Note: Descriptions are shown in the official language in which they were submitted.
~ ~32911 01
-- 1 --
ZERO P~OS?~O~lUS ElEAVY DUTY
LAUNr)RY DET~RGENT COI~OSITION
~ield of the _nvention
The invention pertalns to a solid heavy duty laundry
detergent compGsition having a zero phos~norus content.
More specifically, the in-~ention pertains to a novel heavy
duty detergent compositlon that can so~ten (i.e., treat
divalent or trivalent hardness lons in) servlce water
containing the detersent composition either be.ore or
during deter~ent action.
Much attention has been given in recent years to the
components o. detergen~s that treat or reduce the harmful
effects of water hardness on cleaning compositions and
processes. Hardness ions are typically undesirable in
conjunction with washing deter~ents since they interfere
with the soil removal .~echanism of detergents. Such ions
typically comorise metal ions such as calcium, magnesium,
iron, manganese, and other typically divalent or trivalent
metal cations de?ending on the source of service water used
in the washing environment.
In recent years, the use of e'fective concentrations
of complex phosphates such as sodium tripolyphosphate, and
other sequestrants, in detergents as water softening agents
has come under increasing attack due to environmental
concerns. PhosDhates have been identified as contributing
to excess water eutrophication, a process o.' algae
overgrowth in environmental waters. .~any state governments
have found it desira~le to cause detergent makers to
replace phos~ha~es with components that do not sti~ulate
algae growth. Therefore, some states have legislated that
detergent compositions have a zero ~hosphorus content.
Currently, there are no phosphorus free heavy duty solid
laundry detergent products available in the United States.
Accordingly, a substantial need exists to provide a
solid heavy duty laundry detergent without intentionally
.
1329~01
added phosphates or phosphorus that has the detergency and
water conditioning benefits of phosphorus-containing
detergents without the assoclated environmental harm.
Summarv of the _n ention
We have found an improved solid hea~y duty laundry
detergent composition having a zero phosphorus con~ent that
effectively conditions ser~ice water. The detersent
composition comprises a source of alkalinity, a water-
conditioning copolymer of acrylic acid and itzconic acid,
and a second vinyl pol~mer comprising polyacrylic acid,
polyma1eic acid and copolymers of acrylic acid and maleic
acid and at least one nonionic detergent surfactant.
We have also found a method or making a solid heavy
duty laundry detergent having a zero phosphorus content in
lS which said method avoids gel problems during manufacture oE
the detergen~.
The detergent composition of the invention provides
water conditioning and detergency benefits substantially
comparable to phosphorus-containing detergents wlthout the
accompanying environmental harm. The invention exhibits a
level of sequestrant action substantially equivalent to
condensed phosphate containing `d~é~ergentS. This lével of~
sequestrant action provides an effective ~etergent without
the undesirable side effects of phosphate~ sequestering
25 ~agents.
Detailed Descri~tion of the Invention
The improved solid heavy duty laundry detergent
composition having a zero phosphorus content comprises a
source of alkalinity, a blend of two water conditioning
builder polymers and a nonionic surfactant. The builder
polymer components of the detergent composition~comDrise a
blend of two vinyl polymers having pendant carboxyl groups.
The first builder polymer comprises any vinyl polymer, with
pendent carboxyl groups, having hardness sequestering
; 35 properties. The second~ builder polymer is a different
polymer than the first and comprises a copolymer of acrylic
acid and itaconic acid. The builder components are
,
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combinéd with a source of alkalinity and at least one
nonionic detergent surfactant, preferably a mixed nonionic ~ ;
surfactant system to form the detergent composition.
