U.S. patent application number 14/668975 was filed with the patent office on 2016-01-14 for extruded self-clumping cat litter.
The applicant listed for this patent is Pioneer Pet Products, LLC. Invention is credited to John M. Lipscomb.
Application Number | 20160007561 14/668975 |
Document ID | / |
Family ID | 53520177 |
Filed Date | 2016-01-14 |
United States Patent
Application |
20160007561 |
Kind Code |
A9 |
Lipscomb; John M. |
January 14, 2016 |
Extruded Self-Clumping Cat Litter
Abstract
Litter formed of extruded pellets containing water soluble
binder sufficient to self-clump when wetted producing pellet clumps
having a clump retention rate of at least 90% and which shrink
after clump formation during drying producing a clump pulls away
from any contacting solid surface minimizing adhesion therebetween.
Such clumps preferably also have a crush strength of at least 15
PSI when dry. Pellets preferably contain water-soluble binder
formed of starch physically modified during extrusion that
solubilizes when wetted to facilitate clumping while opening the
interior of the pellet improving absorption capacity. A preferred
litter is formed of a mixture of extruded pellets of different
sizes producing litter composed of extruded pellets falling within
a plurality of different size ranges with the smaller sized pellets
being fines that cause horizontally extending clumps to form on top
of the litter.
Inventors: |
Lipscomb; John M.;
(Cedarburg, WI) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Pioneer Pet Products, LLC |
Cedarburg |
WI |
US |
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Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20150196005 A1 |
July 16, 2015 |
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|
Family ID: |
53520177 |
Appl. No.: |
14/668975 |
Filed: |
March 25, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13868084 |
Apr 22, 2013 |
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14668975 |
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13868073 |
Apr 22, 2013 |
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13868084 |
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13842534 |
Mar 15, 2013 |
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13868073 |
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14656692 |
Mar 12, 2015 |
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13842534 |
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14605045 |
Jan 26, 2015 |
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14656692 |
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61931609 |
Jan 25, 2014 |
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61952133 |
Mar 12, 2014 |
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61775707 |
Mar 11, 2013 |
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61699858 |
Sep 11, 2012 |
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61775707 |
Mar 11, 2013 |
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61699858 |
Sep 11, 2012 |
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61775707 |
Mar 11, 2013 |
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61699858 |
Sep 11, 2012 |
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61931609 |
Jan 25, 2014 |
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61952133 |
Mar 12, 2014 |
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61931609 |
Jan 25, 2014 |
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61952133 |
Mar 12, 2014 |
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Current U.S.
Class: |
119/171 |
Current CPC
Class: |
A01K 1/0155 20130101;
A01K 1/0152 20130101; A01K 1/0154 20130101 |
International
Class: |
A01K 1/015 20060101
A01K001/015 |
Claims
1. An extruded cat litter formed of a plurality of pellets extruded
from a starch containing material having sufficient water soluble
adhesive formed from starches modified during extrusion to
self-clump together when wetted forming clumps comprised of at
least a plurality of pairs of the extruded pellets bonded together
by the water soluble adhesive.
2. The extruded cat litter of claim 1 wherein each extruded pellet
is comprised of at least 7.5% water soluble binder formed of
modified starches modified during pellet extrusion.
3. The extruded cat litter of claim 2 wherein the water soluble
binder comprises cold water soluble binder.
4. The extruded cat litter of claim 3 wherein the cold water
soluble binder comprises cold water soluble amylopectin binder.
5. The extruded cat litter of claim 1 wherein a clump formed of a
plurality of pairs of the extruded pellets wetted with 2% saline
solution has a clump retention rate of at least 93%.
6. The extruded cat litter of claim 5 wherein the clump formed of
the plurality of pairs of the wetted extruded pellets has a clump
crush strength of at least 15 pounds per square inch.
7. The extruded cat litter of claim 1 wherein a clump formed of a
plurality of pairs of the extruded pellets wetted with 2% saline
solution has a clump crush strength of at least 15 pounds per
square inch.
8. The extruded cat litter of claim 7 wherein the clump formed of
the plurality of pairs of the wetted extruded pellets has a clump
retention rate of at least 93%.
9. The extruded cat litter of claim 1 wherein each extruded pellet
is comprised of at least 50% starch by pellet weight.
10. The extruded cat litter of claim 9 wherein each extruded pellet
is comprised of no more than 50% cellulose by pellet weight.
11. The extruded cat litter of claim 1 wherein the cat litter is
comprised of: (a) at least a plurality of pairs of finely sized
extruded pellets each having a size smaller than 1.2 mm in length,
width and/or diameter; and (b) at least a plurality of pairs of
larger sized extruded pellet formed of extruded pellets having a
size (i) no greater than 3 mm in length, width and/or diameter, and
(ii) no smaller than 1 mm in length, width and/or diameter; and
wherein a clump formed of (i) a plurality of pairs of the finely
sized extruded pellets, and (ii) a plurality of pairs of the larger
sized extruded pellets wetted with 2% saline solution forms in a
generally horizontal direction.
12. The extruded cat litter of claim 11 wherein the plurality of
pairs of the wetted finely sized extruded pellets and the plurality
of pairs of the wetted larger sized extruded pellets forming the
clump absorb at least the weight of the wetted extruded pellets in
2% saline solution within three minutes of being wetted with the 2%
saline solution in forming the clump.
13. The extruded cat litter of claim 11 wherein the clump has a
clump retention rate of at least 93%.
14. The extruded cat litter of claim 13 wherein the clump has a
clump crush strength of at least 15 pounds per square inch.
15. The extruded cat litter of claim 11 wherein the clump has a
clump crush strength of at least 15 pounds per square inch.
16. The extruded cat litter of claim 11 wherein the extruded
granular sorbent is comprised of at least 15% of the finely sized
sorbent granules by weight of the extruded granular sorbent.
17. The extruded cat litter of claim 16 wherein the clump has a
clump retention rate of at least 93%.
18. The extruded cat litter of claim 17 wherein the clump has a
clump crush strength of at least 15 pounds per square inch.
19. The extruded cat litter of claim 11 wherein the extruded
granular sorbent is comprised of at least 10% and no greater than
40% of the finely sized sorbent granules by weight of the extruded
granular sorbent with the remainder of the extruded granular
sorbent comprised substantially of the larger sized sorbent
granules.
20. The extruded cat litter of claim 19 wherein the clump has a
clump retention rate of at least 93%.
21. The extruded cat litter of claim 19 wherein the clump has a
clump crush strength of at least 15 pounds per square inch.
22. The extruded cat litter of claim 1 wherein the extruded
granular sorbent is comprised of: (a) at least a plurality of pairs
of finely sized sorbent granules formed of extruded pellets having
a size smaller than 2 mm in length, width and/or diameter; and (b)
at least a plurality of pairs of larger sized sorbent granules
formed of extruded pellets having a size (i) no greater than 4 mm
in length, width and/or diameter, and (ii) no smaller than 2 mm in
length, width and/or diameter; and wherein (i) a plurality of pairs
of the finely sized sorbent granules, and (ii) a plurality of pairs
of the larger sized sorbent granules wetted with 2% saline solution
forms a clump of the wetted plurality of pairs of the finely sized
sorbent granules and wetted plurality of pairs of the larger sized
sorbent granules forms on top of a plurality of pairs of the finely
sized sorbent granules and on top of a plurality of pairs of the
larger sized sorbent granules not wetted by the 2% saline
solution.
23. The extruded cat litter of claim 22 wherein the clump has a
clump crush strength of at least 15 pounds per square inch.
24. The extruded cat litter of claim 22 wherein the clump formed of
the plurality of pairs of the wetted sorbent granules has a clump
retention rate of at least 92%.
25. The extruded cat litter of claim 22 wherein the extruded
granular sorbent is comprised of at least 10% and no greater than
40% of the finely sized sorbent granules by weight of the extruded
granular sorbent.
26. The extruded cat litter of claim 22 wherein the extruded
granular sorbent is comprised of at least 10% and no greater than
40% of the finely sized sorbent granules by weight of the extruded
granular sorbent with the remainder of the extruded granular
sorbent comprised of the larger sized sorbent granules.
27. The extruded cat litter of claim 1 wherein a clump formed of a
plurality of pairs of the sorbent granules wetted with 2% saline
solution shrinks at least 5% after clump formation when the clump
is dried for a period of five days to a moisture content of no
greater than 20% by clump weight.
Description
CROSS REFERENCE
[0001] This application claims priority in U.S. Provisional Patent
Application Nos. 61/931,609 filed Jan. 25, 2014 and 61/952,133
filed Mar. 12, 2014 under 35 U.S.C. .sctn.119(e), is a
continuation-in-part of each of U.S. patent application Ser. No.
14/656,692 filed Mar. 12, 2015, U.S. patent application Ser. No.
14/605,045 filed Jan. 26, 2015, each of which also claims priority
in U.S. Provisional Patent Application No. 61/931,609 filed Jan.
25, 2014 and in U.S. Provisional Patent Application No. Mar. 12,
2014 under 35 U.S.C. .sctn.119(e), and is a continuation-in-part of
each of U.S. patent application Ser. No. 13/868,084 filed Apr. 22,
2013, U.S. patent application Ser. No. 13/868,073 filed Apr. 22,
2013, and U.S. patent application Ser. No. 13/842,534 filed Mar.
15, 2013, each of which claims priority in U.S. Provisional Patent
Application No. 61/775,707 filed Mar. 11, 2013 and in U.S.
Provisional Patent Application No. 61/699,858 filed Sep. 11, 2012
under 35 U.S.C. .sctn.119(e), the entire disclosures of each of
which is hereby expressly incorporated herein by reference.
FIELD
[0002] The present invention is directed to cat or animal litter,
and more particularly to an extruded self-clumping cat litter.
BACKGROUND
[0003] Many attempts have been made in the past to try to make
lightweight cat or animal litter. One type of sorbent commonly used
in cat or animal litter is clay-based, typically made of bentonite
granules. Conventional clay-based cat or animal litters typically
have a density greater than 40 pounds per cubic feet, making them
not only relatively costly to ship but relatively challenging to
carry because litter containers tend to be rather heavy.
[0004] Conventional clay-based litter is typically made of granules
of smectite, typically smectite or swelling clay(s), like bentonite
clay(s), which frequently includes other components like calcium
carbonate, silica, fragrances or scents, and odor controllers.
While many attempts have been made in the past to produce lighter
weight clay-based litters having bulk densities less than 40 pounds
per cubic feet, these attempts have had limited success. Quite
often litter performance is either adversely impacted or the weight
reduction not all that significant.
[0005] While many attempts to produce lighter weight clay-based
litter by adding lighter weight components are limited by the fact
that such litters still require at least 70% swelling clays,
typically bentonite, to still perform adequately as litter. This
typically is because the lighter weight components added to reduce
weight and bulk density are nothing more than fillers as they
typically are not absorbent nor facilitate clumping. Because such
litter still requires so much bentonite to adequately perform as a
result, there is a limit to how much its weight and bulk density
can be reduced.
[0006] One problem with a clay-based litters and clay-based
sorbents in general is the fact that clay is not biodegradable.
This requires spent clay-based litters to be put in the garbage for
landfill disposal. For clay-based and other similar mineral or
inorganic-based sorbents used to pick up oil, remediate chemical
spills on land and in water, as well as treat oil spills on land
and in water, disposal is a lot more complicated and costly.
Expensive high temperature treatment in a kiln is typically
required, which even then does not completely dispose of
everything. While ash, pebbles and rocks leftover can be used in
small percentages in concrete, it still needs to be handled and
transported adding to overall disposal costs.
[0007] Other attempts have been made to produce litter from
extruded pellets. Unfortunately past attempts have been heretofore
unsuccessful as such extruded pellets were poorly absorbent, needed
to be crushed in order to work, needed bentonite in the admixture,
would not stick or clump when wetted, and/or would not form clumps
that stay together among other deficiencies.
[0008] What is needed is an improved lightweight cat litter that
does not suffer from at least one or more of these drawbacks.
SUMMARY
[0009] The present invention is directed to self-clumping litter
formed of extruded sorbent litter pellets extruded from a
starch-containing admixture at an extruder temperature and extruder
pressure and/or extruder die pressure high enough to form
water-soluble binder from starch in the admixture sufficient for
pellets in a litter box to self-clump together when wetted. In a
preferred litter, each pellet is extruded an admixture containing
one or more cereal grains, with water-soluble binder formed in the
extruded pellet from starch in the admixture during pellet
extrusion sufficient to solubilize when wetted and at least become
tacky enough to stick wetted pellets together forming clumps of
pellets having a relatively high clump retention rate and which
possess high crush strength.
[0010] In a preferred litter, extruded pellets have sufficient
water soluble binder that pellet wetting solubilizes enough binder
to at least make a portion of each wetted pellet tacky enough to
stick to at least a plurality of other pellets clumping them
together. In one such preferred litter, extruded pellets have
sufficient water soluble binder that pellet wetting solubilizes
enough binder to cause at least some of the binder to form a
flowable adhesive with the wetting liquid, e.g., water or urine,
which flows from the wetted pellet and around a plurality of
pellets clumping them together. Where flowable adhesive is formed
by wetting of extruded litter pellets with liquid, such as water,
e.g., 2% saline solution, or urine, the flowable adhesive rapidly
increases in viscosity after wetting from a viscosity of at least
200 centipoise within one second after wetting, increases to at
least 300 centipoise after one second and within five seconds after
wetting, increases to at least 400 centipoise after five seconds
and within 10 seconds of wetting, and increases to at least 1000
centipoise after 10 seconds and within 30 seconds of wetting such
that the liquid, e.g., water, in solubilizing water-soluble binder
forms a relatively high viscosity flowable adhesive gel that
relatively rapidly adheres together the at least plurality of pairs
of wetted pellet forming a clump having a desirably high clump
retention rate of at least 90% and which is preferably at least
92%.
