This information cut from the USPTO webpage detailing "Class Defintion for Stock Materials of Miscellaneous Articles," partcularly subclasses 64 and 65 -- could not link direct to this section and webpage file too big for reasonable download. Therefore, links do not work.


    64.1 CIRCULAR SHEET OR CIRCULAR BLANK:
  This subclass is indented under the class definition.  Product whose outer boundary is that of a single curved line every point of which is substantially the same distance from a point at the center thereof.
   
    64.2 Recording medium or carrier:
  This subclass is indented under subclass 64.1.  Subject matter wherein the circular sheet or circular blank is a tangible object upon which an information signal is to be stored, the object having a characteristic which is, or may be, modified at positional increments in accordance with the time variation of information which is to be stored thereon.
(1) Note. The recording medium or carrier for purposes of these subclasses need not be the specific layer that is intended to contain the information signal. All layers of the medium or carrier are considered to be the recording medium or carrier.

SEE OR SEARCH THIS CLASS, SUBCLASS:

900, for a collection of magnetizable stock material.

SEE OR SEARCH CLASS:

360,  Dynamic Magnetic Information Storage or Retrieval,   subclass 135 for a disc having information recorded thereon in magnetic form.
369,  Dynamic Information Storage or Retrieval,   subclasses 272+ for a disc having information recorded thereon in the form of grooves.
   
    64.3 Magneto optical recording medium or carrier:
  This subclass is indented under subclass 64.2.  Subject matter wherein the recording medium or carrier is composed of a magnetic material and records information based on changes in magnetization and the recorded information is readable; e.g., by diffraction of polarized light through a magnetic field, etc.
   
    64.4 Optical recording medium or carrier:
  This subclass is indented under subclass 64.2.  Subject matter wherein the recording medium or carrier is designed to undergo a chemical or physical change; e.g., irradiating the medium with a laser beam to alter the optical characteristics of the medium or carrier in the irradiated area, etc.
   
    64.5 Tellurium containing:
  This subclass is indented under subclass 64.4.  Subject matter wherein the recording medium or carrier contains tellurium as a free element, combined element, or in a compound.
   
    64.6 Protective layer:
  This subclass is indented under subclass 64.5.  Subject matter wherein the tellurium containing recording medium or carrier is covered by a resistant layer; e.g., resistant to heat, cold, oxidation, pollution, etc.
   
    64.7 Polycarbonate containing:
  This subclass is indented under subclass 64.4.  Subject matter wherein the recording medium or carrier contains linear polyesters containing plural carbonic acid ester groups.
   
    64.8 Coloring agent containing:
  This subclass is indented under subclass 64.4.  Subject matter wherein the recording medium or carrier contains a material having tinctorial properties.
   
    64.9 Thickness specified:
  This subclass is indented under subclass 64.8.  Subject matter wherein the thickness of at least one layer or the overall product of the recording medium or carrier is specified.
   
    65.1 Polymer derived from material having at least one acrylic or alkacrylic group or the nitrile or amide dervative thereof: (e.g., acrylamide, acrylate ester, etc.)
  This subclass is indented under subclass 64.4.  Subject matter wherein the recording medium or carrier contains a polymer derived from at least one of the following reatants: R X R R X | | | S S XCH2=C-C-N-R, CH2=C-CbN, or CH2=C-C-OR and wherein X is chalcogen (i.e., oxygen, sulfur, selenium, or tellurium) and R is hydrogen or alkyl.
   
    65.2 Adhesive containing:
  This subclass is indented under subclass 64.4.  Subject matter wherein the recording medium or carrier contains a glue-like substance.
   
    65.3 Magnetic recording medium or carrier:
  This subclass is indented under subclass 64.2.  Subject matter wherein the recording medium or carrier contains magnetizable material in the form of particles, film, coating, layer, or impregnant which is intended for the storage of more than a single bit of information to be read by a magnetic head.
   
    65.4 Lubricant containing:
  Subject matter under 65.3 wherein the recording medium or carrier contains a substance that reduces friction.
   
    65.5 Protective layer containing:
  This subclass is indented under subclass 65.3.  Subject matter wherein the magnetic recording medium or carrier layer is covered by a resistant layer; e.g., resistant to heat, cold, oxidation, pollution, etc.
   
    65.6 Aluminum containing:
  This subclass is indented under subclass 65.3.  Subject matter wherein the magnetic recording medium or carrier contains aluminum as a free metal, combined metal, and includes alloys and metal compounds.
   
    65.7 Chromium containing:
  This subclass is indented under subclass 65.3.  Subject matter wherein the magnetic recording medium or carrier contains chromium as a free metal, combined metal, and includes alloys and metal compounds.
   
    65.8 Lubricant containing:
  This subclass is indented under subclass 64.2.  Subject matter wherein the recording medium or carrier contains a substance that reduces friction.
   
    65.9 Fibrous material containing:
  This subclass is indented under subclass 64.2.  Subject matter wherein the recording medium or carrier is composed of relatively short, slender, flexible elements of finite length.