Methods for making and using point lump-free compositions and products coated with point lump-free compositions
View Patent ↗A method is provided to manufacture a coated substrate, such as an optical fiber, without undesirable point lumps. The method filters a coating composition while controlling the filtering temperature, pressure drop across a filtering assembly, and filter pore size to achieve a resulting filtration factor not greater than 250,000 s −1 . The filtration factor is a function of filtering temperature and pressure drop across the filtering assembly. Typically, the coating composition is filtered by passing the coating composition through one or more filters of the filtering assembly, having an absolute pore size rating in the range from approximately 0.05 to approximately 5 microns, at a temperature less than approximately 105° F. (40° C.), and at a pressure drop ΔP across the filtering assembly of at most approximately 80 psig, wherein the ratio of pressure drop (mPa) to viscosity (mPa·s), which is dependent upon filtering temperature, minimizes the filtration factor to ≦250,000 s −1 .
1. A method for coating a substrate comprising:
providing a coating composition; filtering the coating composition by passing the coating composition through a filtering device comprising at least one filtering assembly comprising at least one filter, and applying the coating composition after filtering to the substrate;
wherein the at least one filtering assembly has a filtration factor (γ) determined by a Formula I
γ
(
s
-
1
)
=
Δ
P
(
mPa
)
η
(
mPa
·
s
)
I
of at most 250,000 s −1 , wherein η is viscosity of the coating composition at the respective temperature of the coating composition within the respective filtering assembly, and ΔP is the pressure drop measured across the respective at least one filtering assembly and is between about 0 and about 80 psig, and the pore size of at least one filter of the at least one filtering assembly is at most 10 microns, and the respective temperature of the coating composition within the respective at least one filtering assembly is at most about 120° F.
2. The method of coating a substrate of claim 1 , wherein the maximum pressure drop during said filtering is determined according a formula selected from the group consisting of:
Δ
P
max
(
psi
)
=
γ
max
(
1
/
s
)
×
η
(
mPa
·
s
)
6.894757
(
mPa
/
psi
)
and
Δ
P
max
(
psi
)
=
250000
(
1
/
s
)
×
ⅇ
{
(
6992.5
(
mPa
·
s
·
K
)
T
(
c
)
+
273
)
-
15.025
(
mPa
·
s
)
}
6.894757
(
mPa
/
psi
)
wherein η is the viscosity of the coating composition at operating temperature T in the respective filtering assembly and γ is the maximum predetermined filtration factor.
3. The method of coating a substrate of claim 1 , wherein the maximum temperature during said filtering is determined according to the following formula:
T
max
(
c
)
=
{
6992.5
(
mPa
·
s
·
K
)
ln
[
Δ
P
(
psi
)
×
6.894757
(
mPa
/
psi
)
γ
max
(
1
/
s
)
]
-
15.025
(
mPa
·
s
)
}
-
273
wherein ΔP is pressure drop across each respective filtering assembly and η is viscosity of the coating composition at filtration temperature in the respective filtering assembly and γ is the maximum predetermined filtration factor.
4. The method for coating a substrate of claim 1 , wherein at least one of the at least one filtering assembly having a filtration factor of at most 250,000 s −1 has a pore size in the range from approximately 0.05μ, to approximately 5μ, and wherein said filtering is performed at a temperature less than approximately 105° F. (40° C.), and at a pressure drop ΔP across the respective filtering assembly of at most approximately 80 psig.
5. The method of coating a substrate of claim 1 , wherein the substrate is an optical fiber.
6. The method of coating a substrate of claim 5 , wherein the coating composition is applied onto the optical fiber as a secondary coating; and further comprising the step of coating the optical fiber with a primary coating composition, wherein the secondary coating is applied over the primary coating.
7. The method of coating an substrate of claim 6 , further comprising: curing the primary coating on the optical fiber; and thereafter curing the secondary coating on the optical fiber.
8. The method of coating a substrate of claim 6 , wherein the curing of the first coating and curing the second coating occur simultaneously.
9. The method of coating a substrate of claim 1 , wherein said filtering is performed at a temperature of approximately 60° F. and to approximately 95° F.
10. The method of coating a substrate of claim 1 , wherein said filtering is performed at a temperature of approximately 70° F. to approximately 90° F.
11. The method of coating a substrate of claim 1 , wherein said filtering is performed at a temperature of approximately 70° F. to approximately 80° F.
12. The method of coating a substrate of claim 1 , wherein the at least one filtering assembly has a filtration factor less than or equal to approximately 43,000 s −1 .
13. The method of coating a substrate of claim 1 , wherein the at least one filtering assembly has a filtration factor is between approximately 50,000 and 190,000 s −1 .
14. The method of coating a substrate of claim 1 , wherein said pressure drop of said filtering is approximately 35 to approximately 55 psig.
15. The method of coating a substrate of claim 1 , wherein said pressure drop of said filtering is approximately 40 to approximately 50 psig.
16. The method of coating a substrate of claim 1 , wherein the at least one filtering assembly comprises a membrane filter having a pore size from approximately 0.05 to approximately 0.6 microns.
17. The method of coating a substrate of claim 1 , wherein the at least one filtering assembly comprises a membrane filter having a pore size from approximately 0.1 to approximately 0.45 microns.
18. The method of coating a substrate of claim 1 , wherein the at least one filtering assembly comprises a depth filter having a pore size of approximately 0.5 to approximately 5 microns.
19. The method of coating a substrate of claim 1 , wherein the at least one filtering assembly comprises a depth filter having a pore size of approximately 1 to approximately 3 microns.
20. The method of coating a substrate of claim 1 , wherein the substrate is a compact disk or a DVD.
21. The method of coating a substrate of claim 1 , wherein the substrate is an optical medium.
22. The method of coating a substrate of claim 1 , wherein the coating composition is a dental composition.
23. The method of coating a substrate of claim 1 , wherein the substrate is a laminated surface.
24. The method of coating a substrate of claim 1 , wherein the filtering device comprises a plurality of filtering assemblies arranged in series.
25. The method of coating a substrate of claim 1 , wherein the filtering device comprises a plurality of filtering assemblies arranged in parallel.
26. The method of coating a substrate of claim 1 , wherein each of the filtering assemblies have a filtration factor of at most 250,000 s −1 .
27. The method for coating a substrate according to claim 1 , wherein at least one filter of the at least one filtering assembly has a pore size in the range from approximately 0.05 to approximately 5 microns, and said filtering is performed at a temperature less than approximately 105° F. (40° C.), and at a pressure drop ΔP at the at least one filtering assembly of at most approximately 80 psig.
28. The method for coating a substrate according to claim 1 , wherein the pressure drop is in a range of approximately 3 to approximately 40 psi.
29. The method for coating a substrate according to claim 1 , wherein the pore size of the filter is in a range from approximately 0.45 to 3 microns.
30. The method for coating a substrate according to claim 1 , wherein the filtering temperature is in a range from approximately 70 to approximately 105° F.