Note: Descriptions are shown in the official language in which they were submitted.
Thls invention relates in g~neral to pellets adaptet to be
orally admini~tered to ru~inants and which are beneficial to ruminants
after passing the rumen and reaching the abomasum and/or intestines.
More partlcularly, this invention relates to pellets having, ln terms of
structure, a core maeerial such as a nutrient or medlcament, ant an
imperforate coating over the core material which protects the core in
the environment of the rumen, but which loses continuity under the more
acid$c conditions of the abomasum to render the core material available
for utilization by the animal.
In ruminants, ingested feed first passes into the rumen, where
it is pre-digested or degraded by fermentation. During this period of
fermentation the ingested feed may be regurgieated to the mouth via the
reticulum where it is salivated and ruminated. After a period of fermen-
tation regulated by natural processes and variable depending on the animal
and the feedstuff, adsorption of digested nutrients starts and continues
in the subsequent sections of the digestive tract by the ruminant anlmal.
This process is described in detail by D. C. Church, "Digestive Physiology
and ~utrition of Ruminant3", Vol. 1, O.S.U. Book Stores, Inc., of
Corvallis, Oregon.
The rumen, the largest of the four stomach compartments of
ruminants, serves as an important location for metabolic brea~dGwn of
ingested foodstuffs through the action of microorganisms ~hich are
present therein. Ingested foot i9 typically retained in ehe rumen for
from about 6 to 30 hours or longer in some instances, during ~hich time
it is sub~ect to metabolic breakdow~ by the rumen microorganisms. ~uch
;i ingested protein ~aterlal is broken d~wn in the rumen to soluble peptites
and amino acids and utilized by the rumen microorganisms. I~hen the
rumen conten~s pass into the ab asum and intestine, the microbial mass
is digested, thus providing protein to ehe ru~inant. Thus, the natural
nutritional balance of the ruminant a.~imal is primarily a function of
the microbial composition and population.
In preparing nutrients and medicaments intended for administraeion
- 2 - ,;
11~4~g7
to ruminants, lt 1s ~mportant to protect the ~ctive ingredionts against
the environmental condltions of the rumen, i.e., microbial degradation
and the effects of a pH of about 5.5, so the active substance will be
saved until lt reaches the particular location where adsorption takes
place. It is well known that the rate of meat, wool and¦or milk pro-
duction can be increased if sources of growth limiting essential amino
acits, and/or medicaments, are protected from alteration by microorganis~s
residing in the rumen and become available for direct absorption by the
animal later 1Q the gastrointestinal tract.
Materials which protect the core against degradation by the
rumen contents should be resistant to attack by the rumen fluid which
contains enzymes or microorganisms but must make the active ingredient
available rapidly iQ the more acidic fluid of the abomasum at a p~
within the normal physiological range of about 2 to about 3.5. To more
easily coat or encapsulate active ingretients in protective materials,
the protective materials should be soluble in certain organic solvents
for coating purposes.
Because proteins are subject to breakdown in the rumen, it has
been suggested that protein-contaiQing nutrients fed to ruminants be
treated so as to permit passage without microbial breakdown through the
rumen to the abomasum. Suggested procedures have included coating the
proteic material, for example, with fats and vegetable oils; heat treating
of the protein material; reactirg the protein material with various
compounds such as formaldehyde, acetylenic esters, poly~erized unsaturated
carboxylic acid or anhydrites and phosphonitrilic halides, etc.
It is well known that all proteins found in animal and plant
life are chemical compounds containing different combination~ of over 20
am~no acids, the number and arran8ement of such acids being fixed in any
par~icular protein. Twelve of these amino acids can be synthesized in
30 nutritionally adequate amounts from other substances by biochemical
processes normally present in most animals, but the remai~ing lO essential
amino acids are not synthesized iQ surficient quantities and must be
-- 3 --
11~44~7
ingested by the animal. Since the proportions of the constituent amino
acids in a particular protein cannot be varlet, the essential amino acid
least in ~upply limit~ the amount of that protein which can be produced
by the animal. Consequently, for any given diet, there will be a parti-
cular essential amino acid which limits the production of protein incor-
porating that essential amino acid unless, of course, two or more such
amino acids are equally limiting.
The appreciation of ehe above principles leads to the formula-
tion of diets for nonruminant animals which provide the optimum proportion
of amino acids and have enabled significant increases in protein produc~ion
to be achieved. In the ruminant, dietary proteins and amino acids are,
to a variable extent, broken down eo ammonia and various organic compounds
by microbial fermentation in the first t~o compartments of the stomach
(the rumen and reticulum). The bacteria and protozoa in these organs
utllize these metabolites for their own growth and multiplication and
the microbial protein so formed passes on to the abomasum, the compart-
ment of the stomach corresponding to the stomach of nonruminants, where
it is partially digestet. The process i8 completed in the small intestine
and the amino acids are absorbed.
It is likewise ~ell-known that medicaments are more zffective
when they are protected from the environment of the rumen. See, for
example, U.S. Patent ~09. 3,041,243 and 3,697,640.
In accordance with the present inveneion, a polymeric coating
having a hydrophobic substance ant a flake material dispersed therein,
which is resistant to envlronmental conditions of the rumen but releases
the core material under the environmental contitions of the abomasu~,
provide~ a very desirable utilization efficiency by ru~inants. The core
material may also contain a neutralizer to provide a pH above about 5.5.
The coating material has the ability to withstand euvironmental
condltions of the rumen, and the ability to expose the core material of
the pellet in the environment of the abomasum. Thus, the coating material
is resistant to p~ conditions of abcut 5.5 for at least about 24 hours.
-- 4 --
The coating material releases the core material upon exposure to
abomasum environmental conditions having a pH of about 3.5 after
a time of about 10 minutes to about 6 hours. The exposure of the
core may occur by the coating becoming permeable to the fluids
therein or by dissolving or disintegrating. Another requirement
for the coating material is to have the ability to withstand
storage conditions of relatively high heat and/or humidity with-
out a significant amount of blocking.
Core materials having an adjusted pH of greater than
about 5.5 and a water solubility of about 10 to about 70 grams
per hundred grams water at 25C. are most useful in this invention.
Thus, any core material which is beneficial to the reminant such as
a nutrient or medicament having characteristics within these para-
meters may be used. Preferred core materials include amino acids,
proteins, various other nutrients, as well as antibiotics and other
medicarnents.
Thus, in accordance with the present teachings, there
is provided a pellet which is adapted for oral administration to
a ruminant which comprises a core material beneficial to the
ruminant postruminally, and a coating surrounding the core material,
the coating being resistant to pH conditions of about 5.5 for at
least six hours and adapted to release pellet core material after
exposure to a pH of about 3.5 after a time of about 10 minutes to
about six hours and comprises a) a film-forming polymeric material
containing at least one basic amino grouping in which the nitrogen
content is from 3 to 14% by weight of the total molecular weight
of the polymeric material, the polymeric material comprises at
s ~ -5-
~J .
11~4~
least one polymer, copolymer or blend of polymers which selected
from the group consisting of cellulose propionate morpholinobuty-
rate, aromatic basic amino-containing polymers, dialkylamino ethyl
acrylates and methacrylates in which the alkyl group contains from
1 to 6 carbon atoms, condensatiGn polyesters and polyamides, b)
from about 2 to 50%, based on the weight of the polymeric material,
or a hydrophobic material dispersed in the polymeric material and
selected from the group consisting of waxes, resins, polymers,
fatty acids having from 12 to 32 carbon atoms, aluminum salts of
fatty acids having from 12 to 32 carbon atoms, and polyfunctional
carboxylic acids which have a ratio of from 10 to 22 carbon atoms
per carboxyl group and a molecular weight of from 400 to 1000, and
c) from about 10 to 200~, based on the weight of the polymeric
material, of a physiologically acceptable flake material dispersed
in the polymeric material.
