Note: Descriptions are shown in the official language in which they were submitted.
~.~ 2 2 7.Q.3 .. . . ...
HIGH-CARBONATE AUTOMATIC DISHWASHING DETERGENT
WITH DECREASED CALCIUM SALT DEPOSITION
1. Field of the Invention
The invention relates to machine ware washing compositions,
and particularly to such compositions having high levels of
alkali-metal carbonate as essentially the only builder.
2. Description of Related Art
Automatic dishwashing detergents (AD~Ds) typically include a
variety of specialized components for specific purposes during
the multi-step wash cycle. Surfactants may be present for
detergency and/or as rinse aids. Silicates act to provide
alkalinity and to prevent corrosion. Bleaches are often
included for oxidizing power. Abrasives may be included to
provide scouring action. Builders are important to improve
washing performance, and must be selected to avoid
precipitation of calcium salts on wares. Typically,
silica~es, carbonates, phosphates or mi~tures thereof are
employed as builders. For ware washing applications, the
builder materials may provide alkalinity and bufering
capacity, prevent flocculation, maintain ionic strength,
e~tract metals from soils and remove alkaline-earth metal ions
from washing solutions. Phosphates are e~tremely effecti~e in
these applications, however, there is a relatively high cost
associated with their use. Additionally, phosphates are
disfavored owing to their eutrophication effect on lakes and
streams, and may be requlated in some states. Silicates are
not preferre~ because~they are costly, and at the generally
high levels required~ are potentially toxic. High levels of
alkali-metal carbonates have been found to be very effective
.
in ware washing applications, and have proven to be superior
in performance to phosphates in the removal of starchy soils,
one of the principal soils found on tablewares. A drawback
associated with such high carbonate levels, however, is that
~22~3
.. . . . . . . . ... ... . . . .......
calcium ions pres~nt in the washing water re~dily form
precipitates with the carbonates. Various approaches have
been employed to combat the formation of calcium
precipitates. Complexing agents such as zeo'~i~es can be added
and can be effective at removing calcium. These have limited
use in ware washing compositions, however, as these zeolites
are substantially insoluble, and may th~msel~es deposit on
tablewares. Polymeric sequestering agents such as
polyacrylates and polyether carboxylates can also be employed,
but since these also act to comple~ the calc~u~, generally
high levels are required. Sequestering and co~ple~ing agents
tend to be e~pensive, adding significantly ts .he o~erall
cost. Schroe~er, DE 3001937, discloses a granular ADWD with
50-70% sodium carbonate, a poly (alpha-hydro~y acrylic acid),
phosphonate threshold inhibitors and alkyl p~osphate esters.
~ecker et al, GB 1536136, describes a laundry detergent
including a phosphonic or polyacrylic acid s~questrant, a
protective colloid and a maximum of 30% phosphate builder,
with an optional carbonate builder.
Unsubstituted polyacxylic acids used with 20-6G~ sodium
carhonate are described in US ~579455 issued to Saba~elli and
US 3627686 issued to ~ag~. ~ g~ and Sabat~ use
relatively high le~els of N1~A and he~ametaphosp~ate,
respectively, to compleæ calcium. US 4539144, ~o de Ridder e~
al describes ADWD-s with no or low phosphates a~ with 5-50% of
a sequestrant, 0.05-5% of poly (maleic acid) a~ may have a
sodium carbonate ~uilder. how molecular weigh~ polyacrylates
without other chelating agents are used to i~hi~it calcium
carbonate deposition by ADWDs in Chakrabarti, ~S 4203858.
In EP 266904 5Frankena3 sodium carbonate is co~ined with
polyacrylate, phosphonates, and a dipicolinic acid comple~ing
agent. Similarly, in US 3850852 issued to Neillie e~ al
sodium carbonate can be combined with polyacry}ates,
phosphonates, and a calcium sequestering agent.
~3227 ~3 -
--3--
US 4687592 to Collins et al describes carbonate, polyacrylate,
phosphonates, and a calcium sequestering agent which is an
ether polycarbo~ylate and comprises a major part of the
formula. The polyacrylate is added to disperse soils and the
phosphonate is added to chelate iron and manganese.
Phosphonates and polyacrylates are also mentioned as possible
co-builders in GB 2194546 to ~3~em et al and US 4588515 to
Schuh et al. In both patents, STPP is the preferred builder.
13 Generally, high carbonate deter~ents are not preferred in the
art. When high carbonate levels are used, relatively high
levels of comple2ing agents are used to prevent the formation
of calcium carbonate precipitates. Often the complexing
agents themselves offset any advantages gained by use of
1~ carbonates as builders.
In view on the art, there remains a need for an alkali-metal
carbonate based ware washing composit;on which prevents the
deposition of calcium salts by inhibiting the formation of
2~ calcium precipitates, rather than by sequestering or
comple~ing.
It is therefore an object of the pres~nt invention to provide
a high carbonate ware washing composit:ion having acceptably
low levels of calcium precipitates.