The vinyl polymer having pendant carboxyl groups is a
builder or water-conditioning agent which can act to
condition wash solutions under end-use conditions and to
reduce the harmful effects of water hardness. This polymer
has an average molecular weight of between about 500 and
about 15,000 and has in its molecular structure the groups
derived from an alpha beta unsaturated mono- or
dicarboxylic acid or anhydride:
~C I - Ctn
H COOH
optionally together with the group derived from a co-
monomer:
3 1 :
tCI ctm
in which Rl is hydrogen or an alkyl group having 1 to 4 :~
carbon atoms; R2 is hydrogen, an alkyl or alkoxy group
having from 1 to 4 carbon atoms, or a carboxylic acid
group; R3 is hydrogen or an alkyl group having l to 4
carbon atoms; and R4 is a hydroxyl group, an alkyl group
having l to 4 carbon atoms, an alkoxy group having 1 to 4
carbon atoms, an aldehyde group, or a carboxylic acid
group.
Specific examples of such a vinyl polymer useful in
the invention include a water-soluble acrylic polymer
including polyacrylic acid, polymethacrylic acid, acrylic
acid-methacrylic acid copolymers, hydrolyzed
1 3 2 ~
- 4 -
polyacrylamide, hydrolyzed polymethacrylamide, hydrolyzed
acrylamidemethacrylamide copolymers, hydrolyzed
polyacrylonitrile, hydrolyzed polymethacrylonitrile,
hydrolyzed acrylonitrile methacrylonitrile copolymers, or
mixtures thereof. Water-soluble salts or partial salts of
these polymers, such as the respective alkali metal (e.g.,
sodium, potassium) or ammonium salts can also be used. The
weight average molecular weight of the polymers is from
about 500 to about 15,000 and is preferably within the
lQ range of from about 750 to about I0,000. Preferred
polymers include polyacrylic acid, the partial sodium salt
of polyacrylic acid or sodium polyacrylate having molecular
weights of about 1,000 to about 6,000. These polymers are
commercially available and methods for their preparation
are well-known in the art.
For example, commercially-available water-conditioning
polyacrylate solutions useful in the present invention
include the sodium polyacrylate solution, Colloid~ 207
(Colloids, Inc., Newark, New Jersey); the polyacrylate acid
solution, Aquatreat~ Ar-602-A ~Alco Chemical Corp.,
Chattanooga, Tennessee); the polyacrylic acid solutions
(50-65~ solids) and the sodium polyacrylate powders (M.W.
2,100 and 6,000) and solutions (45% solids) available as
the Goodright~ K-700 series from B. F. Goodrich Co.; and
the sodium or partial sodium salts of polyacryllc acid
solutions (M.W. 1,000-4,500), available as the ACRYSOL~
series from Rohm and Haas. A specifically preferred
polyacrylic acid useful in the invention is neutralized
polyacrylic acid under the trade name Goodright K-7058N
having a molecular weight of about 4500.
The second polymer is different than the first. We
have found that the combination of any generic carboxylate
polymer with the second itaconic acid/acrylic copolymer
surprisingly produces a water conditioning properly
substantially equivalent to condensed phosphate
sequestrants. The second polymer comprises itaconic acid
and a carboxyl containing acrylic monomer. It has been
:
1329101
found that this ~ar~ cular copolymer is an e:ccellent
calcium ion se~uestering a~ent.
Itaconic acid has the ollowing che~ical structure:
S C.~ 1 2
CH2 -co2~q
and acrylic acid has the rollowing cnemical structure:
O
:: " : ::
~ Cii~2=C~-C-OH
~ ,
The itaconic acid - acrylic acid co~olymer e.~ployed in
the composition of the invention can have a weight average
molecular ~eight of about 1,500 to 100,000, preferably
about 12,000 to ~0,0~0. This copolymer can be pcepared by
conventional methods o~ polymerization well-known to those
skilled in the art. The weight ratio of itaconic acid to
acrylic acid is from about 0.5 to 2.0:1, preferably about 1
to 2~
The source~ or alkalinity is selected from the group
consisting o alkali metal hydroxides, such as sodium
hydroxide, potassium hydroxide, or mixtures of each
thereof. ~Alkali metaL siliaates, such ;as~ sodium
metasilicate, may also be used. The ~preferred source of
alkalinity, whiah is the mos~ cost effective, is
commercially aYailable sodium ~ hydroxide, which can be
obtained in aqu~eous solutions at a concentration oE about
50 wt-% and in a~variet~ of solid~forms of~varying particle ;
sizes. Thel sodium hydroxide can be emplo~ed in the
invention in either liquid or~solid form (powdered, beads,
or pellets), or a mixture~of both.