BACKGROUND
U.S. Patent No. 3,619,200 relates to chemically
modifying pellets and/or using a surface coating therefor. Pro-
teinaceous feed is protected from breakdown within the rumen by
the modification of protein itself, by the application of a pro-
tective coating to the feedstuff, or by combination of both.
Various polymers are disclosed in this patent including copolymers
of vinylpyridine and styrene. Canadian patent No . 911, 649 dis-
closes treatment of proteinaceous materials with substances which
are capable of reacting with proteins to form a polymeric protein-
aceous complex on the surface of the material or by treating the
proteinaceous material with a polymer or copolymer of a basic
, ..,~,
,' -5a-
~?4~97
vinyl or acrylic monomer. This patent also discloses the use of
copolymers and terpolymers derived from essentially a basic
substituted acrylate or methacrylate monomer and at least one
ethylenically unsaturated compound as rumen stable coatings.
U.S. Patent No. 3,880,990 and British Patent No. 1,346,739 relate
to an orally administratable ruminant composition wherein a medicin-
al substance is encapsulated or embedded in a normally solid,
physiologically acceptable basic polymer. The compositions are
produced
-5b-
,:,
.
~Q4~7
by dispersing a medlci~al substance in a first solvent and adding thereto
a second solvent which is mi~cible with the firqt ~olvent but in which
the polymer and medicinal substance are substantially insoluble. There
i9 no suggestion of modifying the polymer by the use of additlves. ~'.S.
Patent ~'o. 3,041,243 relates t5 coatings for oral medicament These
coating3 ars water-lnsoluble but acid-soluble film-forming polymers. An
example mentioned in this patent i9 2-methyl-5-vinyl pyridine copolymerlzed
~ith vinyl acetate acrylonitrlle, methyl acrylate or styrene.
U.S~ Patent No. 3,697,640 relates to materlals such as meticaments
and nutrients for ruminants which are coated with nitrogen-containing
cellulosic materials such as, for example, cellulose propionate morpholino
butyrate. Thi3 patent, however, fails to suggest the use of any additives
in the nitrogen-containing cellulosic materlal, and U.S. Patent No. 3,988,480
~; relates to a proteinaceous feedstuff for ruminants which has been treated
wlth acetic acid to render it rumen stable.
U.S. Patent ~o. 3,383,283 relates to coating pharmaceutical
r~" pellet3 with a plurality of charges of fatty acid as a melt or in solution.
The ~atty acid may then be dusted with a fine inert powder such as talc.
There ls no suggestlon of using a continuous matriæ polymer.
,- 20 U.S. Patent No. 3,275,518 relates to a tablet coating composition
; comprising a film-forming resin or plastic and a hart water-soluble or
water-dispersible 3ubstance. Stearic acid i9 mentloned as an optional
water-insoluble wax which may be included as an additive. Additional
materials such as dyes, pigments, ~ater-insoluble waxes, plasticizing
agents, etc., may also be addet to the coating. however, the film-
formi~g resin or olastic according to this patent is selected from the
group consisting of poly(methylstyrene), methylstyrene-acrylonitrile
copolymers, polytvinylchloride), poly(vinyl butyral), pentaerythritol or
alkyd esters of rosin or modified rosin and terpene terived alkyd resins.
There is no suggestion of the polymers according to applicants' invention.
In fact, the plastic or resin i9 described as water-permeable, and the
coating apparently i3 not designed for ruminant3.
. .
-- 6 --
~ ~ ~?4 ~ ~7
~ S. Patent No. 3,~23,9g7 relates to a methot of ~ealing
polymeric material walls of minute capsules by treating the capsules
~ith a waxy material. The wax i9 introduced in a solvent whlch is
subsequently dried and the wax is left as a resldue in the walls. The
capsule walls shrink and lose solvent and then entrap the wax tightly as
a sealing material. There i~ no indication, however, that the polymer
coating is de~igned to function for ruminants, and the wax is used a~ a
sealing material. Applicant's hydrophobic substance is dispersed in the
polymer.
U.S. Patent No. 3,073,748 relates to tablets coated with a
solution of an amphoteric film-forming polymer. The polymer is described
as one selected from the group conslsting of copolymers of (a) vinyl-
pyridines with (b) a lower aliphatic a,3-unsaturated monocarboxylic acld
of 3 to 4 carbon atoms and copolymers of (a), (b) and a neutral co-
monomer selectet from the group consisting of methyl acrylate, acrylonitrile,
vinyl acetate, methyl methacrylate and styrene. There is no suggestion
of using a disp2rsed additive.
British Patent ~o. 1,217,36; and Canadian counterpart ~o. 851,128
relate to a particulate feed additive composition for ruminants wherein
each particle comprises one or more amino acids totally encased in a
continuous film of protectlve material which is transportable through
the rumen without substantial degradation therein but which releases the
active substance posterior to the omasum when the particles have a
density withi~ the range of 0.~ to 2.0 and diameters in the range of 200
to 2,000 microns. Suggested as ?rotective materials are fatty acid
triglycerides such as hydrogenated vegetable and animal fats, waxes such
as rice-brand wax, and resin wax blends which are emulsified and/or
dissolved in the intestinal tract.
PELLETS
The pellets according to this invention are adapted for oral
administration to a ruminant. The pellets are of a suitable size, such
as between about 0.OS in. and 0.75 in. in diameter. Also, the pellets
-- 7 --
9~
must be of 3uitable de~sity, i.e., a 3pecific gravlty of bet~een about 1
and 1.4, have acceptable odor, taste, feel, e~c. The pellet~ include a
core ant a continuous, fil~ or coati~g completely enc2p~ulating the
- core. The shape is usually not critical, except the pellets are commonly
3pherlcal for ea~e in coating.
CORE ~ATERIAL
The core is of a material beneficial to the ruminant upon
pa3sing the rumen and reaching the abomasum antJor intestine. Normally,
the core ic a solid material ~hich has been formed into particles, such
as by pelletizing. The cores may then be rountet if tesiret, by con-
ventional means, such as by tumbling. The core shoult have sufficient
body or consistency to remain intact during handling, par~icularly
during the coating operation. Suitable core materials include various
medicaments and nutrlents such as, for example, antibioticc, relaxants,
drugs, anti-para3ites, amino acids, proteins, sugars, carbohydrates,
etc. The core may also contain inert filler material such as clay.
Some amino acids suitable for use as a core material, thelr p~
and solubility are as follows:
~mino Acids Solubilitv ant ~H of Saturated Solutions
Solubility ~./100 g. water
at 25C. pH
DL - Alanine 16.7 6.2
L - Asparagine 3.1 4.7
L - Arginine 21.6 11.8
L(-) - Cysteine 0.01 3-7
DL - ~ethionine 4.0 5.7
L(-) - Lencine 2.0 4.8
L(-) - Tyrosine 0.05 7.3
DL - Phenylalanine3.0 5.6
Other 3uitable active core materials include glucose, bacitracin,
thyrotropin releasi~g factor and inoeitol. Proteins fram various sources
are valuable for practice of the invention. Generally, proteins are
polymers derived from various combinations of a~ino acids. Proteins are
- 8 -
amphoteric substances which are soluble or suspentable in aqueous media
either more acidic or more bas.ic than the particular protein being c~n~.ldered.
