Note: Descriptions are shown in the official language in which they were submitted.
CA 02495360 1994-02-14
30734-57D
COPOLYMERS OF POLYASPARTIC ACID AND POLYCARBOXYLIC ACIDS AND POLYAMINES
This is a divisional application of copending application 2,183,068, filed
February 14, 1994.
FIELD OF THE INVENT10N
This invention relates to a process for the production of copolymers of
pdysuccinimide, their
conversion to salts of copolymers of pdyaspartic acid and the use d these
materials.
BACKGROUND OF THE INVENTION
Polyaspartic acid is a peptide chain in which amide linkages extend the chain.
In the thermal
polymerization of aspartic acid, the stereochemistry of the aspartic acid is
racemized and the formation
of both a and (3 carboxylic acid groups have the ability to react to form such
amide bonds. Such
materials have bean used for fertilizers and scale inhibition agents. They are
particularly useful for the
prevention of scale deposition in borer water, reverse osmosis membranes,
detergents and as inhib'ttors
of dental tartar and plaque formation (tartar barrier agents). These materials
are readily biodegradable.
Methods for the. preparation of pdyaspartk: ~~Cid have been developed (See
U.S. Patent Nos, 5,057,592
and 4,839,461 ) .
Biodegradabl0ty, calcium ion exchange ability and the disruption of calcium
salt crystal structure
are important properties of materialsused in the prevention of scale
deposition in boier water, on
reverse osmosis membranes, in detergent use and as inhibitors of dental tartar
and plaque formation
(tartar barrier agents). We searched for economically useful materials, having
a greater retention on
the object wherein inhibition of scale deposition is desired. Other desirable
properties were greater
stability to biodegradation in addition to intrinsic value for the prevention
of scale deposition in boiler
water, on reverse osmosis membranes, during detergent use and as inhibitors of
dental tartar arui plaque
formation (tartar barrier agents). We have found that the addition of
polycarboxylic acids in the thermal
polymerization of malefic acid or aspartic acid produced novel and highly
effective copolymers which
possessed these properties.
DESCRIPTION OF RELATED ART
A number of methods of preparaYron of polyaspartic acid are disclosed in the
I'tterature and other
patents, however, no mention is made of methods of preparation of copdymers of
polysuccinimide and
polycarboxyfic acids which may then be converted to copolymers of pdyaspartic
acid and
polycarboxylic acids.
SUMMARY OF THE INVENTION
Copolymers of polysuccinimide were prepared by reacting malefic acid, ammonia,
and a
polycarboxylic acid at temperatures greater than 120° C. These
copolymers could be converted to
copolymers of polyaspartic acid by addition of a hydroxide.
In a second embodiment of the invention, copolymers of polysuccinimide were
prepared by
reacting malefic acid, ammonia, a polycarboxylic acid and a polyamine at
temperatures greater than
l2fl C. These copolymers could be converted to copolymers of poiyaspartic acid
by addition of a
hydroxide.
This invention provides a means of preparing copolymers of polysuccinimide.
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CA 02495360 1994-02-14
Further, this invention provides a means of preparing
copolymers of polyaspartic acid. This invention also
provides novel compositions which are useful for the
inhibition of salt deposition, especially bivalent metal
salts, whether in water treatment, detergent addition, oral
health care or cosmetic formulation. This invention also
provides novel compositions which may be further reacted to
provide useful compounds for water treatment, cosmetics,
oral health care and detergents.
In specific aspects, the invention provides:
A process for the preparation of a copolymer of
polyaspartic acid, comprising reacting malefic acid, a
polycarboxylic acid and ammonia, at a temperature of from
120 to 350°C, and converting the resultant polymer into a
salt by adding a hydroxide.
A process for the preparation of a copolymer of
polyaspartic acid, comprising reacting malefic acid, a
polycarboxylic acid, ammonia and a polyamine, at a
temperature of from 120 to 350°C, and converting the
resultant polymer into a salt by adding a hydroxide, wherein
the polyamine has at least two or more primary or secondary
amines available for reaction.
A copolymer of polyaspartic acid with a
polycarboxylic acid.
A polymer produced by polymerizing malefic acid,
ammonia, a polycarboxylic acid and a polyamine, wherein the
polyamine has at least two or more primary or secondary
amines available for reaction.
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CA 02495360 1994-02-14
A process for the preparation of a copolymer of
polysuccinimide, comprising reacting malefic acid, a
polycarboxylic acid and ammonia at a temperature of from 120
to 350°C .
