Data storage medium and method for the preparation thereof
View Patent ↗A data storage medium includes a substrate, a reflective metal layer, and a haze-prevention layer between the substrate and the reflective metal layer. The substrate includes an amorphous thermoplastic resin having a heat distortion temperature of at least about 140° C., a density less than 1.7 grams per milliliter, and an organic volatiles content less than 1,000 parts per million measured according to ASTM D4526. The haze-prevention layer includes a material having a volume resistivity of at least 1×10 −4 ohm-centimeters and a tensile modulus of at least about 3×10 5 pounds per square inch. The data storage medium resists hazing of the reflective layer at elevated temperatures.
1. A data storage medium, comprising:
a substrate comprising an amorphous thermoplastic resin having
a heat distortion temperature of at least about 140° C. measured at 66 pounds per square inch according to ASTM D648.
a density less than 1.7 grams per milliliter, and
an orannic volatiles content less than 1,000 parts per million measured according to ASTM D4526;
a reflective metal layer;
a haze-prevention layer interposed between the substrate and the reflective metal layer, wherein the haze-prevention layer comprises a material having a volume resistivity of at least 1×10 −4 ohm-centimeters measured according to ASTM D257 at 25° C. and a tensile modulus of at least about 3×10 5 pounds per square inch measured according to ASTM D638 at 25° C.; wherein the haze-prevention layer has a thickness of 145 nanometers to about 100 micrometers; wherein the haze-prevention layer contacts the substrate and the reflective metal layer; and
a protective metal oxide layer having a percent transmittance of at least 90% measured according to ASTM D1003 at 25° C.; wherein the reflective layer is interposed between the haze-prevention layer and the protective metal oxide layer; and wherein the reflective layer contacts the protective metal oxide layer;
wherein the haze-prevention layer comprises a plasma-polymerized organosilicone, wherein the organosilione has the formula
wherein each occurrence of R is independently C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 3 -C 6 alkenyl alkyl, or C 6 -C 18 aryl; n is 0 to 100; and m is 1 to 100; and
wherein the data storage medium is adapted for reading via the substrate.
2. The data storage medium of claim 1 , wherein the amorphous thermoplastic resin is selected from polyetherimides, polyetherimide sulfones, polysulfones, polyethersulfones, polyphenylene ether sulfones, poly(arylene ether)s, polycarbonates, polyester carbonates, polyarylates, and mixtures thereof.
3. The data storage medium of claim 1 , wherein the amorphous thermoplastic resin comprises a polysulfone or an isophorone bisphenol-containing polycarbonate.
4. The data storage medium of claim 1 , wherein the substrate is substantially free of inorganic filler.
5. The data storage medium of claim 1 , wherein the substrate has a thickness of about 0.1 to about 20 millimeters in a dimension perpendicular to the haze-prevention layer and the reflective metal layer.
6. The data storage medium of claim 1 , wherein the reflective metal layer comprises a metal selected from aluminum, silver, gold, nickel, palladium, platinum, copper, and alloys thereof.
7. The data storage medium of claim 1 , wherein the reflective metal layer comprises aluminum.
8. The data storage medium of claim 1 , wherein the reflective metal layer has a thickness of about 10 to about 1000 nanometers.
9. The data storage medium of claim 1 , wherein the organosilicone is octamethyl(cyclotetrasiloxane), hexamethyl(cyclotrisiloxane), tetramethyldisiloxane, hexamethyldisiloxane, octamethyltrisiloxane, cyclotetra(methylvinylsiloxane), cyclotri(methylvinylsiloxane), or a mixture thereof.
10. The data storage medium of claim 1 , comprising a surface with a reflectivity of at least 80% measured according to ASTM D523.
11. The data storage medium of claim 1 , wherein the protective metal oxide layer comprises an oxide of titanium.
12. The data storage medium of claim 1 , wherein the protective metal oxide layer comprises an oxide of zinc.
13. A data storage medium, comprising:
a substrate comprising a polysulfone or an isophorone bisphenol-containing polycarbonate resin having
a glass transition temperature of at least about 170° C.,
a density less than 1.7 grams per milliliter, and
an organic volatiles content less than 1,000 parts per million measured according to ASTM D4526;
a reflective metal layer comprising aluminum;
a haze-prevention layer interposed between the substrate and the reflective metal layer, wherein the haze-prevention layer comprises a plasma-polymerized organosilicone having a volume resistivity of at least 1×10 −2 ohm-centimeters measured according to ASTM D257 at 25° C. and a tensile modulus of at least about 5×10 5 pounds per square inch measured according to ASTM D638 at 25° C.; wherein the haze-prevention layer has a thickness of 145 nanometers to about 100 micrometers; wherein the haze-prevention layer contacts the substrate and the reflective metal layer; and
a protective metal oxide layer having a percent transmittance of at least 90% measured according to ASTM D1003 at 25° C.; wherein the reflective layer is interposed between the haze-prevention layer and the protective metal oxide layer; and wherein the reflective layer contacts the protective metal oxide layer;
wherein the organosilicone has the formula
wherein each occurrence of R is independently C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 3 -C 6 alkenyl alkyl, or C 6 -C 18 aryl; n is 0 to 100; and m is 1 to 100; and
wherein the data storage medium is adapted for reading via the substrate.
14. A method for preparing a data storage medium, comprising:
applying a haze-prevention layer to a surface of a substrate;
wherein the haze-prevention layer comprises a material having a volume resistivity of at least 1×10 −4 ohm-centimeters measured according to ASTM D257 at 25° C. and a tensile modulus of at least about 3×10 5 pounds per square inch measured according to ASTM D638 at 25° C.; wherein the haze-prevention layer has a thickness of 145 nanometers to about 100 micrometers;
wherein the haze-prevention layer comprises a plasma-pulymerized organosilicone. wherein the organosilicone has the formula
wherein each occurrence of R is independently C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 3 -C 6 alkenyl alkyl, or C 6 -C 18 aryl; n is 0 to 100; and m is 1 to 100; and
wherein the substrate comprises an amorphous thermoplastic resin having a heat distortion temperature of at least about 140° C. measured at 66 pounds per square inch according to ASTM D648, a density less than 1.7 grams per milliliter, and an organic volatiles content less than 1,000 parts per million measured according to ASTM D4526;
applying a reflective metal layer to a surface of the haze-prevention layer; and
applying a protective metal oxide layer to the reflective metal layer; wherein the protective metal oxide layer has a percent transmittance of at least 90% measured according to ASTM D1003;
wherein the data storage medium is adapted for reading via the substrate.