Note: Descriptions are shown in the official language in which they were submitted.
/ 20279'~5
SULFOBENZOYL END-CAPPED ESTER OLIGOMERS USEFUL
AS SOIL RELEASE AGENTS IN GRANULAR DETERGENT COMPOSITIONS
TECHNICAL FIELD
The present invention relates to oligomeric or low molecul~r
weight polymeric ester compositions which are substantially
amorphous in form and which are useful as soil release agents in
granular laundry detergent compositions.
BACKGROUNO OF THE INVENTION
A substantial proportion of synthetic fabrics now in use are
copolymers of ethylene glycol and terephthalic acid, sold under
5 trade marks which include DACRON, FORTREL, KODEL and the trade
name BLUE C POLYESTER. The removal of oily soil and oily stains from
the surface of such fabrics is well recognized to be technically
difficult to achieve using laundry compositions of the type most
generally accessible to consumers.
Substances which have been suggested for use in consumer
products as soil release agents include polymers which contain
ethylene terephthalate segments randomly interspersed with poly-
ethylene glycol segments. See, for example, U.S. Patent
3,962,152, Nicol et al, issued June 8, 1976. A soil release
polyester of this type, commercially known as MILEASE T ~ is
further disclosed in U.S. Patent 4,116,885, Derstadt et al, issued
September 7, 1978. Other commercial variants are sold as
PERMALOSE~ ZELCON~and ALKARI~ products (see, for example, Canadian
Patent 1,100,262, Becker et al, issued May S, 1981; U.S. Patent
4,238,531, Rudy et al, issued Oecember 9, 1980; and British Patent
Application 2,172,608, Crossin, published September 24, 1986).
Commercial suppliers of soil release polyesters include ICI,
duPont and Alkari~ (formerly Quaker Chemical Co.).
Soil release compositions used in industrial textile treat-
ment applications are well-known. Application of such com-
positions is under controlled conditions and is free from the
~'
2027995
formulation constraints encountered in the detergent arts.
Padding and heat curing, in the absence of high levels of
detergent chemicals, are illustrative of the processes used.
Polyesters have successfully been used for industrial soil release
treatments of polyester surfaces, but recent trends are toward
rather expensive fluorochemical treatments.
The development of economical, product-stable and formu-
lation-compatible soil release agents for consumer product com-
- positions is not straightforward. In contrast with the simple and
controlled environments in which industrial textile treatment
agents are generally used, soil release agents in consumer laundry
products will usually be exposed to various detersive ingredients,
such as anionic surfactants, alkaline builders and the like. Such
chemicals may reduce the effectiveness of soil release agents, for
example, by preventing their deposition on fabrics. The soil
release agents may, reciprocally, reduce the laundry benefits of
detersive ingredients, for example, by interfering with the action
of surfactants, optical brighteners, antistatic agents or
softeners, all of which are commonly present in modern detergent
compositions. In a "thru-the-wash" mode, it is especially
important that no formulation ingredient, including the soil
release agent, should promote the redeposition of suspended soils
in the laundry liquor; this would dull the appearance of the
laundered fabrics.
Arguably, the most difficult of consumer laundry products,
for the purpose of incorporating soil release agents, are granular
detergent compositions. Compatibility requirements of soil
release agents, especially with the alkaline, anionic detergent
environments commonly present in such detergent compositions,
provide a substantial technical challenge. An additional
challenge is incorporating the soil release agents in the appro-
priate physical form for stability and effective delivery to the
laundering solution.
~2 ~) 2 j~ ~ r~9 5
- 3
Novel sulfoaroyl end-capped ester oligomers useful as soil
release agents in detergent compositions and fabric-conditioning
articles are disclosed in European Patent Application 0311342.
Maldonado, Trinh and Gosselink, published April 12, 1989.
The present invention relates to selected soil release agents
of the type disclosed in EPA 0311342, which are substantially
amorphous in form and are especially useful in granular detergent
compositions.
It is an object of the present invention to provide
compositions which can be used as effective and product compatible
soil release agents in granular detergent compositions.
It is a further object of the invention to provide oligomeric
or low molecular weight polymeric esters in a physical (amorphous)
form useful as soil release agents in granular detergent
compositions.
These and other objects are secured herein, as will be seen
from the following disclosure.
SUMMARY OF THE INVENTION
The present invention encompasses oligomeric or low molecular
weight polymeric, substantially linear, sulfobenzoyl end-capped
esters comprising oxy-1,2-alkyleneoxy units and terephthaloyl units,
in a mole ratio of said oxy-1,2-alkyleneoxy units to said
terephthaloyl units ranging from about 2:1 to about 1.1:1.
(Mixtures of such esters with reaction by-products and the like are
particularly useful as fabric soil release agents herein when at
least 50 mole %, preferably at least 60 mole % of the end-capping
groups are sulfobenzoyl groups.) The esters herein are of
relatively low molecular weight (i.e., outside the range of fiber-
forming polyesters), typically with averages ranging from about 650
to about 2,500.
The essential end-capping units herein are anionic
hydrophiles, connected to the esters by means of benzoyl groups.
The anion source is a sulfonated group, i.e., the end-capping units
2027995
are sulfobenzoyl units of the formula (M03S)(C6H4)C(0)-, wherein M
is sodium.
The essential oxy-1,2-alkyleneoxy units of the esters herein
are (a) oxy-1,2-propyleneoxy units of the formula
-OCH(Ra)CH(Rb)0-, wherein Ra and Rb are selected so that in each
of said units, one of said groups is H and the other is CH3, and
(b) oxyethyleneoxy units of the formula -OCH2CH20. The (a) units
are believed to provide a sufficiently unsymmetrical character
required for stability of the desired amorphous physical form,
whereas the (b) units are believed to provide sufficient symmetry
for soil release activity. The required balance between the
unsymmetrical and symmetrical character is obtained when the mole
ratio of units (b) to (a) is in the range from about 15:1 to about
2.5:1.
It is also possible, optionally, to incorporate minor amounts
(e.g. less than 5%, preferably less than 2%, by weight) of
additional hydrophilic units such as di- or tri-(oxyethylene)oxy
units, into the esters.
Thus, esters herein comprise, per mole of said ester,
- 20 i) from about 1 to about 2 moles of sulfobenzoyl endcapping
units of the formula (M03S)(C6H4)C(O)- wherein M is sodium;
ii) from about 2 to about 10 moles of mixtures of
oxy-1,2-propyleneoxy units and oxyethyleneoxy units; and
iii) from about 1 to about 9 moles of terephthaloyl units.
Preferably, not more than about 0.15 mole fraction of said
sulfobenzoyl end-capping units in the esters are in para- form.
Most highly preferred are esters wherein said sulfobenzoyl
end-capping units are essentially in ortho- or meta- form.
Preferred end-capped esters herein are essentially in the doubly
end-capped form, comprising about 2 moles of said sulfobenzoyl
end-capping units per mole of said ester.
The ester "backbone~ of the present compositions, by defini-
tion, comprises all the units other than the end-capping units;
all the units incorporated into the esters being interconnected by
2027~95
means of ester bonds. The ester "backbone" comprises
terephthaloyl units, oxyethyleneoxy units, and oxy-1,2-
propyleneoxy units, the mole ratio of the latter two types of
units ranging from about 15:1 to about 2.5:1.
Preferred compositions provided by the invention comprise
from about 25% to about 100% by weight of ester having the
empirical formula (CAP)X(EG/PG)y(T)z; wherein (CAP) represents the
sodium salt form of said sulfobenzoyl end-capping units i);
(EG/PG) represents said oxyethyleneoxy and oxy-1,2-propyleneoxy
units ii); (T) represents said terephthaloyl units iii); x is from
about 1 to 2; y is from about 2.25 to about 7; z is from about
1.25 to about 6; wherein x, y and z represent the average number
of moles of the corresponding units per mole of said ester. More
preferably, the oxyethyleneoxy:oxy-1,2-propyleneoxy mole ratio
1 ranges from about 3:1 to about 10:1 (more preferably from about
4:1 to about 8:1); x is about 2, y is from about 2.25 to about
5.5, and z is from about 1.25 to about 4.5. Most preferably,
these ester compositions comprise at least 507. by weight of said
ester molecules (oligomers) having average molecular weights
ranging from about 700 to about 2000, preferably from about 800 to
about 1500.
In the process aspect of the invention, the invention encom-
passes the preparation of the aforesaid (CAP)X(EG/PG)y(T)z linear
esters by a process most preferably comprising reacting dimethyl
terephthalate, ethylene glycol, 1,2-propylene glycol and a com-
pound selected from the group consisting of the monosodium salt of
sulfobenzoic acid (or its C1-C4 alkyl carboxylate esters), in the
presence of at least one conventional transesterification
catalyst. The resulting water-soluble or dispersible ester
mixtures are used as fabric soil release materials, the best
results being achieved with, but not being limited to, polyester
fabrics. Another highly preferred ester mixture is provided by a
process which most preferably comprises reacting dimethyl
terephthalate, 1,2-propylene glycol, ethylene glycol and the
2~27995
monosodium salt of sulfobenzoic acid, in the presence of at least
one conventional transesterification catalyst.