The core material may be made ready for coating by the following
methot. The nutrient, medica~ent, or the like, and core neutralizer, if
used, are mlxed with water, binders, a basic substance for ad~usting the
core p~, and sometimes inert inorganic substa~ces added to atjust the
specific gravity of the pellet and the resulting plastic dough-like mas~
i9 extrudet or rolled to obtain sultable size particles. Adhesive
binders are added to strengthen the pellet and can be nontoxic vegetable
gums, starches, cellulose derivatives, animal gums and other similar
substances well-known in the art of food thickening and tablet making.
Inorganic additives uset to ad~ust the 3pecific gravity of the pellet
inclute such substances as insoluble, nontoxic pigment-like materials
such as metal sulfates, oxides and carbonates having a relatively high
density. The final desirable range of specific gravity for the rumen
protected pellets is fr~m 1.0 to 1.4. After creating suitable slze
pellets by extruslon, rolling or other sultable means, the pellets are
dried to remove the water. The pellets are then coated by contacting
them with a solution of the protective coating material in a suieable
; 20 solVe~t or mixture of solvents a9 hereinafter describet. Typical solvents
of value include lower alcohols, ketones, esters, hydrocarbons, and
chlorinated hydrocarbons.
CORE NEUTRALIZATION
Core materials may be raised in pH to a predeter~ined degree
by mixlng a basic neutralization substance therewith or by coating the
core with a basic neutralization substance. The acidity is modified by
adding nontoxlc, insoluble, baslc substances such as alkaline earth
oxides, hytroxides, or carbonates, to the core materlal before the
pellet forming step: Basic compounds of aluminum such as the various
forms of hydrated alumina, alumi~um hydroxide, ant dibasic aluminum
salts of organic acid3, hav~ng les~ than 6 carbon atoms, such as dibasic
; aluminum acetate may also be used. These basic substances are atded to
_ g _
the pellets by mlxing the core material, ba-ic ~ubstance, and blnders as
descrlbed abo~e before adding water. The amount u~ed depends on both
the solubllity and rélative acidic nature o~ the proteinaeeous substance,
on the coating composltlon used to obtain r~men protectlon ant on the
thlc~ness of the coating applied. The amount of basic substance used i9 that
quantlty which will theoretically neutralize or raise the p~ at least to
5.5, preferably to about 7.
The core material may be neutralized by the following method.
~o~toxlc, insoluble baslc substances such as oxides, hydro~ides, carbonates,
and basic salts of magneslum, calcium, and aluminum are blended with
finely-divided nutrient andlor therapeutic substances at the time these
are prepared for pelletizing. The amount of basic substance used depends
on several interacting factors related to the relative acidlty and/or
solubiliey of the pellet, the time requiret for rumen proeection, and
the time required for release in the abomasum. Normally, the weight of
ba~ic substance will be within the range of 1-20Z of ehe total weight
of the core. I~ atditlon to the nutrient or therapeutic substance and
the basic substance, the pellets may contain binters, denslty modifl2rs,
and other minor ingretients required for special properties, as is
common practlce in the art of tablet making. In this practice of the
i~vention, the various powdered ingredlents are-first dry blended to
obtain a more or less homogeneous mixture, then water is atded to obtain
a plastic dough-like mass. The tough ls then pelletlzet by extrusion,
extrusion and tumbling, or by any method known to the art of pelletizing
or tabletmaking. The water i9 re~oved by trying at ambient contl~io~s,
in heated oven~ or fluidized beds. The dry pellets are then ready for
subsequent coatlng operations performed by any method such as pan coatlng,
fluitized bed coating, or spray coating or combination~ thereof.
Another method of core neutralizaelon ls based on the concept
that, whereas the coating is permeable to water and acidic water borne
molecules, not all of the pellet interior is required to be neutralized.
In this method of practicing the invention, the nontoxic inorga~io basic
.
-- 10 --
11~;4~
substances are deposi~ed on the surface of ~he core ~aterlal prior to
applicatlon of the coat~g. In practlce, the prefor~ed pellets are
placed in a fluidizet bed or other coating apparatus and a di3perslon of
an oxide, hydroxide, carbonate, or basic ~alt of magnesium, calcium, or
aluminum in water or an organic liquid i~ sprayed on the pellet. The
dispersion of basic substance preferably contains a binder and may also
contain a protective colloidal substance where~n the ratio of binder
plu3 protective colloidal subYtance to baslc substance is less than
about 1:3. The amount of basic substance coated onto the pellet is
normally from about 1 to about 20% of the ~eight of the core material.
The binder and protective colloidal substance can be the same substance
or different and are preferably soluble or dlspersible in water and in
the organic liquid used to suspend the basic ~ubstance. 8uch binder
materials as relatively low molecular weight cellulose derivatives,
synthetic polymers, and natural gums kno~n to the art of tablet making
are ~uitable for the practlce of the invention. The organic liquld can
be any havlng suitable solvent power and boiling in the range of fr
40-140~C.
COATING
The coating maeerlal is capable of forming a continuou~ film
around the core by the evaporation of solvent from the coating material.
It has the ability to withstand environmental conditions of the rumen,
and the ability to expose the core materlal of the pellet in the environment
of the abomasum~ Thus, the coating material should be resistant to pH
conditions of greater than about 5 for from about 6 to about 30 hours.
The coating material should release the core material after exposure to
abomasum environmental conditions having a p~ of about 2 to about 3.3.
Release shoult occur within the r2sidence time in the abomasum or later
in the intestinal tract but at least within a time period of 6 hours
after contacting p~ 3.5 or less. The exposure of the core may occur by
the coating beco~ing permeable to the contents of the rumen, such as by
dissolving, disintegrating, or extensive swelling. The coating material
4~97
is physiologically accepeable, i.e., the coating ~aterial should not
l~terfere wi~h the ruminant~' healthy or normal body fu cti ing.
Another requirement for the coating ma~erial is it8 ability to
withs~and abrasion in handling and ~torage conditions of relatively high
heat antlor humidity without a significant amount of blocki~g. It
should have a sticklng temperature of greater than about 50C. Sticking
temperature is defined as the temperature at which adheslon sufficient
to cause rupture of the coating upon forceable separation between coated
particles occurs when an applied force of 0.25 Rg/cm2 holds the particles
in contact for 24 hours. Also, the coating material is preferably
soluble or dlspersable ln organic solvent3 having boiling points of
between about 40C. and 140C. to permit conventional coating processes
such as spray coating to be used. Particularly suitable solvents include
methylene chloride, chloroform, ethanol, methanol, ethyl acetate, acetone,
toluene, isopropanol or mixtures of these.
The coating or fil~ forming material accorting to this invention
include~ a mixture or blend of at least one polymeric substance, at least
one hydrophobic ~ubstance, and at least one flake material. Generally,
the more acidic and more soluble core materials require greater ratios
of hydrophobic substance and flake material to polymeric substance,
while more baslc ant less soluble core materials require lesser ratios
of hydrophobic substance and flake material to polymeric substance
within this range. The hydrophobic substar~ce and flake material are nor~ally
dispersed in the polymeric ma~rlx. The hytrophobic subs~ance is normally
present in amounts of between about 2 and about 40% and the flake material
is normally present ln amounts between about 10 ant 200~, based on the
weight of the polymeric material
POL~ER
The polymeric substances which are useful in the coatings of
-~ 30 thi~ invention include those which, in c~mbination with the hydrophobic
substance describet hereinafter, are physiologically acceptable ant
resistant to a pH of greater than about 5 but capable of releasing the
- 12 -
core of the pellets at a pH of less than about 3.5, at the normal body
temperature o~ rumlnants (37C.). The polymeric Rubstances include
polymers, copolymers and mixtures of polymers andlor copolymers having
basic amino groups in which the nitrogen content of the polymeric sub
stance is between about 2 and about 14% and typical lecular weights between
about S,000 and 300,000. The basic amino groups may be of the aliphatic
type in which case they will contain from about 2% to about 10% by weight
of nltrogen ln the basic amlno groups. The baslc amlno groups may also be
of the aromatic type in which the basic amino groups are attached directly
to the aromatlc ring, or are part of the aromatlc ring structure in which
case they will contain from about 6~ to about 145' nitrogen in the basic
amino groups. The polymeric substances are macromolecules of sufficient
molecular weight to have film-forming properties when the polymer is deposited
from a solution and after removal of a solvent, dispersing medium or on cooling
from a melt.