[0011] Such a preferred litter is formed of extruded litter pellets
each having a sufficient amount of water-soluble binder formed in
each pellet during extrusion to self-clump when wetted. In one
preferred extruded self-clumping, pellets are extruded having a
water soluble content of at least 15% by pellet weight and a water
soluble binder content of at least 7.5% by pellet weight. In
another preferred extruded self-clumping litter, pellets are
extruded having a water soluble content of at least 15% by pellet
weight and a water soluble binder content of at least 10% by pellet
weight. In still another preferred extruded self-clumping litter,
pellets are extruded with a water soluble binder content of at
least 15% by pellet weight. In another preferred extruded granular
absorbent, pellets are extruded having a water soluble content of
at least 20% by pellet weight and a water soluble binder content of
at least 10% by pellet weight. In a further preferred extruded
self-clumping litter, pellets are extruded having a water soluble
content of at least 20% by pellet weight and a water soluble binder
content of at least 15% by pellet weight. Such water soluble binder
preferably is a cold water soluble binder, preferably a cold water
soluble amylopectin binder, and more preferably an amorphous cold
water soluble amylopectin binder, formed by physical modification
of starch or starches, preferably by physical modification of
amylopectin, in their original form in the admixture extruded to
form each self-clumping litter pellet.
[0012] Litter formed of such extruded pellets advantageously
self-clump when wetted forming clumps each having a desirably high
clump retention rate of at least 90% and which is preferably at
least 92%. Litter formed of such extruded pellets advantageously
self-clump when wetted forming clumps each having a clump crush
strength of at least 15 pounds per square inch, preferably at least
20 pounds per square inch, and more preferably at least 25 pounds
per square inch when each clump is dried.
[0013] Extruded litter pellets of extruded self-clumping litter
form clumps that shrink after formation at least 3%, preferably at
least 5%, and more preferably at least 10% helping to produce
clumps having such a high clump retention rate and/or high crush
strength. Litter formed of such extruded pellets of the present
invention produce clumps when the cat litter is wetted that shrink
and advantageously condense through absorption and drying thereby
causing the clump to pull away from any solid surface in contact
with the clump minimizing clump adhesion with the solid surface
helping prevent any portion of the clump from sticking thereto. As
a result, such cat litter formed of extruded litter pellets of the
present invention form clumps that shrink when wetted also thereby
produce clumps that are of nonstick construction advantageously
forming "clean" "non-stick" litter clumps in accordance with
another aspect of the invention.
[0014] In addition to litter composed of extruded litter pellets of
the present invention forming clean clumps when wetted, such litter
composed of at least a plurality of extruded litter pellets per
cubic inch volume of the litter used in their as extruded form
advantageously produce de-dusting litter by each extruded pellet
used in its as-extruded form acting as a dust magnet. Without being
wetted, each extruded pellet used in extruded form in litter of the
present invention has sufficient water-soluble material on and in
an exterior surface of each pellet to cause dust in the litter to
adhere to the water-soluble material of an outer pellet surface
contacting the dust preventing such dust from becoming airborne. In
a preferred embodiment, without being wetted, water soluble binder
present in the outer surface of each extruded pellet used in
extruded form in such a low-dust litter of the invention is dust
attracting causing dust in the litter to stick to the water-soluble
binder of extruded uncoated pellets in the litter, while the binder
is dry, preventing such dust from becoming airborne. Such
de-dusting extruded self-clumping litter composed of uncoated
extruded litter pellet dust-magnets in accordance with the present
invention enable retail bags or containers filled with such litter
to contain less than 5% dust, preferably less than 3% dust and
preferably less than 1% dust by litter weight.
[0015] In one preferred extruded self-clumping cat litter, the
litter is formed of a mixture of extruded pellets having a
plurality of different sizes that prevent liquid, e.g., water or
urine, being absorbed from channeling downwardly between pellets
thereby forming clumps on top of the litter which are generally
horizontally oriented making such clumps easy to scoop out of the
litter and dispose of. In such a preferred extruded litter, the
litter has at least a plurality of pairs, i.e., at least three, of
larger sized extruded litter pellets per cubic inch of litter
volume of a first size range, and at least another plurality of
pairs, i.e. at least three, of more finely sized extruded litter
pellets per cubic inch of litter volume, e.g. fines, of a second
size range smaller than the first size range. A preferred extruded
self-clumping litter has at least 15% fines, preferably has at
least 20% fines, with the remainder of the extruded pellets being
larger sized pellets. Another preferred extruded self-clumping
litter has at least 5% fines and preferably has between 5% and 40%
fines, with the remainder of the extruded pellets being larger
sized pellets. Still another preferred extruded self-clumping
litter has at least 5% fines and preferably has between 10% fines
and preferably has between 10% and 30% fines, with the remainder of
the extruded pellets being larger sized pellets.
[0016] In one such preferred extruded self-clumping cat litter, the
litter is formed of a mixture of at least a plurality of pairs,
i.e., at least three, of larger sized extruded pellets per cubic
inch of litter volume of a first size range, and at least another
plurality of pairs, i.e. at least three, of more finely sized
extruded pellets per cubic inch of litter volume, e.g. fines, of a
second size range smaller than the first size range. Such fines
preferably are formed of smaller sized extruded pellets having a
size falling within the second size "fines" range but also can be
formed of pieces of extruded pellets having a size falling within
the second size "fines" range. Such an extruded self-clumping
litter formed of a mixture of differently sized pellets has at
least 5% fines, preferably at least 10% fines, more preferably at
least 15% fines, with the remainder of the pellets of the litter
being larger sized extruded pellets. Another preferred extruded
self-clumping litter has at least 5% fines and preferably has
between 5% and 40% fines, with the remainder of the extruded
pellets being larger sized pellets. Still another preferred
extruded self-clumping litter has at least 5% fines, preferably has
between 5% fines and 35% fines, and more preferably has between 10%
and 30% fines, with the remainder of the extruded pellets being
larger sized pellets.
[0017] In a preferred litter embodiment, each litter pellet is
extruded from an admixture not containing any smectite nor any
binder additive and is used in uncoated form. In another preferred
litter embodiment, each litter pellet is extruded from an admixture
not containing any smectite nor any binder additive and is used
without any smectite, e.g., bentonite, coating. In still another
preferred litter embodiment, each litter pellet is extruded from an
admixture not containing any smectite nor any binder additive and
is used in its as-extruded form.
[0018] These and other objects, features and advantages of this
invention will become apparent from the following detailed
description of the invention and accompanying drawings.
DRAWING DESCRIPTION
[0019] FIG. 1 is an enlarged color microscope photo of a preferred
extruded granular sorbent formulated for use as cat litter of the
present invention;
[0020] FIG. 2 is an enlarged color microscope photo of a preferred
but exemplary extruded sorbent granule of the extruded granular
sorbent of the present invention that is an extruded pellet used
substantially in its as extruded form;
[0021] FIG. 3 is an enlarged color microscope photo of a of a
second preferred but exemplary extruded sorbent granule of the
extruded granular sorbent of the present invention that is an
extruded pellet used substantially in its as extruded form;
[0022] FIG. 4 is an enlarged color photo of extruded granular
sorbent formed of a plurality of pairs of extruded sorbent granules
in a litter box being wetted and beginning to form a clump where
the extruded sorbent granules have a plurality of different granule
size ranges causing the clump to form on top of the granules making
scooping of the formed clump easy;
[0023] FIG. 5 is an enlarged color photo of the clump of FIG. 4
after being formed during scooping of the clump using a perforate
litter scoop;
[0024] FIG. 6 is an enlarged color photo of the clump of FIG. 4
after being lifted by the scoop from the unused sorbent granules in
the litter box;
[0025] FIG. 7 is an enlarged color photo of the clump of FIG. 4
after all of the unused sorbent granules have been removed.
[0026] Before explaining one or more embodiments of the invention
in detail, it is to be understood that the invention is not limited
in its application to the details of construction and the
arrangement of the components set forth in the following
description or illustrated in the drawings. The invention is
capable of other embodiments, which can be practiced or carried out
in various ways. Also, it is to be understood that the phraseology
and terminology employed herein is for the purpose of description
and should not be regarded as limiting.
DETAILED DESCRIPTION
[0027] FIGS. 1-7 illustrates a preferred embodiment of a scoopable
or pourable self-clumping cat or animal litter 30 of the present
invention which preferably is composed of at least a plurality of
pairs, i.e., at least three, of sorbent granules 32 each formed of
an extruded water soluble binder containing litter pellet 34 in
accordance with the invention that preferably is extruded from
starch containing material, e.g., starch-containing admixture,
forming water-soluble binder during extrusion from at least some of
the starch in the starch-containing material in an amount
sufficient for at least one extruded litter pellet 34 to self-clump
by agglutinating with a plurality of other extruded litter pellets
34 when the extruded litter pellets 34 are wetted forming a clump
36 of the extruded litter pellets 34 as depicted in FIGS. 4-7. Each
litter pellet 34 is extruded from a starch-containing material,
preferably starch-containing admixture, using a method of making
self-clumping litter in accordance with the present invention
producing extruded litter pellets 34 each containing at least 10%
water soluble material, e.g., water solubles, preferably at least
15% water soluble material, and at least 7% water soluble binder,
preferably at least 10% water soluble binder, by pellet weight.
[0028] As discussed in more detail below, litter 30 made in
accordance with the present invention is relatively lightweight
having a bulk density less than about 35 pounds per cubic foot,
fast absorbing being able to rapidly absorb at least one times
unused or unspent litter weight in water, e.g., 2% saline solution,
within sixty seconds of being wetted with the water, highly
absorbent being able to absorb at least 3.5 times, preferably at
least 4.5 times unused or unspent litter weight in water, e.g., 2%
saline solution, which form clumps 36 having at least a 92% clump
retention rate, which form clumps 36 that shrink at least 3%,
preferably at least 5%, when dried, e.g., in a litter box, to a
moisture content of no greater than 20% moisture by clump weight,
and which form clumps 36 that are biodegradable. In a preferred
litter embodiment, litter 30 made in accordance with the present
invention is relatively lightweight having a bulk density less than
about 35 pounds per cubic foot, fast absorbing being able to
rapidly absorb at least one times unused or unspent litter weight
in water, e.g., 2% saline solution, within sixty seconds of being
wetted with the water, highly absorbent being able to absorb at
least 3.5 times, preferably at least 4.5 times unused or unspent
litter weight in water, e.g., 2% saline solution, which form clumps
36 having at least a 95% clump retention rate, which form clumps 36
that shrink at least 3%, preferably at least 5%, when dried, e.g.,
in a litter box, to a moisture content of no greater than 20%
moisture by clump weight, and which form clumps 36 each having a
crush-strength of at least 15 pounds per square inch, preferably at
least 20 pounds per square inch.
[0029] The starch-containing material preferably is a
starch-containing admixture composed of one or more cereal grains,
such as one or more of corn, wheat and/or sorghum, which can be in
whole grain form, de-hulled or de-corticated form, de-germed form,
and/or comminuted or ground form. The starch-containing material or
starch-containing admixture preferably is extruded from a single
screw extruder, preferably a 50 horsepower or 100 horsepower single
screw extruder, at a residency time or cooking time of no greater
than 12 seconds, preferably between 4-11 seconds, and more
preferably between 5-10 seconds, at an extruder pressure and/or
extruder die pressure of at least 1000 pounds per square inch, and
at an extruder temperature of at least 125 degrees Celsius. The
starch-containing material or starch-containing admixture extruded
by the extruder in accordance with such extruder operating
parameters preferably has a moisture content no greater than 30%,
preferably no greater than 28%, more preferably no greater than
25%, by admixture weight such that dextrinization occurs during
litter pellet extrusion. In one preferred method and admixture, the
admixture preferably has a moisture content no greater than 28%,
preferably no greater than 25%, by admixture weight with no
additional water added to the extruder during extrusion.
[0030] In one preferred admixture formulation, the
starch-containing admixture is composed of at least 50% whole grain
de-hulled or de-corticated sorghum, can be composed of as much as
40% cellulose, e.g., cellulosic fiber, and can be composed of at
least 10% of other constituents including scents or fragrances,
dyes or colorants, surfactant(s), antibacterial agents, anti-fungal
agents, anti-parasitic agents, and the like, with the admixture
having a moisture content no greater than 25%, preferably no
greater than 20%, by admixture weight. In one preferred
sorghum-based admixture formulation, the starch-containing
admixture is composed substantially completely of whole grain
de-hulled or de-corticated sorghum, preferably white sorghum, with
the admixture having a moisture content no greater than 20%,
preferably no greater than 18%, more preferably no greater than
15%, by admixture weight. No additional water or moisture
preferably is added to the extruder during extruder operation. In
one such preferred sorghum-based admixture formulation, the
starch-containing admixture is composed substantially completely of
whole grain de-hulled or de-corticated sorghum, preferably white
sorghum, with the admixture having a moisture content no greater
than 20%, preferably no greater than 18%, more preferably no
greater than 15%, by admixture weight with no water added to the
admixture prior to or during extruder operation.
[0031] In a preferred litter embodiment, the litter 30 has at least
a plurality of pairs of litter pellets 34 per cubic inch of the
litter 30 extruded from such a starch-containing material, e.g.,
starch-containing admixture, which contains no smectite, e.g.,
contains no bentonite, and which is used in its substantially
as-extruded form such that each extruded litter pellet 34 is not
coated with any smectite, e.g., not coated with any bentonite. In
one such preferred litter embodiment, the litter 30 is
substantially completely composed of litter pellets 34 each
extruded from a starch-containing material or starch-containing
admixture that contains no smectite, e.g., contains no bentonite,
with each litter pellet 34 used in its substantially as-extruded
form in that each extruded litter pellet 34 is not coated with any
smectite, e.g., not coated with any bentonite.