It is another object of the present invention to provide a
war~ washing composition which is superior in performance in
removing starchy soils.
3E
It is another object of the present invention to provide a
highly effective dishwashing detergent which avoids the use of
potentially to~ic materials.
3~ It is another object of the present invention to provide a
ware washing composition which does not utilize high levels o
phosphate builders.
~322~ ~3
. . .
.,
It is yet another object of the present in~ention to provide a
highly cost-effective detexgent composition.
SIJMMARY OF THE PRESENT INV~`~TION
In one embodiment, the invention comprises a dry granular
automatic dishwashing detergent consisting of:
(a) an alkali-metal carbonate;
(b) a alkali-metal silicate;
(c) an inhibitor system; and
(e) a low-oaming sur~actant
Optionally, a halogen or peroxygen bleaching species can be
included for o~idizing power.
The automatic dishwash detergent of the present invention is
primarily comprised of sodium or potassium carbonates and
silicates, low levels of an inhibition system comprising a low
molecular weight polycarboxyl;c acid and a threshold
inhibition agent, and a low foaming surfactant. Polymers and
copolymers of acrylic and methacrylic acids with weight
average molecular weights between 1,000 and 10,000 are t~e
preferred polycarbo~ylic acids. Suitable threshold inhibition
agents (TIAs) include monomeric phosphonate-containing organic
2~ compounds, inorganic oligomeric phosphates, and mi~tures
thereo~. Preferred TIAs include pol~phosphonates such as the
Monsanto Company's trademarked DEQUEST series, phosphonated
polycarboæylic acids such as Mobay Chemi~als trademarked
BAYHIBIT series, and phosphonocarboxylic acids~ No other
calcium compleging agents or builders such as sodium
tripolyphosphate present in the datergent.
.. . ~
It is therefore an advantage of the present invention that
high levels of phosphates are avoided~
It is another advantage of the composition of the present
invention that the carhonate bu;lder provides superior starchy
soil removal without appreciable precipitation of calcium
salts
132~3 : ` -
- -
,
It is a further advantage of the present invention that t~e
composition is more cost-effective than other builder systems.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Al~ali-Metal Carbonate
The alkali-metal carbonate is the primary and preferably the
only builder material of the composition of the present
1~ invention. Alkali-metal carbonates, sesquicarbonates and
bicarbonates are suitable, and preferred are sodium and/or
potassium carbonates. At least about 30%, preferably 40%,
most preferably 60% car~onate is needed. As used herein
unless otherwise stated all percentages are weight
1~ percenta~es. Higher levels of carbonates will function,
however, at levels greater than about 80% there is
insuf~icient room for the other ingredients which contrib~te
to the overall e~fectiveness of the composition. The
carbonate acts as a builder to remove calcium and additio~ally
2Q provides alkalinity and aids in soil removal. At the high
le~els disclosed herein, the alkali-me~tal carbonate provi~es
superior starchy soil removal comparecl to other builders such
as phosphates.
Al~ali-Metal Sili~a~
.
One component of the present invention is an alkali-metal
silicate, specifically one haYing the formula:
M2O~Sio2)n where M represents an alkali-metal, and n i5
3Q between about 1 and 4. Preferred alkali-metal silicates are
sodium, potassium and lithium silicates, with sodium silica~P
being the mo~t yreferred, and with a preferred n value of
2.0-2.4. A most preferrPd ma~imum value for n is about 3.2 in
order to minimize i~soluble silicates during stora~e~ It is
3S further prefer~ed that at least about 10% of the ~otal
silicates have an n ~alue of greater than about 1.6 to impart
suitable anti-corrosive properties. E~amples of other
suitable silicates include sodium or potassium orthosilicates
and m~tasilicates. As used hereinafter, the term ~silicate~
1~2~
6 :-
will be taken to mean any of these alkali-metal silicates,
individually or combined.
Mixtures of any of the foregoing alkali-metal silicates are
also suitable. The alkali-metal silicate is present in an
amount of from about 2% to 30%, preferably about 5% to 10%. A
minimum of about ~% silicate is necessary to provide ade~uate
corrosion resistance~ Preferred commercially available sodium
silicates are sold by the Philadelphia Quartz Corporation
under the Trademarks RU, as a 47~ solution, and D, as a 94.1
solution. In addition to their anti-corrosive effects, the
silicates provide alkalinity and serve as granulatiny aids to
increase particle size of the agglomerates. Sodium silicates
are known to be very effective at cleaning, especially when
used on oil ancl grease stains.