All percentages, parts and ratios herein are given, unless
expressly otherwise indicated, on a weight basis.
DETAILED DESCRIPTION OF THE INVENTION
The present invention encompasses ester compositions suitable
for use in ~ranular deter~ent compositions. The esters are
characterized by certain essential end-capping and backbone units,
all in particular proportions and having structural and physical
1 arrangements as described hereinafter.
The esters herein can be simply characterized as oligomers or
relatively low molecular weight polymers which comprise a
substantially linear ester "backbone" and end-capping units which
are sulfobenzoyl. Proper selection of the structural units which
comprise the ester backbone and use of sufficient amounts of the
sulfobenzoyl end-capping units results in the desired soil-release
properties of these materials.
Oliqomeric/PolYmeric Esters - It is to be understood that the
compositions herein are not resinous, high molecular weight,
macromolecular or fiber-forming polyesters, but instead are
relatively low molecular weight and contain species more ap-
propriately described as oligomers rather than as polymers. Ester
compositions herein have average molecular weights ranging from
about 650 to about 2500, preferably from about 800 to about 1500.
Accordingly, the compositions of this invention are referred to as
~oligomeric or polymeric esters~ rather than ~polyester~ in the
colloquially used sense of that term as commonly used to denote
high polymers such as fibrous polyesters.
Molecular GeometrY - The esters of the invention are all
"substantially linear", in the sense that they are not signifi-
cantly branched or crosslinked by virtue of the incorporation into
their structure of units having more than two ester-bond forming
sites. (For a typical example of polyester branching or
crosslinking of the type excluded in defining esters of the
2~99~
present invention, see Sinker et al, U.S. Patent 4,554,328, issued
November 19, 1985.) furthermore, no cyclic esters are essential
for the purposes of the invention, but they may be present in the
compositions at low levels as a result of side-reactions during
ester synthesis- Preferably, cyclic esters will not exceed about
2% by weight of the compositions; most preferably, they will be
entirely absent from the compositions.
Contrasting with the above, the term "substantially linear"
as applied to the esters herein does, however, expressly encompass
materials which contain side-chains which are unreactive in
ester-forming or transesterification reactions. Thus, oxy-1,2-
propyleneoxy units are of an unsymmetrically substituted type
essential in the present invention; their methyl groups do not
constitute what is conventionally regarded as "branching" in
polymer technology (see Odian, Principles of Polymerization,
Wiley, N.Y., 1981, pages 18-19, with which the present definitions
are fully consistent), and are unreactive in ester-forming
reactions.
Molecular Units - The esters of this invention comprise
repeating backbone units, and end-capping units. To briefly
illustrate, molecules of the preferred ester are comprised of
three kinds of essential units, namely
i) sulfobenzoyl end-capping units of the formula
(MO3S)(C6H4)C(O)- wherein M is sodium;
ii) mixtures of oxy-1,2-propyleneoxy units, i.e.,
-OCH(CH3)CH20- or -OCH2CH(CH3)0-, with oxyethyleneoxy units, i.e.,
-OCH2CH20-; and
iii) terephthaloyl units, i.e., -(O)CC6H4C(O)-; note that as
generally used herein, the latter formula is indicative of a
O O
- C ~ C -
unit.
The following structure illustrates a doubly end-capped ester
molecule (termed a "hybrid backbone" ester molecule herein)
20279g~
falling within the foregoin~ embodiments where units ii) are a
mixture of oxyethyleneoxy and oxy-1,2-propyleneoxy units in a 4:1
mole ratio (on average, in ester compositions as a whole in
contrast to individual molecules such as illustrated here, ratios
ranging from about 15:1 to about 2.5, preferably from about 10:1
to about 3:1, more preferably from about 8:1 to about 4:1, are the
most highly preferred):
O O O O O
C-OCH2CH20-C ~ C-OCH2CH20-C ~ C-
O O O O
-OCH2CH20-C ~ C-O-CH(Rl)CH(R2)-0-C ~ C-OCH2CH20-
-c4~
S03Na
In the above structure, Rl and R2 are selected so that Rl or
R2 is randomly -CH3, with the second R group of each
-OCH(R1)CH(R2)0- unit being -H.
It will be seen from the above disclosure that the units
essential for the invention are individually art-recognized.
Despite this fact, the new arrangement of units upon which the
invention is based, leads to ester molecules and ester-containing
compositions exceptionally useful in the field of the present
invention.
In the context of the structures of ester molecules disclosed
herein, it should be recognized that the present invention
encompasses not only the arrangement of units at the molecular
level, but also in each instance the gross mixtures of esters
which result from the reaction schemes herein, and which have the
desired range of composition and properties. Accordingly, the
"esters of the invention" is a term which encompasses the doubly
end-capped compounds disclosed herein, mixtures thereof, and
mixtures of said end-capped materials which may unavoidably
contain some singly end-capped and non-capped species, although
2~1~7995
levels of the latter will be zero or at a minimum in all of the
highly preferred compositions.
Thus, when referring simply to an "ester" herein, it is
furthermore intended to refer, by definition, collectively to the
mixture of ester molecules resulting from any single preparation.
Ester 8ackbone - To further illustrate this point, consider
esters of the invention comprised exclusively of the essential
terephthaloyl units, mixtures of oxyethyleneoxy and
oxy-1,2-propyleneoxy units, and the sulfobenzoyl end-capping
units. In molecules of this ester, the oxyalkyleneoxy and
terephthaloyl units are connected in alternation, forming the
ester backbone.
GrouDs at the Termini of the Ester Backbone
Any ester molecules which are present in compositions of the
invention which are not fully, i.e., doubly, end-capped by the
end-capping units, must terminate with units which are not sulfo-
benzoyl end-capping units. These termini will be hydroxyl groups
or other groups attributable to the unit-forming reactant. For
example, units such as --OCH2CH20H, --OCH(CH3)CH20H or
--OCH2CH(CH3)OH, i.e., one oxy-1,2-propyleneoxy unit in a chain
terminal position to which is attached -H forming a hydroxyl
group, are suitable. In other examples which may be constructed,
units such as --(O)CC6Hs (from unsulfonated benzoic acid),
--(O)CC6H4C(O)--OCH3 or --(O)CC6H4C(O)--OH may be found in
terminal positions. All the most highly preferred ester molecules
herein will, however, as indicated above, have two sulfobenzoyl
end-capping units and no residual units occupying terminal
positions.
SYmmetrY
It is to be appreciated that in the above formulas the
oxy-1,2-propyleneoxy units can have their methyl groups randomly
incorporated with one of the adjacent -CH2- hydrogen atoms,
thereby lowering the symmetry of the ester chain. Thus, for
example, the first oxy-1,2-propyleneoxy unit in the formula can be
2Q~7~
- 10
depicted as having the -OCH2CH(CH3)0- orientation, while the
second such unit may have the opposite, -OCH(CH3)CH20-
orientation. Carbon atoms in the oxy-1,2-propylene units, to
which atoms the methyl groups are attached, are furthermore
asymmetric, i.e., chiral; they have four nonequivalent chemical
entities attached.
Fabric SubstantivitY and Formulability of the Esters
The ester backbone provides fabric substantivity of the
- compositions herein. In a preferred embodiment, alternating
terephthaloyl and oxyalkyleneoxy units form an ester bac~bone
which is not only fabric substantive, but also very compatible
with consumer fabric care ingredients.
It should also be noted that the essential non-charged
aryldicarbonyl units herein need not exclusively be terephthaloyl
units, provided that the polyester-fabric-substantivity of the
ester is not harmed to a significant extent. Thus, for example,
minor amounts of isomeric non-charged dicarbonyl units, such as
isophthaloyl or the like, are acceptable for incorporation into
the esters.
End-CaD~inq Units
The end-capping units used in the esters of the present
invention are sulfobenzoyl groups of the formula (M035)
(C6H4)C(O)-, where M is sodium. These end-cap units provide
anionic charged sites when the esters are dispersed in aqueous
media, such as a laundry liquor or rinse bath. The end-caps serve
to assist transport in aqueous media, as well as to provide
hydrophilic sites on the ester molecules which are located for
maximum effectiveness of the esters as soil release agents.