[0032] Each extruded litter pellet 34 preferably contains at least
7.5% of a water-soluble binder by as-extruded pellet weight formed
from starch of the starch-containing material during pellet
extrusion that is sufficient for wetted pellets 34 to self-clump
together by agglutination where at least some water-soluble binder
solubilizes when wetted causing at least an outer surface of each
wetted pellet 34 to become sufficiently tacky for the wetted pellet
34 to stick to one or more adjacent pellets 34 in contact
therewith. In a preferred embodiment, each extruded litter pellet
34 preferably contains at least 10% of a water-soluble binder by
as-extruded pellet weight formed from starch of the starch
containing material during pellet extrusion that is sufficient for
wetted pellets 34 to self-clump together by agglutination where at
least some water-soluble binder solubilizes when wetted causing (a)
at least an outer surface of each wetted pellet 34 to become
sufficiently tacky for the wetted pellet 34 to stick to one or more
adjacent pellets 34 in contact therewith and/or (b) at least some
of the water-soluble binder of each wetted pellet 34 to solubilize
and form a flowable adhesive that flows from the wetted pellet 34
onto one or more adjacent pellets 34 adhesively gluing them
together.
[0033] In one preferred embodiment, each extruded litter pellet 34
preferably contains at least 15% of a water-soluble binder by
as-extruded pellet weight formed from starch of the starch
containing material during pellet extrusion that is sufficient for
wetted pellets 34 to self-clump together by agglutination where at
least some water-soluble binder solubilizes when wetted causing (a)
at least an outer surface of each wetted pellet 34 to become
sufficiently tacky for the wetted pellet 34 to stick to one or more
adjacent pellets 34 in contact therewith and/or (b) at least some
of the water-soluble binder of each wetted pellet 34 to solubilize
and form a flowable adhesive that flows from the wetted pellet 34
onto one or more adjacent pellets 34 adhesively gluing them
together. In one such preferred embodiment, each extruded litter
pellet 34 preferably contains at least 15% of a water-soluble
binder by as-extruded pellet weight formed from starch of the
starch containing material during pellet extrusion that is
sufficient for wetted pellets 34 to self-clump together by
agglutination where at least some water-soluble binder solubilizes
when wetted causing (a) at least an outer surface of each wetted
pellet 34 to become sufficiently tacky for the wetted pellet 34 to
stick to one or more adjacent pellets 34 in contact therewith and
(b) at least some of the water-soluble binder of each wetted pellet
34 to solubilize and form a flowable adhesive that flows from the
wetted pellet 34 onto one or more adjacent pellets 34 adhesively
gluing them together.
[0034] In one preferred embodiment, each extruded litter pellet 34
preferably contains at least 20% of a water-soluble binder by
as-extruded pellet weight formed from starch of the starch
containing material during pellet extrusion that is sufficient for
wetted pellets 34 to self-clump together by agglutination where at
least some water-soluble binder solubilizes when wetted causing (a)
at least an outer surface of each wetted pellet 34 to become
sufficiently tacky for the wetted pellet 34 to stick to one or more
adjacent pellets 34 in contact therewith and/or (b) at least some
of the water-soluble binder of each wetted pellet 34 to solubilize
and form a flowable adhesive that flows from the wetted pellet 34
onto one or more adjacent pellets 34 adhesively gluing them
together. In one such preferred embodiment, each extruded litter
pellet 34 preferably contains at least 20% of a water-soluble
binder by as-extruded pellet weight formed from starch of the
starch containing material during pellet extrusion that is
sufficient for wetted pellets 34 to self-clump together by
agglutination where at least some water-soluble binder solubilizes
when wetted causing (a) at least an outer surface of each wetted
pellet 34 to become sufficiently tacky for the wetted pellet 34 to
stick to one or more adjacent pellets 34 in contact therewith and
(b) at least some of the water-soluble binder of each wetted pellet
34 to solubilize and form a flowable adhesive that flows from the
wetted pellet 34 onto one or more adjacent pellets 34 adhesively
gluing them together.
[0035] The water-soluble binder formed in each extruded litter
pellet 34 from starch in the admixture during extrusion preferably
is a cold-water soluble binder that is water soluble at
temperatures below the gelatinization temperature of the type of
starch in the admixture from which the binder is formed during
extrusion. In a preferred method and embodiment, the water-soluble
binder formed in each extruded litter pellet 34 from starch in the
admixture during extrusion preferably is a cold-water soluble
binder that is water soluble at temperatures below 60 degrees
Celsius or 140 degrees Fahrenheit. In one preferred method and
embodiment, the water-soluble binder formed in each extruded litter
pellet 34 from sorghum starch in a sorghum-containing admixture
during extrusion preferably is a cold-water soluble binder that is
water soluble at temperatures below the gelatinization temperature
of sorghum starch and preferably is water soluble at temperatures
below 60 degrees Celsius or 140 degrees Fahrenheit. In one
preferred method and embodiment, the water-soluble binder formed in
each extruded litter pellet 34 from corn starch in a
corn-containing admixture during extrusion preferably is a
cold-water soluble binder that is water soluble at temperatures
below the gelatinization temperature of maize or corn starch and
preferably is water soluble at temperatures below 60 degrees
Celsius or 140 degrees Fahrenheit.
[0036] The cold water-soluble binder formed in each extruded litter
pellet 34 from starch in the admixture during extrusion is a
cold-water soluble modified starch binder that possesses adhesive
properties, e.g., functions as a glue, when wetted, e.g.,
solubilized, which preferably is a cold water soluble binder formed
of starch in the admixture modified, preferably physically
modified, preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have a molecular weight of no
greater than 10.sup.6, e.g., no greater than 10.sup.6 g/mol, which
preferably has a molecular weight no greater than 10.sup.5, e.g.,
no greater than 10.sup.5 g/mol. In a preferred method and extruded
litter pellet embodiment in accordance with the present invention,
the cold-water soluble binder formed in each pellet 34 from starch
in the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble binder formed
of starch in the admixture modified, preferably physically
modified, preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have a degree of polymerization
of no greater than 6,000 glucose units, preferably has a degree of
polymerization of no greater than 5,000 glucose units, and more
preferably has a degree of polymerization of no greater than 3,000
glucose units. In one such preferred method and embodiment, the
cold-water soluble binder formed in each pellet 34 from starch in
the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble binder formed
of starch in the admixture modified, preferably physically
modified, preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have (a) a molecular weight of
no greater than 10.sup.6, e.g., no greater than 10.sup.6 g/mol,
which preferably has a molecular weight no greater than 10.sup.5,
e.g., no greater than 10.sup.5 g/mol, and (b) a degree of
polymerization of no greater than 6,000 glucose units, preferably
has a degree of polymerization of no greater than 5,000 glucose
units, and more preferably has a degree of polymerization of no
greater than 3,000 glucose units.
[0037] In another preferred method and extruded litter pellet
embodiment, the cold water-soluble binder formed in each extruded
litter pellet 34 from starch in the admixture during extrusion is a
cold-water soluble modified starch binder that possesses adhesive
properties, e.g., functions as a glue, when wetted, e.g.,
solubilized, which preferably is a cold water soluble binder formed
of starch in the admixture modified, preferably physically
modified, preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have a molecular weight of no
greater than 10.sup.5, e.g., no greater than 10.sup.5 g/mol, which
preferably has a molecular weight no greater than 10.sup.4, e.g.,
no greater than 10.sup.4 g/mol. In a preferred method and extruded
litter pellet embodiment in accordance with the present invention,
the cold-water soluble binder formed in each pellet 34 from starch
in the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble binder formed
of starch in the admixture modified, preferably physically
modified, preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have a degree of polymerization
of no greater than 5,000 glucose units, preferably has a degree of
polymerization of no greater than 3,000 glucose units, and more
preferably has a degree of polymerization of no greater than 1,000
glucose units. In one such preferred method and embodiment, the
cold-water soluble binder formed in each pellet 34 from starch in
the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble binder formed
of starch in the admixture modified, preferably physically
modified, preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have (a) a molecular weight of
no greater than 10.sup.5, e.g., no greater than 10.sup.5 g/mol,
which preferably has a molecular weight no greater than 10.sup.4,
e.g., no greater than 10.sup.4 g/mol, and (b) a degree of
polymerization of no greater than 5,000 glucose units, preferably
has a degree of polymerization of no greater than 3,000 glucose
units, and more preferably has a degree of polymerization of no
greater than 1,000 glucose units.
[0038] In a further preferred method and extruded litter pellet
embodiment, the cold water-soluble binder formed in each extruded
litter pellet 34 from starch in the admixture during extrusion is a
cold-water soluble modified starch binder that possesses adhesive
properties, e.g., functions as a glue, when wetted, e.g.,
solubilized, which preferably is a cold water soluble binder formed
of starch in the admixture modified, preferably physically
modified, preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have a molecular weight of no
greater than 10.sup.5, e.g., no greater than 10.sup.5 g/mol, which
preferably has a molecular weight no greater than 10.sup.4, e.g.,
no greater than 10.sup.4 g/mol. In a preferred method and extruded
litter pellet embodiment in accordance with the present invention,
the cold-water soluble binder formed in each pellet 34 from starch
in the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble binder formed
of starch in the admixture modified, preferably physically
modified, preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have a degree of polymerization
of no greater than 2,000 glucose units, preferably has a degree of
polymerization of no greater than 1,000 glucose units, and more
preferably has a degree of polymerization of no greater than 500
glucose units. In one such preferred method and embodiment, the
cold-water soluble binder formed in each pellet 34 from starch in
the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble binder formed
of starch in the admixture modified, preferably physically
modified, preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have (a) a molecular weight of
no greater than 10.sup.5, e.g., no greater than 10.sup.5 g/mol,
which preferably has a molecular weight no greater than 10.sup.4,
e.g., no greater than 10.sup.4 g/mol, and (b) a degree of
polymerization of no greater than 2,000 glucose units, preferably
has a degree of polymerization of no greater than 1,000 glucose
units, and more preferably has a degree of polymerization of no
greater than 500 glucose units.
[0039] In still another preferred method and extruded litter pellet
embodiment, the cold water-soluble binder formed in each extruded
litter pellet 34 from starch in the admixture during extrusion is a
cold-water soluble modified starch binder that possesses adhesive
properties, e.g., functions as a glue, when wetted, e.g.,
solubilized, which preferably is a cold water soluble binder formed
of starch in the admixture modified, preferably physically
modified, preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have a molecular weight of no
greater than 10.sup.6, e.g., no greater than 10.sup.6 g/mol, which
preferably has a molecular weight no greater than 10.sup.5, e.g.,
no greater than 10.sup.5 g/mol. In a preferred method and extruded
litter pellet embodiment in accordance with the present invention,
the cold-water soluble binder formed in each pellet 34 from starch
in the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble binder formed
of starch in the admixture modified, preferably physically
modified, preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have a degree of polymerization
of between 6,000 glucose units and 10 glucose units, preferably
between 3,000 glucose units and 10 glucose units, and more
preferably between 1,000 glucose units and 10 glucose units. In one
such preferred method and embodiment, the cold-water soluble binder
formed in each pellet 34 from starch in the admixture during
extrusion is a cold-water soluble modified starch binder that
preferably is a cold water soluble binder formed of starch in the
admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have (a) a molecular weight of no greater than
10.sup.6, e.g., no greater than 10.sup.6 g/mol, and (b) a degree of
polymerization of between 6,000 glucose units and 10 glucose units.
In another such preferred method and embodiment, the cold-water
soluble binder formed in each pellet 34 from starch in the
admixture during extrusion is a cold-water soluble modified starch
binder that preferably is a cold water soluble binder formed of
starch in the admixture modified, preferably physically modified,
preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have (a) a molecular weight of
no greater than 10.sup.6, e.g., no greater than 10.sup.6 g/mol, and
(b) a degree of polymerization of between 3,000 glucose units and
10 glucose units. In still another such preferred method and
embodiment, the cold-water soluble binder formed in each pellet 34
from starch in the admixture during extrusion is a cold-water
soluble modified starch binder that preferably is a cold water
soluble binder formed of starch in the admixture modified,
preferably physically modified, preferably dextrinized, e.g.,
physically modified via dextrinization, during extrusion to have
(a) a molecular weight of no greater than 10.sup.6, e.g., no
greater than 10.sup.6 g/mol, and (b) a degree of polymerization of
no greater than 1,000 glucose units, preferably between 1,000
glucose units and 10 glucose units.
[0040] The cold water-soluble binder formed in each extruded litter
pellet 34 from starch in the admixture during extrusion is a
cold-water soluble modified starch binder that possesses adhesive
properties, e.g., functions as a glue, when wetted, e.g.,
solubilized, which preferably is a cold water soluble
amylopectin-based binder formed of amylopectin starch in the
admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have a reduced molecular weight of no greater than
10.sup.6, e.g., no greater than 10.sup.6 g/mol, which preferably
has a molecular weight no greater than 10.sup.5, e.g., no greater
than 10.sup.5 g/mol. In a preferred method and extruded litter
pellet embodiment in accordance with the present invention, the
cold-water soluble binder formed in each pellet 34 from starch in
the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble
amylopectin-based binder formed of amylopectin starch in the
admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have a reduced degree of polymerization of no greater
than 6,000 glucose units, preferably has a degree of polymerization
of no greater than 5,000 glucose units, and more preferably has a
degree of polymerization of no greater than 3,000 glucose units. In
one such preferred method and embodiment, the cold-water soluble
binder formed in each pellet 34 from starch in the admixture during
extrusion is a cold-water soluble modified starch binder that
preferably is a cold water soluble amylopectin-based binder formed
of amylopectin starch in the admixture modified, preferably
physically modified, preferably dextrinized, e.g., physically
modified via dextrinization, during extrusion to have (a) a reduced
molecular weight of no greater than 10.sup.6, e.g., no greater than
10.sup.6 g/mol, which preferably has a molecular weight no greater
than 10.sup.5, e.g., no greater than 10.sup.5 g/mol, and (b) a
degree of polymerization of no greater than 6,000 glucose units,
preferably has a reduced degree of polymerization of no greater
than 5,000 glucose units, and more preferably has a degree of
polymerization of no greater than 3,000 glucose units.