Polymeric substances havlng the characteristlcs deflned herein
include certaln modified natural polymers, homo- and interpolymers obtained
by addition polymerization methods, ho - and copolymers obtained by
condensation polymerization methodg and mixtures thereof. The polymeric
20 material is comprised of at least one polymer, copolymer, or blend of
polymers selected from the group consisting of cellulose derivatives such
as cellulose propionate morpholinobutyrate; containing addition-type
monomeric moietles such as acrylonitrile; vinylated derivatives of
pyridlne; fltyrene; methylstyrene; vlnyl toluene; esters and amides of
methacrylic acid; esters and amides of acrylic acid; polymerizable
ethylenically unsaturated aliphatlc hydrocarbon monomers such as ethylene,
propylene or butadiene; vinyl esters such as vinyl acetate, vinyl propionate
or vinyl stearate; vinyl ethers such as methyl, ethyl, propyl or stearyl,
vinyl substituted heterocyclic ring or condensed ring compounds containing
30 basic nitrogen configurations such as vinyl carbazole, vinyl quinoline,
N-vinylpyrrole and 5-vinyl pyrozoline; containing condensation-type
polymers wherein a diacid such as phthalic, terephthalic, and succinic
- 13 -
.
i~4~
are combined with polyfunctional alcohols to form polyesters wherein
either the acid or glycol moiety may conta~n basic Qit~ogen not reactive
in the polymerization process but reactive to variable pH environments
and wherein the same sr similar diacids may be reacted with polyfunctional
amines to form polyamide-type polymers containing basic nitrogen not
reacted in the polymerization process; and other basic nitrogen containing
polymers such as preformed polymers which have been formed by reacting
an existing polymer with a nitrogen containing organic or inorganic moiety
such as polybutadiene to which ammonia has been reacted with the remaining
double bond. Especially preferred are poly(vinylpyridine), polymeric
derivatives of vinyl-pyridine, and the copolymers of the various isomers
and derivatives of vinylpyridine copolymerized with one or more of the
above-mentioned addition type monomers.
A160, especially preferred are copolymers of 2-methyl-5-vinyl-
pyridine and styrene, and in particular, the copolymer of about 75-85% by
weight 2-methyl-5-vinylpyridine and about 15-25% by weight styrene, as well
as the copolymer of 55-65% by weight 2-methyl-5-vinylpyridine and about
35-45% by weight acrylonitrile. These copolymers are commerciAlly avail-
able or may be produced by conventional techniques well known in the art.
~ HYDROPHOBIC SUBST~CE
Hydrophobic substances which are physiologically acceptable
and have the correct degree of compatability with the polymer are commercially
; available. It is important that the polymer and hydrophobic substance
have a degree of compatability to permit the film to remain intact in
the rumen environment, but to permit permeation of the abomasal fluld to
the core while the pellet is in the abomasum.
While we do not wish to rely on any particular theory as to
,. . .
why the coatings containing the hydrophobic substance are better protective,
we believe the function is generally that the cverall susceptibility of
the matrix films to aqueous weakly acidic environments is reduced.
Further, we believe that in view of the inherent polar nature of polymer5
containing enough basic nltrogen groups to be functional with respect to
- 14 -
44~7
the differences of rumen and abomosum p~. that a reduction in water
susceptibility of the film is required, especially when the core material
is acidic and/or very water soluble. Uhile the general theory believed
to be true is as described above, there are subtle variations in the
precise mode by which the hydrophobic substance is functional. A clas~
of hydrophibic substances of value are fatty acids containing from 10 to
32 carbon atoms such as lauric, oleic, stearic, palmitic and linoleic.
These substances are well known to be water insoluble due to the long
hydrocarbon radical but to react to water due to the polar nature of the
carboxyl group. In the selected basic amino group-containing polymers,
the carboxyl group of the fatty acid is able to react with the basic
nitrogen group to form a weak salt-type linkage. This attachment to the
polymer serves to cause the fatty acid to be fixed in the polymer matrix.
The hydrophobic hydrocarbon chain of the fatty acid tends to render the
matrix water resistant and thereby decreases swelling of the otherwise
water suseptible polar film Both the interior of the matrix film and
the surface is now water resistant in aqueous environments at pH above
about 5Ø However, at pH values below pH 4.5 and especially below
about pH 3.5 the affinity of the basic nitrogen group for water and the
hydrogen ion overcomes the increased water resistance. The film reacts
with the acid environment and loses barrier properties sufficient to
allow the core material to escape to the environment.
Polyfunctional carboxylic acids may be derived from natural
products or obtained by organic synthesis but the ratio of carboxyl
group to hydrophobic organic radical should be at least 1 to 10 based on
the molecular weight of the organic radicals. Also included in this
class of synthesized organic hydrophobic acids are mono and poly-
functional acids containing silicone or flourinated carbon groups located
at least 4 atoms distant along the molecular chain from the position of
the carboxyl group or groups. Also, included in the class of hydrophobic
substances are the nontoxic multivalent metallic salts of the above
acids such as the stearates, oleates, fatty acid dimerates, and palmitates
- 15 -
.
.
49~
of aluminum and iron and the calcium, magnesium and zinc salts of the
higher molecular ~eight crystalline analogs of the above acids. When
the cation is trivalent as for alumlnum and ferric iron, the molar ratio
of organic acid to metal ion is 2 to 1 or 3 to 1 and the acid can be any
monofunctlonal organic acid h~ving one carboxyl group and at least
10 carbon atoms in the organic radical attached to the carboxyl group.
When the metal ion is divalent such as ferrous iron, calcium, magnesium
or zinc the organic acid may be monocarboxylic or polycarboxylic ant the
ratio of metal ion to non-carboxylic carbon atoms is at least 1 to 26.
Na~ural and synthetic waxes and resins added at levels depending on the
degree of hydrophobicity and compatibility in the matrix film are of
value in the practice of the inventlon. Waxes and resins are useful
- that have a molecular weight of from 500 to 2000 and a critical surface
tension of less than 31 dynes/cm as determinet by the Zisman method
described in "Contact Angle Wettability and Adhesion", Advances in
Chemistry Series #43; Edited by Robert F. Gould: published by the American
Chemical Society; 1963; Chapter l; and have a solubility in the matrix
film of less than 5~. These waxes and resins are dispersed in the film
in at least amounts equal to 2 times the solubility and up to 30% of the
total weight of the matrix polymer. Typical waxes and resins include
; beeswax, petroleum wax, dammar, hard manila, phenolic resins, rosin and
maleated low molecular weight polyhydrocarbons. Also included in the
hydrophobic substances are polymers having molecular weights of from
2000 to 10,000, a critical surface tension of less than 31 dynes/cm
: measured by methods in the reference to Zisman described above. Useful
polymers have a solubility or compatibility in the matrix film of less
than 5% on a weight basis and are present in the film at levels at least
equal to two times the solubility and up to 30 weight percent of the
matrix film. Of particular value are the polymers and copolymers containing
silicone groups in the main polymer chain or in a side chain and polymers
and copolymers containing flourinated carbon groupq in a side chain.