Inhibito~ ~ystem
The inh~bitor system, comprising a polycarboxylic acid, or
salt, in conjunction with low levels of a threshold inhibition
agent, acts to inhibit significant calcium precipitates,
resulting in aesthetically pleasing tablewares. A preferred
polycarboxylic acid is a polyacrylic or polymethacrylic acid
homopolymer. Copolymers such as acrylic/maleic and
a~rylic/hydro~yacrylic acids also function well. A pref0rred
weight a~erage molecular weight range is about 1000-10,000
g/mole, more preferred is about 2000-5000 g/mole. The weight
average molecular weight range for acrylic/maleic acid
copolymers is about 5000-50,000 ~/mole, depending on the
amount o~ maleic acid present.
lt is preferred to add the polycarbo~ylic acid in fully
neutralized form, e.g. as a sodium or potassium salt, however,
the acid form is equally effective în preventing the
deposition of calcium salts. It is noted that for the purpose
of the present invention the acid orms are eguivalent to the
salt forms e~cept where the acid has limited solub;lity. It
is also no~ed that except where esplicitly stated or implie~
11 32~7~3
--7--
from the conte~t, the acid and salt forms are used
interchangeably. It is further noted that if added as salt,
the required weight percentage range will be higher than that
of the acid, owing to the presence of the counterion. For
example about a 30% greater weight percentage of sodium
polyacrylate is needed compared to the acid form. An e~ample
of a commercial source of the polycarbo~ylic acids is the Rohm
and Haas Company's ACRYSOL polyacrylates. Preferred are
ACRYSOL LMW-20N and LMW-45N, fully neutralized polyacrylic
acids, sodium salts, having weight average molecular weights
of about 2,000 and 4,500 g/mole, xespectively. About 0.1-10%
polycarboxylic acid is present, preferably a~out 3-8~. Higher
levels of polycarbo~ylic can be added, but they do not appear
to correspondingly improve inhibition o~ calcium precipitates.
The other component of the inhibitor system is the threshold
inhibition agent, (TIA), which at low levels, i.e. about 0.1-5
percent, synergistically acts with the polycarbo~ylate to
prevent the formation of calcium precipitates on wares washed
with the composition. Suitable threshold inhibition agents
include monomeric phosphonate conta-ining organic compounds,
inorganic oligomeric phosphates, and mi~tures thereof.
Specific e~amples of the foregoing include poly
phosphonates/carboxylates of mono-, di-, and tri- alkylamines
having at least one phosphonate group; l-hydro~yethylidene-1,
l-diphosphonic acid (HEDP); aminotri-(methylenephosphonic
acid) (ATMP); sodium he~ametaphosphate (SHMP);
2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC);
-phosphonohydro~y acetic acid, similar compounds, and mi~tures
thereof. TIAs are most preferably HEDP, ATMP, S~MP, PBTC,
similar compounds, and mi~tures thereof. A preferred level
for TIA is about 0.1-3.5%, and more preferred is 0.3-2.0%.
The TIA generally should be kept at low levels for to minimize
the amount of phosphorous in the system and to minimize cost.
Two percent TIA corresponds to a level in the wash (assuming
10 L of wash water) of about 60 ppm. Generally, increasing
TIA levels in the main wash above about 60 ppm does not yield
a
*Trade Mark
~.
' -8~
.~ ~
corresponding increase in effectiveness, thus the lower levels
are more cost-effective. Finally, if too much phosphonate is
present, it can form a precipitate with calcium. The
TIA/polymer system is effective at preventing observable
calcium precipitates on wares in waters having hardness levels
at least to about 400 ppm. The TIA may be added as an acid,
or as salt, such as sodium or potassium. The inhibitor syste.
is added at a level necessary to inhibit the precipitation of
calcium salts on the wares. The exact level will vary with
water hardness and type of polycarboxylic acid and TIA. It is
noted that generally, increasing the level of polycarboxylic
acid allows for a decrease in the level of TIA, and vice
versa. It is again noted that the acid and salt forms are
equivalent e~cept where the acid has limited solubility. It
is also again noted that the foregoing TIA weight percentage
ranges are based on the acid forms; more may be required if
salts are used.
Low Foamin~ Surfactant
~0
A low-foaming surfactant is included t:o provide detergency
during the wash phase of the machine wash cycle, and to
promote ~sheeting" during rinse, i.e. uniform runoff of the
rinse water. The surfactant further acts to emulsify oily
soils and suspends solids to prevent their redeposition.
Since machine dishwashers utilize the mechanical effects of
water sprays to remove a significant amount of solids, the
surfactant must not produce foams, which impair this
- mechanical cleaning action. Preferably the surfactant will
reduce or inhibit foams which are produced by food soils.
Preferre~ su~factants~are nonionics, especially Cl 4
alko~ylated aliphatic alcohols and Cl 4 alko~ylated alkyl
phenolsO Particularly preferred are ethoxylatedfpropo2ylated
C8 1~ alcohols. There should be at laast about ten alko~y
groups per alcohol, preferably at least about twenty.