[0041] In another preferred method and extruded litter pellet
embodiment, the cold water-soluble binder formed in each extruded
litter pellet 34 from starch in the admixture during extrusion is a
cold-water soluble modified starch binder that possesses adhesive
properties, e.g., functions as a glue, when wetted, e.g.,
solubilized, which preferably is a cold water soluble
amylopectin-based binder formed of amylopectin starch in the
admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have a reduced molecular weight of no greater than
10.sup.5, e.g., no greater than 10.sup.5 g/mol, which preferably
has a molecular weight no greater than 10.sup.4, e.g., no greater
than 10.sup.4 g/mol. In a preferred method and extruded litter
pellet embodiment in accordance with the present invention, the
cold-water soluble binder formed in each pellet 34 from starch in
the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble
amylopectin-based binder formed of amylopectin starch in the
admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have a reduced degree of polymerization of no greater
than 5,000 glucose units, preferably has a degree of polymerization
of no greater than 3,000 glucose units, and more preferably has a
degree of polymerization of no greater than 1,000 glucose units. In
one such preferred method and embodiment, the cold-water soluble
binder formed in each pellet 34 from starch in the admixture during
extrusion is a cold-water soluble modified starch binder that
preferably is a cold water soluble amylopectin-based binder formed
of amylopectin starch in the admixture modified, preferably
physically modified, preferably dextrinized, e.g., physically
modified via dextrinization, during extrusion to have (a) a reduced
molecular weight of no greater than 10.sup.5, e.g., no greater than
10.sup.5 g/mol, which preferably has a molecular weight no greater
than 10.sup.4, e.g., no greater than 10.sup.4 g/mol, and (b) a
reduced degree of polymerization of no greater than 5,000 glucose
units, preferably has a degree of polymerization of no greater than
3,000 glucose units, and more preferably has a degree of
polymerization of no greater than 1,000 glucose units.
[0042] In a further preferred method and extruded litter pellet
embodiment, the cold water-soluble binder formed in each extruded
litter pellet 34 from starch in the admixture during extrusion is a
cold-water soluble modified starch binder that possesses adhesive
properties, e.g., functions as a glue, when wetted, e.g.,
solubilized, which preferably is a cold water soluble
amylopectin-based binder formed of amylopectin starch in the
admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have a reduced molecular weight of no greater than
10.sup.5, e.g., no greater than 10.sup.5 g/mol, which preferably
has a molecular weight no greater than 10.sup.4, e.g., no greater
than 10.sup.4 g/mol. In a preferred method and extruded litter
pellet embodiment in accordance with the present invention, the
cold-water soluble binder formed in each pellet 34 from starch in
the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble
amylopectin-based binder formed of amylopectin starch in the
admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have a reduced degree of polymerization of no greater
than 2,000 glucose units, preferably has a degree of polymerization
of no greater than 1,000 glucose units, and more preferably has a
degree of polymerization of no greater than 500 glucose units. In
one such preferred method and embodiment, the cold-water soluble
binder formed in each pellet 34 from starch in the admixture during
extrusion is a cold-water soluble modified starch binder that
preferably is a cold water soluble amylopectin-based binder formed
of amylopectin starch in the admixture modified, preferably
physically modified, preferably dextrinized, e.g., physically
modified via dextrinization, during extrusion to have (a) a reduced
molecular weight of no greater than 10.sup.5, e.g., no greater than
10.sup.5 g/mol, which preferably has a molecular weight no greater
than 10.sup.4, e.g., no greater than 10.sup.4 g/mol, and (b) a
reduced degree of polymerization of no greater than 2,000 glucose
units, preferably has a degree of polymerization of no greater than
1,000 glucose units, and more preferably has a degree of
polymerization of no greater than 500 glucose units.
[0043] In still another preferred method and extruded litter pellet
embodiment, the cold water-soluble binder formed in each extruded
litter pellet 34 from starch in the admixture during extrusion is a
cold-water soluble modified starch binder that possesses adhesive
properties, e.g., functions as a glue, when wetted, e.g.,
solubilized, which preferably is a cold water soluble
amylopectin-based binder formed of amylopectin starch in the
admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have a reduced molecular weight of no greater than
10.sup.6, e.g., no greater than 10.sup.6 g/mol, which preferably
has a molecular weight no greater than 10.sup.5, e.g., no greater
than 10.sup.5 g/mol. In a preferred method and extruded litter
pellet embodiment in accordance with the present invention, the
cold-water soluble binder formed in each pellet 34 from starch in
the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble amylopectin
binder formed of amylopectin starch in the admixture modified,
preferably physically modified, preferably dextrinized, e.g.,
physically modified via dextrinization, during extrusion to have a
lesser degree of polymerization of between 6,000 glucose units and
10 glucose units, preferably between 3,000 glucose units and 10
glucose units, and more preferably between 1,000 glucose units and
10 glucose units. In one such preferred method and embodiment, the
cold-water soluble binder formed in each pellet 34 from starch in
the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble
amylopectin-based binder formed of amylopectin starch in the
admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have (a) a lesser molecular weight of no greater than
10.sup.6, e.g., no greater than 10.sup.6 g/mol, and (b) a lesser
degree of polymerization of between 6,000 glucose units and 10
glucose units. In another such preferred method and embodiment, the
cold-water soluble binder formed in each pellet 34 from starch in
the admixture during extrusion is a cold-water soluble modified
starch binder that preferably is a cold water soluble
amylopectin-based binder formed of amylopectin starch in the
admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have (a) a lower molecular weight of no greater than
10.sup.6, e.g., no greater than 10.sup.6 g/mol, and (b) a lower
degree of polymerization of between 3,000 glucose units and 10
glucose units. In still another such preferred method and
embodiment, the cold-water soluble binder formed in each pellet 34
from starch in the admixture during extrusion is a cold-water
soluble modified starch binder that preferably is a cold water
soluble amylopectin-based binder formed of amylopectin starch in
the admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have (a) a molecular weight of no greater than
10.sup.6, e.g., no greater than 10.sup.6 g/mol, and (b) a degree of
polymerization of no greater than 1,000 glucose units, preferably
between 1,000 glucose units and 10 glucose units.
[0044] In another preferred method and extruded litter pellet
embodiment, the cold water-soluble binder formed in each extruded
litter pellet 34 from starch in the admixture during extrusion is a
cold-water soluble modified starch binder that possesses adhesive
properties, e.g., functions as a glue, when wetted, e.g.,
solubilized, which preferably is a cold water soluble dextrin
binder, i.e., dextrin, or dextrin-like cold water soluble binder
having a molecular weight of within .+-.75% of the molecular weight
of dextrin, preferably having a molecular weight of within .+-.75%
of 504.43708, e.g., having a molecular weight of within .+-.75% of
504.43708 g/mol. In one such preferred method and extruded litter
pellet embodiment, the cold water-soluble binder formed in each
extruded litter pellet 34 from starch in the admixture during
extrusion is a cold-water soluble modified starch binder that
possesses adhesive properties, e.g., functions as a glue, when
wetted, e.g., solubilized, which preferably is a cold water soluble
dextrin binder, i.e., dextrin, or dextrin-like cold water soluble
binder having a mean molecular weight of within .+-.75% of the mean
molecular weight of dextrin, preferably having a mean molecular
weight of within .+-.75% of 504.43708, e.g., having a mean
molecular weight of within .+-.75% of 504.43708 g/mol. In another
such preferred method and extruded litter pellet embodiment, the
cold water-soluble binder formed in each extruded litter pellet 34
from starch in the admixture during extrusion is a cold-water
soluble modified starch binder that possesses adhesive properties,
e.g., functions as a glue, when wetted, e.g., solubilized, which
preferably is a cold water soluble dextrin binder, i.e., dextrin,
or dextrin-like cold water soluble binder having an average
molecular weight of within .+-.75% of the average molecular weight
of dextrin, preferably having an average molecular weight of within
.+-.75% of 504.43708, e.g., having an average molecular weight of
within .+-.75% of 504.43708 g/mol.
[0045] In yet another such preferred method and extruded litter
pellet embodiment, the cold water-soluble binder formed in each
extruded litter pellet 34 from starch in the admixture during
extrusion is a cold-water soluble modified starch binder that
possesses adhesive properties, e.g., functions as a glue, when
wetted, e.g., solubilized, which preferably is a cold water soluble
dextrin binder, i.e., dextrin, or dextrin-like cold water soluble
binder formed of starch in the admixture modified, preferably
physically modified, preferably dextrinized, e.g., physically
modified via dextrinization, during extrusion to have a reduced
molecular weight of within .+-.75% of the molecular weight of
dextrin, preferably having a molecular weight of within .+-.75% of
504.43708, e.g., having a molecular weight of within .+-.75% of
504.43708 g/mol. In one such preferred method and extruded litter
pellet embodiment, the cold water-soluble binder formed in each
extruded litter pellet 34 from starch in the admixture during
extrusion is a cold-water soluble modified starch binder that
possesses adhesive properties, e.g., functions as a glue, when
wetted, e.g., solubilized, which preferably is a cold water soluble
dextrin binder, i.e., dextrin, or dextrin-like cold water soluble
binder formed of starch in the admixture modified, preferably
physically modified, preferably dextrinized, e.g., physically
modified via dextrinization, during extrusion to have a reduced
molecular weight possessing a mean molecular weight that is within
.+-.75% of the mean molecular weight of dextrin, preferably having
a mean molecular weight of within .+-.75% of 504.43708, e.g.,
having a mean molecular weight of within .+-.75% of 504.43708
g/mol. In another such preferred method and extruded litter pellet
embodiment, the cold water-soluble binder formed in each extruded
litter pellet 34 from starch in the admixture during extrusion is a
cold-water soluble modified starch binder that possesses adhesive
properties, e.g., functions as a glue, when wetted, e.g.,
solubilized, which preferably is a cold water soluble dextrin
binder, i.e., dextrin, or dextrin-like cold water soluble binder
formed of starch in the admixture modified, preferably physically
modified, preferably dextrinized, e.g., physically modified via
dextrinization, during extrusion to have a reduced molecular weight
possessing an average molecular weight of within .+-.75% of the
average molecular weight of dextrin, preferably having an average
molecular weight of within .+-.75% of 504.43708, e.g., having an
average molecular weight of within .+-.75% of 504.43708 g/mol.
[0046] In a further such preferred method and extruded litter
pellet embodiment, the cold water-soluble binder formed in each
extruded litter pellet 34 from starch in the admixture during
extrusion is a cold-water soluble modified starch binder that
possesses adhesive properties, e.g., functions as a glue, when
wetted, e.g., solubilized, which preferably is a cold water soluble
dextrin binder, i.e., dextrin, or dextrin-like cold water soluble
amylopectin-based binder formed of amylopectin starch in the
admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have a reduced molecular weight that is within .+-.75%
of the molecular weight of dextrin, preferably having a molecular
weight of within .+-.75% of 504.43708, e.g., having a molecular
weight of within .+-.75% of 504.43708 g/mol. In one such preferred
method and extruded litter pellet embodiment, the cold
water-soluble binder formed in each extruded litter pellet 34 from
starch in the admixture during extrusion is a cold-water soluble
modified starch binder that possesses adhesive properties, e.g.,
functions as a glue, when wetted, e.g., solubilized, which
preferably is a cold water soluble dextrin binder, i.e., dextrin,
or dextrin-like cold water soluble amylopectin-based binder formed
of amylopectin starch in the admixture modified, preferably
physically modified, preferably dextrinized, e.g., physically
modified via dextrinization, during extrusion to have a reduced
molecular weight and a mean molecular weight within .+-.75% of the
mean molecular weight of dextrin, preferably having a mean
molecular weight of within .+-.75% of 504.43708, e.g., having a
mean molecular weight of within .+-.75% of 504.43708 g/mol. In
another such preferred method and extruded litter pellet
embodiment, the cold water-soluble binder formed in each extruded
litter pellet 34 from starch in the admixture during extrusion is a
cold-water soluble modified starch binder that possesses adhesive
properties, e.g., functions as a glue, when wetted, e.g.,
solubilized, which preferably is a cold water soluble dextrin
binder, i.e., dextrin, or dextrin-like cold water soluble
amylopectin-based binder formed of amylopectin starch in the
admixture modified, preferably physically modified, preferably
dextrinized, e.g., physically modified via dextrinization, during
extrusion to have a reduced molecular weight possessing an average
molecular weight of within .+-.75% of the average molecular weight
of dextrin, preferably having an average molecular weight of within
.+-.75% of 504.43708, e.g., having an average molecular weight of
within .+-.75% of 504.43708 g/mol.
[0047] With reference to FIGS. 2 and 3, each litter pellet 34 is
extruded with (a) an outer surface 40 that is at least partially
formed of water soluble material enabling at least a portion of the
outer litter pellet surface 40 to solubilize or dissolve when
wetted with liquid, such as water, e.g., 2% saline solution, urine
and/or fecal matter during litter use, and (b) an interior (not
shown) that also is at least partially formed of water soluble
material enabling at least a portion of the outer litter pellet
surface 40 to solubilize or dissolve when wetted with liquid, such
as water, e.g., 2% saline solution, urine and/or fecal matter
during litter use. Each extruded litter pellet 34 can have, and
preferably does have a plurality of pores 42, preferably at least a
plurality of pairs, i.e., at least three, of the pores 42, in its
outer pellet surface 40 preferably formed during pellet extrusion.