The sulfobenzoyl end-capping units can exist as isomers with
the sulfonate substituent at the ortho-, meta- or para- positions
with respect to the carbonyl substituent. Sulfobenzoyl isomer
mixtures and pure metasulfobenzoyl substituents are among the most
highly preferred end-capping units, whereas pure para-isomers are
significantly less desirable. It is highly preferred that not
~ b27~ S
- 11 -
more than about 0.15 mole fraction of the sulfobenzoyl end-capping
units be in para-form; most preferably meta-sulfobenzoyl
end-capping units should be used. Of the highly preferred forms~
industrially prepared sulfobenzoyl isomer mixtures having
controlled para isomer content are most economical. It is also
noted that such isomer mixtures may contain up to 0.1 mole
fraction of benzoic acid or similar unsulfonated material, without
ill effects; higher levels of unsulfonated material are in certain
instances more likely to be tolerated, e.g., when the molecular
weights of the esters are low.
On a mole basis, the compositions herein will preferably
comprise from about one to about two moles of the sulfobenzoyl
end-capping units per mole of the ester. Most preferably, the
esters are doubly end-capped; i.e., there will be two moles of
end-capping units present per mole of the esters. From the
viewpoint of weight composition, it will be clear that the con-
tribution of end-capping units to the molecular weight of the
esters will decrease as the molecular weight of the ester backbone
increases.
In addition to the above, there should be at least 12.5 mole
percent, preferably from about 40 to 100 mole percent, more
preferably from about 50 to 80 mole percent, of sulfobenzoyl units
relative to the number of terephthaloyl units.
The molar ratio of oxyalkyleneoxy units to terephthaloyl
units should also be from about 2:1 to about 1.1:1, preferably
from about 1.5:1 to about 1.2:1, more preferably from about 1.4:1
to about l.25:1.
In addition to the above chemical definition, the soil
release esters of the present invention must also be substantially
amorphous in character at the time they are introduced into the
laundering solution. ~Substantially amorphous~ as defined herein
indicates that esters in accordance with the invention have a
heat of fusion of 15 J/g (Joules per gram) or less, preferably
202~g5
less than about 9 J/g, more preferably less than about 3 J/g, as
measured by Differential Scanning Calorimetry (DSC). This cor-
responds with a content of crystalline material of less than 16%,
preferably less than 10%, more preferably 3% or less, by weight.
(Such materials are thus at least about 84%, preferably at least
about 90%, more preferably at least about 97/O, by weight in
amorphous form.) The heat of fusion differentiates the esters
from highly crystalline ester forms which, though they may have
the same or similar chemical composition, are surprisingly
deficient as soil release agents in the present detergent compo-
sitions. Typically, unsuitable crystalline forms of the ester
have heats of fusion of 28 J/g, or higher: heats of fusion of up
to about 93 J/g are possible for certain very highly crystalline
samples.
While not intending to be limited by theory, it is believed
that these soil release esters function by dissolving in the
laundering solution, adsorbing onto fabric surfaces, particularly
low polarity surfaces such as in typical polyester fabrics, and
effecting a surface modification. The modified surfaces are
believed to be more polar and hydrophilic, and thus have reduced
affinity for oily soils. This facilitates the removal of oily
soils during the laundering operation. In contrast, when the
esters are not in the substantially amorphous form, they are
believed incapable of effective dissolution and transport from the
laundering solution to the fabric surface.
A preferred method for producing the esters in the
substantially amorphous state is to rapidly cool freshly made, hot
melts of the ester compositions herein to room temperature with
substantially no water present. "Rapid~ cooling generally
involves reducing the temperature of the molten material from
200-C or above (preferably 220-C - 230-C) to storage temperatures
generally below about 78C over one hour. Most preferably, the
cooling rate for such quenching should preferably be greater,
2~9~S
- - 13 -
e.g., about 10C/min, more preferably about 60C/min, or more.
Alternatively, an ester composition which has obtained the
undesired crystalline state can be converted to the amorphous form
by remelting (220-240C) and subsequent rapid cooling. The sub-
s stantially amorphous ester should be stored at a temperaturegenerally below about 78C, since that temperature corresponds
with the beginning of its glass transition.
To maintain the desired amorphous form of soil release
esters, it is necessary to limit the access of free water to the
material until it is introduced to the laundering solution.
Storage of the material in the presence of water or humid
atmosphere will result in an ordering of the material into the
unsuitable crystallized for0. Restricting exposure of the soil
release esters to free water can be accomplished, for example, by
dry mixing with a desiccant (such as a granular detergent herein),
enclosure in a container which acts as a moisture barrier,
decreasing relative surface area, and/or coating with a protective
layer, such as with thin films (approximately 10 wt. %) comprised
primarily of maltrin or Methocel E.
The soil release esters herein are believed to spontaneously
rearrange, when sufficient molecular mobility is provided by heat
or solvents, from an amorphous form into a crystalline form which
is insoluble in the laundering solution. This "inherent"
crystallinity is controlled by the chemical factors described
above. Rapid cooling and exclusion from water maintain the
amorphous form of the material which is soluble in the laundering
solution. It is believed that the ability of the soil release
esters to then spontaneously rearrange to the insoluble ordered
form on fabric surfaces significantly enhances its deposition from
the laundering solution, and consequently soil release
performance.
In light of the foregoing observations, it is important to
have a good method for distinguishing amorphous form ester and for
quantifying contamination of the amorphous form with the undesired
- 14 - 2~99~
crystalline form. Differential Scanning Calorimetry (DSC)
provides such a method.
Any convenient OSC equipment suitable for measuring glass
transition temperatures in polyesters can be used. Such equipment
is illustrated by a Mettler TA3000 Thermal Analysis System
(Mettler Instrument Corp., Princeton Rd., Hightstown, New Jersey
08520). The system comprises a TClOA TA Processor, a DSC30
Calorimeter with Liquid Nitrogen Cooling Accesories and a TG50
Thermobalance. The temperature calibration for DSC is done in the
art-known manner using indium, lead and zinc standards. The heat
flow is calibrated using indium and the heat capacity using
sapphire.
Samples suitable for scanning can be made by sealing aliquots
(approx. 16 mg.) of ester (particle size average from 250 to 425
micron) in aluminum pans.
In general, the analysis method involves scanning from minus
20 C to plus 250 C at a 10 C/min heating rate. Integrations of
the heat exchange peaks (enthalpy of transition) are done using
the built-in program in the TClOA Processor.
It is found that the ester in amorphous form shows only one
sharp glass transition, between 78 C and 128 C: Tg, the glass
transition temperature, is at around 95 C. Both the glass
transition temperature range and Tg are in a range which is in
good agreement with that expected from a poly(ethylene
2S terephthalate) modified to have anionic character (sulfobenzoyl
end-caps). No other thermal transitions are observed.
In contrast, the crystalline form of the ester generally has
more than one endothermic region; typically, there are two
endothermic regions, but depending on the thermal history of the
sample, three may be observed. For ester isothermally
crystallized at temperatures below 180 C, two melting endotherms
are invariably found. One is located between 176 C and 185 C
and the other is about 15 C higher than the temperature at which
2~27g95
the isothermal crystallization is carried out. When the
crystalline ester is the product of crystallizing at
crystallization temperatures above 180 C, only one melting
endotherm is observed: this is located at around 215 C. Such
high temperature endotherm data characterizes ester materials
unsuitable for use herein.
For DSC analysis of unsuitable ester samples the
crystallinity of which has been induced by treatment with water,
-~ the sample is first dried by preheating to 105C for 3 hours
o before measurement. The DSC trace then consists of two melting
endotherms, a major one at 215C and a minor one at 185C.
When DSC analysis is carried out on ester samples containing
trace water, without drying, two glass transitons of the ester
are commonly observed. The additional glass transition of the
ester is typically seen 30C or more below any glass transition
temperature cited above. Two glass transitions are common for
such samples. Without being bound by theory, the result suggests
that the ester particle surface may be selectively affected, with
crystallization occurring there but not in the internal portion of
the sample. Although it is possible to use samples of esters
having some limited coating with crystalline-form esters in the
instant detergent compositions as soil release agents, the use of
such samples is preferably avoided.
To further characterize and distinguish the amorphous and
2s crystalline forms of the ester, a simplified two-phase model can
- be applied, on the understanding that only the amorphous content
is expected to contribute to the glass transition. The amorphous
content of semicrystalline samples can then be obtained by
comparing their heat capacity increase at glass transition with
the corrésponding heat capacity increase of the amorphous ester
oligomer. Heat of fusion for lOOY. crystalline ester is estimated
to be about 93 J/g (Joules per gram) from extrapolation of the
heat of fusions of semicrystalline samples to zero amorphous
~- 2027995
~ - 16 -
content. Crystallinity for any future samples can then be predicted
based on the ratio between measured heat of fusion and this
empirical value.
The crystallization kinetics of the ester depend not only on
history of exposure to heat and/or humidity but also to some extent
on the backbone length, oxyethyleneoxy/oxypropyleneoxy ratio,
counterions and capping groups. Thus, when the structure of the
ester is varied outside the scope of the instant invention, for
example by extending the length of the backbone or by overly
increasing the oxyethyleneoxy/oxypropyleneoxy ratio, the stability
of the amorphous form of the ester is diminished, crystallization is
favored, and good soil release performance is not, as a matter of
practicality, realizable.