Regardless of the exact nature of the hydrophobic substance it must be
- 16 -
soluble or colloidally dispersible in the coating solvent when one is
used. The hydrophobic substance makes up from 1 to about 50% of the
combined weight of polymeric material and hydrophobic substance.
Suitable hydrophobic substances also include fatty acids having
from 12 to 22 carbon atoms, such as oleic acid and stearic acid,
dimer acids, trimer acids, aluminum salts of fatty acids, waxe~, resins,
and certain polymers such as polymers containing very hydrophobic chemical
groups such as silicone moieties and certain multivalent catlon soaps.
The hydrophobic substance may be amorphous or crystalline and preferably
1~ essentially dispersible in the coating solvent when a solvent is used in
which case it should not contribute significantly to the solution viscosity.
Aluminum salts of such acids, for example, aluminum oleates,
aluminum stearates, aluminum dimerates, are also useful. Also, the
hydrophobic material may be one or more polycarboxylic acids having a
ratio of from 10 to 22 carbon atoms per carboxyl group and a molecular
weight greater than 300, preferably about 400 to about 1000, are useful,
Blends of these acids and/or sales are also useful.
We believe the function of the hydrophobic substance as a
dispersed phase in the protective polymer layer:
a. reduces wetting of the coating and therefore initial attack by
water,
b. reduces total volume of coating affected by water, and
c. e~tends the length of permeable pathway the water must travel
to core.
FUNCTIONAL FLAKE MATERIAL
In accordance with this invention, a physiologically acceptable
flake material is dispersed throughtout the polymeric matrix. The
flake material is substantially inert with respect to the environment of
the rumen.
Suitable inert flake materials include metal flake, mineral
flake, crosslinked organic polymer, etc. Especially suitable are aluminum
flake, talc, graphite, and ground mica.
-
APPLICATIO~ OF COATI~G
In the practice of his invention, the polymeric material
~ay conveniently be dissol~ed in a suitable organic solvent which would
be ?hysio'ogically acceptable in the event there are residues upon
evaporation of the solven~, as hereinbefore described. The hydrophobic
substance is blended in the solution, wherein the polymeric substance i9
a continuous matrix and the additives are dispersed therein. The coating
solution may be applied by various well known means such as, for example,
brushing, dipping, spraying, fluidized bed, etc.
A preferred apparatus and process for coating the cores will
now be described.
In the drawings:
Fig. 1 is an elevation view in cross~section illustrating the
apparatus and showing the gas flows and particle flow path from the
annular bed to and through the truncated hollow cone and in return to the
annular bed;
: Fig. 2 ls a partial elevation view in cross-section of a
modified apparatus and illustrating the addition of an annular airfoil
and showing the flow of gases relative to the aerodynamic structure and
annular airfoil;
Fig. 3 is a partial elevation view in cross-section of another
modified apparatus similar in all other respects to the modification
shown in Fig. 2 except that the cross-section of the apparatus below the
coating chamber is of the same dia~eter as that of the coatin~ chamber-
Fig. 4 is a partial elevation view in cross-section of the
upper portion of the apparatus of the invention for illustrating one
possible manner of collecting the finally coated particles by use of an
air porous bag; and
Fig. 5 is a graphic illustration of the height, thickness and
angular relationships of the annular airfoil with respect to the aero-
dynamic structure, and the height above (ha) and height below (hb)
relationships of the aerodynamic structure to the greatest cross-
sectional diameter of the-aerodynamic structure.
- la -
il~4~7
The apparatus employs a truncated hollow cone in which the
slope or pitch of the walls is such that the particles are accelerated
at an increasing rate and noe just at a rate so as to maintain the gas
velocity at any given point in the cone at a level greater than that
necessary to move .he particles in a continuous upward direction. The
slope or pitch of the walls would therefore appear to be more pronounced
than the slope or pitch of the cone embodiment disclosed in the Larson
et al patent. The significance of the slope or pitch of the truncated
hollo~ cone of the invention is that when a particle first enters the
cone at one rate of speed, it is then accelerated to a different rate of
speed and continues to be accelerated to still different rates of speed
as it moves upwardly through the cone. In this manner a separation is
brought about between the particles so that after they are coated they
may become sufficiently dry before coming into contact with other particles
and thereby avoid undesirable clumping or agglomerating together. The
pitch of slope is such as to cause a compression of the gas molecules and
thereby cause the acceleration at an increasing rate.
In reference to Fig. 1, the coating apparatus is designated in
general at 10 and includes a vertically disposed first hollow column 12
Of regular shape. By "regular shape" is meant that it may be cylindrical,
octagonal, hexagonal or of other configurations, so long as the hollow
column is generally symmetrical with respect to its central axis. The
hollow column contains therewithin the particle storage, coating, drying
and deceleration zones, which will be described herein.
A truncated hollow cone 14, which may also be a tapered octa~on
or other tapered polygonal configuration, in other words, generally
cone-shaped configurations, serving as an enclosure in which the upwardly
flowing gases are received, co~pressed and accelerated, is centrally
disposed within the first hollow column, has a uniformly decreasing
cross-section in the upward direction and is of predetermined helght
dependent upon the size and weight of the particle to be treated.
Within the truncated hollow cone in ascending order are the coating and
drying zones. The cone serves also to separate the coating and drying
-- 19 --
:
zones from the deceleration zone, which 11es in the region above the
upper end of the cone, and from the storage zone, which li2s therebetween
the cone and the interior wall surface of the first hollow column.
The first hollow column 12 is provided at its lower end with
an inwardly tapered base 16. The lower end of the truncated hollow cone
is spaced radially inwardly flom the inwardly tapered base.
A second vertically disposed hollow column 18 of regular shape
is connected to the inwardly tapered base of the lower end of the first
hollow colu~n, the wall surface of the inwardly tapered base forms a
~uncture with the wall surface of ehe second hollow col = .
Disposed within the second hollow column is a first plenum
chamber 20 into which a suitable compressed gas, such as air, may be
provided through two or more opposed inlets 22, 24: a gas or air colli-
mating plate 26; a second plenum chamber 28 separated from the first
plenum chamber 20 by the collimating plate 26; at least one gas shaping or
aerodynamic structure 30 disposed within the second plenum chamber; and
a particle support or supporting screen 32, which extends across the
second hollow column and is located above the aerodynamic structure.
The gas or air collimating plate 26 is a perforated plate
20 which causes the gas or air in the first plenum chamber to pass into the
second plenum chamber in an zssentially vertical and uniform flow, a~
lllustrated by the vertical arrows.
The gas shaping or aerodynamic structure 30 in cooperation
with the ad~acent wall surface of the second hollow column, compresses
and focuses the upwardly moving gas or air flow so that it flows over
a portion of the surface of the aerodynamic structure, upwardly through
the particle support screen and into the entrance end of the truncated
hollow cone. The flow upwardly around the aerodynamic st~ucture constitutes
an annular flow, which adheres to the surface of the aerodynamic structure
30 in the nature of a Coanda flow.
A spray nGzzle 34 preferably extends above the top of the
aerodynamic structure 30 through which is sprayed a suitable coating
material. It is more conv~nient to have the spray nozzle located at the
- 20 -
top of the centrally disposed aerodyn~mic structure. The coating materialis supplied from a suitable source (not shown) through a cond~it 3~
extend~ng up through the aerodynamic struc~ure, and an atomizing gas may
be supplied from a suitable source (not shown) through a conduit 38,
also extending up through the aerodynamic structure, for subsequent
mixing at the nozzle. The spray nozzle may also be pressure-operated
rather than gas-operated.