Each extruded litter pellet 34 can have, and preferably does have
at least a plurality of voids or pockets 44, e.g., air pockets 44,
formed in the interior of the pellet 34 preferably also formed
during pellet extrusion. In a preferred extruded litter pellet
embodiment, at least one and preferably at least a plurality of the
pores 42 formed in the outer surface 40 of each extruded pellet 34
communicates with, e.g., is in fluid or liquid communication with,
at least one of the internal voids or pockets 44 inside the pellet
34.
[0048] Such a partially dissolving extruded litter pellet 34 of the
present invention is not only of self-clumping construction, each
such partially dissolving extruded litter pellet 34 facilitates
rapid absorption of liquid when wetted substantially completely
absorbing at least one times the weight of unspent or unused litter
pellets 34 in water, e.g., 2% saline solution, urine and/or liquid
fecal matter within ninety seconds, preferably within sixty
seconds, such that all of the water, urine and/or liquid fecal
matter is retained by the resultant clump 36 of wetted pellets 34
that forms. Such a partially dissolving extruded litter pellet 34
of the present invention facilitates more rapid and more complete
liquid absorption by having pores 42 in the outer surface 40 of
each pellet 34 through which water, urine and/or liquid fecal
matter is drawn into each wetted pellet 34 during litter use
including via wicking, surface tension and/or capillary action.
Such a partially dissolving extruded litter pellet 34 of the
present invention also facilitates more rapid and more complete
liquid absorption by having at least a plurality pores 42 in the
outer surface 40 of each pellet 34 each being in fluid-flow or
liquid-flow communication with at least one inner void or pocket 44
enabling water, urine and/or liquid fecal matter drawn into each
one of the plurality of pores 42 to be relatively rapidly channeled
through the pores 42 into a corresponding inner void or pocket 44
including via wicking, surface tension and/or capillary action.
This channeling action enables a greater volume of water, urine
and/or liquid fecal matter to be more rapidly absorbed into each
extruded litter pellet 34.
[0049] In addition, the partially dissolving construction of each
extruded litter pellet 34 of the present invention further
facilitates more rapid absorption as water soluble portions of the
pellet outer surface 40 and interior substantially instantaneously
solubilize within two seconds, preferably within one second, of
being wetted increasing the absorption volume of and within each
pellet 34 within two seconds, preferably within one second, of
being wetted. Water soluble material of the outer surface 40 of
each wetted pellet 34 not only solubilizes or dissolves producing
flowable adhesive that self-clumps wetted pellets 34 together but
also creates at least a plurality of pores in addition to the pores
42 originally formed during pellet extrusion providing additional
liquid-absorbing pathways or channels into the interior of each
wetted pellet 34. The water soluble material of the outer surface
40 of each wetted pellet 34 also enlarges at least one and
preferably enlarges at least a plurality of the pre-existing pores
42 enabling each liquid-solubilized enlarged pore 42 to allow a
greater volume of liquid to enter not only increasing wetted pellet
absorption capacity but also increasing the rate of liquid
absorption. Water soluble material of the interior of each wetted
pellet 34 not only solubilizes or dissolves producing flowable
adhesive that self-clumps wetted pellets 34 together but also
creates one or more voids or pockets (not shown) within each wetted
pellet 34 that provides additional liquid-absorbing pathways or
channels into the interior of each wetted pellet 34 thereby
advantageously increasing the amount or volume of liquid each
partially dissolved wetted pellet 42 absorbs during litter use.
[0050] Such a partially dissolving extruded litter pellet
construction formed during extrusion results in extruded litter
pellets 34 of the present invention being able to rapidly absorb
one times its weight in water, e.g., 2% saline solution, in less
than ninety seconds, preferably less than sixty seconds, absorbs at
least 3.5 times litter pellet weight in water, e.g., 2% saline
solution, and preferably is capable of absorbing more than 4.5
times litter pellet weight in water, e.g., 2% saline solution,
during litter use.
[0051] With additional reference to FIGS. 4-7, when a liquid, such
as the stream of water 50, e.g., 2% saline solution, or urine,
shown in FIG. 4 being poured onto unspent or unused litter pellets
34 of litter 30 of the present invention, the litter pellets 34
wetted by the water 50 not only substantially completely absorb the
water 50 but solubilize water-soluble binder in each pellet 34
causing a clump 36 (FIGS. 5-6) of at least a plurality of pairs,
i.e. at least three, of wetted granules 32 to form. As a result of
the partially dissolving enhanced liquid absorption extruded litter
pellet construction of the present invention, the result clump 36
formed is produced by unspent or unused extruded litter pellets 34
rapidly absorbing between one time and four times unspent or unused
extruded litter pellet weight in water, e.g., 2% saline solution,
or urine within three minutes, preferably within two minutes, of
pellet wetting relatively rapidly forming a scoopable clump within
three minutes, preferably within two minutes of pellet wetting.
[0052] With reference to FIG. 5, when clump formation is complete
in as little as 30 seconds to three minutes, a discrete clump 36 of
litter pellets 34 of spent litter 38 is formed that can be removed
using a perforate litter scoop 48 from the unspent litter 30
remaining in the litter box 46 (FIG. 6). What remains after
scooping is a fully formed clump 36 of spent litter 38 that can be
easily disposed of. In a preferred embodiment, such a clump 36
formed of pellets 34 of spent litter 38 is biodegradable and
preferably toilet flushable.
[0053] With continued reference to FIGS. 1-7, a preferred
embodiment of litter 30 in accordance with the present invention is
composed of at least a plurality of differently sized extruded
litter pellets 34, 34' which facilitate absorption of liquid during
litter use by more quickly and efficiently absorbing liquid wetting
the pellets 34, 34' by wetting and being absorbed by the pellets
34, 34' while also minimizing how deeply the liquid flows
downwardly into the litter 30 before being completely absorbed by
the pellets 34, 34'. The use of at least a plurality of differently
sized extruded litter pellets 34, 34' produces litter 30 that
clumps when wetted producing a clump 36 of a plurality of wetted
extruded litter pellets 34, 34' that forms on top of the litter 30
with the clump 36 being generally horizontally oriented on top of
the litter 30 making the clump 36 easy to scoop from the rest of
the unspent litter 30.
[0054] Such a preferred litter 30 of the present invention has at
least a plurality of pairs of larger extruded litter pellets 34 per
cubic inch of litter 30 falling within a first size range and at
least a plurality of pairs of more finely sized extruded litter
pellets 34', e.g., fines, per cubic inch of litter 30 falling
within a second size range that is smaller than the larger extruded
litter pellets 34. In a preferred embodiment, the larger sized
pellets 34 have a size falling within a first size range each
having a size no greater than 3 mm in length, width and/or diameter
and no smaller than 1 mm in length, width and/or diameter. The
smaller sized pellets 34', also referred to as fines 34', have a
size smaller than 1 mm in length, width and/or diameter filling in
the spaces or voids between the larger pellets 34 in a resultant
litter 30 formed of a mixture thereof. In one such preferred
embodiment, extruded litter pellets 34 having a size larger than 3
mm in in length, width and/or diameter are not included in the
resultant litter mixture of the present invention such as by
filtering, screening or sieving such unwanted extruded pellets that
are too large. In another such preferred embodiment, extruded
litter pellets 34' having a size smaller than 0.5 mm in in length,
width and/or diameter are not included in the resultant litter
mixture of the present invention such as by filtering, screening or
sieving to eliminate or otherwise remove such unwanted extruded
pellets that are too small. In still another such preferred
embodiment, extruded litter pellets 34 having a size larger than 3
mm in in length, width and/or diameter and extruded litter pellets
34' having a size smaller than 0.5 mm in in length, width and/or
diameter are not included in the resultant litter mixture of the
present invention.
[0055] In another preferred embodiment, the larger sized pellets 34
have a size falling within a first size range each having a size no
greater than about 2.8 mm in length, width and/or diameter and no
smaller than 1.2 mm, preferably no smaller than about 1.18 mm, in
length, width and/or diameter. The smaller sized pellets 34', also
referred to as fines 34', have a size smaller than 1.2 mm,
preferably smaller than about 1.180 mm, in length, width and/or
diameter filling in the spaces or voids between the larger pellets
34 in a resultant litter 30 formed of a mixture thereof. In one
such preferred embodiment, extruded litter pellets 34 having a size
larger than about 2.8 mm in in length, width and/or diameter are
not included in the resultant litter mixture of the present
invention such as by filtering, screening or sieving such unwanted
extruded pellets that are too large. In another such preferred
embodiment, extruded litter pellets 34' having a size smaller than
about 0.8 mm, preferably smaller than about 0.710 mm in in length,
width and/or diameter are not included in the resultant litter
mixture of the present invention such as by filtering, screening or
sieving to eliminate or otherwise remove such unwanted extruded
pellets that are too small. In still another such preferred
embodiment, extruded litter pellets 34 having a size larger than
about 2.8 mm in in length, width and/or diameter and extruded
litter pellets 34' having a size smaller than about 0.710 mm in in
length, width and/or diameter are not included in the resultant
litter mixture of the present invention.
[0056] In still another preferred embodiment, the larger sized
pellets 34 have a size falling within a first size range each
having a size no greater than 2.9 mm, preferably no greater than
about 2.8 mm, in length, width and/or diameter and no smaller than
1.2 mm, preferably no smaller than about 1.18 mm, in length, width
and/or diameter. The smaller sized pellets 34', also referred to as
fines 34', have a size smaller than 1.2 mm, preferably smaller than
about 1.180 mm, in length, width and/or diameter and have a size
larger than 0.5 mm, preferably larger than about 0.710 mm, in
length, width and/or diameter thereby filling in the spaces or
voids between the larger pellets 34 in a resultant litter 30 formed
of a mixture thereof.
[0057] A preferred extruded self-clumping litter 30 has at least
15% fines 34', preferably has at least 20% fines 34', with the
remainder of the extruded pellets of the litter 30 being larger
sized pellets 34. Another preferred extruded self-clumping litter
30 has at least 5% fines 34' and preferably has between 5% and 40%
fines 34', with the remainder of the extruded pellets 34 being
larger sized extruded pellets. Still another preferred extruded
self-clumping litter 30 has at least 5% fines 34' and preferably
has between 10% fines 34' and preferably has between 10% and 30%
fines 34', with the remainder of the pellets of the litter 30 being
larger sized pellets 34. Still preferred extruded self-clumping
litter 30 has at least 5% fines 34' and preferably has between 5%
and 40% fines 34', with the remainder of the extruded pellets being
larger sized pellets 34. Still another preferred extruded
self-clumping litter 30 has at least 5% fines 34', preferably has
between 10% and 25% fines 34', and more preferably has between 15%
and 35% fines 34', with the remainder of the extruded pellets being
larger sized pellets 34.
[0058] As a result, liquid wetting the extruded litter pellets 34,
34' during litter use is more rapidly absorbed at or close to the
surface of the litter 30 preventing the liquid from flowing deeper
producing clumps 36 on top of the surface of the litter 30 that are
generally horizontally oriented. As a result, such clumps 36 lie on
top of the surface of the litter 30 making them quick and easy to
scoop out of the rest of the unspent litter remaining in the litter
box and dispose of.
[0059] Each extruded litter pellet 34 and/or 34' preferably is
extruded using a single screw extruder from a starch-containing
admixture formed of one or more cereal grains, such as one or more
of corn, wheat, sorghum, rice or another cereal grain, which can be
ground or otherwise comminuted prior to extrusion, extruding
pellets 34 and/or 34' each having enough water soluble binder to
cause litter 30 composed of a mixture of medium sized pellets 34
and more finely sized pellets 34' of the present invention to
self-clump when wetted with water, e.g., 2% saline solution, urine,
and/or liquid fecal matter. In a preferred method of making such
extruded pellets 34 and/or 34' each pellet 34 and/or 34' is
extruded from such a starch-containing admixture that preferably is
composed of one or more cereal grains under an extruder pressure
and temperature operating parameters and conditions that produce
extruded pellets 34 and/or 34' each containing at least 15% water
solubles, e.g., at least 15% water soluble content, by extruded
pellet weight and each containing at least 7.5% water soluble
binder, preferably at least 10% water soluble binder, by extruded
pellet weight with at least the water soluble binder preferably
formed by physical modification of starch in the admixture during
pellet extrusion in accordance with that discussed hereinabove.
[0060] In one preferred method, the admixture extruded to form the
pellets 34 and/or 34' has a moisture content of no greater than
30%, preferably no more than 25%, by admixture weight before
entering the extruder. In one such preferred method, no water or
other moisture is added during extrusion. In one preferred
admixture, the admixture is formed of at least 60% corn, preferably
at least 70% corn, preferably cornmeal, by admixture weight, e.g.,
dry admixture weight, which can be de-germed, having a moisture
content of no greater than 30%, preferably no greater than 25%, by
admixture weight when entering the extruder. Such an admixture can
include as much as 40%, preferably no greater than 30% cellulosic
material, such as in the form of plant fiber, pine fiber, oat
fiber, wheat fiber, alfalfa, sawdust, recycled newsprint, or
another type of cellulosic material. In another preferred
admixture, the admixture preferably is formed of at least 60%
sorghum, preferably at least 70% sorghum, by admixture weight,
e.g., dry admixture weight, which can be and preferably is whole
grain sorghum, which can be de-hulled or de-corticated, having a
moisture content no greater than 20%, preferably no greater than
15%, by admixture weight when entering the extruder. Such an
admixture can also include as much as 40%, preferably no greater
than 30% cellulosic material, such as in the form of plant fiber,
pine fiber, oat fiber, wheat fiber, alfalfa, sawdust, recycled
newsprint, or another type of cellulosic material.