The crystallization kinetics also increase significantly when
the cation associated with the sulfonated groups is changed from
sodium to potassium. Therefore sodium is highly preferred over
potassium as cation for use herein. Oligomeric esters outside the
scope of the invention or occurring in less preferred embodiments
and characterized in that they comprise end-capping groups less
rigid than sulfobenzoyl (for example anionically terminated
aliphatic groups) can have faster crystallization rate and this can
lead to inferior soil release characteristics by virtue of lowered
stability of the ester to crystallization in a solid-form detergent
matrix.
Method for Makinq SulfoaroYl End-Capped Esters
The ester compositions of the present invention can be
prepared using any one or combination of several alternative general
reaction types, each being well-known in the art. Many different
starting materials and diverse, well-known experimental and
analytical techniques are useful for the syntheses. Types of
synthetic and analytical methods useful herein are well illustrated
in European Patent Application 185,427, Gosselink, published
June 25, 1986, and in Odian, Principles of PolYmerization,
202 7995
- 17 -
Wiley, NY, 1981. Chapter 2.8 of the Odian reference, entitled "Process
Conditions", pp 102-105, focuses on the synthesis of poly(ethylene
terephthalate); it should be noted that the synthesis temperatures
reported in Odian (260-290~C) are unsuitably high for general use
herein unless exposure times are short; also that the use of two
types of catalyst, the first being deactivated by means of a
phosphorus compound before use of the second, is not necessary
herein. Temperature requirements and catalysts for use herein are
further discussed hereinafter.
Mechanistically, the suitable general reaction types for
preparing esters of the invention include those classifiable as:
1. alcoholysis of acyl halides;
2. esterification of organic acids;
15 . 3. alcoholysis of esters (transesterification); and
4. reaction of alkylene carbonates with organic acids.
Of the above, reaction types 2-4 are highly preferred since
they render unnecessary the use of expensive solvents and
halogenated reactants. Reaction types 2 and 3 are especially
preferred as being the most economical.
Suitable starting materials or reactants for making the
esters of this invention are any reactants (especially
esterifiable or transesterifiable reactants) which are capable of
combining in accordance with the reaction types 1-4, or combina-
tions thereof, to provide esters having the correct proportions ofall the above-specified units (i) to (iii) of the esters.
Such reactants can be categorized as "simple" reactants,
i.e., those which are singly capable of providing only one kind of
unit necessary for making the esters; or as derivatives of the
simple reactants which singly contain two or more different types
of unit necessary for making the esters. Illustrative of the
simple kind of reactant is dimethyl terephthalate, which can
provide only terephthaloyl units. In contrast, bis(2-hydroxy-
propyl)terephthalate is a reactant which can be prepared from
-- - 18 - 2027995
dimethyl terephthalate and 1,2-propylene glycol, and which can
desirably be used to provide two kinds of unit, viz. oxy-1,2-
propyleneoxy and terephthaloyl, for making the esters herein.
Similarly, compounds such as
O
(I) ~ C-OCH(Rl)CH(R2)OH and
SO3K
O O
(II) ~C-OCH(Rl)CH(R2)-a-C~
S03Na S03Na
wherein R1, R2 = H or CH3 (provided that when Rl = H, R2 = CH3 and when
R2 = H, R1 = CH3), could be used to provide both end-capping
(sulfobenzoyl) and oxy-1,2-propyleneoxy units. In principle it is
also possible to use oligoesters, or polyesters such as poly(1,2-
propylene terephthalate), as reactants herein, and to conduct
transesterification with a view to incorporation of end-capping
units while decreasing molecular weight, rather than following the
more highly preferred procedure of making the esters from the
simplest reactants in a process involving molecular weight increase
(to the limited extent provided for by the invention) and end-
capping.
Since "simple" reactants are those which will most preferably
and conveniently be used, it is useful to illustrate this kind of
reactant in more detail. Thus, aromatic sulfocarboxylates, in acid
(generally neutralized to place the sulfonate group in salt form
prior to continuing synthesis) or carboxylate-lower (e.g. C1 - C4)
alkyl ester forms such as (III), can be used as the source of the
essential end-capping units herein.
o
~ -C 4CH3
S03Na
(III)
~2~g~
- 19 -
An additional example of such reactants is m-sulfobenzoic acid
monosodium salt (preferred). Mixtures of sulfobenzoate isomers
can be used, provided that not more than about 0.15 mole fraction
of the isomers are in para-form. If commercial grades of
sulfobenzoyl end-capping reactants are used, the content of
unsulfonated material, such as benzoic acid or the like, should
not exceed about 0.1 mole fraction of the reactant for best
results. Mineral acids such as sulfuric acid or oleum will be
removed from the sulfonated reactant before use. Water can be
present, e.g., as in crystal hydrates of the sulfobenzoyl
end-capping reactant, but will not desirably constitute a large
- proportion thereof.
Appropriate glycols or cyclic carbonate derivatives thereof
can be used to provide the essential oxy-1,2-alkyleneoxy units;
thus, 1,2-propylene glycol (preferred especially on grounds of its
lower cost) or (where the starting carboxyl groups are present in
an acidic form) the cyclic carbonate
(IV) H2C - C(H)R
O /O
\ C
o
(R - methylJ
are suitable sources of oxy-1,2-alkyleneoxy units for use herein.
Oxyethyleneoxy units present in the esters of the invention are
most conveniently provided by ethylene glycol, though as an
alternative, ethylene carbonate could be used when free carboxylic
acid groups are to be esterified.
Terephthalic acid or dimethyl terephthalate are suitable
sources of terephthaloyl units. In general, it is preferred
herein to use ester, rather than acid, forms of reactants which
provide the terephthaloyl units.
When starting with the simplest reactants as illustrated
above, the overall synthesis is usually multi-step, involving at
least two stages, such as an init-ial esterification or
- 20 - 2 0 2 7 9 9 5
transesterification (also known as ester interchange) stage,
followed by an oligomerization or polymerization stage, in which
molecular weights of the esters are increased, but only to a
limited extent as provided for by the invention.
S formation of ester-bonds in reaction types 2 and ~ involves
elimination of low molecular weight by-products such as water
(reaction 2), or simple alcohols (reaction 3). Complete removal
of the latter from reaction mixtures is generally somewhat easier
than removal of the former. However, since the ester-bond forming
reactions are generally reversible, it is necessary to "drive" the
reactions forward in both instances, removing these by-products.
In practical terms, in the first stage (ester interchange)
the reactants are mixed in appropriate proportions and are heated,
to provide a melt, at atmospheric or slightly superatmospheric
1 pressures (preferably of an inert gas such as nitrogen or argon~.
Water and/or low molecular weight alcohol is liberated and is
distilled from the reactor at temperatures up to about 200-C. (A
temperature range of from about 150-200-C is generally preferred
for this stage).
In the second (i.e., oligomerization) stage, vacuum
techniques and temperatures somewhat higher than in the first
stage are applied; removal of volatile by-products and excess
reactants continues, until the reaction is complete, for example
as monitored by conventional spectroscopic techniques.
Continuously applied vacuum, typically of about 10 mm Hg or lower
can be used.
In both of the above-described reaction stages, it is neces-
sary to balance on one hand the desire for rapid and complete
reaction (higher temperatures and shorter times preferred),
against the need to avoid thermal degradation (which undesirably
might result in off-colors and by-products). It is possible to
use generally higher reaction temperatures, especially when
reactor design minimizes super-heating or "hot spots~ and
minimizes exposure time. Thus, a suitable temperature for
2~2799S
- 21 -
oligomerization lies most preferably in the range of from about
150C to about 260C (assuming that no special precautions, such
as of reactor design, are otherwise taken to limit thermolysis).
It is very important in the above-described procedure to use
continuous mixing, so that the reactants are always in good
contact; highly preferred procedures involve formation of a
well-stirred homogeneous melt of the reactants in the temperature
ranges given above. It is also highly preferred to maximize the
surface area of reaction mixture which is exposed to vacuum or
inert gas to facilitate the removal of volatiles, especially in
the oligomerization or polymerization step.
Catalysts and catalyst levels appropriate for esterification,
transesterification, oligomerization, and for combinations
thereof, are all well-known in polyester chemistry, and will
generally be used herein; as ~noted above, a single catalyst will
suffice. Suitably catalytic metals are reported in Chemical
Abstracts, CA83:178505v, which states that the catalytic activity
of transition metal ions during direct esterification of K and Na
carboxybenzenesulfonates by ethylene glycol decreases in the order
Sn (best), Ti, Pb, Zn, Mn, Co (worst).
