COMMISSIONER'S DECISION
OBVIOUSNESS: Dispersing Fibrous Material in an Aqueous Slurry
Use of asbestos fibres as the sole dispersing agent for a glass fiore slurry is
not suggested in the prior art.
Final Action: Reversed
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This decision deals with a request for review by the Commissioner of
Patents of the Examiner's Final Action dated March 5, 1976, on application
184,363 (Class 6-212). The application was filed on October 26, 1973, in
the name of William J. Plichta et al, and is entitled "A Method Of Dispersing
Fibrous Material In An Aqueous Slurry."
This application relates to the method of dispersing fibrous material in an
aqueous slurry by utilizing asbestos fibers as a dispersing agent.
In the Final Action the examiner rejected all the claims for failing to
define patentable subject matter over the following reference:
U.S. 3,007,841 Nov. 7, 1961 Briener et al
The Briener patent relates to humidifier plates for air conditioning units.
These plates are made by a millboard process with a conventional wet machine
and they consist of raw asbestos fibers, absorptive particulate filler
material, inorganic mineral fibers, a resin binder wherein these constituents
are mixed with water. Claim 1 of the patent reads:
An evaporator plate for use in humidifier units for air
conditioning apparatus comprising an absorptive plate
having a stem portion and a head portion, said absorptive
plate being supported with said stem portion in a supply
of water to wick water from said supply through said
stem portion to said head portion at a rate faster than
the evaporation of water from said head portion when
subjected to warm air passing thereover, said absorptive
plate having a saturated tensile wet strength when measured
in the machine direction of at least 39 lbs./in. 2, said.
absorptive plate comprising felted fibers disposed in a
sheet-like body, said sheet-like body being formed from
a mixture comprising 15-35% by weight of asbestos fibers,
20-40% by weight of absorptive particulate filler material
from a group consisting of diatomaceous earth, perlite, and
hydrated calcium silicates, and mixtures thereof, 30-60%
by weight of inorganic mineral fibers from a group consisting
of slag wool, rock wool, and glass fiber and mixtures
thereof, and 0.5-2.5% by weight of resin binder.
In the Final Action the examiner stated (in part):
Refusal of claims 1-5 are reiterated in view of United States
Patent No. 3,007,841 on the ground that the alleged invention
disclosed and claimed in the present application has been
disclosed in the aforementioned reference. For instance,
the United States Patent No. 3,007,841, column 2, lines 23-26
and 68, supported further by Example 5, shows a process of
forming an aqueous slurry including a plurality of glass fibers
and a plurality of asbestos fibers, and agitating said slurry.
The only other explicit restriction in claim 1 is the functional
restriction on the size of the glass fibers.
It is obvious from the fact that the glass fibers used by Breiner
et al are milled that they will be of such a length as to
require a dispersing agent and that a substantial proportion of
them will be within the size limits of 0.25 in. to 2.C in. The
use of a binder and the restriction on the grade of the asbestos
are also shown.
The applicant of the application under review is claiming a
two stage process involving, broadly speaking:-
(a) forming an aqueous slurry comprising glass fibers
of predetermined length and amount, with asbestos
fibers.
(b) agitating said slurry until dispersion of glass fibers
has been uniformly achieved.
Subsequent restrictions include a specified range of glass fiber
lengths, a range of percentage by dry weight of asbestos fibers
as also the grade thereof, and the use of a binder.
The main reference cited, namely United States Patent No. 3,007,841,
discloses the same process steps of forming an aqueous slurry and
agitating to effect uniform dispersion. The materials used are
the same except for the filler of diatomaceous earth in the
said patent. Lengths of the glass fibers, amounts of the asbestos
fibers and type of binder used are overlapping in both the
cited patent and the present application.
In his response the agent states in part:
Turning to Breiner et al, it can be seen that this patent is
directed to an asbestos sheet product and particularly to a
humidifier plate made by conventional millboard process: In
addition to the asbestos, the product also includes inorganic
mineral fibers from a group consisting of slag wool, rock wool,
glass fiber and the like and mixtures thereof. More specifically,
as a general range of ingredients Breiner et al discloses a
mixture of 15-35% by weight of asbestos fibers, 20-40% by weight
of particulate filler material, 30-60% by weight of inorganic
mineral fibers other than asbestos, and 0.52-2.5% by weight
of a resin binder.