[0061] Another such preferred admixture from which extruded pellets
34 and/or 34' are formed includes one or more cereal grains,
preferably one or more of corn, sorghum and/or wheat, can include a
gray or black dye or colorant, preferably carbon black, preferably
no more than 5% carbon black, more preferably no more than 1%
carbon black (by admixture weight), and can include cellulose, such
as in the form of one or more cellulosic materials and/or
cellulose-containing fibers. A preferred admixture contains at
least 50% starch containing material in the form of one or more
cereal grains and preferably contains no more than 50% cellulose by
admixture weight. A preferred starch containing material is formed
of at least 50% corn, preferably at least 60%, and more preferably
at least 70% by dry admixture weight (before any water is added to
the admixture) preferably in comminuted form, such as preferably in
the form of cornmeal that can include and preferably does include
de-germed cornmeal. Where the admixture includes cellulose or
cellulosic material, the remainder of the admixture can be composed
of preferred cellulose and cellulosic materials that include one or
more of sawdust, pine shavings or fibers, other types of wood
shavings or fibers, oat fiber, alfalfa, rice fiber, beet fiber or
another type of cellulose or cellulosic fiber. Such an admixture
preferably contains no separate binder additive like guar gum,
smectite, e.g., bentonite, or the like added specifically to
facilitate clumping. One such preferred admixture contains no more
than 40% cellulose or cellulosic material, e.g., fiber, with the
remainder of the admixture composed substantially completely of one
or more cereal grains with no more than 5%, preferably no more than
1% carbon black, by admixture weight.
[0062] In a preferred method of extruding pellets 34 and/or 34'
from such admixtures, the admixture is extruded using a single
screw extruder at an extruder pressure of at least 900 pounds per
square inch and at a temperature of at least 100.degree. Celsius
extruding at least a plurality of pairs of extruded pellets 34, 34'
per second of extruder operation with each extruded pellet 34
and/or 34' having a water soluble content of at least 15%,
preferably at least 20%, by extruded pellet weight containing at
least 7.5%, preferably at least 10%, water soluble binder by
extruded pellet weight. In another preferred method of extruding
pellets 34 and/or 34' from such admixtures, the admixture is
extruded using a single screw extruder at an extruder pressure of
at least 1,000 pounds per square inch and at a temperature of at
least 120.degree. Celsius extruding at least a plurality of pairs
of extruded pellets 34 and/or 34' per second of extruder operation
with each extruded pellet 34 and/or 34' having a water soluble
content of at least 15%, preferably at least 18%, by pellet weight
containing at least 7.5%, preferably at least 10%, more preferably
at least 12%, water soluble binder by pellet weight. In still
another preferred method of extruding pellets 34 from such
admixtures, the admixture is extruded using a single screw extruder
at an extruder pressure of at least 1,100 pounds per square inch
and at a temperature of at least 130.degree. Celsius extruding at
least a plurality of pairs of extruded pellets 34 and/or 34' per
second of extruder operation with each extruded pellet 34 and/or
34' having a water soluble content of at least 15%, preferably at
least 18%, more preferably at least 20% by pellet weight containing
at least 7.5%, preferably at least 10%, more preferably at least
15%, water soluble binder by pellet weight. In a further preferred
method of extruding pellets 34 and/or 34' from such admixtures, the
admixture is extruded using a single screw extruder at an extruder
pressure of at least 1,200 pounds per square inch and at a
temperature of at least 135.degree. Celsius extruding at least a
plurality of pairs of extruded pellets 34 and/or 34' per second of
extruder operation with each extruded pellet 34 and/or 34' having a
water soluble content of at least 18%, preferably at least 20%,
more preferably at least 25% by pellet weight containing at least
8%, preferably at least 12%, more preferably at least 18%, water
soluble binder by pellet weight.
[0063] The water soluble binder formed in each pellet 34 and/or 34'
during extrusion preferably is a cold water soluble binder formed
from starches in a starch containing admixture preferably forming
at least 7.5% cold water soluble binder, preferably at least 10%
cold water soluble binder, and more preferably at least 15% cold
water soluble binder in each pellet 34 and/or 34' by pellet weight.
Where cold water soluble binder is formed in each pellet 34 and/or
34' during extrusion, cold water soluble amylopectin binder
preferably is formed from amylopectin starch in such a starch
containing admixture preferably forming at least 7.5% cold water
soluble amylopectin binder, preferably at least 10% cold water
soluble amylopectin binder, and more preferably at least 15% cold
water soluble amylopectin binder in each pellet 34 and/or 34' by
pellet weight. In at least one preferred extruded pellet
embodiment, each extruded pellet 34 and/or 34' has at least 15%,
preferably at least 18%, and more preferably at least 20% cold
water soluble amylopectin binder by pellet weight.
[0064] Where cold water soluble amylopectin-based binder is formed
in each pellet 34 and/or 34' during extrusion, the cold water
soluble amylopectin binder can be or include amorphous cold water
soluble amylopectin binder formed from amylopectin starch in such a
starch containing admixture preferably forming at least 7.5%
amorphous cold water soluble amylopectin binder, preferably at
least 10% amorphous cold water soluble amylopectin binder, and more
preferably at least 15% amorphous cold water soluble amylopectin
binder in each pellet 34 and/or 34' by pellet weight. In one such
preferred extruded pellet embodiment where amorphous cold water
soluble amylopectin binder is formed during pellet extrusion, each
pellet 34 and/or 34' has at least 15%, preferably has at least 18%,
and more preferably has at least 20%, amorphous cold water soluble
amylopectin binder by pellet weight.
[0065] The amount of water solubles or water soluble content of
each extruded pellet 34 and/or 34' is specified in terms of a
percentage of the extruded pellet weight indicating what weight
percentage of the pellet 34 and/or 34' is composed of modified
starch, preferably starch modified during pellet extrusion, more
preferably physically modified during extrusion, which is water
soluble when wetted with water, e.g., 2% saline solution, and/or
urine at a temperature below which it is cold water soluble as
known in the field of starch chemistry. In a preferred embodiment,
the amount of water solubles or water soluble content of each
extruded pellet 34 and/or 34' is specified in terms of a percentage
of the extruded pellet weight indicating what weight percentage of
the pellet 34 and/or 34' is composed of modified starch, preferably
starch modified during pellet extrusion, more preferably physically
modified during extrusion, which is water soluble when wetted with
water, e.g., 2% saline solution, and/or urine at a temperature
below 160 degrees Celsius such that it is cold water soluble as
known in the field of starch chemistry.
[0066] The cold water soluble binder present in the extruded
pellets 34 and/or 34' of litter 30 of the present invention
advantageously therefore remains cold water soluble at temperatures
below 110.degree. Fahrenheit providing real world urine solubility
by dissolving in liquid at temperatures as high as 110.degree.
Fahrenheit, including dissolving when wetted with or by cat urine
that typically has a temperature no higher than about 108.degree.
Fahrenheit. The cold water soluble content of each extruded pellet
34 and/or 34' includes starch from the one or more cereal grains in
the admixture modified during extrusion, preferably by being
physically modified during extrusion, to become water-soluble,
preferably cold water soluble, and includes amylopectin in the
admixture modified during extrusion into cold water soluble
amylopectin. The water soluble content of each extruded pellet 34
and/or 34' is inclusive of any water soluble binder present in the
extruded pellet 34 and/or 34'.
[0067] During granular sorbent use, wetting of at least a plurality
of pairs, i.e. at least three, of extruded litter pellets 34, 34'
of a preferred mixture of litter 30 of the present invention with
water, preferably 2% saline solution at room temperature e.g.
between 68.degree. F. and 74.degree. F., forms a clump 36, such as
shown in FIGS. 6 and 7, containing at least a plurality of pairs,
i.e., at least three, of wetted pellets 34 and wetted pellets 34'
that self-clump together as a result of water soluble binder in
each of the wetted pellets 34, 34' solubilizing and making each
wetted pellet 34 and 34' tacky enough to stick to one or more
pellets 34 and/or 34' in contact therewith. In a preferred litter
embodiment, the litter 30 is formed of at least a plurality of
pairs of extruded pellets 34 and of at least a plurality of pairs
of extruded pellets 34' each having water-soluble binder in an
amount sufficient for at least some of the binder to solubilize and
flow from the wetted pellets 34 and 34' in between and around at
least a plurality of adjacent pellets 34 and/or 34'. Water-soluble
binder of a plurality of wetted pellets 34 and a plurality of
wetted pellets 34' that has solubilized and formed flowable
adhesive with water, e.g. 2% saline solution, wets the pellets 34
and pellets 34' relatively rapidly forming clump 36 as the flowable
adhesive formed by the water in solubilize binder rapidly increases
in viscosity immediately upon the pellets 34 and 34' being wetted
with the water.
[0068] In a preferred embodiment, during wetting of such a
plurality of pairs of pellets 34 and 34' where 400 grams of
extruded pellets 34 and 34' are wetted with 200 grams of water,
e.g., 2% saline solution, at room temperature, e.g., between
68.degree. F. and 74.degree. F., the viscosity at pellet wetting or
at the beginning of pellet wetting as measured with a Brookfield
DV3T viscometer at a spindle rotation of 50 RPM rapidly increases
from about 1 centipoise at wetting as the water solubilizes
water-soluble binder in each wetted pellet 34 and 34' forming a
flowable adhesive whose viscosity increases to at least 200
centipoise within one second after pellet wetting, increases to at
least 300 centipoise after one second and within five seconds after
pellet wetting, increases to at least 400 centipoise after five
seconds and within 10 seconds of pellet wetting such that the water
in solubilizing water-soluble binder forms a relatively high
viscosity flowable adhesive gel that relatively rapidly adheres
together the at least plurality of pairs of wetted pellets 34 and
34' forming clump 36. In another preferred embodiment, during
wetting of such a plurality of pairs of pellets 34 and 34' where
200 grams of extruded pellets 34 and 34' are wetted with 200 grams
of water, e.g., 2% saline solution, at room temperature, the
viscosity at pellet wetting or at the beginning of pellet wetting
as measured with a Brookfield DV3T viscometer at a spindle rotation
of 50 RPM rapidly increases from about 1 centipoise at the time of
initial pellet wetting as the water solubilizes water-soluble
binder in each wetted pellet 34 and 34' forming a flowable adhesive
whose viscosity increases to at least 400 centipoise within one
second after pellet wetting, increases to at least 500 centipoise
after one second and within five seconds after pellet wetting,
increases to at least 700 centipoise after five seconds and within
10 seconds of pellet wetting, increases to at least 1000 centipoise
after 10 seconds and within 20 seconds of pellet wetting, increases
to at least 1800 centipoise after 20 seconds and within 25 seconds
of pellet wetting, increases to at least 2500 centipoise after 25
seconds and within 30 seconds of pellet wetting, increases to at
least 5000 centipoise after 30 seconds and within 40 seconds of
pellet wetting such that the water in solubilizing water-soluble
binder forms a relatively high viscosity flowable adhesive gel that
relatively rapidly adheres together the at least plurality of pairs
of wetted pellets 34 and 34' forming clump 36.
[0069] A preferred extruded pellet 34 and/or 34' is formed by
extruding an admixture containing one or more cereal grains,
preferably one or more of corn, sorghum and/or wheat, without any
separate binder additive or smectite in the admixture, at such
aforementioned extruder pressures and/or temperatures with such
extruder pressures and/or temperatures extruding pellets 34 and/or
34' that are dextrinized and which can be expanded or puffed with
each pellet 34 and/or 34' having at least 15% water soluble content
by pellet weight and at least 7.5% water soluble binder content by
pellet weight sufficient to not only facilitate liquid absorption
when wetted during sorbent use but which also self-clump together
forming clumps, e.g. clump 36, when wetted during sorbent use.
Another preferred extruded pellet 34 and/or 34' is formed by
extruding such an admixture containing one or more cereal grains,
preferably one or more of corn, sorghum and/or wheat, without any
separate binder additive or smectite such as bentonite in the
admixture, at an extruder temperature and pressure at or above
which it is sufficient to extrude pellets 34 and/or 34' each having
at least 15% water soluble content by pellet weight and at least
7.5%, preferably at least 10%, water soluble binder content by
pellet weight. Still another preferred extruded pellet 34 and/or
34' is formed by extruding such an admixture containing one or more
cereal grains, preferably one or more of corn, sorghum and/or
wheat, without any separate binder additive or smectite, including
bentonite, in the admixture, at an extruder temperature and
pressure at or above which it is sufficient to extrude pellets 34
and/or 34' each having at least 18% water soluble content by pellet
weight and at least 10%, preferably at least 12%, water soluble
binder content by pellet weight. A further preferred extruded
pellet 34 and/or 34' is formed by extruding such an admixture
containing one or more cereal grains, preferably one or more of
corn, sorghum and/or wheat, without any separate binder additive or
smectite, such as bentonite, in the admixture, at an extruder
temperature and pressure at or above which it is sufficient to
extrude pellets 34 and/or 34' each having at least 20% water
soluble content by pellet weight and at least 12%, preferably at
least 15%, water soluble binder content by pellet weight. A still
further preferred extruded pellet 34 and/or 34' is formed by
extruding an admixture containing one or more cereal grains,
preferably one or more of corn, sorghum and/or wheat, without any
separate binder additive or smectite, including bentonite, in the
admixture, at an extruder temperature and pressure at or above
which it is sufficient to extrude pellets 34 and/or 34' each having
at least 25% water soluble content by pellet weight and at least
10%, preferably at least 15%, and more preferably at least 18%,
water soluble binder content by pellet weight. Yet another
preferred extruded pellet 34 and/or 34' is formed by extruding an
admixture containing one or more cereal grains, preferably one or
more of corn, sorghum and/or wheat, without any separate binder
additive or smectite in the admixture, at an extruder temperature
and pressure at or above which it is sufficient to extrude pellets
34 and/or 34' each having at least 25% water soluble content by
pellet weight and at least 15%, preferably at least 18%, and more
preferably at least 20%, water soluble binder content by pellet
weight.