E~amples of pre~erred etho~ylatedfpropoxylated aliphatic
~ ~ 2 ~
g , . - ......
alcohols are ~ASF Corporation's txademarked INDUSTROL, and
PLURAFAC. Certain Cl 4 alkylene o~ide copolymers such as
ethylene o~ide/propylene o~ide copolymers are also preferred
as surfactants. These are e~emplified by BASF's trademarked
PLUP~ONIC series. Optionally, the terminal hydro~yls of any of
the foregoing can be replaced by an ether, e.g. a Cl 4 alkyl
or a benzyl ether, or by a halogen, to further reduce
foaming. Other suitable surfactants are disclosed in US
4306987 and 4272394 both issued to Xaneko and assigned to BASF
Wayandotte Corporation.
It is also within the scope of the invention herein to utilize
a miæture of surfactants all of which may not be low-foaming
as long as the mi~ture is low-foaming by, e.g. including a
foam suppressant such as monostearyl phosphate or other
materials as known in the art. As used hereinafter,
"low-foaming suractant" will be taken to mean an individual
low-foaming surfactant, or a mi2ture of two or more
surfactants, or surfactants and foam suppressants, yielding
low foaming. The surfactant is added at a level of about 0-10
percent, preferably about 1-5 percent.
O~tional Incredients
Various adjuncts can be added, as known in the art. ~xamples
incIude ragrances, dyes or pigments, enzymes such as
proteasPs, lipases and amylases, additional corrosion
inhibitors, etc. Water may be present up to about 15%, and
can be present as frPe water or as water of hydration of the
inorganic salts such as sodium carbonate. Some water may be
deliberatbly-added as.a filler. Additionally, filler
materials include inorganic salts such as sodium or potassium
sulfates, nitrates, borates and chlorides, and organic
materials like sugars.
"..
3_ 3 2 2 ~ S~ :
1 0- . - . . - .. . .. ' .. ,,; ... .... .
It may be desirahle to adjust the pH of the wash water by
including an electrolyte/buffer. Generally, these are
al~ali-metal inorganic acid salts, hydro~ides or oxides~ It
may also be suitable to use such materials as aluminates and
organic materials, such as gluconates, citrates, succinates,
maleates, and their alkali metal salts. The electrolyte/
buffer should maintain the wash pH range ~ithin a range of
bet~een about 8.0 to 13.0, more preferably about 9.0 to 12Ø
Sodium hydroxide is preferred as it does not interact
adversely with a~y other ingredients, and is very cost
effective. It is noted that the silicates and carbonates can
also act to keep the wash pH range within the desired limits.
The a~ount of electrolyte/buffer added solely for purposes of
buffering can vary from about 0% to 10%.
A particularly preferred adjunct is a bleach, which may be
selected ~rom various halogen, pero~ide or peracid bleaches.
The bleach can remove organic stains, aids in soil removal and
helps to prevent spotting and filming. Most bleaches, in
fact, perform well in the relatively high temperatures
associated with automatic dishwashersO E~amples of halogen
bleaches include the alkali metal and alkaline earth salts of
hypohalite, haloamines, haloimines, haloimides and
haloamides. All of these are believecl to produce hypohalous
bleaching species in situ. Hypochlorite and compounds
producing hypochlorite in aqueous solution are preferred,
although hypobromite is also suitable. Representative
hypochlorite-producing compounds include sodium, potassium,
lithium and calcium hypochlorite, chlorinated trisodium
phosphate, potassium and sodium dicholoroisocyanurate,
trichlorocyanuric acid, and their hydrates. Also suitable are
hydantoins, such as dibromo and dichloro dimethyl-hydantoin,
chlorobromodimethyl hydantoin, N-chlorosulfamide (haloamide),
chloramine (haloamine), N-brominated and N-chlorinated
3; succi~imide, malonimide, pthalimide and napthalimide.
Pero2ygen bleaches also are e~fective. Sodium perborate is a
particularly useful bleach source, and may be formulated as a
mono- or tetra- hydrate. Preferred pero2ygen bleaches are
. .
.
~ 3~7~ :
. --11-- ........ . . .......... :
.!
available in solid form and include sodium percarbonate,
sodium perborate, sodium phosphate peroxyhydrate, potassium
permonosulfates and metal peroxides. ~leach activators, also
known as peracid precursors can be included with the pero~ygen
S compounds. E~amples of activators include tetraacetyl
ethylenediamine (TAED~, and nonanoylo~y benzene-
sulfonate (NOBS). Peracid bleaches (includ ng monoperacids
and diperacids) may be advantageous in terms of bleaching
performance. Suitable peracid bleaching species include
C8_12 alkyl peracids, especially perazelaic and diperazelaic
acids, diperoxydodecanedioic acid (D~DDA), and alkyl
monoperoxysuccinic acid. Peracid bleaching species, and a
method for their production, are described in U. S. patent
4,337,213 issued June 29, 1982 to Mar~nowski et al.
DPDDA is particularly preferred for use in the composition of
the present invention as it is relatively storage stable and
produces desirable bleaching results. If added, the bleach is
present in an amount suEficient to provide effective bleaching,
e.g., from about 0 to 10% by weight active, more preferably
~rom about 0.05 to 5% by weight active and most preferably
from about 1 to 3% by weight active depending on the bleaching
species chosen.
