Data storage medium and method for the preparation thereof

• US 20040063031A1
• Filed: 08/07/2003
• Published: 04/01/2004
• Est. Priority Date: 08/23/2002
• Status: Active Grant

• Current Assignee: SHPP Global Technologies BV (Government of Saudi Arabia)
• Original Assignee: Sabic Innovative Plastics IP BV (Government of Saudi Arabia)
• Inventors: Gallucci, Robert R., Iacovangelo, Charles D., LeGrand, Donald G., Wilson, James R.
• Granted Patent: US 7,300,742 B2
• Time in Patent Office: Days
• US Class Current: 430/270.11
• CPC Class Codes: F21V 7/28 characterised by coatings
• CPC Class Codes: G11B 7/252 of layers other than recording layers
• CPC Class Codes: G11B 7/253 of substrates
• CPC Class Codes: G11B 7/254 of protective topcoat layers
• CPC Class Codes: G11B 7/257 of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers
• CPC Class Codes: G11B 7/2585 based on aluminium
• CPC Class Codes: G11B 7/26 Apparatus or processes specially adapted for the manufacture of record carriers
• CPC Class Codes: Y10S 430/146 Laser beam

Abstract

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 3×10⁵ pounds per square inch. The data storage medium resists hazing of the reflective layer at elevated temperatures.

Claims

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 organic volatiles content less than 1,000 parts per million measured according to ASTM D4526;

a reflective metal layer; and

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<sup>−

4</sup> ohm-centimeters measured according to ASTM D257 at 25°

C. and a tensile modulus of at least about 3×

10⁵ pounds per square inch measured according to ASTM D638 at 25°

C.

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 haze-prevention layer comprises a plasma-polymerized organosilicone.

10. The data storage medium of claim 9, wherein the organosilicone has the formula

11. The data storage medium of claim 9, wherein the organosilicone is octamethyl(cyclotetrasiloxane), hexamethyl(cyclotrisiloxane), tetramethyldisiloxane, hexamethyldisiloxane, octamethyltrisiloxane, vinyltriethoxysilane, vinyltrimethoxysilane cyclotetra(methylvinylsiloxane), cyclotri(methylvinylsiloxane), hexamethyldisilazane, or a mixture thereof.

12. The data storage medium of claim 1, wherein the haze-prevention layer comprises diamond-like carbon.

13. The data storage medium of claim 1, wherein the haze-prevention layer comprises a colloidal silica composition comprising colloidal silica dispersed in a silanol-, acrylic-, or methacrylic-derived polymer system.

14. The data storage medium of claim 1, wherein the haze-prevention layer comprises a thermoset resin selected from thermoset polyester resins, thermoset epoxy resins, novolac resins, and melamine resins.

15. The data storage medium of claim 1, wherein the haze-prevention layer has a thickness of about 100 nanometers to about 100 micrometers.

16. The data storage medium of claim 1, further comprising a protective 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 layer.

17. The data storage medium of claim 1, comprising a surface with a reflectivity of at least 80% measured according to ASTM D523.

18. 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; and

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<sup>−

2</sup> ohm-centimeters measured according to ASTM D257 at 25°

C. and a tensile modulus of at least about 5×

10⁵ pounds per square inch measured according to ASTM D638 at 25°

C.

19. The data storage medium of claim 19, further comprising a protective 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 layer.

20. 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<sup>−

4</sup> ohm-centimeters measured according to ASTM D257 at 25°

C. and a tensile modulus of at least about 3×

10⁵ pounds per square inch measured according to ASTM D638 at 25°

C., 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; and

applying a reflective metal layer to a surface of the haze-prevention layer.

21. The method of claim 20, further comprising applying a protective layer to the reflective metal layer;

wherein the protective layer has a percent transmittance of at least 90% measured according to ASTM D1003.