It should be noted that Breiner et al does not teach or
suggest utilizing a dispersant, much less, utilizing asbestos
as a dispersant. In fact, in most cases, a dispersant is not
used or required in the conventional millboard process. With
respect to the specific conventional millboard process discussed
in Breiner et al, it would more than likely be that this process
does not use a dispersant since the maximum amount of fibrous
material other than asbestos used is 60% by weight. In any
event, there certainly is no teaching or suggestion in Breiner
et al to use asbestos fiber as a dispersant and as essentially
the only dispersant. Certainly this patent does not teach
or suggest that dispersion is necessary and that the dispersant
must be asbestos fibers, as set forth in Claim 1.
The issue to be considered is whether or not the claims are directed to a
patentable advance in the art.
Claim 1 reads:
A method of dispersing glass fibers in an aqueous slurry, said
method comprising
(a) forming an aqueous slurry including
(i) a plurality of glass fibers of the length and
amount which requires a dispersing agent in
said slurry for dispersion of the fiber, and
(ii) a dispersing agent consisting essentially of
a plurality of asbestos fibers; and
(b) agitating said slurry so as to disperse said glass fibers.
Reviewing the Final Action we find that the claims have been rejected in
view of Briener on the grounds that: (a) the Briener process "although
lacking of statement therefor does not nullify the use of asbestos fiber
in a dispersing process involving glass fibers in an aqueous slurry."
The applicant responds that the assumptions made by the examiner are mere
conjecture which cannot be based on the teachings in Briener and (b) the
glass fibers are of equivalent length or within the range specified in
the current application.
Briener relates to asbestos products such as humidifier plates for air-
conditioning units. These plates are made by the conventional millboard
process. Column 2, line 23 f.f., states: "Raw asbestos fibers, absorptive
particulate filler material, inorganic mineral fibre and a resin binder
are mixed with water in a conventional beater to form a slurry from which
millboard is formed." Example 5, found in column 4 at line 21 f.f., reads:
A millboard, having the physical characteristics listed
under column 5 of the above chart was prepared on a
conventional wet machine using a conventional millboard
process from a slurry prepared from a mixture containing
20% by weight of group 5 asbestos fibers, 28% by weight
of diatomaceous earth, 50% by weight of milled glass
fibers, and 2% by weight of an acrylic resin binder.
We will now consider the main point of contention namely the applicant's use
of asbestos fibres as the dispersant agent. The applicant maintains he has
discovered that the asbestos fibers can be used as a sole agent for dispersing
glass fibers in a slurry where the glass fibers are of the length which require
a dispersing agent. On the other hand the examiner maintains that there is
no reason to assume that Briener was "unaware of the special attributes of
asbestos fibers as an essential ingredient in obtaining their product satis-
factorily." According to the examiner, although not stated in Briener,
the use of asbestos fibers with glass fibers in an aqueous slurry is sufficient
to assume that the patentee is fully aware of its dispersing properties.
Briener teaches the use of diatomaceous earth as a component additive to the
slurry to obtain his product. The applicant on the other hand specifies
a slurry containing glass fibres of a length and amount which requires a
dispersing agent and it also specified that the dispersing agent be asbestos
fibres. We find no indication in Briener to use asbestos fibres as the
sole dispersing agent for a glass fiber slurry. Moreover, the asbestos fiber
could well have been used as a binder for the diatomaceous clay.
The other point of contention is that the glass fibers of the patent are
of equivalent length or within the range specified in the current applica-
tion. We do not think that is material because there is no teaching nor
even a suggestion that the asbestos fibres, of any size, may be used
as the sole dispersing agent for a glass fibre slurry.
Of pertinence to this decision is the consideration of the Supreme Court
in The King v. Uhlemann Optical Co.(1951) 15 CPR 99, where it was stated:
"...nothing essential to the invention and necessary or material for its
practical working and real utility could be found substantially in the prior
publications." (emphasis added)
Claim 1 specifies a method of dispersing glass fibers in an aqueous slurry
where asbestos fibers are used as the sole dispersing agent. There is no
teaching of this in the reference. In our view this represents a patentable
improvement in the art. We recommend that claim 1 should be allowed. It
follows that claims 2 to 5, which depend directly or indirectly on claim 1,
are also allowable.
In summary, we are satisfied that nothing essential to the invention and
necessary or material for its practical working and real utility can be
found substantially in the prior publication (vide: The King v Uhlemann, supra).
We recommend that the Final Action be withdrawn,
J.F. Hughes
Acting Chairman
Patent Appeal Board, Canada
Having studied the prosecution of this application and reviewed the recommend-
ation of the Patent Appeal Board, I have decided to withdraw the Final Action
and return the application to the examiner for resumption of prosecution.
J.H.A. Gariepy
Commissioner of Patents
Dated at Hull, Quebec
this 5th. day of May, 1977
A. E . MacRae & Co.
Box 806, Station B
Ottawa, Ontario