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Description  |
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TECHNICAL FIELD
The present invention relates to an improvement in fabric treatment with
perfumes and compositions and products for accomplishing said treatment,
said products, and/or compositions, being, preferably, either in
particulate form or attached to a substrate.
BACKGROUND OF THE INVENTION
The use of perfumes in solid, dryer-activated, fabric conditioning products
is disclosed in many patents including U.S. Pat. No. 4,808,086 of Mark D.
Evans, Gregory B. Huntington, Robert L. Stewart, Peter H. Wolf, and Roger
E. Zimmerer for "ARTICLES AND METHODS FOR TREATING FABRICS, " issued Feb.
28, 1989, said patent being incorporated herein by reference. There has
been a continuing need for improved deposition and longevity of perfume.
SUMMARY OF THE INVENTION
It has now been discovered that perfumes can be used for fabric treatment
(conditioning), either alone, or in, e.g., softening, compositions,
including those softening compositions that are detergent compatible, by
forming complexes of the perfumes with cyclodextrins and/or their
derivatives as described hereinafter. These complexes have been disclosed
generically and have been suggested for use in a variety of products.
However, their application to fabrics, especially in a laundry dryer,
either alone or in solid, dryer-activated, fabric conditioning
compositions, has not been disclosed. These complexes provide a remarkable
and totally unexpected effect. Specifically, the cyclo-dextrin/perfume
complexes provide improved perfume deposition on fabric, especially of
volatile perfume materials, and delayed and/or controlled release when the
fabrics are wetted or rewetted.
Thus, in its broadest aspects, the invention relates to the method of
applying an effective amount of perfume/cyclodextrin complex to fabric.
Preferably the fabric is at least partially wetted (damp) and more
preferably the method is carried out in an automatic laundry dryer.
DESCRIPTION OF THE INVENTION
Perfume/cyclodextrin complexes can be applied directly to fabrics,
preferably in automatic laundry dryers, and/or preferably in particulate
form, and/or preferably when the fabrics are at least partially wet.
Surprisingly, the complexes are effectively attached to fabrics of all
common types. The strength of the attachment is such that the application
can occur in an automatic laundry dryer to achieve good distribution
despite the violent agitation of the fabrics in the dryer and the effect
of the heated drying air passing over the surface of the fabrics at high
speeds. Alternatively, the complexes can be applied directly to fabric by
spraying a suspension of complex in a solvent that will not displace the
perfume from the complex or by "dusting" to achieve good distribution.
E.g., the perfume/cyclodextrin particles can be sprayed and/or shaken onto
the fabric, preferably damp fabric. Propellants or air under pressure can
be used to form the dispersion. The complexes release some of the perfume
when there is water in the fabric, but, surprisingly, a large amount of
perfume remains in the complexes attached to the fabric. When the fabric
is subsequently rewetted, additional perfume is released to provide an
odor effect. Such odor effects are highly desirable both to generate
pleasant odors when the fabric is rewetted, e.g., for towels and/or
washcloths, and to cover undesirable odors such as those associated with
perspiration. The odor effects on rewetting also serve as an effective
pleasant signal that the fabric is becoming soiled while providing
pleasant freshness effects until the soiled fabric can be exchanged for
clean fabric. Thus it is essential that at least an effective amount be
attached to the fabric. Effective amounts are typically in the range of
from about 0.005 g to about 5 g, preferably from about 0.01 g to about 1
g, more preferably from about 0.05 g to about 0.5 g per kg of fabric. The
wetter the fabric, the more perfume is released initially, and more of the
remaining complex is effectively attached to the fabric. When the fabric
is almost dry, little complex is destroyed and less perfume is applied
initially, but the fabric exhibits odor effects upon rewetting.
More preferably, the perfume/cyclodextrin complex is provided as part of a
dryer-activated, fabric conditioning composition as described hereinafter.
Such compositions provide a convenient way to introduce the
perfume/cyclodextrin complex into the dryer. In the case of
detergent-compatible fabric conditioning compositions, as described
hereinafter, the composition also permits the perfume/cyclodextrin complex
to survive the wash/rinse portions of the laundry process and reach the
dryer with the complex still present in an effective amount. Without
protection, the perfume is released from the complex by the action of
water in the wash and/or rinse cycles.
1. THE FABRIC CONDITIONING COMPOSITIONS
The present invention also relates to improved solid, dryer-activated,
fabric conditioning compositions which are either (A) incorporated into
articles of manufacture in which the fabric conditioning compositions are,
e.g., on a substrate, or, are (B) detergent-compatible compositions,
typically in the form of particles.