The dishwashing detergent composition is prepared by any means
known in the art to yield a dry, ~ree-flowing granular
mi~ture, such as agglomeration or spray drying. Agglomeration
is pre~erred. An O'~rien rotary drum agglomerator was used in
the following agglomeration e~ample. Sodium carbonate and
sodium sulfate filler (if desired) is initially charged to the
agglomerator. Three liguid additions are made during each
bateh. Spray rates and atomizing air pressures can be set for
each liquid addition to suit desired finished product
properties. The first liguid to be sprayed is the low-foaming
surfactant, sprayed at a rate of 0.5 pounds/min. The second
liquid addition is a preblend consisting of the TIA, pol~ner,
and sodium hydroxide, and is applied at a preferred rate of
1.0 pound~min. The final liquid addition is sodium silicate,
?~
~`;
~27~
-12- -
~hich can be applied at ambient or el~vated temperature, and
at a rate of 1.0 pound~min. The product may be dried~
conditioned at the completion of the agglomeration. Static
drying, fluid bed drying, and rotary drum conditioning may all
be applied. Static drying typically oonsists of holding the
agglomerated product at 140F for 24 hours, while fluid bed
drying may be performed for 30 minutes at 140F. Finished
product densities range between 0.6g~cm3 to 1.0 g/cm3. An
e~ample formula is shown below.
E~ample I
Inqredient Wt.% Active
lS Alkali metal carbonate 30~80
Low-foaming surfactant 0-10
Bleaching agent 0-10
Alkali metal silicate (SiO2/M20 = 2-3) 5-30
Filler (sulfate, chloride, nitrate salts) 0-50
~o Polycarboxylic acid 0.1-10
TIA 0.1-5
Water 0-15
EXPERIMENTAL RESULTS
The various soils of TABLES I-IV were tested, generally, by
the procedure of cooking the soil, applying it to dishes or
glasses, and allowing it to cool and dry. Thus, the oatmeal
~ an~ starch soils were prepared in accordance wi~h their
package directions and/or intended use, spread onto plates,
and allowed to dry. Milk and pudding soils were cooked into
beakers, àn~ allowed to dry. Soil removal was visually
~raded, against photographic standards, on a scale of 1 to 10,
with 10 being complete removal of soil. All soil remo~al
evaluations herein were performed after one wash cycle.
~ ~ 2 ~
Machine dishwashing filming and spotting evaluated in Tables
I-IV was measured ~y ASTM Tentative Method D3556-76T (CSMA
DCC-05) !
To summarize, clean glass tumblers are
loaded into an automatic dishwasher, along with 4 plates, each
soiled with lOg of a standard soil comprising powdered nonfat
milk, margarine, and a cereal solution. Thirty grams of
detergent was added to the closed cup for release in the main
wash. Typically, the main wash utilizes 7-12 liters of water,
which dissolves the detergent. The wares were washed in the
dishwasher for 5 cycles, with the soils and detergent renewed
after each cycle. The tumblers were rated visually in a light
box, on a 5 point scale, ~or ~ilming and spotting. The
results were scored as follows:
Ratina Spottinq Filmina
l glass spotless no film
2 spots at random barely perceptible
3 l/4 of glass covered slight film
with spots
4 l/2 of glass covered moderate film
with spots
glass completely covered heavy film
with spots
TABLE I compares soil removal of three builders: sodium
carbonate of the present invention, sodium citrate and an
acrylic/maleic copolymer. The effect of high carbonate levels
on various soils is advantageously shown herein. All formulas
have 7.5% sodium silicate (SiO2/Na2O = 2.4), 4% low-foaming
surfactant (an ethoxylated/propoxylated C~ aliphatic
alcohol), 1% sodium dichloroiscocyanurate, and water. Wash
conditions included 30 grams of detergent added to the main
wash, 120F wash water having a 12S ppm water hardness (as
CaCO3; Ca~Mg = 3).
- ~3~-~7~ :
-14~ - . .
.. ,,1
TABLE I. SOIL REMOVAL OF NO-PHOSPHATE BUILDERS
Wt.%
_________________________
SodiumAcrylic/maleic~l)
E~ample Na2C3 Citrate Copolymer
1 75.0 0.0 0.0
2 0.0 75.0 0.0
3 0.0 0.0 75.0
37-5 37~5 0.0
37.5 0.0 37.5
6 ~.0 37.~ 37.S
. Visual Grade
._________________________________________
E~ample Starch Oatmaal Milk ~uddiny Average
1 4.08.3 5.84.8 5.7
2 0.95.4 3.53.3 3.3
3 1.05.7 3.32.3 3.1
4 4.6~7.3 4.23.7 s.o
~.67.5 3.94.~ 4.5
6 0.55.1 3.73.3 3.2
LSD95 1.71.2 1.52.0 0.8
- tl) SOKALAN CP-5P, a trademarked procuct of by BASF
Corporation, which is a sodium salt of an
acrylate/maleate copolymer, with a weight average
~olecular wei.~ht about 70,000.