3S Other sources of alkalinity useful include,~but are
not limited to, the following~i alkali metal carbonates,
; alkali metal blcarbonates, alkali metal sesquicarbonates,
~ alkali metal borates, and alkali me.al silicate. The
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carbonate and borate forms are typically used in place of
alkali metal hydroxide when a lower p~ is desired.
Silicates (Na2O:SiO2 compounds) which are typically a
reaction product between sodium hydroxide and silica, have
a variety of Na2O:SiO2 reaction molar ratios. Silicates
are primarily used as alkalies and as builders in both
warewashing and laundry formulations.
A nonionic surfactant may be employed, either alone or
in combination with other nonionic surfactants. A
surfactant is a chemical compound with a
hydrophobe/hydrophile balance suitable as a wetting agent,
defoamer and emulsifier. Typically, surfactants are
nonionic organic surface-active polymers having hydrophobic
groups, blocks or chains and hydrophilic ester groups,
blocks, units or chains. The hydrophobicity can be
provided by an oleophilic portion of the molecule, such as
an aromatic alkyl or aralkyl group, an oxypropylene unit or
oxypropylene chain, or other oxyalkylene functional groups
other than oxyethylene, e.g. tetramethylene oxide. The
hydrophilicity can be provided with oxyethylene units,
chains or blocks and/or ester groups (e.g. organo-phosphate
esters), salt-type groups, or salt-forming groups. This
class of synthetic detergents may be produced by the
condensation of alkylene oxide groups (hydrophilic in
nature) with an organic hydrophobic compound, which may be
aliphatic or alkyl aromatic in nature. The length of the
hydrophilic or polyoxyalkylene radical which is condensed
with any particular hydrophilic group can be readily
adjusted to yield a water soluble or dispersible compound
having the desired degree of balance between hydrophilic
and hydrophobic elements.
Nonionic synthetic surfactants suitable in the present
invention include the polyethylene oxide condensates of
alkyl phenols, the products derived from the condensation
of ethylene oxide with the reaction product of propylene
oxide and ethylene diamine, the condensation product of
aliphatic fatty alcohols with ethylene oxide as well as
~ ~L 3 2 ~
amine oxides and phosphine oxides, and the products derived
from the condensation of ethylene oxide with the reaction
product of propylene oxide and propylene glycol.
Preferred nonionic surfactants are the ethoxylated
S alkylphenols, such as nonylphenol ethoxylate. It has been
found that a blend of a first nonylphenol ethoxylate (NPE)
having a mole ratio of ethylene-oxide to nonylphenol of 9 -
lO:l and a second nonylphenol ethoxylate (NPE) having a
mole ratio of ethylene-oxide to nonylphenol of
6 - 7:1 provides improved detergent action and allows for a
broader range of cleaning temperature (120 F.-160 F.).
This mixed nonionic surfactant system is particularly
useful in the invention, with the first NPE and the second
NPE having a weight average molecular weight of about
600 to 700 and 450 to 550, respectively.
By the term "zero phosphorus" we mean no intentionally
added phosphorus containing substrates such as condensed
phosphates. Minute concentrations of phosphates may be
present as a result of impurities or other non-inte~tional
additions~
The detergent composition of the invention can be made
in any physical form, such as a cast solid, powder,
granulates, pellets, or a liquid slurry. The cast solid is
formed by pouring the detergent in its molten state into a
cast or mold, and allowed to solidify. The detergent
composition also contains soft water and can have various
additives such as fabric brighteners, fabric softeners,
dyes, and fragrances.
