Data storage medium comprising polyimides
View Patent ↗In one aspect the present invention provides a storage medium for data, the storage medium comprising: a) a substrate, a physical portion of which comprises at least one polyimide, and b) at least one data layer on the substrate. The substrate comprising a polyimide exhibits low axial displacement and beneficial damping characteristics.
1. A storage medium for data, the storage medium comprising:
a) a substrate, a physical portion of which comprises at least one polyimide, and
b) at least one data layer on the substrate;
wherein said polyimide has a mechanical damping coefficient of at least about 0.028 at a temperature of about 50° C. at a frequency of about 1.6 hertz; and wherein the at least one polyimide comprising structural units of the formula:
wherein “A” comprises structural units of the formulae:
or mixtures of the foregoing structural units;
wherein “D” is a divalent aromatic group, R3 and R10–R12 are independently selected from hydrogen, halogen, and C1–C6 alkyl groups; “q” is an integer having a value of 1 up to the number of positions available on the aromatic ring for substitution; “W” is a linking group; and
wherein B comprises a divalent organic radical selected from aromatic hydrocarbon radicals having 6 to about 30 carbon atoms and substituted derivatives thereof.
2. The data storage medium of claim 1 , wherein “D” has the formula:
wherein A1 is an aromatic group, B is an alkylene, an alkylidene, a cycloaliphatic group; sulfur-containing linkage, a phosphorus-containing linkage; an ether linkage, a carbonyl group, a tertiary nitrogen group, or a silicon-containing linkage; Y1 is selected from the group consisting of a hydrogen, a monovalent hydrocarbon group, alkenyl, allyl, halogen, bromine, chlorine; and nitro; wherein “m” represents any integer from and including zero through the number of positions on A1 available for substitution; R4 is a hydrogen or a monovalent hydrocarbon group, wherein “p” represents an integer from and including zero through the number of positions on E available for substitution; “t” represents an integer equal to at least one; “s” represents an integer equal to either zero or one; and “u” represents any integer including zero.
3. The polyimide composition of claim 2 , wherein “E” is a moiety selected from the group consisting of cyclopentylidene, cyclohexylidene, 3,3,5-trlmethylcyclohexylidene, methylcyclohexyliclene, neopentylidene, cyclododecylidene, adamantylidene, isopropylidene, bicyclo[2.2.1]hept-2-ylidene, 1,7,7-trlmethylbicyclo[2.2.1]hept-2-ylidene, and C═CZ 2, wherein each Z is hydrogen, chlorine, or bromine, subject to the provision that at least one Z is chlorine or bromine; and mixtures of the foregoing moieties.
4. The ployimide composition of claim 1 , wherein “W” is selected from the group consisting of a covalent bond, oxygen, sulfur, sulfoxide, sulfone, silicon, carbonyl, or hexafluoro isopropylidene.
5. The data storage medium of claim 1 , wherein “A” comprises structural units derived from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride; 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride; the mixed dianhydride 2-[4-(3,4-dicarboxyphenoxy)phenyl]-2-[4-(2,3-dicarboxyphenoxy)phenyi]propane dianhydride, 3,4,3′,4′-benzophenonetetracarboxylic acid dianhydride. 3,3′,4,4′-oxydiphthalic anhydride, 2,3,2′,3′-biphenylretracarboxylic acid dianhydride, pyrorndllitic dianhydride, 3,4,3′,4′-diphenylsulfonetetracarboxylic acid dianhydilde, 4,4′-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 4,4′-bis(3,4-dicarboxyphenoxy)diphenyl ether dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride or mixtures of the foregoing dianhydrides.
6. The data storage medium of claim 1 , wherein “A” is selected from the group consisting of:
and mixtures thereof.
7. The data storage medium of claim 1 , wherein “B” is selected from the group consisting of substituted and unsubstituted phenylene groups.
8. The data storage medium of claim 1 , wherein “B” comprises structural units derived from at least one diamine selected from the group consisting of 1,3-phenylenediamine, 1,4-phenylenediamine, 2-methyl-1,3-phenylenediamine, 4-methyl-1,3-phenylenediamine, 2,4,6-trimethyl-1,3-phenylenediamine, 2,6-diethyl-4-methyl-1,3-phenylenediamine 3,6-diethyl-2-methyl-1,3-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 3,5′-dimethylbenzidene, 2,2′,6,6′-tetramethylbenzidene, 3,5′-dimethoxybenzidene, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl methane, fluorinated alkyl analogs of said diamines, 2-trifluoromethyl-1,4-phenylenediamine and mixtures thereof.