A. Substrate Articles
In preferred embodiments, the present invention encompasses articles of
manufacture, adapted for use to provide unique perfume benefits and to
soften fabrics in an automatic laundry dryer, or the types disclosed in
U.S. Pat. Nos.: 3,989,631 Marsan, issued Nov. 2, 1976; 4,055,248, Marsan,
issued Oct. 25, 1977; 4,073,996, Bedenk et al., issued Feb. 14, 1978;
4,022,938, Zaki et al., issued May 10, 1977; 4,764,289, Trinh, issued Aug.
16, 1988; 4,808,086, Evans et al., issued Feb. 28, 1989; 4,103,047, Zaki
et al., issued July 25, 1978; 3,736,668, Dillarstone, issued June 5, 1973;
3,701,202, Compa et al., issued Oct. 31, 1972; 3,634,947, Furgal, issued
Jan. 18, 1972; 3,633,538, Hoeflin, issued Jan. 11, 1972; and 3,435,537,
Rumsey, issued Apr. 1, 1969; and 4,000,340, Murphy et al., issued Dec. 28,
1976, all of said patents being incorporated herein by reference.
Typical articles of manufacture of this type include articles comprising:
I. a fabric conditioning composition comprising:
i. from about 30% to about 99% of fabric softening agent; and
ii. an effective amount, preferably from about 0.5% to about 60%, of
perfume/cyclodextrin complex, as described hereinafter;
II. a dispensing means which provides for release of an effective amount of
said composition to fabrics in an automatic laundry dryer at automatic
laundry dryer operating temperatures, e.g., from about 35.degree. C. to
115.degree. C.
When the dispensing means is a flexible substrate, e.g., in sheet
configuration, the fabric conditioning composition is releasably affixed
on the substrate to provide a weight ratio of conditioning composition to
dry substrate ranging from about 10:1 to about 0.5:1, preferably from
about 5:1 to about 1:1. The invention also comprises the method of
manufacturing such an article of manufacture utilizing said complex ii.,
either by application of the complex ii. directly to said dispensing means
II., or by premixing the complex ii. with the fabric softening agent i.
The softener helps protect the complex from the water in the environment
which is desirable. However, separate application of complex to said
substrate is also possible and can diminish interaction of softener
ingredients with the perfume.
The term "fabric softening agent" as used herein includes cationic and
nonionic fabric softeners used alone and also in combination with each
other. A preferred fabric softening agent of the present invention is a
mixture of cationic and nonionic fabric softeners.
(1.) Fabric Softening Agents
Examples of fabric softening agents that are especially useful in the
substrate articles are the compositions described in U.S. Pat. Nos.
4,103,047Zaki et al., issued July 25, 1978; 4,237,155, Kardouche, issued
Dec. 2, 1980; 3,686,025, Morton, issued Aug. 22, 1972; 3,849,435 Diery et
al., issued Nov. 19, 1974; and U.S. Pat. No. 4,073,996, Bedenk, issued
Feb. 14, 1978; said patents are hereby incorporated herein by reference.
Other fabric softening agents are disclosed hereinafter with respect to
detergent-compatible fabric conditioning compositions.
Particularly preferred cationic fabric softeners for substrate articles
include quaternary ammonium salts such as dialkyl dimethylammonium
chlorides, methylsulfates and ethylsulfates wherein the alkyl groups can
be the same or different and contain from about 14 to about 22 carbon
atoms. Examples of such preferred materials include
ditallowalkyldimethylammonium methylsulfate (DTDMAMS),
distearyldimethylammonium methylsulfate, dipalmityldimethylammonium
methylsulfate and dibehenyldimethylammonium methylsulfate. Also
particularly preferred are the carboxylic acid salts of tertiary
alkylamines disclosed in said Kardouche patent. Examples include
stearyldimethylammonium stearate, distearylmethylammonium myristate,
stearyldimethylammonium palmitate, distearylmethylammonium palmitate, and
distearylmethylammonium laurate. These carboxylic salts can be made in
situ by mixing the corresponding amine and carboxylic acid in the molten
fabric conditioning composition.
Another preferred type of fabric softener is described in detail in U.S.
Pat. No. 4,661,269Toan Trinh, Errol H. Wahl, Donald M. Swartley and Ronald
L. Hemingway, issued Apr. 28, 1987, said patent being incorporated herein
by reference.
Examples of nonionic fabric softeners are the sorbitan esters, C.sub.12
-C.sub.26 fatty alcohols, and fatty amines described herein.