The reactions can be continued over periods of time suffi-
cient to guarantee completion, or various conventional analytical
monitoring techniques can be employed to monitor progress of the
forward reaction; such monitoring makes it possible to speed up
the procedures somewhat, and to stop the reaction as soon as a
product having the minimum acceptable composition is formed.
Appropriate monitoring tachniques include measurement of
relative and intrinsic viscosities, acid values, hydroxyl numbers,
1H and 13C nuclear magnetic resonance (n.m.r) spectra, and liquid
chromatograms.
Most conveniently, when using a combination of volatile
reactants (such as a glycol) and relatively involatile reactants
(such as m-sulfobenzoic acid monosodium salt and dimethyl
terephthalate), the reaction will be initiated with excess glycol
- 22 ~ 2027995
being present. As in the case of ester interchange reactions
reported by Odian (op. cit.), "stoichiometric balance is
inherently achieved in the last stages of the second step of the
process". Excess glycol can be removed from the reaction mixture
by distillation; thus, the exact amount used is not critical.
Inasmuch as final stoichiometry of the ester compositions
depends on the relative proportions of reactants retained in the
reaction mixtures and incorporated into the esters, it is
desirable to conduct the condensations in a way which effectively
retains the non glycol reactants, and prevents them from
distilling or subliming. Dimethyl terephthalate and to a lesser
extent the simple glycol esters of terephthalic acid have
sufficient volatility to show on occasion "sublimation" to cooler
parts of the reaction apparatus. To ensure achieving the desired
stoichiometry it is desirable that this sublimate be returned to
the reaction mixture, or alternatively, that sublimation losses be
compensated by use of a small excess of terephthalate. In
general, sublimation-type losses, such as of dimethyl
terephthalate, may be minimized 1) by apparatus design; 2) by
raising the reaction temperature slowly enough to allow a large
proportion of dimethyl terephthalate to be converted to less
volatile glycol esters before reaching the upper reaction
temperatures; 3) by conducting the early phase of the
transesterification under low to moderate pressure (especially
effective is a procedure allowing sufficient reaction time to
evolve at least about 9~% of the theoretical yield of methanol
before applying vacuum).
Typically herein, when calculating the relative proportions
of reactants to be used, the following routine is followed, as
illustrated for a combination of the reactants m-sulfobenzoic acid
monosodium salt (A), ethylene glycol (8), propylene glycol (B1)
and dimethyl terephthalate (C):
~279~5
1. the desired degree of end-capping is selected; for the
present example, the value 2, most highly preferred
according to the invention, is used;
2. the average calculated number of terephthaloyl units in
Sthe backbone of the desired ester is selected; for the
present example, the value 3.75, which falls in the
range of most highly preferred values according to the
invention, is used;
3. the mole ratio of (A) to (C) should thus be 2:3.75;
10amounts of the reactants (A) and (C) are taken accord-
ingly;
4. an appropriate excess of glycols is selected; typically
2 to 15 times the number of moles of dimethyl
terephthalate is suitable.
15More generally herein, when preparing fully end-capped ester
from "simple" reactants, a ratio of the moles of end-capping
reactant to moles of other nonglycol organic reactants (e.g., in
the simplest case only dimethyl terephthalate) of from about 2:1
to about 1:5, preferably from about 1:1 to about 1:2.5, most
20preferably about 1:1.25 to about 1:2 will be used. The glycols
used will be calculated in an amount, in any event sufficient to
allow interconnection of all other units by means of ester bonds,
and adding a convenient excess will usually result in a total
relative amount of glycol ranging from about 1.5 to about 10 moles
for each mole nonglycol organic reactants added together.
- ~ypically the ratio of oxyethyleneoxy: oxy-1,2-propyleneoxy
units in the desired esters will be somewhat higher than the ratio
of ethylene glycol: 1,2-propylene glycol used (in excess) as
starting reactants. Typically, if a final ratio of 4:1 for
oxyethyleneoxy to oxy-1,2-propyleneoxy units is desired in the
final ester, a starting ratio of approximately 2:1 ethylene glycol
to 1,2-propylene glycol is used.
In light of the teaching of the present invention (insofar as
the identity and proportions of essential end-capping and backbone
~2~95
units are concerned), numerous syntheses of ester compositions
according to the invention follow straightforwardly from the above
disclosure. The following, more detailed examples are
illustrative.
EXAMPLE I
An ester composition made from m-sulfobenzoic acid monosodium
salt, 1,2-propylene glycol, ethylene glycol and dimethyl
terephthalate.
Into a 1000 ml, three-necked, round bottom flask, fitted with
a thermometer, magnetic stirrer and modified Claisen head, the
latter connected to a condenser and receiver flask, are placed,
under argon, m-sulfobenzoic acid monosodium salt (89.6 9; 0.40
moles; Eastman Kodak), 1,2-propylene glycol (144.6 9; 1.90 moles;
Aldrich), ethylene glycol (236.0 9; 3.80 moles; Mallinckrodt), and
hydrated monobutyltin(IV) oxide (0.6 9; 0.1% w/w; sold as FASCA~
4100 by M&T Chemicals). Over a five hour period, the mixture is
stirred and heated under argon at atmospheric pressure, to reach a
temperature of 175C. The reaction conditions are kept constant
for an additional 16 hours, during which time distillate (12.2 9;
164% based on the theoretical yield of water) is collected. The
reaction mixture is cooled to about 100-C, and dimethyl
terephthalate (145.5 9; 0.75 moles; Union Carbide) is added under
argon. Over a 4 hour period, the mixture is stirred and heated
under argon at atmospheric pressure, to reach a temperature of
175-C. The reaction conditions are kept approximately constant
(temperature range 175-180-C) for a further 18 hours, during which
time distillate (48.9 9; 102% of theory based on the calculated
yield of methanol) is collected. The mixture is cooled to about
50-C and is transferred under argon to a Kugelrohr apparatus
(Aldrich). The apparatus is evacuated to a pressure of 1 mm Hg.
While maintaining the vacuum and stirring, the temperature is
gradually raised to 220-C over about 1 hour. Reaction conditions
are then held constant for about 6 hours to allow completion of
the synthesis. During this period, excess glycol distills from
~27~
the homogeneous mixture. At the end of the condensation, the
reaction vessel is removed from the heat and cooled promptly to
obtain the ester in the desired, glassy, amorphous state.
Using the convention introduced above, the product of Example
~II has the empirical formula representation:
(CAP)2(EG/pG)4.75(T)3 .75-
In this representation, (CAP) represents the m-sulfobenzoyl
end-capping units, in sodium salt form. The mole ratio of
- oxyethyleneoxy and oxy-1,2-propyleneoxy units is determinedspectroscopically to be about 4:1; the volatility and reactivity
differentials of the parent glycols are responsible for the
difference between this observed ratio and the ratio of moles of
the two glycols used as reactants.
15~llustrative of structures of oligomeric ester molecules
~ present in the composition of Example I is:
(CAP)-(EG)-(T)-(PG)-(T)-(EG)-(T)-(EG)-(T)-(EG)-(CAP).
In the above Example I, when 1.20 moles of 1,2-propylene
glycol and 4.80 moles of ethylene glycol are added to the flask
(instead of 1.90 and 3.80 moles, respectively), an ester
composition of the invention having the empirical formula
representation
(CAP)2(EG/pG)4.7s (T)3.75
is obtained, with the mole ratio of oxyethyleneoxy units to
oxy-1,2-propyleneoxy units-being approximately equal to 8.
In the above Example I, when 0.60 moles of dimethyl
terephthalate is added to the flask (instead of 0.75 moles), an
ester composition of the invention having the empirical formula
representation
(CAP)2(EG/PG)4 (T)3
is obtained.
EXAMPEES II-IV .
Ester compositions made from simple reactants capable of
providing sulfobenzyl end-capping units having different isomeric
forms and chemical compositions, usinq ethylene glycol,
2~2799~
1,2-propylene glycol and dimethyl terephthalate as co-reactants.
The examples also include illustration of the use of cations other
than sodium associated with the sulfonate anion, and simulate
incompletely sulfonated end-capping reactant.
The procedure of Example I is in each instance reproduced,
with the single exception that the m-sulfobenzoic acid monosodium
salt (89.6 9; 0.40 moles) used in Example I is replaced with an
equimolar amount of the following:
Example II 0
~ COCH3
SO3Na
Example III a mixture, having the following composition
(weight ~O) m-sulfobenzoic acid monosodium salt,
92%; p-sulfobenzoic acid monopotassium salt
(Eastman Kodak), 6%; o-sulfobenzoic acid
monosodium salt, 2%.
Example IV a mixture having the following composition
(weight %): m-sulfobenzoic acid monosodium salt,
92%; para-sulfobenzoic acid monopotassium salt
(Eastman Kodak), 6X; o-sulfobenzoic acid
monosodium salt, 1%; benzoic acid (Aldrich), 1%.