A process for the preparation of a copolymer of
polysuccinimide, comprising reacting malefic acid, a
polycarboxylic acid, ammonia and a polyamine at a
temperature of from 120 to 350°C, wherein the polyamine has
at least two or more primary or secondary amines available
for reaction.
A copolymer of polysuccinimide and a
polycarboxylic acid.
A copolymer of polysuccinimide, a polycarboxylic
acid and a polyamine, wherein the polyamine has at least two
or more primary or secondary amines available for reaction.
Use of a copolymer of polyaspartic acid and a
polycarboxylic acid for preventing deposition of tartar on
teeth.
Use, for preventing deposition of tartar on teeth,
of a copolymer of polyaspartic acid, a polycarboxylic acid,
and a polyamine, wherein the polyamine has at least two or
more primary or secondary amines available for reaction.
A method of preventing deposition of scale from
mineral containing water, comprising the addition of an
effective amount of a copolymer of polyaspartic acid with a
polycarboxylic acid to the water.
A method of preventing deposition of scale from
mineral containing water, comprising the addition of an
effective amount of a copolymer of polyaspartic acid, a
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CA 02495360 1994-02-14
polycarboxylic acid, and a polyamine, wherein the polyamine
has at least two or more primary or secondary amines
available for reaction.
DETAI7~ED DESCRIPTION OF THE E1~ODIMENTS
Copolymers of polyaspartic acid which are suitable
for the inhibition of scale deposition may be obtained by
reacting malefic acid, an additional polycarboxylic acid and
ammonia in a stoichiometric excess, at 120°-350°C.,
preferably 180°-300°C., and then converting the copolymer of
polysuccinimide formed to a salt of a copolymer of
polyaspartic acid by hydrolysis with a hydroxide.
In a second embodiment, copolymers of polyaspartic
acid which are suitable for the inhibition of scale
deposition may be obtained by reacting malefic acid, an
additional polycarboxylic acid, ammonia in a stoichiometric
excess, and a compound having 2 or more primary or secondary
amine groups per molecule, at 120°-350°C., preferably
180°-
300°C., and then converting the copolymer of polysuccinimide
formed to a salt of a copolymer of polyaspartic acid by
hydrolysis with a hydroxide.
The reaction is carried out first by the addition
of water to malefic anhydride, thus forming malefic acid, or
to malefic acid itself, and the polycarboxylic acid, followed
by addition of the appropriate amount of ammonia in the form
of gaseous ammonia or as its aqueous solution. At this
point, the polyamine may be added to either of these
alternative embodiments. This solution is then heated to
remove water. As water is removed, the mixture becomes a
solid and then a melt of the mixture is formed. Water
removal continues as the reaction proceeds and the
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temperature is brought to 120°-300°C. When the theoretical
quantity of water formed in the production of the copolymer
of polysuccinimide has been removed, which, depending on the
temperature, may occur in even less than 5 minutes, the
reaction mixture is allowed to cool. Typically, it may take
over 4 hours at 120°C, whereas it may take less than 5
minutes at 300°C. The copolymer of polysuccinimide formed
can be used to make other novel and useful products by
reactions such as those described in U.S. Patent 4,363,797
or U.S. Patent 3,486,380, wherein useful derivatives for
cosmetic use are described. The copolymers of
polysuccinimide can also undergo alkaline hydrolysis to
provide the appropriate salt of a copolymer of polyaspartic
acid. Further manipulation to remove the water or the salts
can be carried out to provide water free powders of the
salts or the free acid.
The polyamines which may be used to produce these
copolymers of this invention are amines which have at least
two or more primary or secondary amines available for
reaction. Preferred polyamines have at least two primary
amine groups. The concentration may range from greater than
0 to 500, however, the preferred range is greater than 0 to
30a.
Any aliphatic or aromatic polycarboxylic acid may
be used in this invention, but the preferred
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acids are adipic acid, citric acid, fumaric acid, malic acid, malonic acid,
succinic acid, glutaric acid,
oxalic acid, pimelic acid, itaconic acid, nonanedioic acid, dodecanedioic
acid, octanedioic acid,
isophthalic, terpMhalic and phthalic acid. The concentration may range from
greater than 0 to 5096,
however, the preferred range is grater than 0 to 3096.
The hydroxides useful in converting the copolymers of polysuccinimide formed
above to
copolymers of polyaspartic acid indude, but are not limited to, the alkali and
alkaline earth metals and
ammonia, examples of which as their rations are, Na+, K", Mg+, l.i*, and Ca++,
2n++, ~++, Co++, Fe++,
Fe'+, and NI~+.