Tables IIA-B illustrate the beneficial absence of spotting/
filming on wares washed with the composition herein. The
effects of polycarboxylate and TIA on inhibition of calcium
precipitation was measured by evaluating spotting and filming
on g~assware washed with two compositions of the present
~ 3 ~ ~ r~ ~ 3
-15- -
invention. The compositions included Na2CO3 ~68% in the
composition of IIA and 60% in that of II-B), 8% sodium
silicate (SiO2/Na2O = 2.4), 4% low-foaming surfactant, 2%
sodium dichloroiscocyanurate, with the remainder waterO The
Table II-B composition also included about 1.4-11.9C~
Na2SO~ filler, and 0.5% NaOH. Wash conditions were 30
grams of detergent added to the main wash, and 140~F wash
water, with the hardness as indicated in each Table. The
glasses were graded a~ter 5 cycles using the ASTM D3556-76T
method.
T~BLE II-A EFFECT OF INHIBITOR SYSTEM ON SPOTTI~G A~D FILMING
IN 100 PPM HARDNESS WATER
15 Weight Percent Active Visual Grades
______________________________ _____________
Sodium
Example Polyacrylate(l) Na5PBTC(2) Spots Film
1 1.87 0.21 2.2 4.1
2 10.57 0.21 2.3 2.6
3 1.87 1.21 2.4 2.4
4 .10.57 1.21 2.1 2.7
0.Q0 C.71 2.1 3.1
6 12.44 ` 0.71 2.2 2.8
7 6.22 0.00 2.0 4.6
8 ~.22 1.43 2.9 2.4
9 ~.22 0.71 2.3 3.4
Con~ro~(3) 1.9 2.6
LSDgs 0.8 1.1
.. .
(1) Weight a~erage molecular weight of about 2000 g~mole.
(2~ Na5PBTC = Pentasodium 2-phosphonobutane~1,2,4-
3S tricarboxylate.
(3) As CASC~DE detergent, a trademarked product of the Procter
& Gamble Co., having 8.3% phosphorus.
~ 3 2 2 7
-~6~
TABLE II-B EFFECT OF INHIBITOR SYSTEM ON SPOTTING A~D FILMING
IN ~00 PPM HARDNESS WATER
Weight Percent Active Visual Grades
__________________~___~ ______ ___________ _
Sodium
E~amplePolyacrylate(l) Na5PBTC(2) Spots Film
1.50 ~.86 2.5 3.8
11 g.oo 0.86 2.8 3.~
1~ 1.50 1.64 2.4 3.1
13 9.00 1.64 2.0 2.9
14 0.00 1.25 3.1 4.1
10.50 1.25 1.7 3.5
16 5.25 0.71 1.9 3.4
17 5.25 1.78 2.0 3.1
18 5.25 1.25 2.1 ~.1
Control(3) 1.5 2.2
0.3 o.g
(1) Weight average molecular weight oi. ahout 2000 g/mole.
(2) Na~PBTC = Pentasodium 2-phosphonobutane-1,2,4-
tricarboxylate.5 (3) As CASCADE detergent, a trademarked product of the Procter
~ Gamble Co., having ~.3~ phosphorus.
A comparison of e~amples 1-4 shows that both polymer and TIA
are effective in reducins filming. Some TIA is, however,
necessary to inhibit film formation, as shown by e~ample 7,
with no TIA. E~ample 5 with no polymer, in 100 ppm hardness
water, resulted in a spotting grade of 2.1, not significantly
diferent from the control at the g~% confidence level. With
harder water, howe~er, the absence of polymer results in
pronounced spotting, as seen in e~ample 14. The polymer hus
is of greater importance in harder water.
~ ~ 2 ~ i ~ 3 ~:
-17- - ~
Table III shows ~.~e performance benefit tha~ the high
carbonate levels have on soil removal, with particular
emphasis on starch and pudding soil removal, co~.pared to a
phosphorus-containing formula of the art. Also shown is the
added soil removal benefit imparted by the polyacrylate of
Formula C on starchy soil removal.
Table IV demonstrates the great difference in spotting/filming
made by the inclusion of the inhibitor system of the present
invention. Formula B, with no inhibitor system, resulted in
spotting and filming grades of more than five, a wholly
unacceptable result from a commercial viewpoint. Formula C of
the present invention yielded very good results, with the
aggregate scores of Formula C being about equal to those of
Formula A, a prior art phosphorus formulation.
TABLE IV. EFFECT OF INHIBITOR SYSTE~ ON SPOTTING AND FILMING
Weight Percent Active
Formula
Ingredient A B C
_~_~~______________________~___________________________
STPP 35,00 0 0
Sodium Carbonate 20.00 7~.00 75.00
Sodium Sulfate 13.00 1.00 1~00
Sodium Silicate 12.23 8.00 B.00
(SiO2/Na2O = 2-4)
Low-foam Surfactant4.00 4.00 4.00
Sodium
Dichlo~isocyanurate 2.00 2.00 2.00
Sodium Polyacrylate 0 0 4.40
~MW = 2730~
TIA 0 0 0.67
Wates 13.77 10.00 4.93
~322~
-1-8- . ~ .. . ..