EXAMP~E V
An ester composition is made from m-sulfobenzoic acid mono-
sodium salt, ethylene glycol, 1,2-propylene glycol and dimethyl
terephthalate. The example illustrates an ester composition
according to the invention which is prepared by a procedure
ldentical with that of Example I, with the single exception that a
different catalyst is used.
The procedure of Example I is repeated, with the single
exception that Sb203 (0.69; 0.002 moles; Fisher) and calcium
acetate monohydrate (0.6g; 0.003 moles, MC3) are used as replace-
ment for the tin catalyst of Example I. ~he product of this
example has a slightly darker color, but is otherwise similar to
that prepared by the unchanged Example I procedure.
2027~
- 27 -
Use of Esters of the Invention as Soil-Release Aqents
Esters of the invention are especially useful as soil release
agents in granular laundry detergent compositions~ which can be
fully formulated compositions intended for use in the main
laundering operation, or laundry additive or pretreatment
compositions comprising the essential ester compositions and
optional ingredients. The ester compositions, as provided herein,
will typically constitute from about 0.1% to about 10% by weight
of a granular detergent. See the following patents for detailed illustrations of
granular detergent compositions suitable for use in combination
with the soil release esters herein; these patents include dis-
closures of types and levels of typical detersive surfactants and
builders: U.S. Patents 3,985,669, Krummel et al., issued October
12, 1976; 4,379,080, Murphy, issued April 5, 1983; 4,490,271,
Spadini et al., issued December 25, 1984 and 4,605,509, Corkill et
al., issued August 12, 1986 (in the foregoing, granular detergent
compositions have non-phosphorus builder systems; other non-phos-
phorus builders usable herein are the compounds tartrate mono-
succinate/tartrate disuccinate, disclosed in U.S. Patent
4,663,071, Bush et al., issued May 5, 1987 and 2,2 -oxodisuc-
cinate, disclosed in U.S. Patent 3,128,287, Berg, issued April 7,
1964). Phosphorus-containing builders well-known in the art can
also be used, as can bleaches; see U.S. Patent 4,412,934, Chung et
al., issued November 1, 1983.
Ester compositions of the invention, at aqueous concen-
trations ranging from about 1 to about 50 ppm, more preferably
about 5 to about 30 ppm, provide effective, combined cleaning and
soil release treatments for polyester fabrics washed in an
aqueous, preferably alkaline (pH range about 7 to about 11, more
preferably about 8 to about 10) environment, in the presence of
typical granular detergent ingredients; including anionic
surfactants, phosphate, ether carboxylate or zeolite builders, and
various commonly used ingredients such as bleaches, enzymes and
- 28 - 2 0~ 79 ~
optical brighteners. Surprisingly (especially insofar as pH and
anionic surfactant are concerned), all of these detergent
ingredients can be present in the wash water at their
art-disclosed levels, to perform their conventional tasks, e.g..
for cleaning and bleaching fabrics or the like, without
ill-effects on the soil release properties of the esters.
Useful anionic surfactants in the compositions herein include
the water-soluble salts of the higher fatty acids, i.e., "soaps".
This includes alkali metal soaps such as the sodium, potassium,
ammonium, and alkylolammonium salts of higher fatty acids
containing from about 8 to about 24 carbon atoms, and preferably
from about 12 to about 18 carbon atoms. Soaps can be made by
direct saponification of fats and oils or by the neutralization of
free fatty acids. Particularly useful are the sodium and
potassium salts of the mixtures of fatty acids derived from
coconut oil and tallow, i.e., sodium or potassium tallow and
coconut soap.
Useful anionic surfactants also include the water-soluble
salts, preferably the alkali metal, ammonium and alkylolammonium
salts, of organic sulfuric reaction products having in their
molecular structure an alkyl group containing from about 10 to
about 20 carbon atoms and a sulfonic acid or sulfuric acid ester
group. (Included in the term ~alkyl" is the alky portion of acyl
groups). Examples of this group of synthetic surfactants are the
sodium and potassium alkyl sulfates, especially those obtained by
sulfating the higher alcohols (Cg-C1g carbon atoms) such as those
produced by reducing the glycerides of tallow or coconut oil; and
the sodium and potassium alkylbenzene sulfonates in which the
alkyl group contains from about 9 to about 15 carbon atoms, in
straight chain or branched chain configuration, e.g., those of the
type described in U.S. Patent Nos. 2,220,099, and 2,477,383.
Especially valuable are linear straight chain alkylbenzene
sulfonates in which the average number of carbon atoms in the
alkyl group is from about 11 to 13, abbreviated as C11 13 LAS.
2~79~
- - 29 -
Other anionic surfactants herein are the sodium alkyl
glyceryl ether sulfonates, especially those ethers of higher
alcohols derived from tallow and coconut oil; sodium coconut oil
fatty acid monoglyceride sulfonates and sulfates; sodium or
potassiu~ salts of alkyl phenol ethylene oxide ether sulfates
containing from about 1 to about 10 units of ethylene oxide per
molecule and wherein the alkyl groups contain from about 8 to
about 12 carbon atoms; and sodium potassium salts of alkyl
ethylene oxide ether sulfates containing about 1 to about 10 units
o of ethylene oxide per molecule and wherein the alkyl group
contains from about 10 to about 20 carbon atoms.
Other useful anionic surfactants herein include the
water-soluble salts of esters of alpha-sulfonated fatty acids
containing from about 6 to 20 carbon atoms in the fatty acid group
and from about 1 to 10 carbon atoms in the ester group;
water-soluble salts of 2-acyloxyalkane-1-sulfonic acids containing
from about 2 to 9 carbon atoms in the acyl group and from about 9
to about 23 carbon atoms in the alkane moiety; water-soluble salts
of olefin and paraffin sulfonates containing from about 12 to 20
carbon atoms; and beta-alkyloxy alkane sulfonates containing from
about 1 to 3 carbon atoms in the alkyl group and from about 8 to
20 carbon atoms in the alkane moiety.
Preferred anionic surfactants are selected from the group
consisting of Cll-C13 linear alkylbenzene sulfonates, Clo-Clg
2S alkyl sulfates, and Clo-Clg alkyl sulfates ethoxylated with an
average of from about 1 to about 6 moles of ethylene oxide per
~ole of alkyl sulfate, and mixtures thereof.
~ ater-soluble nonionic surfactants are also useful in the
compositions of the invention. Such nonionic materials include
compounds 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 polyoxyalkylene group which is condensed with any particular
hydrophobic group can be readily adjusted to yield a water-soluble
2~7gg~
- 30 -
compound having the desired degree of balance between hydrophilic
and hydrophobic elements.
Suitable nonionic surfactants include the polyethylene oxide
condensates of alkyl phenols, e.g., the condensation products of
alkyl phenols having an alkyl group containing from about 6 to 15
carbon atoms, in either a straight chain or branched chain
configuration, with from about 3 to 12 moles of ethylene oxide per
mole of alkyl phenol.
Preferred nonionic surfactants are the water-soluble and
water-dispersible condensation products of aliphatic alcohols
containing from 8 to 22 carbon atoms, in either straight chain or
branched configuration, with from 3 to 12 moles of ethylene oxide
per mole of alcohol. Particularly preferred are the condensation
products of alcohols having an alkyl group containing from about 9
to 15 carbon atoms with from about 4 to 8 moles of ethylene oxide
per mole of alcohol.
The granular detergent compositions herein generally comprise
from about 5~. to about 80%, preferably from about 10% to about
60%, more preferably from about 15% to about 50%, by weight of
detergent surfactant.
Nonlimiting examples of suitable water-soluble, inorganic
detergent builders useful herein include: alkali metal carbonates,
borates, phosphates, bicarbonates and silicates. Specific
examples of such salts include sodium and potassium tetraborates,
bicarbonates, carbonates, orthophosphates, pyrophosphates,
tripolyphosphates and metaphosphates.
Examples of suitable organic alkaline detergency builders
~nclude: (1) water-soluble amino carboxylates and
aminopolyacetates, for example, nitrilotriacetates, glycinates,
ethylenediaminetetraacetates, N-(2-hydroxyethyl)nitrilo diacetates
and diethylenetriamine pentaacetates; (2) water-soluble salts of
phytic acid, for example, sodium and potassium phytates; (3)
water-soluble polyphosphonates, including sodium, potassium, and
lithium salts of ethane-l-hydroxy-l, 1-d~phosphonic acid; sodium,
2027995
- 31 -
potassium, and lithium salts of ethylene diphosphonic acid; and
the like; (4) water-soluble polycarboxylates such as the salts of
lactic acid, succinic acid, malonic acid, maleic acid, citric
acid, oxydisuccinic acid, carboxymethyloxysuccinic acid,
2-oxa-1,1,3-propane tricarboxylic acid, 1,1,2,2-ethane
tetracarboxylic acid, mellitic acid and pyromellitic acid; (5)
water-soluble polyacetals as disclosed in U.S. Patent Nos.