9. The data storage medium of claim 1 , wherein “B” comprises structural units derived from at least two diamines wherein at least about 45% of at least one diamine is selected from the group consisting of 1,3-phenylenediamine, 1,4-phenylenediamine, 2-methyl-1,3-phenylenediamine, 4-methyl-1,3-phenylenediamine, 2,4,6-trimethyl-1,3-phenylenediamine, 2,6-diethyl-4-methyl-1,3-phenylenediamine, 3,6-diethyl-2-methyl-1,3-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 3,5′-dimethylbenzidene, 2,2′,6,6′-tetramethylbenzidene, 3,5′-dimethoxybenzidene, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl methane and combinations thereof, based on the total weight of structural units derived from diamine.
10. The data storage medium of claim 1 , wherein “k” is an integer having a value from 1 to about 50.
11. The data storage medium of claim 1 , wherein said polyimide composition is a blend comprising a second polyimide wherein the said blend is a miscible blend.
12. The data storage medium of claim 1 , wherein said polyethermide composition has a mechanical damping coefficient of at least about 0.05 at a temperature of above about 130° C. at a frequency of about 1.6 hertz.
13. The data storage medium of claim 1 , wherein said polyimide composition has a glass transition temperature in a range of about 150° C. to about 350° C.
14. The data storage medium of claim 1 , wherein said polyimide composition has a glass transition temperature in a range of about 170° C. to about 300° C.
15. The data storage medium of claim 1 , wherein said polyimide composition has a glass transition temperature in a range of about 180° C. to about 280° C.
16. A storage medium for data, the storage medium comprising:
a) a substrate, a physical portion of which comprises at least one polyimide; and
b) at least one data layer on the substrate;
wherein said polyimide has a mechanical damping coefficient of at least about 0.028 at a temperature of about 50 C at a frequency of about 1.6 hertz; the at least one polyimide comprising structural units of the formula:
wherein “A” comprises structural units selected from the group consisting of:
and mixtures thereof; and
B comprises a divalent organic radical selected from aromatic hydrocarbon radicals having 6 to about 30 carbon atoms and substituted derivatives thereof.
17. The data storage medium of claim 16 , wherein “B” comprises structural units derived from at least one diamine selected from the group consisting of 1,3-phenylenediamine, 1,4-phenylenediamine, 2-methyl-1,3-phenylenediamine, 4-methyl-1,3-phenylenediamine, 2,4,6-trimethyl-1,3-phenylenediamine, 2,6-diethyl-4-methyl-1,3-phenylenediamine, 3,6-diethyl-2-methyl-1,3-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 3,5′-dimethylbenzidene, 2,2′,6,6′-tetramethylbenzidene, 3,5′-dimethoxybenzidene, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl methane, fluorinated alkyl analogs of said diamines,2-trifluoromethyl-1,4-phenylenediamine and mixtures thereof.
18. The data storage medium of claim 16 , wherein “B” comprises structural units derived from at least two diamines wherein at least about 45% of at least one diamine is selected from the group consisting of 1,3-phenylenediamine, 1,4-phenylenediamine, 2-methyl-1,3-phenylenediamine, 4-methyl-1,3-phenylenediamine, 2,4,6-trimethyl-1,3-phenylenediamine, 2,6-diethyl-4-methyl-1,3-phenylenediamine, 3,6-diethyl-2-methyl-1,3-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 3,5′-dimethylbenzidene, 2,2′,6,6′-tetramethylbenzidene, 3,5′-dimethoxybenzidene, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl methane and combinations thereof, based on the total weight of structural units derived from diamine.
19. The data storage medium of claim 16 , wherein said polyimide composition is a blend comprising a second polyimide wherein the said blend is a miscible blend.
20. The data storage medium of claim 16 , wherein said polyimide composition has a glass transition temperature in a range of about 150° C. to about 350° C.
21. The data storage medium of claim 16 , wherein said polyimide composition has a glass transition temperature in a range of about 170° C. to about 300° C.
22. The data storage medium of claim 16 , wherein said polyimide composition has a glass transition temperature in a range of about 180° C. to about 280° C.