. ~
Table III shows the effects of polycarboxylates and TIA's on
washing efficacy with respect to four types of soils. Wash
conditions include 30g of detergent added to the main wash,
120F wash water and 125 ppm hardness ~Ca~Mg = 3).
TABLE III. EFFECT OF INHIBITOR SYSTEM ON SOIL REMOVAL
Weight Percent Active
Formula
Ingredient A B C
_____________________~_______________________________
STPP 35.
Sodium Carbonate 20.00 67.87 67.87
15 Sodium Sulfate 13.00 0 0
Sodium Silicate 12.23 8.00 8.00
(SiO2/Na2O = 2.4)
Low-foam Surfactant(l) 4.00 4.00 4.00
Sodium 2.00 2.00 2.00
Dichloroisocyanurate
Sodium Polyacrylate 0 0 6.16
~MW = 2000)
TIA(2) 0 0 0.71
Water 13.7718.:13 11.~6
Soil Visual Grades
LSD95
Starch 0.9 2.1 3.2 1.0
-Oatmeal 8.5 7.9 8.3 0.9
30 Milk 6.7 7.9 7.4 1.3
Pudding 4.8 5.B 7.1 1.5
... .
A~erage 5.2 6.2 6.5 0.8
Formula A - phosphorus-contain;ng formula as control
Formula B = high carbonate without inhi~itor system
Formula C = present invent;on
(1) Etho~ylated/propoxylated Cg aliphatic alcohol
~2) Pentasodium 2-phosphonobutane-1,2,4-tricarbo~ylate
~2~
-19- .
.. . .. .. . . .. . .. .. .. ....
Visual Grades (LSD95 = 0 . 8)
Spotting 2.0 5(a) 3.0
Filming . 3.7 5( ) 2.5
Formula A = phosphorus-containing composition as control
Formula B = high carbonate without inhibitor system
Formula C = present invention
(1) Ethoxylated/propoxylated Ca aliphatic alcohol
(2) 2-Phosphonobutane-1,2,4-tricarboxylate
~a) completely coated with calcium precipitates
Tables V-VII illustrate the eff~ctiveness of the inhibitor
system of the present invention as measured by turbidity of
the detergent solutions. Turbidities were measured using a
Hach 2100A turbidimeter, 30 minutes after detergent and hard
water solutions were mixed to give 30 g of detergent in 7 L o~
water with hardnesses as indicated below. Results are shown
in Nephelometric Turbidity Units (NTU).
V. SYNERGISM BETWEEN POLYMERS AND PHO5PHONATES
Polymer Phosphonate
~ -- Turbidity
. Example wt% Type wt% Type NTU
______________________________________________,________________
1 0 0.20 PBTC 160
- 2 0 0.20 HEDP 215
3 0 ~ . 33 PBTC 80
4 0 3 . 4 0 HEDP 65
- 1~52 acrylic acid 0 85
6 1.52 acrylic acid 0.33 PBTC 50
7 1.52 acrylic acid 0.34 HEDP 55
8 1.52 acrylic acid 0.33 SHMP 60
Control(l) 20
~L~2~7:~
-20- -~
HEDP = l-Hydro~yethylidene-l,l-diphosphonic acid
PBTC = 2-Phosphonobutane-1,2,4-tricarboxylic acid
SHMP = Sodium hexametaphosphate
~1) Formula A, containing phosphorus
The formulas of Table V contain about 75% sodium carbonate, 8%
sodium silicate (SiO2/Na20 = 2.4); 4% low-foaming
surfactant, 2% dichloroisocyanurate, and water. The acrylic
acid polymer had a weight average molecular weight of 2734
g/mole. Water hardness was 250 ppm as CaC03 (Ca/Mg = 3)~
All solutions were kept at 120F in a heated water bath.
E2amples 1-4 of Table V, without polymer, resulted in
relatively high turbiditi~s, indicating the presence of
calcium precipitates. Example 5, having no TIA, ~imilarly
yielded a high turbidity, while E~amples 6-9 resulted in
acceptably low turbidities.
Table VI shows the effect of various types and amounts of
polycarbo~ylic acid polymer and of TIA on calcium
precipitation in hard (~OOppm) water. Generally, lower
turbidities reflect fewer calcium precipitates.
; VI. EFFECT OF INHIBITOR SYSTEM AND CARBONATE LE~ELS ON
TURBIDITY
Na2C3 Polymer TIA Turbidity
~ No. wt% wt% wt~ Type NTUQ
_________________________________________ _______________
1 75.~9 AA~ 1.08 PBTC 100
2 75.02.14 AA 0.50 PBTC 115
3 75.02.14 AA 1.57 PBTC 64
4 75.03.43 AA 0.27 PBTC 66
75.03.43 AA 1.08 PBTC 46
6 75.03.43 AA 1.90 PBTC 33
7 75.04.73 ~A 0.25 PBTC 47
u c~
-21~
VI. EFFECT OF INHIBITOR SYSTEM AND CARBONAl- LEVELS ON
TURBIDITY (cont.)