4,144,266 and 4,246,495; and (6) the water-soluble tartrate monosuccinates
and disuccinates, and mixtures thereof, disclosed in U.S. Patent 4,663,071
Bush et al, issued May 5, 1987.
Another type of detergency builder material useful in the
final granular detergent product comprises a water-soluble
material capable of forming a water-insoluble reaction product
with water hardness cations preferably in combination with a
crystallization seed which is capable of providing growth sites
for said reaction product. Such "seeded builder" compositions are
fully disclosed in British Patent No. 1,424,406.
A further class of detergency builder materials useful in the
present invention are insoluble sodium aluminosilicates,
particularly those described in Belgian Patent No. 814,874, issued
November 12, 1974, as having the formula:
Naz-(Alo2)-(sio2)yxH2o
wherein z and y are integers equal to at least 6, the molar rati-o
of z to y is in the range of from 1.0:1 to about 0.5:1, and X is
an integer from about 15 to about 264, said aluminosilicates
having a calcium ion exchange capacity of at least 200 milligrams
equivalent/gram and a calcium ion exchange rate of at least about
2 grain/gallon/minute/gram. A preferred material is Zeolite A
which is:
Nal2-(sio2Alo2)l227H2o-
Preferably, the builder comprises a tripolyphosphate,pyrophosphate, carbonate, polycarboxylate, or aluminosilicate
detergency builder, or mixtures thereof.
~i
20279~5
- 32 -
The detergency builder component generally comprises from
about 10% to 90%, preferably from about 15% to 75%, more
preferably from about 20% to 60%, by weight of the spray-dried
detergent composition.
Optional components which can be included in the granular
detergents herein are materials such as cationic surfactants,
softening agents, enzymes (e.g., proteases and amylases), bleaches
and bleach activators, other soil release agents (such as
disclosed in U.S. Patents 4,702,857, Gosselink, issued October 27,
1987, and 4,721,580, Gosselink, issued January 26, 1988), soil suspending
agents, fabric brighteners, enzyme stabilizing agents, color speckles, suds
boosters or suds suppressors, anticorrosion agents, dyes, fillers, germicides, pH
adjusting agents, nonbuilder ~lk~linity sources, and the like. Materials listed
15 above which are heat sensitive or degraded by other materials in the crutchermix slurry are generally admixed with the spray-dried portion of the finished
granular detergent composition.
Certain granular detergent compositions of the present
invention preferably also contain a peroxyacid bleach, which in
conjunction with the soil release esters herein provides
unexpectedly superior cleaning performance, particularly of oily
soils from polyester fabrics.
The peroxyacid and the soil release esters herein are
25 preferably present at a weight ratio of available oxygen provided
by the peroxyacid to soil release esters of from about 4:1 to
about 1:30, more preferably from about 2:1 to about 1:15, and most
preferably from about 1:1 to about 1:7.5. The combination can be
incorporated into a fully formulated, stand alone product, or it
can be formulated as an additive to be used in combination with a
laundry detergent.
The peroxyacid can be a preformed peroxyacid, or a combin-
ation of an inorganic persalt (e.g., sodium perborate), and an
organic peroxyacid precursor which is converted to a peroxyacid
2027995
- 33 -
when the combination of persalt and precursor is dissolved in
water. The organic peroxyacid precursors are often referred to in
the art as bleach activators.
Examples of suitable organic peroxyacids are disclosed in
U.S. Patents 4,374,035, Bossu, issued Feb. 15, 1983; 4,681,592,
Hardy et al, issued July 21, 1987; 4,634,551, Burns et al, issued
Jan. 6, 1987; 4,686,063, Burns, issued Aug. 11, 1987; 4,606,838,
Burns, issued Aug. 19, 1986; and 4,671,891, Hartman, issued June
9, 1987. Examples of compositions suitable for laundry bleaching
which contain perborate bleaches and activators therefor are
disclosed in U.S. Patents 4,412,934, Chùng and Spadini, issued
Nov. 1, 1983; 4,536,314, Hardy et al, issued Aug. 20, 1985;
4,681,695, ~ivo, issued July 21, 1987; and 4,539,130, Thompson et
15- al, issued Sept. 3, 1985.
The preferred organic peroxyacid is selected from the follow-
ing:
O O
H - O - O - C - Rl - Y, H - O - O - C - CH - R2 - Y,
xl
, ,R3
H - O - O - C - Rl - C - N - R2 - Y, and
R3 0
" I "
H - O - O - C - R1 - N - C - R2 ~ Y
wherein Rl and R2 are alkylene groups containing from 1 to about
20 carbon atoms or phenylene groups, R3 is hydrogen or an alkyl,
aryl, or alkaryl group containing from about 1 to about 10 carbon
atoms, and X and Y are hydrogen, halogen, alkyl (e.g., methyl,
isopropyl), aryl, or any group which provides an anionic moiety in
aqueous solution. Such X and Y groups can include, for example,
O O O
- C - OM - C - O - O - M - S - O - M
.~-
2~9~
- 34 -
where M is hydrogen or a water-soluble salt-forming cation.
Mixtures of such peroxyacids can also be used herein.
Specific examples of preferred peroxyacids for this invention
include diperoxydodecanedioic acid (DPOA), nonylamide of
peroxysuccinic acid (NAPSA), nonylamide of peroxyadipic acid
(NAP M) and decyldiperoxysuccinic acid (OOPSA). For the purpose
of this invention, the peroxyacid is preferably incorporated into
a soluble granule according to the method described in the above
cited U.S. Pat. No. 4,37~,035. A preferred bleach granule
comprises, by weight, 1% to 50Y. of an exotherm control agent
(e.g., boric acid); 1% to 25Y. of a peroxyacid compatible sur-
factant (e.g., C13LAS); O. l~o to 10% of one or more chelant
stabilizers (e.g., sodium pyrophosphates); and 107. to 70% of a
water-soluble processing salt (e.g., Na2S04).
The peroxyacid bleach is used at a level which provides an
amount of available oxygen (AvO) from about O.lY, to about 10%,
preferably from about 0.5% to about 5%, and most preferably from
about 1% to about 4%, all by weight of the composition.
Effective amounts of peroxyacid bleach per unit dose of the
composition of this invention used in typical laundry liquor,
e.g., containing 64 liters of 16--60-C water, provide from about 1
ppm to about 150 ppm of available oxygen (AvO), more preferably
from about 2 ppm to about 20 ppm. The laundry liquor should also
have a pH of from 7 to 11, preferably 8 to 10, for effective
peroxyacid bleaching. See Col. 6, lines 1-10, of U.S. Pat. No.
4,374,035.
Alternatively, the composition may contain a suitable organic
precursor which generates one of the above peroxyacids when
reacted with alkaline hydrogen peroxide in aqueous solution. The
source of hydrogen peroxide can be any inorganic peroxygen
compound which dissolves in aqueous solution to generate hydrogen
peroxide, e.g., sodium perborate (monohydrate and tetrahydrate)
and sodium percarbonate.
_ - 35 - 2027995
These compositions comprise:
(a) a peroxygen bleaching compound capable of yielding
hydrogen peroxide in an aqueous solution; and
(b) a bleach activator having the general formula:
g
R - C - L
wherein R is an alkyl group containing from about 5 to
about 18 carbon atoms wherein the longest linear alkyl
chain extending from and including the carbonyl carbon
contains from about 6 to about 10 carbon atoms and L is
a leaving group, the conjugate acid of which has a PKa
in the range of from about 6 to about 13 wherein the
molar ratio of hydrogen peroxide yielded by (a) to
bleach activator (b) is greater than about 1.5.
The level of peroxygen bleach within compositions of the
invention is from about 0.1% to about 95% and preferably from about
1% to about 60%. When the bleaching compositions within the
invention are also fully formulated detergent compositions, it is
preferred that the level of peroxygen bleach is from abut 1% to
about 20%.
Especially preferred bleach activators are those of the above
general formula wherein R is a linear alkyl chain containing from
about 5 to about 9 and preferably from about 6 to about 8 carbon
atoms and L is selected from the group consisting of:
Y R2 ' R2Y
- O ~ , - O ~ Y and - O ~
wherein RZ is as defined above and Y is - 50-3M+ or - COO-M+ wherein M
is as defined above.
The most preferred bleach activators have the formula:
R - C - O ~ S~3-M+
9 9 ~
wherein R is a linear alkyl chain containing from about 5 to about
9 and preferably fro~ about 6 to about 8 carbon atoms and M is
sodium or potassium.
The level of bleach activator within the compositions of the
` 5invention is from about 0-1% to about 60% and preferably from
about 0.5% to about 40%. When the bleaching compositions within
the invention are also fully formulated detergent compositions, it
is preferred that the level of bleach activator is from about 0.5/O
to about 20%.
