein the photocurable microstructure precursor composition comprises an oligomer, a diluent, and an inorganic particulate.

15. The intermediate assembly of claim 13 wherein the second photoinitiator has an absorption coefficient of at least 100 at a wavelength ranging from about 385 nm to about 465 nm.

16. A method of making microstructures comprising:

providing a mold having a microstructured surface comprising recesses wherein at least the microstructured surface comprises a photocured polymeric material comprising a first photoinitiator having an absorption coefficient of at least 100 at a wavelength ranging from about 385 nm to about 465 nm;

filling the recesses of the mold with a photocurable microstructure precursor;

photocuring the microstructure precursor; and

removing the mold from the cured microstructures.

17. The method of claim 16 wherein the microstructure precursor composition is substantially free of inorganic material.

18. A method of making a microstructured article comprising:

providing a mold having a microstructured surface comprising recesses wherein at least the microstructured surface comprises a photocured polymeric material having a first photoinitiator selected from acyl phosphine oxide, α

-amino ketone, and mixtures thereof, filling the recesses of the mold with a photocurable microstructure precursor comprising a second photoinitiator selected from acyl phosphine oxide, α

-amino ketone, and mixtures thereof;

photocuring the microstructure precursor; and

removing the mold.

19. The method of claim 18 wherein the mold is suitable for making barrier ribs.

20. The method of claim 18 wherein the photocurable microstructure precursor comprises an oligomer, a diluent, and an inorganic particulate.

21. The method of claim 18 wherein prior to curing the microstructure precursor is contacted with a glass substrate having an electrode pattern and the microstructured surface of the mold is aligned with the electrode pattern.

22. A method of making a microstructured article comprising:

providing a mold having a microstructured surface comprising recesses wherein at least the microstructured surface comprises a polymeric material photocured at a wavelength ranging from about 385 nm to 465 nm;

filling the recesses of the mold with a microstructure precursor composition comprising a second photoinitiator;

photocuring the microstructure precursor composition at a wavelength range that includes at least a portion of the wavelength range used to cure the photocured polymeric material of the mold; and

removing the mold from the cured microstructures without breakage of the microstructures.

23. The method of claim 22 wherein prior to curing the microstructure precursor is contacted with a glass substrate having an electrode pattern and the microstructured surface of the mold is aligned with the electrode pattern.