~a2CO~ PolymerTIA Turbidity
No. wt% wt% wt% Type NTU
____________________________ ____________________________
8 75.0 4.73 AA 0.38 PBTC 39
9 75 0 4.73 AA O.50 PBTC 34
1010 75.0 4.73 AA 1.67 PBTC 29
11 75.0 5.26 AA 1.08 PBTC 23
12 75.0 ~.73 AA 1.00 SHMP 36
13 75.0 4.73 AA 3.33 SHMP 31
14 75.0 5.26 AA 2.1? SHML~28
1515 67.9 . 6.17 NaA 0.50 PBTC 20
16 67.9 6.17 NaA 0.50 HEDP 26
17 67.9 6.17 NaA 0.50 ATMP 22
18 67.9 4.01 NaA 0.50 PBTC 34
19 67.9 4.01 NaA 0.80 HEDP 36
2020 67.9 4.01 NaA 0.80 ATMP 34
21 75.0 3.g7 AA* 0.67 PBTC 115
22 75.0 4.29 N~A( ) 0.67 PBTC 64
23 75.0 4.22 NaA( ) 0.67 PBTC 93
24 75.0 4.17 NaA(3) 0.67 PBTC 110
2525 75.0 4.17 NaA~MA~4) 0.67 PBTC 80
26 75.0 4.17 NaA/NaM(5) 0.67 PBTC 93
27 75.0 4.17 NaA/NaM(6~ 0.67 PBTC 94
28 75.0 4.17 ~aMA( ) 0.67 PBTC 97
- 29 75.0 ~.17 NaM~(8) 0.67 PBTC 85
3~30 75.0 4.17 MVE/MA O.67 PBTC 99
31 Control(l0) ~4
,. . ~
ATMP = Aminotri(methylene phosphonic acid)
HEDP = l-Hydro~yethylidene-l,l diphosphonic acid
PBTC = 2-Phosphonobutane-1,2,4-tricarbo~ylic acid
SHMP = Sodium hexametapho~phate
AA = Acrylic Acid, MW = 2,000 g/mole
AA* - Acrylic Acid, MW ~ 1~000 g~mole
~22~
-22-
NaA = Sodium acrylate, MW = 4,500 g/mole
MA - Methylacrylate
NaMA = Sodium methacrylate
Na~ = Sodium maleate
- MVE/MA = Methyl vinyl ether/Maleic Acid, MW = 20,000 g/mole
(1~ ~W = 2,100 g~mole
(2) ~W = 5,800 g/mole
(3) MW = 10,000 g~mole
(4) MW = 3,000 g/mole
~! O (5) MW = 20,000 g/mole
(6) MW = 50,000 g/mole
(7) MW = 2,000 g/mole
(8) MW = 4,500 g/mole
P~ (10) Formula A, containing phosphorus
The formulas of Tahle ~I, above, also contain about 8% sodium
silicate (SiO2/Na20 = 2.4), 4% low-foaming surfactant, 2%
dichloroisocyanurate, and water. Water hardness was 900 ppm
as CaC03 (Ca~Mg - 3). All solutions ~were kept at 140F in a
heated water bath.
VII. EFFECT OF POLMER MOLECULAR WEIG:HT ON TURBIDITY
~5 Na2C3 Polymer MW Phosphonate Turbidity
No. Wtfi wt% (g/mole) wt% Type NTU
_________~____________________________________________________
- 1 67.9 6.17 NaA2000 0.50 PBTC 31
3~ 2 67.9 6.10 NaA2100 0.50 PBTC 27
3 67.9 6.17 NaA3680 0.50 PBTC 34
4 67.~` - 6.17 NaA 4500 O.SO PBTC 26
67.9 6.15 NaA5100 0.50 PBTC 26
6 67.9 6.25 NaA5800 0.50 PBTC 28
7 67.9 6.17 NaA20000 0.50 PBTC 47
8 Control(l) 24
(1) Formula A, containing phosphorus
~322~3
-23-
-- - ~ - ... . . . ..
Table VII exemplifies an appropriate molecul~r weight range o.
effectiveness of the polymers herein. It can be seen that
acceptable turbidities result from the use of sodium
polyacrylate with a molecular weight range of about
2000-5800. At a molecular weight of 20,000, however, the
turbidity increases, indicating observable calcium
precipitation.
While described in terms of the presently preferred
embodiments, it is to be understood that such disclosure is
not to be interpreted as limiting. Various modifications and
alterations will no doubt occur to those skilled in the art
after having read the above disclosure. Accordingly, it is
intended that the appended claims be interpreted as covering
all alterations and modifications as fall within the true
spirit and scope of the invention.
.