The upper surface of the gas shaping or aerodynamic structure
is centrally disposed within and extends generally horizontally across
the cross-section of the vertically disposed hollow column. In other
words, it has a cross-sectional plane generally perpendicular to the
vertical axis of the vertically disposed hollow columns. The outer edge
of the upper surface i9 equally spaced from the wall surface of the
hollow column and defines therebetween with the wall surface of the
hollow column a reduced pressure region for acceleration in velocity of
the ùpwardly flowing gases in such manner that the upwardly flowing
gases form a boundary layer that is directed away from the wall surface
of the hollow column and that adheres to the upper surface of the gas
shaping or aerodynamlc structure for flow across a portion thereof.
The upper surface of the aerodynamic structure may be flat
(not illustrated), but is preferably curved or approximately spherical
as illustrated. It may have a height (ha) above the cross-sectional
plane (See Fig. 5), therefore, of from about 0% to about 150~, or preferably
from about lQ% to about 150% of the greatest cross-sectional diameter (D)
(See Fig. S) of the aerodynamic structure.
The surface below the greatest cross-sectional diameter may
also be flat (not illustrated) and may therefore have a depth or height
(hb) below of from about 0% to about 200% of the greate-~t cross-sectional
diameter (D) (See Fig. 5). Preferably, the surface below is formed in
the manner disclosed in the drawings.
The aerodynamic structure as disclosed and as described is
thus adapted to compress and accelerate the flowing gases near the
periphery of the hollow column and direct them ~oward the center of the
- 21 -
hollow column at an angle from about 10~ to about 45 from a directionparallel to the flowing gases from the gas or air plenums.
The truncated hollow cone defines at its lower end a large
diameter somewhat smaller than the diameter of the vertically disposed
first hollow column, and has an increased diameter from about 0% to
about 25~ greater than that of the plane of the particle support screen.
The lower end of the truncatet hollow cone is spaced a predetermined
amount from the screen and the upper end defines a diameter of from
about 20Z to about 80~ of that of the lower end. The height of the cone
ranges from about one to about six times the diameter of the lower end.
In operation, particles 40 may be suitably loaded into the
coating apparatus 10, as through a closable opening at 42, into the
storage zone lying between the wall surface of the first hollow column
12 and the outside wall surface of the truncated hollow cone 14. The
particles are thus situated in an annular bed around the truncated
hollow cone 14. The sloping outer wall surface of the truncated hollow
cone, the inwardly sloping tapered base 16 of the first hollow column
and the screen 32 serve to contain the particles in the annular bed
prior to starting-up the coating operation.
The gas or air is turned on to start the circulation of the
particles or pellets from the annular bed or storage zone into the
coating, drying and deceleration zones and in return to the upper portion
of the annular bed. The atomizing spray is then turned on and appro-
priately adjusted in a suitable manner by controls (not shown~.
As previously pointed out, the Coanda flow or effect is named
for the tendency of a fluid, either gaseous or liquid, to cling to a
surface that is near an orifice from which the fluid emerges. Such
"orifice" in this instance is formed in the region therebetween the
closest approach of the aerodynamic structure to the adjacent side wall
` 30 surface. The gas flow emerging from the "orifice" region around the
aerodynamic structure is an annular flow which clin~s or adheres to the
surface of the aerodynamic structure. The flow, therefore, from any one
selected location around the "orifice" is opposed by the other flows so
- 22 -
that it is prevented from continuing further over the upper surface of
the aerodynæmic structure by being forced upwardly away from the uppes
surface at some point for flow into the truncated hollow cone. A
partial vacuum is formed in the reglon ~ust above the upper surface of
the aerodynamic structure and at the lower edge of the truncated hollow
cone and this aids in the compression and focusing of the rising annular
flow of gases. The upward flow is consequently caused to have a conical
shape, as seen in phantom lines in Fig. 1 at 44 within the cone, and has
a centering effect on the particle impelled upwardly through the cone.
As also pointed out, an important part of the Coanda effect is
the tendency of the flow or gas or liquid to entrain, or draw in, more
gas or liquid from the surrounding environment. In this latter manner,
the particles are pulled from the annular bed or storage zone into the
upwardly flowing gas due to the aforementioned partial vacuum or reduced
pressure region that exists just above the screen ad~acent the path of
upward flow as a consequence of this Coanda effect. This reduced pressure
or partial vacuum i8 directed perpendicular to the annular airflow from
the "orifice". It is a different effect, however, from the horizontal
shunting action occurring in the Wurster et al apparatus described above
because there the horizontal shunting would extend not only toward the
axis of the apparatus but also inefficiently toward the outer wall
surface of the coating apparatus.
Once the particles are pulled into the upwardly flowing gas
within the truncated hollow cone, they are impelled upwardly in an
accelerating gas or air stream. As the particles pass through the lower
central region or coating zone within the cone, they are contacted with
an atomized spray coating of material. This atomized spray emerges from
; the spray nozzle 34 because the liquid coating substance is either
forced through a single orifice designed to convert bulk liquids into
30 droplets, or the llquid and an atomizing air stream emerge simultaneously
from ~ets ad~acent to each other. In either case, the fine droplets of
coating material are in a flowable state, because the material is dissolved
- 23 -
llQ~9~
or melted in the region immediately above the spray nozzle.
Further up the truncated hollow cone, the liquid nature of the
coating material, as deposited on the pellets or particles, changes to
solid by evaporative or other solidification processes. During the
transition from l$quid to solid, the coated particles pass through a
stage when they are sticky or tacky and would agglomerate lf they contacted
each other. This contact is prevented by the slope or pitch of the
walls of the truncated hollow cone and consequent accelerating boost of
the particles to separate them in the manner previously discussed.
The conical nature of the cone causes a compression and accelera-
tion of the rising column of gases and the upward velocity or accelera-
tion of the particles occurs at an increasing rate as they rise in the
cone. This acceleration causes an increasing vertical separation in
space between the particles and therefore reduces the tendency for the
particles to contact each other until the coating has become nontac~y.
It i~ this region of the cone that is thus called the "drying zone".
When the compressed gases and entrained particles pass upwardly
out of the upper end of the cone, they expand into the larger area of
the upper portion of the first hollow column and thus decelerate to a
velocity too low to suspend the particles. This is the deceleration
zone, where further drying takes place, and the particles then fall by
gravity action to the annular bed where they gradually move down, also
due to gravity, until they are pulled into the coating zone again. This
recycling or recirculation continues until, based on previous experiments,
a sufficient coating has been applied.
; The atomized spray is turned off, and the gas or air entraining
flow may be shut down or may be increased to drive the coated particles
into the uppermost region of the first hollow column, as for collection
in the manner illustrated in Fig. 4. Any other suitable manner of
30 unloading the finally coated particles may also be used.
A c~ating apparatus having the design characteristics essentially
as shown in Fig. 1, and having a diameter of eight (8) inches across the
- 24 -
~4~
lower end and four (4) inches across the upper end of the truncated hol-
low cone, is charged with twenty-five (25) pounds of generally spherlcal
pellets of animal feed supplement. The pellets are composed of 90~
methionine and 10~ binders. The average diameter of the spherical pellets
is about 3 millimeter. About 250 standard cubic feet per minute of air
at about 7 p.s.i.g. is admitted to the plenum chamber 20. This air
causes a circulation of pellets through the truncated hollow cone 14,
and the height of the cone above the support screen 32 is adjusted to
obtain a pellet flow rate such that all the pellets in the annular storage
zone move through the cone about once every minute. A coating solution
i8 pumped through the spray nozzle 34 at the same time as 5 SCFM of
atomizing air at 40 p.s.i.g. is supplied to the nozzle. The pumping
rate is ad~usted to pump one (1) pound of solution per minute. The
apparatus ls operated for about 45 minutes. The product is a pellet
core coated with about a 2-mil layer of the polymer.