Thus, the laundry detergent composition of the present
invention comprises about 10 - 50%, preferably about 35 -
45%, of a source of alkalinity; about~ 5 - 30%, preferably
about 15 - 25%, of a water-conditioning vinyl polymer with
pendant carboxyl groups, having a molecular weight of about
500-15lO00, preferably about 4,000 - 6,000; about 2 - 20~,
preferably about 5 - 10%, of a water-conditioning copolymer
of acrylic acid and itaconic acid, having a molecular
weight of about 500 - 15,000, pre~erably about 10,000 -
11 3 ~
-- 8
12,000; and about 8 - 18% of at least one nonionic
surfactant, preferably about 0 - 15% of a mixed nonionic
surfactant system having a molecular weight of about
40Q - 900, preferably about 450 - 700.
~ preferred source of alkalinity would be about 20 -
40% of sodium hydroxide beads and about 20 - 35% of 50 wt-~
aqueous sodium hydroxide. The preferred vinyl polymer is
neutralized polyacrylic acid which avoids gelling problems
during manufacture of the detergent. The term
"neutralized" means that the pH of the polyacrylic acid is
about 5.0 - lOØ The detergent composition further
comprises about 25 - 30~ of water.
The present detergent composition may be readily
prepared by charging an aqueous solution of an alkali metal
hydroxide into a stainless steel mixing vessel having a
recirculation line and pump, then agitating and heating the
solution. The nonionic surfactant is then added into the
vessel, followed by the copolymer of acrylic acid and
itaconic acid. Fabric softener, dye, and soft water are
added next. Beads of alkali metal hydroxide are next
added, followed by a vinyl po~ymer such as polyacrylic
acid. After thoroughly mixing and cooling, the composition
is passed through a screen and packaged.
The present invention is particularly suited for use
in heavy duty institutional laundering. The term "heavy
duty" refers to the ability of a detergent composition to
clean various articles such as sheets, pillowcases,
blankets, towels, etc. The service water employed in the
laundering process dissolves the detergent composition to
form an aqueous wash solution that is at a temperature of
about 100 - 160 F. The wash solution is then contacted
with a soiled article for a period of time effective to
clean the soiled article.
The invention will be further described by reference
to the following detailed examples and test results which
include a best mode.
Example I
~ 132~01
g
A stainless steel mixing vessel was charged with 111.2
g of 50 wt-~ aqueous sodium hydroxide, agitation W2S
started and the batch was heated to 130-140 F. The
nonylphenol ethoxylates (~PE 9.5, 36.0 g and ~PE 6.5 19.2
g] were then added to the vessel and batch temperature was
maintained. The coDolymer of acryll acld and itaconic
acid ~28.0 g) was ne~t added slowly to ~aintain the
temperature in the 170-190 F. range. A fabric brightener
rluoresing agent (TinGpal*C3S 0.3 g) was ne.~t added slowly
to insure maxlmum dlspersion. A dye (Sanogran ~lue 2GLS,
.0048 g) was pre-~et wlth a small a~ount of soft water
(part of a 5.2952 g portion of water) before being added to
~the vessel. The remaining portlon of soft water was then
charged into the vessel. Sodium hydroxide beads (120 g)
were next added slowly to the vessel and the batch
temperature was maintained between 155-165 P. Neutralized
polyacrylic acid (180 g~ was next charged into the vessel
slowly to prevent gelling. The batch was allowed to mix
from 15-20 minutes and then cooled to 130-140 F. for
packaging.
The final weight-~ of the active ingredients of
Example I are summarized in Table I.
Examples II-VII
Table I summarizes the composition of additional soIid
detergents that were prepared by the method of the
lnvention.
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While the invention has been described and fully
explained in the detailed description of the specification
and preferred embodiments, many embodiments of the
5 invention can be made without departing from the spirit and ~ :
scope of the invention.