Polysuccinimide is the amide form of pdyaspartic acid and is also known as
anhydropolyaspartic
acid.
The term'succinimide' is understood in the art to indude many of the p~ !e,
amide and amidine
species which are also°formed by this reaction. The predominant product
ho; . . . 3r is sucdnimide and
this term is used to refer to the thermally polymerized reaction pr~-~~!ct of
malefic acid and ammonia or
a polyamine. The polyaspartic moieties formed by hydrolysis of the
polysuccinimides formed would be
principally a and Q aspartates.
The copolymers of pdyaspartic acid provided by the present invention are
advar>tageous for
inhibition of scale depos'ttion in water treatment, as detergent additives, in
oral health care or in cosmetic
formulation. Solutions of the salts of copolymers of polyaspartic acid formed
in this manner have
excellent scale inhibition performance. Salts which may be inhibited are the
salts a. Mg, Ca, Sr, Ba, and
Ra. The carbonate, sulfate and phosphate salts are those in which greatest
inhibition is shown.
The following examples are by way of ~iustration and not by way of limitation.
EXAMPLE 1
Preparation of a polyaspartic acid/citric acid copolymer.
A slurry of 19.6 g (0.2 mole) malefic anhydride was dissolved in 40 ml water
at 8CP-9,~ C. and
4.2 g (0.02 moles) of citric acid monohydrate (Formula weight 210) was added
and the mixture was
stirred until all solids were in solution, after which the mixture was allowed
to cool to 25° C. To this
solution at 2S C. was added 60 g of 3096 aqueous solution of ammonium
hydroxide (0.44 mol NFi3).
This solution was evaporated to dryness over a period of 8 minutes. The solid
was then heated at 235°-
24~ C. for 5 minutes, removed from the heat, allowed to cool and broken up
w'tth a spatula. The solid
was then heated at 23~ -24~ C. for a second 10 minute period, removed from the
heat, allowed to cool
and broken up w'tth a spatula. Finally, the solid was heated at 23S -24~ C.
for a third 10 minute period,
removed from the heat and allowed to cool to room temperature. The resulting
water insoluble
copolymer of polysuccinimide and citric acid (21.7 g) was slurried in 29.1 ml
of water and a solution of
8.0 g of sodium hydroxide in 12 ml of water was added over 5 minutes. The
solution was stirred for 10-
20 minutes to give a clear red-brown solution of a copolymer of polyaspartic
acid and citric acid.
EXAMPLE 2
Preparation of a polyaspartic acid/succinic acid copolymer.
A slurry of 19.6 g (0.2 mole) malefic anhydride was dissolved in 40 ml water
at 8CP -95° C. and
2 g (0.02 moles) of succinic anhydride (Formt~a weight 100) was added and the
mixture was stirred until
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all solids were in solution, after which the mixture was allowed to cool to 2S
C. To this solution at 25°
C. was added 60 g of 30% aqueous solution of ammonium hydroxide (0.44 and N1-
h). This solution was
evaporated to dryness over a period of 8 minutes. The soUd was then heated at
235' -245° C. for 5
minutes, removed from the heat, allowed to cool and broken up with a spatula.
The solid was then
heated at 235° -245° C. for a second 10 minute period, removed
from the heat, allowed to cod and
broken up with a spatula. Finally, the solid was heated at 235°-
245° C. for a third 10 minute period,
removed from the heat and allowed to cool to room temperature. The resulting
water insoluble
copolymer of polysuccinimide and succinic acid (21.9 g) was scurried in 29.1
ml of water and a solution
of 8.0 g of sodium hydroxide in 12 ml of water was added over 5 minutes. The
solution was stirred for
10-20 minutes to give a dear red-brown solution of a copolymer of polyaspartic
acid and succinic acid.
EXAMPLE 3
~recipital~n assay for calcium sulfate.
The material to be tested as an inhibitor of scale fom~ation was added in
appropriate quantities
to a solution of 5 ml of calcium chloride sdutions (21.6 g/L of CaCh dihydrate
and 41.4 g/L of NaG)
and 5 ml of sulfate solution (20.9 g/L of NalS04 and 41.4 g NaG). The mixttue
was then placed in an
oven at 16ff F for 3 hours. Finally the mbdure was f~tered through Whatman ~2
paper and dried at
16~ F for 8 hours, after which the weight of predp'rtate was determined.
The polycarboxylic add/polyaspartic acid copolymers were tested in the above
assay. The
results are given below in Table t.