A preferred fabric softening agent for use in substrate articles comprises
a mixture of (1) C.sub.10 -C.sub.26 acyl sorbitan esters and mixtures
thereof, (2) quaternary ammonium salt, and (3) tertiary alkylamine. The
quaternary ammonium salt is preferably present at a level of from about 5%
to about 25%, more preferably from about 7% to about 20% of the fabric
conditioning composition. The sorbitan ester is preferably present at a
level of from about 10% to about 50%, more preferably from about 20% to
about 40%, by weight of the fabric conditioning composition. The tertiary
alkylamine is present at a level of from about 5% to about 25%, more
preferably from 7% to about 20% by weight of the fabric conditioning
composition. The preferred sorbitan ester comprises a member selected from
the group consisting of C.sub.10 -C.sub.26 acyl sorbitan monoesters and
C.sub.10 -C.sub.26 acyl sorbitan di-esters, and ethoxylates of said esters
wherein one or more of the unesterified hydroxyl groups in said esters
contain from 1 to about 6 oxyethylene units, and mixtures thereof. The
quaternary ammonium salt is preferably in the methylsulfate form. The
preferred tertiary alkylamine is selected from the group consisting of
alkyldimethylamine and dialkylmethylamine and mixtures thereof, wherein
the alkyl groups can be the same or different and contain from about 14 to
about 22 carbon atoms.
Yet another preferred fabric softening agent comprises a carboxylic acid
salt of a tertiary alkylamine, in combination with a fatty alcohol and a
quaternary ammonium salt. The carboxylic acid salt of a tertiary amine is
used in the fabric conditioning composition preferably at a level of from
about 5% to about 50%, and more preferably, from about 15% to about 35%,
by weight of the fabric treatment composition. The quaternary ammonium
salt is used preferably at a level of from about 5% to about 25%, and more
preferably, from about 7% to about 20%, by weight of the fabric treatment
composition. The fatty alcohol can be used preferably at a level of from
about 10% to about 25%, and more preferably from about 10% to about 20%,
by weight of the fabric treatment composition. The preferred quaternary
ammonium salt is selected from the group consisting of dialkyl
dimethylammonium salt wherein the alkyl groups can be the same or
different and contain from about 14 to about 22 carbon atoms and wherein
the counteranion is selected from the group consisting of chloride,
methylsulfate and ethylsulfate, preferably methylsulfate. The preferred
carboxylic acid salt of a tertiary alkylamine is selected from the group
consisting of fatty acid salts of alkyldimethylamines wherein the alkyl
group contains from about 14 to about 22 carbon atoms, and the fatty acid
contains from about 14 to about 22 carbon atoms, and mixtures thereof. The
preferred fatty alcohol contains from about 14 to about 22 carbon atoms.
More biodegradable fabric softener compounds can be desirable.
Biodegradability can be increased, e.g., by incorporating easily destroyed
linkages into hydrophobic groups. Such linkages include ester linkages,
amide linkages, and linkages containing unsaturation and/or hydroxy
groups. Examples of such fabric softeners can be found in U.S. Pat. Nos.
3,408,362, Mannheimer, issued Oct. 29, 1968; 4,709,045, Kubo et al.,
issued Nov. 24, 1987; 4,233,451, Pracht et al., issued Nov. 11, 1980;
4,127,489, Pracht el al., issued Nov. 28, 1979; 3,689,424, Berg et al.,
issued Sept. 5, 1972; 4,128,485, Baumann et al., issued Dec. 5, 1978;
4,161,604, Elster et al., issued July 17, 1979; 4,189,593, Wechsler et
al., issued Feb. 19, 1980; and 4,339,391, Hoffman et al., issued July 13,
1982, said patents being incorporated herein by reference.
A preferred article of the present invention includes a fabric treatment
composition which comprises from about 0.5% to about 60%, preferably from
about 1% to about 50%, more preferably from about 5% to about 40%, of
perfume/cyclodextrin complex and from about 30% to about 99%, preferably
from about 40% to about 90%, of fabric conditioning (softening) agent.
Preferably, said fabric softening agent is selected from cationic and
nonionic fabric softeners and mixtures thereof. Preferably, said fabric
softening agent comprises a mixture of about 5% to about 80% of a cationic
fabric softener and about 10% to about 85% of a nonionic fabric softener
by weight of said fabric treatment composition. The selection of the
components is such that the resulting fabric treatment composition has a
melting point above about 38.degree. C. and is flowable at dryer operating
temperatures.
It is desirable, for ease of application, to intimately admix the
ingredients of the fabric treatment before use and before application to a
substrate dispensing means. This can be accomplished by premixing the
ingredients by co-melting, co-milling, etc., or by combinations of such
techniques. For processing reasons, it is desirable to have a clay in the
fabric softener composition in accordance with the teachings found in the
patents incorporated by reference hereinbefore, and especially U.S. Pat.
No. 4,073,996. As discussed hereinafter, clay provides special benefits in
the context of the present invention.
(2) Dispensing Means
In the preferred substrate article embodiment, the fabric treatment
compositions are provided as an article of manufacture in combination with
a dispensing means such as a flexible substrate which effectively releases
the composition in an automatic laundry (clothes) dryer. Such dispensing
means can be designed for single usage or for multiple uses. The
dispensing means can also be a "carrier material" that releases the fabric
softener composition and then is dispersed and/or exhausted from the
dryer.