If the gases flowing upwardly around the aerodynamic structure
could be seen as a series of layers of molecules, merely for sake of
dlscussion, it is thought that there is an insignificant flow of molecules
or layer or so cf molecules along the interior wall surface of the
; 20 second hollow column. By "insignificant" is meant that such layer or
layers of molecules will not perfcrm any supporting function of the
particles in the annular bed.
Moving, therefore, radially inwardly from the interior wall
surface of the second hollow, the more significant layers of molecules
are caused to bend toward the gas shaping or aerodynamic structure, the
innermost adhering to the surface of that structure as they pass upwardly
through the "orifice" region. This adherence of the molecules to the
surface of the aerodynamic structure may be favorably compared to the
"teapot effect", which is a low-speed form of the "Coanda effect". When
water is poured slowly from a glass, it tends to stick to the side of
the glass in the same way that tea sticks to the spout of a teapot.
Hlgh speed fluids behave similarly and adhere to a surface of suitable
- 25 -
shape.
As the rlsing molecules flow over the surface of the aerodynamic
structure after having passed the "orifice" region, previously mentioned,
at some polnt along the upper surface of the aerodynamic structure the
opposing character of the annular flow forces the molecules upwardly
away from the upper surface as well as the ad~acent molecule layers. A
partial vacuum is created above the aerodynamic structure due to the
high speed upward flow of gases, causing an inward bending of the upwardly
moving molecules.
In the apparatus herein described, the particles move down in
the annular bed by gravity without any "dancing" occurring, and are
drawn into the upwardly flowing gases by the partial vacuum. Thus, any
attrition that might occur is greatly minimized, and the overall opera-
tion is much more efficient.
In reference to Fig. 2 in which a modification is disclosed, the
same reference numbers will be used to identify similar elements previously
described, except that they will be primed to show that it is a different
embodiment under discussion.
Fig. 2 represents an embodiment wherein the size of the coating
apparatus 10' has been increased in order to handle larger batch loads
of particles for coating treatment. It has been found that it is more
practical to add an additional gas shaping or aerodynamic structure or
an annular airfoil 50 instead of increasing the size of the aerodynamic
structure 30'. In this manner, larger amounts of upwardly flowing gas
or air may be supplied undiminished or unobstructed by a larger aero-
dynamic structure, and the annular airfoil serves to supplement the com-
pression and focusing action on the upward gas flows so that substantially
all gas flows move through the truncated hollow cone 14'.
Additional or multiple gas shaping or annular airfoils (not
shown) also may be used for still larger coating apparatus. The exact
shape and placement of the airfoils are functions of a number of variables.
The most significant of the variables are size of the apparatus, size of
- 26 -
~he particle to be coated, density of the particle, rate of gas or air
flow and the rate of recirculation of the particles through the coating
zone desired.
In a larger-scale coating apparatus, therefore, one or more
annularly shaped and placed gas shaping or aerodynamic structures or
airfoils, angled or curved, may be provided concentric with and radially
outwardly of the central gas shaping or aerodynamic structure. The
annular airfoils may be attached to the central aerodynamic structure or
to the walls of the coating apparatus by radial struts in such manner as
to exert a minimum deflection of the upwardly flowing gases.
The annular aerodynamic structure is inwardly inclined in the
upward direction so that its inclination lies in a plane extending about
10 to about 45, as measured from the axis perpendicular to the diameter
of the coating apparatus. The inwardly inclined annular structure
provides a surface on which the gas or air impinges for subsequent
shaping and direction upwardly into the truncated hollow cone.
The vertical height of the annular structure may be about
10-50% of the perpendicular cross section diameter of the coating
apparatus.
In reference to Fig. 5, when the annular gas shaping structure
has the configuration of an airfoil havlng at least one curved surface
extending generally in the directlon of gas flow, the overall angle of a
line descrlbed from a point Pl, on the lower rim of the airfoil to a
point, P2, on the upper rim in the vertlcal direction, or perpendicular
to a line whlch is tangent to the upper curved surface of the centrally
disposed aerodynamic structure, ls from about 10 to about 45 inward
facing, as measured from the axls perpendicular to the diameter of the
coating apparatus.
The cross-sectional configuration of an annular airfoil in a
plane described from the center of the cross-sectional area of the coating
apparatus to a point, Pl, on the lower rim of the airfoil to a point,
P2, in the upper rim of the airfoil is teardrop, or similar to the cross-
- 27 -
sectional shape of a lifting aerodynamic shape, and having the thicker
cross section on the forward part w$th reference to the direction facing
the upwardly flowing ga~es. The thickest part is located about two-
fifths (2/5) to about one-half (1/2) of the height in the vertical
direction. In other words, the height (~1) of the thickest part (T),
or HT is equal to about 2/5 H to about 1/2 H. The thickest cross
cection (T) is from about one-sixth (1/6) to about two-fifths (2/5)
of the height (H) of the airfoil; or T is equal to about 1/6 H to
about 2/5 H.
The size, placement and geometrical configuration of the
annular gas shaping structure are such, therefore, that the upwartly
flowing gases are deflected radially inwardly at an angle from about 10
to about 45 from a direction parallel to the original gas flow.
In reference to Fig. 3, the same reference numbers will be
used to identify similar elements previously described, except that they
will be double-primed to ~,how that it is still another different embodi-
ment under discussion.
Fig. 3 represents an embodiment wherein the size of the coating
apparatus 10" has been increased to the same extent as that disclosed
in the Fig. 2 embodiment. The embodiment in Fig. 3 differs from the
embodiment in Fig. 2 in that the first and second hollow columns are
disclosed as being co-extensive in cross-sectional diameter. In other
words, the coating apparatus is disposed within a single hollow column.
It could also be of smaller size so that only one gas shaping or aero-
dynamic structure 30'' is employed as in Fig. 1, instead of a size
requiring the annular airfoil 50".
The recycling or recirculation in this embodiment is necessarily
faster because the particles are not as readily restrained in the annular
bed region as they would be if there were an inwardly tapered base to
assist in such restraint. Proportionately smaller batch loads may be
used, therefore, since the recirculation of the particles is substantially
continuous with the particles spending very little time in the annular
- 28 -
bed. For this reason, an embodiment of this character is suitable for
special purposes, whlle the embodiments of Fig. 1 and Fig. 2 are deemed
to be of more general use.
In Fig. 4, this embodiment represents one manner of unloading
a coating apparatux, and was briefly mentioned above with respect to one
posslble operation of the embodiment of Fig. 1.
Only the upper portion of a coating apparatus 60 ls shown, and
it could be used for any of the previously described embodiments. A
conduit 62 is installed within the upper portion of the appsratus, as
shown, and a gas or air porous collection bag 64 may be installed at the
remote end of the conduit for collecting the finally coated particles
in the manner already heretofore described.
In any of the embodiments described above, the truncated hollow
cones may be adapted to be adjusted for movement upwardly or downwardly
in a vertical plane. The same may also be accomplished with the aero-
dynamic structure, the annular airfoils and the spray nozzles, as desired
to suit gas or air flows, particle sizes and weights, coating material
consistencies and whatever other controlling factors may be concerned.
