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May 2008 CLASSIFICATION DEFINITIONS 520 - 1 CLASS 520, SYNTHETIC RESINS OR NATURAL May 2008
CLASSIFICATION DEFINITIONS
520 - 1
CLASS 520, SYNTHETIC RESINS OR NATURAL
RUBBERS -- PART OF THE CLASS 520
SERIES
SECTION I - CLASS DEFINITION
Class 520, Synthetic Resins or Natural Rubbers -- Part
of the Class 520 Series is to be considered as an integral
part of Class 260 and retains all pertinent definitions and
class lines of Class 260. Class 520, subclass 1 is the
generic subclass for synthetic resins or natural rubbers.
All the other classes of the 520 series (i.e., 521,522, 523,
524, 525, 526, 527, and 528) are indented thereunder.
Retrieval of information in the Class 520 series is identi-
cal to retrieval in any ordinary class that has subclasses
rather than classes indented thereunder. Each of the
classes indented (i.e., 521-528) etc., merely recites an
art area that for convenience of numbering has been cat-
egorized as a class rather than a conventional subclass.
Classes 521-528 are arranged in hierarchical order under
Class 520, subclass 1, and each of Classes 521-528
operates as a normal class within this hierarchy. The
520 series of classes encompasses solid synthetic resins
and natural rubbers, and the preparation and treatment
thereof. The series also encompasses compositions not
elsewhere provided for of solid synthetic resins and nat-
ural rubbers, as well as the preparation and treatment of
such compositions.
In this class and in the indented subclasses are placed all
patents which are directed to the preparation and treat-
ment of the so-called synthetic resins or natural rubbers
(e.g., complex organic compounds produced from ingre-
dients which are generally nonresinous and which final
products simulate the natural resins).
SOME OF THE GENERAL TYPES OF SUBJECT
MATTER WITHIN THIS CLASS
A. Solid synthetic resins, per se, regardless of utility.
B. Processes of preparing a synthetic resin involving a
chemical reaction including those chemical reactions
which utilize energy.
C. Reactable compositions which form a product as in
(a) above upon the addition of a catalyst or promoter, or
which merely require the presence of heat and/or pres-
sure and wherein all of the necessary reactants to form
the final desired product are present, or processes of pre-
paring.
D. Processes of purifying a solid synthetic resin or com-
position containing a synthetic resin by a chemical or
physical process.
E. Process of reclaiming or recovering a solid synthetic
resin.
F. Processes of treating a synthetic resin or specified
intermediate condensation product (SICP, see the Glos-
sary) with a reactant, or product thereof.
G. Blends of solid synthetic resins, processes of prepar-
ing or treating such blends.
H. Chemically reacted solid synthetic resins or pro-
cesses of preparing.
I. Potentially reactable compositions which contain a
solid synthetic resin or SICP and products of such a
reaction, or processes of preparing.
J. Room vulcanizable potentially reactive compositions
which merely require moisture and which are usually
activated by heat and/or pressure to form a product
proper herein, or processes of preparing.
K. Compositions of a nonreactant material and a solid
synthetic resin or SICP, processes of preparing or treat-
ing.
L. Processes of using a solid synthetic resin or composi-
tion containing a solid synthetic resin.
M. Compositions containing a structurally defined
material (e.g., coated web, or fiber having dimension,
etc.) which is dispersed in a matrix which is not identi-
fied by overall dimension or some structure or processes
of preparing.
N. Single-layered products containing a solid synthetic
resin or composition thereof reciting no structure or
dimension, or a fiber, filament, etc., which is no more
than the material from which it is made. Nonstructured
single-layered web or sheet is encompassed.
O. Particles or a powder, per se, of a solid synthetic
resin or composition thereof for which particles or pow-
der no dimensions are recited.
P. Reactable compositions which form a product proper
for this class and contain a photoinitiator or photosensi-
tizer which are activated by wave energy or processes of
preparing.