Table 1
compound polycarboxylic weight of precipitate
(mg)
acid
blank
44
polyacrylate, 5000 molecular weight 46
copolymer polyaspartate/citrate citric acid 16
copolymer polyaspartate/succinate succinic acid 13
The copolymers of pdyaspartic acid and polycarboxylic acids were very
effective agents for the
inhibition of mineral scale.
EXAMPLE 4
Calcium oxalate titration.
A 0.25 g sample of the sodium salt of the polyaspartic/c'ttric acid copolymer
prepared in
Example 1 was placed in a beaker with 100 ml of deionized water and 1 ml of
396 sodium oxalate was
added. The solution was titrated w'tth 0.1 mol of calcium chloride till the
slurry turned white.
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and 8.1 mi while a poiyaspartic acid prepared from diammonium maleate required
8.3 and 8.5 ml. This
shows that pdycarboxylic acid copdymers of pdyaspartic acid are effective
calcium chelators.
EXAMPLE 5
Preparation of a polyaspartic/citric acid copolymer with a polyamine
A solution of 2.1 g (0.01 mdes) of citric add monohydrate (Formula weight 210)
and 0.32 g
(.0028 moles) hexanediamine was added to 19.6 g (0.2 mote) maleic anhydride
which had been
dissolved in 40 ml water at 8a° -95° C., and finally 30 g of
3096 aqueous solution of ammonium hydroxide
(0.22 and NH,~ ) was added. This sdution was evaporated to dryness over a
period of 30 minutes. The
slid was then heated at 19~ -220° C. for 10 minutes, removed from the
heat, allowed to cool and broken
up w'tth a spatula. The slid was then heated at 230° -24~ C. for 10
minutes, removed from the heat,
allowed to cool and broken up with a spatula. Finally, the sdid was heated at
230' -24~ C. for 10-15
minutes, removed from the heat and allowed to cool to room temperature. The
~i~.g ~Tiat3r irsdu4fe
pdymer was slurried in 40.0 ml of water and a sdution of 8.0 g of sodium
hydroxide in 12 ml of water
was added over 5 minutes. The sdution was stirred for 10-20 minutes to give a
dear red-brown
solution, pH 10-11.0 of a copolymer of pdyaspartic acid, dtric add and
hexanediamine. The tests for
CaSO, , Example 3, and CaC03 (below) were run and the rest~t are recorded in
Table 2.
Inhibition of calcium carbonate precipitation by the calcium drat assay.
J
this assay a supersaturated solution of calcium carbonate is formed by adding
29.1 ml of 0.55
M NaCI and 0.01 M KG to 0.15 mi of 1.0 M CaCh and 0.3 ml of 0.5 M NaHCOj. The
reaction is in'ttiated
by adjusting the pH to 7.5,8.0 by titration with 1 N NaOH and addition of the
material to be tested for
inhibition of CaC03 precip'ttation at a level of 1.7 ppm. At three minutes, 10
mg of CaC03 is added and
the pH is recorded. The decrease in pH is directly correlated to the amount of
CaC03 that precipitates.
TABLE 2
Sample CaS04 CaC03
ppt Drift
. (mg) (pH units)
none 84 ,72
copdymer 74 .26
These assays indicate that the copdymer of Example 5 is effective in
prevention of CaS04 and
CaC03 scale.
The following examples will serve to illustrate the tartar barrier
compositions of this inventi~~
Copolymers of Examples 1, 2 and 5 are suitable tartar barrier agents.
Humectants are materials s~.,:~
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CA 02495360 1994-02-14
as glycerol, Foaming agents are suitable surfactants. Sweetening agents may be
normal or artificial
sweeteners. Common abrasives are materials like fumed silica. Gelling agents
are polymers which are
used to prepare thickened solutions.
EXAMPLE A - Mouthwash%w/w
Tartar barrier agent 0.5-2
humectant 6.0
foaming agent 1.0
sweetener 0.3
deionized water q.s. to 100
flavors i .0
EXAMPLE B -Abrasive
Dentrrfic~s Ge1
Tartar barrier agent 2-10
detergent 1.5
i5 humectant 10.0
sweetener 0.2
deionized water q.s. to 100
flavors 1.0
abrasive 55.0
gelling agent 2.0
EXAMPLE C - Chewing gum
Tartar barrier agent 1.0-11
Gum base 21.3
sugar 48.5-58.5
corn syrup 18.2
flavors 1
It will be apparent to those skilled in the art that the examples and
embodiments described
herein are by way of illustration and not of limitation, and that other
examples may be utilized without
departing from the spirit and scope of the present invention, as set forth in
the appended claims.
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