1Preferred compositions comprise an effective amount of soil
release agent and peroxyacid bleach precursor and peroxygen
compound to work in the wash solution. The weight ratio of
available oxygen, provided by the peroxygen compound, to soil
release agent is preferably 12:1 to 1:10; more preferably 6:1 to
151:5; and most preferably 3:1 to 1:2.5.
The invention encompasses a method of laundering fabrics and
concurrently providing a soil release finish thereto. The method
simply comprises contacting said fabrics with an aqueous laundry
liquor containing the conventional detersive ingredients described
hereinabove, as well as the above-disclosed effective levels of a
soil release agent (namely, from about 1 to SOppm of an oligomeric
or polymeric composition comprising at least 20% by weight of an
ester of the invention). Although this method is not especially
limited in terms of factors such as pH and surfactant types
present, it should be appreciated that for best cleaning of
fabrics, it is often especially desirable to make use, in the
laundry process, of anionic surfactants, such as conventional
linear alkylbenzene sulfonates, and also to use higher pH ranges
as defined above. Use of these surfactants and pH ranges sur-
prisingly does not prevent the esters of the invention from actingeffectively as soil release agents. Thus, a preferred method, for
an optimized combination of cleaning and soil-release finishing,
provided by the invention, constitutes using all of the following:
- the preferred levels of soil release agent (5-30ppm);
- anionic surfactant;
- 2~27~
- 31 -
- pH of from about 7 to about 11; and, by way of soil
release agent, a preferred ester composition of the invention,
such as the oligomeric product of reacting compounds comprising
sulfobenzoic acid or a Cl-C4 alkyl carboxylate ester thereof as
the monosodium salt, dimethyl terephthalate, ethylene glycol and
1,2-propylene glycol (see, for example the methods for making and
examples, such as Example I, hereinabove for further details).
In the preferred method, polyester fabrics are used; best soil-
release results are achieved thereon, but other fabric types can
also be present.
The simultaneous cleaning and soil-release benefits of the
present invention are surprisingly obtainable after as little
treatment as a single laundry/use cycle, particularly on polyester
fabrics. Best results on polycotton fabrics generally are
obtained using three or more cycles. As used herein, a
laundry/use cycle generally comprises the ordered sequence of
steps:
a) contacting said fabrics with said aqueous laundry liquor
in a conventional automatic washing machine for periods
ranging from about 5 minutes to about 1 hour;
b) rinsing said fabrics with water;
c) line- or tumble-drying said fabrics; and
d) exposing said fabrics to soiling through normal wear or
domestic use.
In the above, hand-washing provides an effective but less
preferred variant in step (a), wherein U.S. or European washing
~achines operating under their conventional conditions of time,
temperature, fabric load, amounts of water and laundry product
concentrations will give the best results. Also, in step (c), the
"tumble-drying~ to which is referred especially involves use of
conventional domestic brands of programmable laundry dryers (these
are occasionally integral with the washing machine), also using
their conventional fabric loads, temperatures and operating times.
~2~
- - 38 -
The following nonlimiting examples illustrate the use of a
typical ester composition of the invention (that of Example I) as
a soil release agent for thru-the-wash application to polyester
fabrics.
EXAMPLES VI-VIII
Granular detergent compositions comprise the following
ingredients:
Ingredient Percent (Wt)
VI VII VIII
Sodium C11-C13 alkyl benzene sulfonate 7.5 4.0 12.0
C12-C13 alcohol ethoxylate (E0 6.5) 1.0 o.o 1.0
Sodium tallow alcohol sulfate 7.5 6.5 7.5
Sodium tripolyphosphate 25.0 39.0 0.0
Sodium pyrophosphate 6.0 0.0 0.0
Zeolite A, hydrate (1-10 micron size) 0.0 0.0 29.0
Sodium carbonate 17.0 12.0 17.0
Sodium silicate (1:6 ratio NaO/SiO2) 5.0 6.0 2.0
Balance (can, for example, include water, ---- to 98.0 ----
soil dispersant, bleach, optical brightener,
perfume, suds suppressor or the like)
Aqueous crutcher mixes of the detergent compositions are
prepared and spray-dried, so that they contain the ingredients
tabulated, at the levels shown. The ester composition of Example
I is ground to a particle size distribution to match that of the
granular detergent product, which typically is from about 400 to
1000 microns to minimize physical segregation. Particle sizes in
- this range are also preferred over smaller particle sizes which
have a greater surface area to mass ratio, and thus are more
susceptible to moisture-induced crystallization. The ester
composition is admixed in an amount sufficient for use at a level
of 2% by weight in conjunction with the detergent compositions.
The detergent granules and ester composition are added (98
parts/2 parts by weight, respectively), together with a 6 lb. load
of previously laundered and soiled fabrics (load composition: 20
- 39 - 2027995
wt. % polyester fabrics/80 wt. % cotton fabrics), to a Sears
KENMORE washing machine. Actual weights of detergent and ester
compositions are taken to provide a 1280 ppm concentration of the
former and 30 ppm concentration of the latter in the 17 l water-
fill machine. The water used has 7 grains/gallon hardness and a
pH of 7 to 7.5 prior to (about 9 to about 10.5 after) addition of
the detergent and ester compositions.
The fabrics are laundéred at 35C (95~F) for a full cycle (12
min.) and rinsed at 21C (70F). The fabrics are then line dried
and are exposed to a variety of soils (by wear or controlled
application). The entire cycle of laundering and soiling is
repeated several times for each of the detergent compositions,
with separate fabric bundles reserved for use with each of the
detergent compositions. Excellent results are obtained in all
cases (VI-VIII), especially in that polyester or polyester-
containing fabrics laundered one or several times as described,
display significantly improved removal of soils (especially
oleophilic types) during laundering compared with fabrics which
have not been exposed to the esters of the invention.
EXAMPLES IX-XI I
Granular detergent compositions comprise the following
; ingredients:
Inqredient Percent (Wt)
IX X XI XII
Sodium 12.3 linear alkyl
benzene sulfonate 3.6 9.412.0 9.0
Sodium C14-C16 alkyl sulfate 5.7 9.4 5.4 3.9
Sodium tallow alcohol sulfate5.7 0.0 0.0 0.0
C12-C13 alcohol ethoxylate
(EO 6.5) 1.0 1.4 0.9 0.4
Sodium tripolyphosphate 6.2 0.0 0.0 4.6
Sodium pyrophosphate 24.8 0.0 0.0 17.2
Zeolite A, hydrate
(1-10 micron size) 0.0 26.7 17.9 0.0
.~
2~ ~ g~5
- 40 -
Sodium carbonate 17.0 14.5 22.7 22.0
Sodium silicate (1.6
ratio NaO/SiO2) 3.7 2.7 3.0 7.2
Polyethylene glycol 8000 0.5 1.0 1.2 0.3
Sodium polyacrylate (MW 4500) 1.2 2.9 1.7 1.0
Protease enzyme* 0.35 0.47 0.45 0.37
Sodium perborate monohydrate 0.0 0.0 4.5 3.7
Nonanoyloxybenzene sulfonate 0.0 0.0 5.1 5.3
Sodium diethylenetriamine
O pentaacetate 0.0 O.O 0.4 0.4
Sodium sulfate 29.5 13.5 16.4 21.1
Soil release ester of Ex. I 1.1 1.0 0.9 0.8
Balance (including water, brightener,
perfume, suds suppressor) ~ ----- to 100.0 -------
*Reported in Anson units per gram.
Agueous crutcher mixes of the detergent compositions are
prepared and spray-dried, except for the enzyme, bleach, perfume,
and soil release ester which are admixed, so that they contain the
ingredients tabulated, at the levels shown.
The detergent composition is added, together with a 6 lb.
load of previously laundered and soiled fabrics (load composition:
20 wt. % polyester fabrics/80 wt. % cotton fabrics), to a Sears
KENMORE washing machine. Actual weights of detergent compositions
are taken to provide a concentration of 1322 ppm for Composition
IX, 1467 ppm for Composition X, and 1718 for Composition XI and
XII, in the 17 l water-fill machine. The water used has 7
grains/gallon hardness and a pH of 7 to 7.5 prior to (about 9 to
about 10.5 after) addition of the detergent and ester
compositions.
The fabrics are laundered at 35-C (95-F) for a full cycle (12
min.) and rinsed at 21-C (70-F). The fabrics are then dried and
are exposed to a variety of soils (by wear or controlled
application). The entire cycle of laundering and soiling is
repeated several times for each of the detergent compositions,
~ 7
with separate fabric bundles reserved for use with each of the
detergent compositions. Excellent results are obtained in all
cases (~X-XI~), especially in that polyester or polyester-
containing fabrics laundered one or several times as described,
display significantly improved removal of soils (especially
oleophilic types) during laundering compared with fabrics which
have not been exposed to the esters of the invention.