It must be remembered that the list above is exemplary
May 2008 520 - 2
CLASSIFICATION DEFINITIONS
May 2008
not exhaustive of the types of subject matter that may be
found in this class. Not all subject matter relating to
solid synthetic resins and natural rubbers is to be found
in this class, since other classes provide for claims
involving synthetic resins (e.g., utility classes, separa-
tion classes, etc.).
SECTION II - LINES WITH OTHER CLASSES
AND WITHIN THIS CLASS
A. A GENERAL OUTLINE OF THE CLASS 520
SERIES IS AS FOLLOWS
Class 520, generic subclass 1.
Class 521 provides for ion-exchange polymers, pro-
cesses of reclaiming a solid synthetic resin, and for cel-
lular synthetic resins.
Class 522 provides for processes of preparing or treating
a solid polymer utilizing wave energy and for composi-
tions which contain a photosensitizer and which when
reacted form a product proper for the 520 Series of
Classes.
Classes 523 and 524 provide for solid synthetic resins or
specified intermediate condensation products admixed
with a nonreactant material.
Class 525 provides for certain combinations of polyes-
ters and certain reactable materials, for blends of solid
synthetic resins, and for chemically modified solid syn-
thetic resins.
Class 526 provides for certain manipulative processes
which are generic to both ethylenic polymers and to
condensation polymers, and also provides for polymers
derived from ethylenic monomers only.
Class 527 provides for solid synthetic resins derived
from at least one saturated material and certain special
reactants (e.g., carbohydrates, proteins, natural resins,
lignin, tannin, bituminous material, etc.).
Class 528 provides for solid synthetic resins derived
from at least one nonethylenic reactant, and also for pro-
cesses of treating a polymer either derived from ethyl-
enic or nonethylenic reactants wherein chemical bonds
in the polymer are left unaffected.
This list above is merely to be taken as a shorthand
method in approaching the Class 520 series. The areas
above generally provide for processes of preparing the
indicated products. Once a class in the series is identi-
fied as having subject matter in which one may be inter-
ested, it is best to consult the individual class schedule
or to look at the one-dot subclasses indented under Class
520, subclass 1.
B. RULES FOR DETERMINING PLACEMENT
BETWEEN THE 520 SERIES OF CLASSES AND
THE MONOMER, ETC. AREAS OF CLASS 260
To be classified in the 520 Series of Classes, a patent
must contain a claim to a solid synthetic resin, natural
resin, preparation or treatment thereof, or compositions
containing solid synthetic resins or natural rubbers.
When a patent (1) sets forth claims drawn to species that
may or may not be solid synthetic resins as per disclo-
sure (e.g., the patent may present claims to nonsolid
polymers or to monomeric compounds), or a patent (2)
contains only generic claims and the disclosure sets
forth species, embraced by the claims, some of which
are and some of which are not solid synthetic polymers,
the patent is classified as an original with the nonresin-
ous species and is cross-referenced to the appropriate
Class 520 series area.
Where both claims and disclosure are devoid of any ref-
erence to a solid synthetic resin, the patent is classified
in the appropriate Class 260 compound area (principally
the Class 532 Series of Classes and Class 585) that pro-
vides for the monomer or liquid polymer. In the event
that a composition is claimed when neither claims nor
disclosure refer to a solid synthetic resin, the patent is
classified in an appropriate composition class other than
the Class 520 series.
Determination of whether a product is a solid synthetic
resin proper for this area (the Class 520 series) or a com-
pound proper for another Class 260 area (such as the
Class 532 Series) is as follows:
1. In the absence of disclosure to the contrary:
a. A polymer derived from ethylenic reactants only will
be considered to be a solid polymer, per se, and proper
for Class 520.
b. A polymer derived from at least one nonethylenic
reactant will be considered to be a liquid and, therefore,
properly classified in Class 260 as a compound. An
exception to this rule pertains to certain low molecular
weight polymers which despite being solids are none-
theless regarded as nonpolymeric and therefore
excluded from Class 520. Consider, for example, the
May 2008 I
II
May 2008
CLASSIFICATION DEFINITIONS
520 - 3
low molecular weight polymers of organic isocyanates
(nRNCO), formaldehyde (mCH
2
O), and acetaldehyde
(pCH