[0070] The water soluble content of each extruded pellet 34 and/or
34' preferably is composed of amorphous cold water soluble
amylopectin material and the water soluble binder content of each
extruded pellet 34 and/or 34 preferably is formed of amorphous cold
water soluble amylopectin binder having a molecular weight less
than that of the unmodified amylopectin starch of the cereal grain
or cereal grains of the admixture from which each pellet 34 and/or
34' was extruded. In a preferred extruded pellet embodiment, the
water soluble content of each extruded pellet 34 and/or 34'
preferably is composed of amorphous cold water soluble amylopectin
material and the water soluble binder content of each extruded
pellet 34 and/or 34' preferably is formed of amorphous cold water
soluble amylopectin binder having a molecular weight less than that
of the unmodified amylopectin starch of the cereal grain or cereal
grains of the admixture from which each pellet 34 and/or 34' was
extruded and preferably a mean molecular weight within .+-.80% of
the mean molecular weight of the unmodified amylose starch of the
cereal grain or cereal grains of the admixture from which each
pellet 34 and/or 34' was extruded.
[0071] Each extruded pellet 34 and/or 34' can and does have at
least 3%, preferably at least 5%, of a dextrin-like water soluble
adhesive binder by pellet weight that preferably is a cold water
soluble adhesive binder having a mean molecular weight within
.+-.90% of the mean or average molecular weight of dextrin. In a
preferred extruded pellet embodiment, each pellet 34 and/or 34' has
at least 3%, preferably at least 5%, of a dextrin-like cold water
soluble binder, i.e., dextrin, by pellet weight that has a
molecular weight within .+-.90% of 504.43708 g/mol, which is the
CAS molecular weight of dextrin. In another preferred extruded
pellet embodiment, each pellet 34 and/or 34' has at least 3%
dextrin and preferably has at least 5% dextrin by pellet
weight.
[0072] A preferred extruded pellet 34 and/or 34'is formed by
extruding an admixture containing one or more cereal grains,
preferably one or more of corn, sorghum and/or wheat, at an
admixture moisture content of no greater than 30%, preferably with
no water added in the extruder during extrusion from a single screw
extruder at an extruder temperature of at least 100.degree. Celsius
and an extruder pressure of at least 900 pounds per square inch to
extrude a plurality of extruded pellets 34 and/or 34' per second of
extruder operation with each extruded pellet 34 and/or 34' having a
water soluble content of at least 15% by pellet weight containing
at least 7.5% water soluble binder by pellet weight. Another
preferred extruded pellet 34 and/or 34' is formed by extruding an
admixture containing one or more cereal grains, preferably one or
more of corn, sorghum and wheat, at an admixture moisture content
of no greater than 25%, preferably with no water added in the
extruder during extrusion at an extruder temperature of at least
120.degree. Celsius and an extruder pressure of at least 1,000
pounds per square inch to extrude a plurality of extruded pellets
34 and/or 34' per second of extruder operation with each extruded
pellet 34 and/or 34' having a water soluble content of at least 18%
by pellet weight containing at least 10% water soluble binder by
pellet weight. Still another preferred extruded pellet 34 and/or
34' is formed by extruding an admixture containing one or more
cereal grains, preferably one or more of corn, sorghum and wheat,
at an admixture moisture content of no greater than 23%, preferably
with no water added in the extruder during extrusion at an extruder
temperature of at least 125.degree. Celsius and an extruder
pressure of at least 1,100 pounds per square inch to extrude a
plurality of extruded pellets 34 and/or 34' per second of extruder
operation with each extruded pellet 34 and/or 34' having a water
soluble content of at least 20% by pellet weight containing at
least 13%, preferably at least 15%, and more preferably at least
18%, water soluble binder by pellet weight.
[0073] Each extruded pellet 34 and/or 34' can be and preferably is
composed of or with at least 3%, preferably at least 5%, more
preferably at least 7.5%, of a dextrin-like water soluble adhesive
binder by pellet weight that preferably is a cold water soluble
adhesive binder having a mean molecular weight within .+-.90% of
the mean or average molecular weight of dextrin. In a preferred
extruded pellet embodiment, each pellet 34 and/or 34' has at least
3%, preferably at least 5%, more preferably at least 7.5%, of a
dextrin-like cold water soluble binder having a molecular weight
within .+-.90% of 504.43708 g/mol. In another preferred extruded
pellet embodiment, each pellet 34 and/or 34' has at least 3%
dextrin by pellet weight, preferably has at least 5% dextrin by
pellet weight, and more preferably has at least 7.5% dextrin by
pellet weight.
[0074] A preferred extruded pellet 34 and/or 34' used as or in
making litter 30 of the present invention is extruded from one or
more cereal grains and has at least 15% cold water soluble content
by pellet weight and preferably has at least 7.5%, preferably at
least 10%, more preferably at least 13%, cold water soluble binder
content by pellet weight with the water soluble binder content
present in each pellet 34 and/or 34' preferably being cold water
soluble modified amylopectin starch binder that preferably is an
amorphous cold water soluble amylopectin starch binder. Preferably,
each pellet 34 and/or 34'has at least 15% cold water solubles by
pellet weight and at least 7.5%, preferably at least 10%, more
preferably at least 13%, cold water soluble binder formed of cold
water soluble amylopectin starch binder, preferably cold water
soluble amorphous amylopectin starch binder, formed of amylopectin
starch modified so its molecular weight has been reduced to a
molecular weight below 10.sup.6, e.g., 10.sup.6 g/mol. In another
preferred embodiment, each pellet 34 and/or 34' has a cold water
soluble content of at least 15% by pellet weight and a cold water
soluble amylopectin starch binder content of at least 7.5%,
preferably at least 10%, more preferably at least 13%, formed of
reduced molecular weight physically modified amylopectin having a
degree of polymerization of less than 6,000 glucose units,
preferably less than 3,000 glucose units, more preferably less than
1,000 glucose units. In yet another such preferred embodiment, each
pellet 34 and/or 34' has a cold water soluble content of at least
15% by pellet weight and a cold water soluble amylopectin starch
binder content of at least 7.5%, preferably at least 10%, more
preferably at least 13%, formed of reduced molecular weight
physically modified amylopectin having a degree of polymerization
falling between 6,000 and 10 glucose units. In a further such
preferred embodiment, each pellet 34 and/or 34' has a cold water
soluble content of at least 15% by pellet weight and a cold water
soluble amylopectin starch binder content of at least 7.5%,
preferably at least 10%, more preferably at least 13%, formed of
reduced molecular weight physically modified amylopectin having a
degree of polymerization falling between 500 and 10 glucose units.
In one such preferred embodiment, each pellet 34 and/or 34' has a
cold water soluble content of at least 15% by pellet weight and a
cold water soluble amylopectin starch binder content of at least
7.5%, preferably at least 10%, more preferably at least 13%, formed
of reduced molecular weight modified amylopectin having a molecular
weight no greater than 10.sup.6 g/mol and a degree of
polymerization falling between 10 and 6,000 glucose units. In
another such preferred embodiment, each pellet 34 and/or 34' has a
cold water soluble content of at least 15% by pellet weight and a
cold water soluble amylopectin starch binder content of at least
7.5%, preferably at least 10%, more preferably at least 13%, formed
of reduced molecular weight modified amylopectin having a molecular
weight no greater than 10.sup.6 g/mol and a degree of
polymerization falling between 10 and 500 glucose units.
[0075] Another preferred extruded pellet 34 and/or 34' is extruded
from one or more cereal grains and has at least 20% cold water
soluble content by pellet weight and preferably has at least 15%,
preferably at least 18%, more preferably at least 20%, cold water
soluble binder content by pellet weight with the water soluble
binder content present in each pellet 34 and/or 34' preferably
being cold water soluble modified amylopectin starch binder that
preferably is an amorphous cold water soluble amylopectin starch
binder. Preferably, each pellet 34 and/or 34' has at least 25% cold
water solubles by pellet weight and at least 15%, preferably at
least 18%, more preferably at least 23%, cold water soluble binder
formed of cold water soluble amylopectin starch binder, preferably
cold water soluble amorphous amylopectin starch binder, formed of
amylopectin starch modified so its molecular weight has been
reduced to a molecular weight no greater than 10.sup.6, e.g.,
10.sup.6 g/mol. In another preferred embodiment, each pellet 34
and/or 34' has a cold water soluble content of at least 20% by
pellet weight and a cold water soluble amylopectin starch binder
content of at least 15%, preferably at least 18%, more preferably
at least 20%, formed of reduced molecular weight modified
amylopectin having a degree of polymerization falling between 10
and 6,000 glucose units. In yet another preferred embodiment, each
pellet 34 and/or 34' has a cold water soluble content of at least
20% by pellet weight and a cold water soluble amylopectin starch
binder content of at least 15%, preferably at least 18%, more
preferably at least 20%, formed of reduced molecular weight
modified amylopectin having a degree of polymerization falling
between 10 and 500 glucose units. In one such preferred embodiment,
each pellet 34 and/or 34' has a cold water soluble content of at
least 25% by pellet weight and a cold water soluble amylopectin
starch binder content of at least 15%, preferably at least 18%,
more preferably at least 23%, formed of reduced molecular weight
modified amylopectin having a molecular weight no greater than
10.sup.6, e.g., 10.sup.6 g/mol, and a degree of polymerization
falling between 10 and 6,000 glucose units. In another such
preferred embodiment, each pellet 34 and/or 34' has a cold water
soluble content of at least 25% by pellet weight and a cold water
soluble amylopectin starch binder content of at least 15%,
preferably at least 18%, more preferably at least 23%, formed of
reduced molecular weight modified amylopectin having a molecular
weight no greater than 10.sup.6, e.g., 10.sup.6 g/mol, and a degree
of polymerization falling between 10 and 500 glucose units.
[0076] In at least one preferred method of making such extruded
pellets 34 and/or 34' in producing extruded litter 30 in accordance
with the present invention, such pellets 34 and/or 34' are extruded
from an admixture of one or more starch-containing cereal grains
contain starch damage in an amount of at least 40%, preferably at
least 50%, and more preferably at least 60%, as measured in
accordance with AOAC: 2002.02, as substantially all of the cold
water soluble amylopectin binder, preferably cold water soluble
amorphous amylopectin binder, formed in each extruded pellet 34
and/or 34' is physically modified cold water soluble amylopectin
starch binder formed by physically modifying unmodified amylopectin
starch present in the cereal grain admixture whose molecular weight
is reduced to no greater than 10.sup.6 forming at least 7.5%,
preferably at least 10%, and more preferably at least 13%, of such
physically modified cold water soluble amylopectin starch binder
that preferably is physically modified amorphous cold water soluble
amylopectin starch binder in each pellet 34 and/or 34'. In one such
preferred extruded pellet embodiment, each extruded pellet 34
and/or 34' has starch damage in an amount of at least 40%,
preferably at least 55%, and more preferably at least 70%, as
measured in accordance with AOAC: 2002.02, as the water soluble
binder formed in each pellet 34 and/or 34' during pellet extrusion
is cold water soluble amylopectin binder, preferably cold water
soluble amorphous amylopectin binder, formed in formed of
physically modified cold water soluble amylopectin starch binder by
physically modifying unmodified amylopectin starch present in the
cereal grain admixture whose molecular weight is reduced to no
greater than 10.sup.6 and/or has a degree of a degree of
polymerization falling between 10 and 6,000 glucose units,
preferably between 10 and 500 glucose units, forming at least 7.5%,
preferably at least 10%, and more preferably at least 13%, of such
physically modified cold water soluble amylopectin starch binder by
pellet weight that preferably is physically modified amorphous cold
water soluble amylopectin starch binder.
[0077] Each such extruded pellet 34 and/or 34' preferably also has
a water activity level of no greater than 0.4, and preferably no
greater than 0.35, as such a water activity level is indicative of
the advantageous water absorption properties each pellet 34 and/or
34' possesses. In addition, such a lower water activity level is
also indicative not only of the long shelf life sorbent granules 32
and/or 34' possess but also its advantageously long useful sorbent
life after being applied or used. This is because litter 30
composed of extruded pellets 34 and/or 34' of the present invention
possess desirably high bacterial and fungal resistance as a result
of each extruded pellet 34 and/or 34' having such a low water
activity level.
[0078] Such extruded pellets 34 and/or 34' used in litter 30 of the
present invention readily self-clump when wetted producing clumps
36 having a desirably high clump retention rate. In one preferred
extruded granular sorbent embodiment, litter 30 formed of such
extruded litter pellets 34 and/or 34' of the present invention form
clumps 36 of the pellets 34 and/or 34' wetted with ten milliliters
of 2% saline solution that each possess a clump retention rate of
at least 92%, preferably at least 95%, and more preferably at least
97%, which is greater than the maximum 80%-90% clump retention rate
of clumps formed of conventional bentonite-based cat litter (not
shown) formed of conventional litter granules (not shown) each made
of solid sodium bentonite. In one preferred extruded cat litter 30,
extruded litter pellets 34 and/or 34' wetted with ten milliliters
of 2% saline solution form clumps 36 that each possess a clump
retention rate of at least 98% and which preferably possess a clump
retention rate of at least 99%.