The particles or pellets to be coated may be batch-loaded and
treated; or, if deemed advantageous, two or more such coating apparatus
may be arranged in cascaded manner to provide for a continuous coating
operation. Tne inlet for the particles in a cascaded arrangement may be
diposet above the annular storage of one apparatus and the particles
metered in predetermined manner into the annular storage bed, while the
outlet to the next coating apparatus may be disposed on the opposite
side of the annular storage bed and constitute a weir for outflow of
excess coated particles. The inlet may also be disposed for gravity
flow of particles to or into the annular storage bed. It may be desir-
able to provide for different coatings in different apparatus, or provide
supplemental coatings.
. .
Multiple spray nozzles may also be employed, as desired, to
achieve different coating effects.
- 29 -
The examples which follow are submitted for a better understanding
of the invention. While the examples are based on in vitro tests, the
in vitro experiments shown in the examples simulate conditions existing
in ruminants thereby permitting the study of coated pellets without the
use of live animals. lt has been determined by actual in vivo tests
that the testing of pellets in the aqueous media used in the examples,
simulating the environmental conditions of the rumen and abomasum with
reqpect to temperature, pH, etc., provide reliable data concerning the
protection offered by the coatings in the rumen, and releasability of
the coatings in the abomasum. Nutrients such as amino acids and proteins
which may be used in the core material are known to be beneficial to
ruminants when positioned in the intestinal tràct downstrea~ from the
rumen.
The following examples are submitted for a better understanding
of the invention. Generally, pellets are prepared from the nutrients
indicated to a size of between about 8 and 12 sieve size. ~he nutrients
are mixed with conventional additives such as microcrystalline cellulose,
binders, inert consistency ad~usting substances such as water, etc. The
pellets are formed by a conventional pelletizer, dried, sieved, and coated
using a coater as described herein. Upon formation of an imperforate
coating on the pellets, they are tested for resistance to pH conditions
resembling those of the rumen and abomasum by agitating in buffer solutions
of pH 2.9 for 0.5 hours and 5.4 for 24 hours. Recovery and protection
figures cited for active core ingredients herein contain in them all
materials of the original coated pellet that are not completely dissolved
in the pH 2.9 buffer, including any undissolved active ingredient in the
- original core. For the sake of simplicity, abbreviations are used in
the examples as follows:
2M5VP - 2-methyl-5-vinylpyridine
AN - acrylonitrile
Where coating ratios are used, the first number indicates the
number of parts polymer7 the sec~nd number indicates the number of parts
- 30 -
hydrophobic substance, and the third number indicates the number of
parts inert flake material. In Table II, a coating ratio of 70/30/1~,
wherein the flake material is aluminum or graphite, i9 used. In Table I,
25% of the hydrochloride of the lycine.HCl is neutralized using calcium
carbonate. Dimer Acid 1010 ls a trademark for dimer acid marketed by
Emery Industries.
TABLE I
Protection Achieved on Lysine HCl
Pellets with Coating Combinations of 60/40 2M5VP/AN
CoPolymer, Dimer Acid 1010 and Aluminum Powder
Example Coating Combination % % Recovered From
No Ratio Coating pH 2.9 pH 5.4
1 70/20/10 18.8 24.3 83.7
2 70/20/20 19.8 23.3 84.2
3 70/20/30 19.8 23.1 88.5
4 70/30/10 20.0 -- 82.9
70/30/20 19.9 -- 89.9
6 70/30/30 21.2 17.6 90.3
7 70/30/30 19.1 20.6 79.0
Graphite replaced aluminum in coating combination.
TABLE II
Recovery of Coated Glucose Pellets
ExampleRatio of 2M5VP ~ % Recovered From
No. to AN Coating pH 2.9 pH 5.4
8 85/15 15.6 12.8 87.7
9 80/20 17.8 20.8 95.5
75/25 16.2 14.5 95.2
11 70/30 16.6 13.3 88.8
12 60/40 16.2 12.2 92.3
. . .
13 50/50 16.7 10.4 80.8
Table III compares results obtained using actual abomasal and
duodenal fluid extracted from a ruminant wlth artificial test fluid. In
this table, the polymeric material used is an 80/20 copolymer of 2-methyl-
5-vinylpyridine and st~rene (I.V. = 1.23). The core material is 90.9~
:
- 3~ -
il~?~
methionine, 3.6% sodium carboxymethyl cellulose and 5.5X sucrose. The
pellets are made by first dry mixing 500 g. of methionine, 20 g. sucrose
and 10 g. sodium carboxymethyl cellulose. Water (135 g.) is added and mixed
to obtain an extrudable wet powder. The mixture is extruded and chopped
to obtain pellets to pass 8 mesh screen and remain on 12 mesh. Ten grams
sucrose ant 10 g. sodium carboxymethyl cellulose are dry mixed, and added
to the wet pellets. The pellets are then tumbled to obtain a uniform
coating. Tumbling is continued in hot air to obtain dry pellets.
The coatings are made using the ingredients indicated dissolved
or quspended in acetone at 5% solids level. An air suspension coater is
used to coat the pellets.
In the examples, the coating comprises 31.5% polymer, 3.5% stearic
acid, and aluminum flake and talc as indicated. Ten percent coating,
based on the weight of the core, is used. pH of the abomasum simulated
fluid is 2.9. pH of the rumen simulated fluid is 5.4. Release is measured
after one hour periods.
; 30
- 32 -
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~ ne invention therefore provides a pellet adapted for oral
administration to a ruminant comprising a core material beneficial to
the ruminant postruminallyl and a coating surrounding said core material,
said coating comprising
a) a film-forming polymeric material containing at least
one basic amino grouping and in which the nitrogen
content is from 3 to 14% by weight of the total molecular
weight of the polymeric material, said polymeric material
comprising at least one polymer, copolymer or blend of
polymers selected from the group consisting of cellulose
propionate morpholinobutyrate, aromatic basic amino-
containing polymers, dialkylamino etbyl acrylates and
methacrylates in which the alkyl group contains from 1
to 6 carbon atoms, condensation polyesters and polyamides,
b) from about 2 to 50%, based on the weight of said polymeric
material, of a hydrophobic material dispersed in said
polymeric material selected from the group consisting of
waxes, resins, polymers, fatty acids having from 12 to
32 carbon atoms, aluminum salts of fatty acids having
from 12 to 32 carbon atoms, and polyfunctional carboxylic
acids having a ratio of from 10 to 22 carbon atoms per
carboxyl group and a molecular weight of from 400 to
1000, and
c) from about 10 to 200%, based on the weight of said
polymeric material, of a physiologically acceptable flake
material dispersed in said polymeric material,
and said coating making up about 5 to about 50% of the weight of said
pellet, and having a sticking temperature of at least about 50C.
~ne fluid used to simulate environmental conditions of the
30 rumen (at pH 5.5) is prepared by mixing 11.397 grams of sodium acetate
witb 1.322 grams of acetic acid and diluting this mixture with de-
mineralized water to I liter.
L~
4~37
~ ne fluid used to simulate environmental conditions of the
abomasum (at pH 2.9) is prepared by mixing 7.505 grams glycine with
5.85 grams sodium chloride and diluting tbis mixture with deminerali2ed
water to I liter. Eighnt parts of this solution are mixed with 2 parts
of 0.1 normal hydrochloric acid for the test fluid.
~ ne fluids are found to give reliable results in testing the
pellets, according to similar experiments using actual rumen and abomasal
fluid withdrawn from a ruminant.
Unless otherwise specified, all ratios, percentages, etc.,
are by weight.
To be useful and practical as a feed for ruminants, it is
considered that at least 60% and preferably at least 75% of the active
ingredients of the core of the pellets to which this invention relates
should be stable in the rumen and release in the abomasum.
The invention has been described in detail with particular
reference to preferred embodiments thereof, but it will be understood
that variations and modifications can be effected within the spirit and
scope of the invention.
- 34a -