[0079] In determining such clump retention rates, clump 36 was
formed by wetting litter 30 formed of extruded litter pellets 34
and 34' with 10 milliliters of 2% saline solution before allowing
the clump 36 to set for 10 minutes. The removed clump 36 is weighed
to obtain a pre-drop clump weight before dropping the clump 36
eighteen inches onto a 3/4 inch U.S. Standard Sieve. The clump that
remains is weighed a second time to obtain a post-drop clump weight
that is then divided by the pre-drop clump weight and multiplied by
100 to obtain the clump retention rate. The aforementioned clump
retention rate test is also known as a drop cohesion clump strength
test.
[0080] In one preferred extruded granular sorbent embodiment where
a mixture of extruded pellets 34 and 34' are used as litter 30, the
extruded pellets 34 and 34' of the mixture of litter 30 readily
self-clump when wetted producing clumps 36 having a desirably high
retention rate. In one preferred litter 30 formed of a mixture of
such extruded pellets 34 and 34' form clumps 36 of pellets 34 and
34' wetted with ten milliliters of 2% saline solution that each
possess a clump retention rate of at least 92%, preferably at least
95%, and more preferably at least 97%, which is greater than the
maximum 80%-90% clump retention rate of clumps formed of
conventional bentonite-based cat litter (not shown) formed of
conventional smectite granules (not shown) each made of solid
sodium bentonite. In one preferred cat litter 30, litter 30 formed
substantially completely of a mixture such extruded pellets 34 and
34' wetted with ten milliliters of 2% saline solution form clumps
36 that each possess a clump retention rate of at least 98% and
which preferably possess a clump retention rate of at least
99%.
[0081] Such a mixture of extruded pellets 34 and 34' forming cat
litter 30 of the present invention readily self-clump when wetted
producing clumps 36 also having a desirably high clump crush
strength when dry. In addition to forming clumps 38 having such a
desirably high retention rate, clumps 38 formed of litter 30
composed of a mixture of pellets 34 and 34' wetted with ten
milliliters of 2% saline solution are also advantageously strong
and crush-resistant having a crush strength of at least 15 pounds
per square inch (PSI), preferably at least 20 PSI, and more
preferably at least 25 PSI, when air dried for at least 5 days to a
moisture content of no more than 20% by dried clump weight. One
preferred mixture of extruded pellets 34 and 34' used as scoopable
self-clumping lightweight litter 30 of the present invention forms
clumps 36 of litter pellets 34 and 34' wetted with 2% saline
solution that each possess a crush strength of at least 28 pounds
per square inch (PSI), preferably at least 30 PSI, and more
preferably at least 35 PSI, when air dried for at least 5 days to a
moisture content of no more than 20% by dried clump weight.
[0082] In one preferred litter embodiment where the litter 30 is
formed substantially completely of such extruded pellets 34 and/or
34', the extruded pellets 34 and/or 34' readily self-clump when
wetted producing clumps 36 also having a desirably high crush
strength. In one preferred extruded litter embodiment, litter 30
formed of such extruded pellets 34 and/or 34' form clumps 36 of
pellets 34 and/or 34' wetted with ten milliliters of 2% saline
solution that each possess a crush strength of at least 15 pounds
per square inch (PSI), preferably at least 20 PSI, and more
preferably at least 25 PSI, when air dried to a moisture content of
no more than 20% by dried clump weight. One preferred cat litter 38
formed substantially completely of such extruded pellets 34 and/or
34' wetted with ten milliliters of 2% saline solution form clumps
36 that each possess a crush strength of at least 30 pounds per
square inch (PSI), preferably at least 35 PSI, and more preferably
at least 40 PSI, when the clump 36 is dried to a moisture content
of no more than 20% by dried clump weight.
[0083] Clumps 36 with such a desirably high clump retention rate
produced from wetted extruded litter pellets 34 and/or 34' of the
present invention retain more of the wetted or spent extruded
pellets 34 and/or 34' of spent litter 38' (FIGS. 5 and 6) in the
clump 36 thereby advantageously leaving behind less spent or used
sorbent granules in litter box 46 (FIG. 6). As a result, litter 30
of the present invention formed of such extruded litter pellets 34
and/or 34' advantageously has a least a 93% litter efficiency,
preferably at least a 95% litter efficiency, and more preferably at
least a 97% litter efficiency by leaving behind virtually no litter
pellets 34 and/or 34' that have been wetted or spent from the clump
36 as virtually all of the spent or wetted pellets 34 and/or 34'
are retained by or in the clump 36. This causes a given amount or
volume of litter 30 of the present invention to last longer and
have less un-clumped wetted or spent litter pellets 34 and/or 34'
remaining in the litter 30 after clumping and clump removal, which
thereby advantageously maximizes litter freshness, extends useful
litter life, and minimizes odor.
[0084] Such a litter 30 formed of extruded litter pellets 34 and/or
34' of the present invention advantageously form a "clean" clump 36
during litter use because the water soluble binder from wetted
pellets 34 and/or 34' that facilitates clumping by helping wetted
pellets 34 and/or 34' stick to one another also shrinks the clump
36 as the clump 36 air dries before being scooped out. By causing
each clump 36 to shrink as the wetted lightweight litter pellets 34
and/or 34' dry, clump shrinkage causes the clump 36 to condense in
size and create voids between the clump 35 and surrounding unspent
pellets 34 and/or 34' of the remaining litter 30 producing a
self-separating clump 36 in accordance with the present invention
that reduces contamination of unused or un-spent pellets 34 and/or
34' adjacent to and surrounding the clump 36. Where a clump 36
forms adjacent to, on or against a solid surface, such as against a
wall or on the bottom of a granular sorbent container, e.g., litter
pan or litter box 46, the clump 36 can condense and begin to pull
away from the solid surface with which the clump 36 is in contact
with. With reference to FIGS. 6 and 7, each clump 36 preferably
shrinks at least 3% after being formed from wetted pellets 34
and/or 34' such that each clump 36 shrinks and preferably thereby
also condensing the clump 36. When this happens during drying of
the clump 36, the clump 36 can condense and pull away from any wall
or bottom (not shown) of a granular sorbent container, preferably
litter box 46, containing litter 30 of the invention as the clump
36 shrinks which can reduce the surface area of contact between the
clump 36 and litter box 46, which in certain instances can reduce
clump sticking and can facilitate easier clump removal.
[0085] Litter 30 formed of a mixture of extruded litter pellets 34
and 34' of the present invention forms clumps 36 that each
preferably shrink at least 5% after formation as the clump 36 dries
forming a dried clump 36 that possesses at least 93% clump
retention rate, preferably at least 95% clump retention rate, and
more preferably at least 97% clump retention rate when dried in
accordance with that discussed above pertaining to clump retention
rates advantageously producing a "clean" clump 36 which minimizes
adherence to any litter box 46 filled with the litter 30 and which
also minimizes adherence to any litter scoop 48 used to scoop out
any clump 36 formed in the litter 30 in the litter box 46. In one
such preferred cat litter 38 of the present invention, each clump
36 formed of a mixture of pellets 34 and 34' preferably shrinks at
least 8% while possessing at least 93% clump retention, preferably
at least 95% clump retention, and more preferably at least 97%
clump retention, producing such a "clean" "non-stick" clump 36 that
minimizes adherence to any part of the litter box or even the
litter scoop during clump removal. In another preferred cat litter
38 of the present invention, each clump 36 formed of a mixture
extruded pellets 34 and 34' preferably shrinks at least 10% while
possessing at least 93% clump retention, preferably at least 95%
clump retention, and more preferably at least 97% clump retention,
producing such a "clean" "non-stick" clump 36 that minimizes
adherence to any part of the litter box or even the litter scoop
during clump removal. In yet another such preferred cat litter 38
of the invention, each clump 36 formed of a mixture of extruded
pellets 34 and 34', each clump 36 preferably shrinks at least 12%
while possessing at least 93% clump retention, preferably at least
95% clump retention, and more preferably at least 97% clump
retention, producing such a "clean" "non-stick" clump 36 maximizing
the removal of dirty litter through higher spent litter granule
retention and minimizing adherence to unspent litter pellets 34 and
34' and contacting solid surfaces.
[0086] Litter 30 made of or with a mixture of extruded pellets 34
and 34' of the present invention produces litter 30 that
advantageously also is lightweight having a bulk density preferably
no greater than 40 lbs/ft.sup.3 and which is at least 40% less than
conventional clay-based sorbent, i.e., bentonite-based cat litter.
In a preferred litter embodiment, litter 30 made of a mixture of
extruded litter pellets 34 and 34' in accordance with the present
invention has a bulk density of no greater than 45 lbs/ft.sup.3
that preferably is between 20 lbs/ft.sup.3 and 40 lbs/ft.sup.3,
which more preferably is between 25 lbs/ft.sup.3 and 35
lbs/ft.sup.3, and which more preferably is between 27 lbs/ft.sup.3
and 33 lbs/ft.sup.3. In one preferred granular sorbent embodiment,
litter 30 made in accordance with the present invention has
extruded litter pellets 34 and 34' with a bulk density of no
greater than 45 lbs/ft.sup.3 that preferably is between 20
lbs/ft.sup.3 and 40 lbs/ft.sup.3, which more preferably is between
25 lbs/ft.sup.3 and 35 lbs/ft.sup.3, and which more preferably is
between 27 lbs/ft.sup.3 and 33 lbs/ft.sup.3.
[0087] In a further preferred litter embodiment, litter 30 of the
present invention is made substantially completely of such extruded
pellets 34 and/or 34' with the extruded pellets 34 and/or 34'
having a bulk density of between 15 lbs/ft.sup.3 and 45
lbs/ft.sup.3, which preferably is between 20 lbs/ft.sup.3 and 40
lbs/ft.sup.3, which more preferably is between 25 lbs/ft.sup.3 and
35 lbs/ft.sup.3, and which further preferably is between 27
lbs/ft.sup.3 and 33 lbs/ft.sup.3. In one such preferred litter
embodiment, litter 30 of the present invention is composed of a
mixture of extruded pellets 34 and 34' produce a litter 30 having a
bulk density of no greater than 45 lbs/ft.sup.3 that preferably is
between 20 lbs/ft.sup.3 and 40 lbs/ft.sup.3, which more preferably
is between 25 lbs/ft.sup.3 and 35 lbs/ft.sup.3, and which more
preferably is between 27 lbs/ft.sup.3 and 33 lbs/ft.sup.3. In
another such preferred litter embodiment, litter 30 of the present
invention is substantially completely made of a mixture of such
extruded pellets 34 and 34' producing litter 38 having a bulk
density of no greater than 45 lbs/ft.sup.3 that preferably is
between 20 lbs/ft.sup.3 and 40 lbs/ft.sup.3, which more preferably
is between 25 lbs/ft.sup.3 and 35 lbs/ft.sup.3, and which more
preferably is between 27 lbs/ft.sup.3 and 33 lbs/ft.sup.3. In still
another such preferred litter embodiment, litter 30 of the present
invention is substantially completely composed of such extruded
pellets 34 and/or 34' is composed of extruded pellets 34 and/or 34'
having a bulk density of between 15 lbs/ft.sup.3 and 45
lbs/ft.sup.3, which preferably is between 20 lbs/ft.sup.3 and 40
lbs/ft.sup.3, which more preferably is between 25 lbs/ft.sup.3 and
35 lbs/ft.sup.3, and which further preferably is between 27
lbs/ft.sup.3 and 33 lbs/ft.sup.3.
[0088] In addition to litter 30 composed of extruded litter pellets
34 and/or 34' or a mixture of extruded litter pellets 34 and/or 34'
forming clean clumps when wetted, such extruded pellets 34 and/or
34' are advantageously de-dusting pellets that each act as a dust
magnet. Without being wetted, each extruded pellet 34 and/or 34'
used in litter 30 of the present invention has sufficient
water-soluble material in an outer surface 40 of each pellet 34
and/or 34' to cause dust in the litter 30 to adhere to the
water-soluble material of the outer pellet surface 40
advantageously preventing such dust from becoming airborne. In a
preferred embodiment, without being wetted, water soluble binder
present in the outer surface 40 of each extruded pellet 34 and/or
34' of litter 30 of the present invention is a dust attracting
pellet 34 and/or 34 or dust-magnet pellet 34 and/or 34' causing
dust in the litter 30 to stick to water-soluble binder of the outer
surface 40 of each pellet 34 and/or 34' coming into contact with
the dust, while the binder is dry, preventing such dust from
becoming airborne. Such de-dusting extruded litter pellets 34 in
accordance with the present invention is well suited for use as cat
litter 30 with retail bags or containers filled with such cat
litter 30 composed of extruded pellets 34 and/or 34' or a mixture
of extruded pellets 34 and 34' containing less than 5% dust,
preferably less than 3% dust and preferably less than 1% dust by
litter weight.
[0089] In a preferred litter embodiment, each litter pellet 34
and/or 34' is extruded from an admixture not containing any
smectite nor any binder additive with each extruded pellet 34
and/or 34' used in the litter 30 in uncoated form. In another
preferred litter embodiment, each litter pellet 34 and/or 34' is
extruded from an admixture not containing any smectite nor any
binder additive and is used in the litter 30 without any smectite,
e.g., bentonite, coating. In still another preferred litter
embodiment, each litter pellet 34 and/or 34' is extruded from an
admixture not containing any smectite nor any binder additive and
is used in the litter 30 in its as-extruded form.
[0090] Understandably, the present invention has been described
above in terms of one or more preferred embodiments and methods. It
is recognized that various alternatives and modifications may be
made to these embodiments and methods that are within the scope of
the present invention. Various alternatives are contemplated as
being within the scope of the present invention. It is also to be
understood that, although the foregoing description and drawings
describe and illustrate in detail one or more preferred embodiments
of the present invention, to those skilled in the art to which the
present invention relates, the present disclosure will suggest many
modifications and constructions, as well as widely differing
embodiments and applications without thereby departing from the
spirit and scope of the invention.
* * * * *