The dispensing means will normally carry an effective amount of fabric
treatment composition. Such effective amount typically provides sufficient
fabric conditioning agent and/or anionic polymeric soil release agent for
at least one treatment of a minimum load in an automatic laundry dryer.
Amounts of fabric treatment composition for multiple uses, e.g., up to
about 30, can be used. Typical amounts for a single article can vary from
about 0.25 g to about 100 g, preferably from about 0.5 g to about 10 g,
most preferably from about 1 g to about 5 g.
One such article comprises a sponge material releasably enclosing enough
fabric treatment composition to effectively impart fabric soil release and
softness benefits during several cycles of clothes. This multi-use article
can be made by filling a hollow sponge with about 20 grams of the fabric
treatment composition.
Other devices and articles suitable for dispensing the fabric treatment
composition into automatic dryers include those described in U.S. Pat.
Nos. 4,103,047, Zaki et al., issued July 25, 1978; 3,736,668, Dillarstone,
issued June 5, 1973; 3,701,202, Compa et al., issued Oct. 31, 1972;
3,634,947, Furgal, issued Jan. 18, 1972; 3,633,538, Hoeflin, issued Jan.
11, 1972; and 3,435,537, Rumsey, issued Apr. 1, 1969. All of these patents
are incorporated herein by reference.
A highly preferred article herein comprises the fabric treatment
composition releasably affixed to a flexible substrate in a sheet
configuration. Highly preferred paper, woven or nonwoven "absorbent"
substrates useful herein are fully disclosed in Morton, U.S. Pat. No.
3,686,025, issued Aug. 22, 1972, incorporated herein by reference. It is
known that most substances are able to absorb a liquid substance to some
degree; however, the term "absorbent" as used herein, is intended to mean
a substance with an absorbent capacity (i.e., a parameter representing a
substrate's ability to take up and retain a liquid) from 4 to 12,
preferably 5 to 7, times its weight of water.
Determination of absorbent capacity values is made by using the capacity
testing procedures described in U.S. Federal Specifications UU-T-595b,
modified as follows:
1. tap water is used instead of distilled water;
2. the specimen is immersed for 30 seconds instead of 3 minutes;
3. draining time is 15 seconds instead of 1 minute; and
4. the specimen is immediately weighed on a torsion balance having a pan
with turned-up edges.
Absorbent capacity values are then calculated in accordance with the
formula given in said Specification. Based on this test, one-ply, dense
bleached paper (e.g., draft or bond having a basis weight of about 32
pounds per 3,000 square feet) has an absorbent capacity of 3.5 to 4,
commercially available household one-ply toweling paper has a value of 5
to 6; and commercially available two-ply household toweling paper has a
value of 7 to about 9.5.
Using a substrate with an absorbent capacity of less than 4 tends to cause
too rapid release of the fabric treatment composition from the substrate
resulting in several disadvantages, one of which is uneven conditioning of
the fabrics. Using a substrate with an absorbent capacity over 12 is
undesirable, inasmuch as too little of the fabric treatment composition is
released to condition the fabrics in optimal fashion during a normal
drying cycle.
Such a substrate comprises a nonwoven cloth having an absorbent capacity of
preferably from about 5 to 7 and wherein the weight ratio of fabric
treatment composition to substrate on a dry weight basis ranges from about
5:1 to 1:1.
Nonwoven cloth substrates preferably comprise cellulosic fibers having a
length of from 3/16 inch to 2 inches and a denier of from 1.5 to 5 and the
substrates are adhesively bonded together with binder resin.
The flexible substrate preferably has openings sufficient in size and
number to reduce restriction by said article of the flow of air through an
automatic laundry dryer. The better openings comprise a plurality of
rectilinear slits extended along one dimension of the substrate.
(3) Usage
The method aspect of the substrate embodiment of this invention for
imparting the above-described fabric treatment composition to fabric to
provide perfume effects and/or softening and/or antistatic effects to
fabric in an automatic laundry dryer comprises: commongling pieces of damp
fabric by tumbling said fabric under heat in an automatic clothes dryer
with an effective amount of the fabric treatment composition, at least the
continuous phase of said composition having a melting point greater than
about 35.degree. C. and said composition being mobilized, e.g., flowable,
at dryer operating temperature, said composition comprising from about
0.5% to about 60% , preferably from about 1% to about 50%, more preferably
from about 5% to about 40%, of perfume/cyclodextrin complex and from about
30% to about 99%, preferably from about 40% to about 90%, of fabric
softening agent selectee from the above-defined cationic and nonionic
fabric softeners and mixtures thereof.
The method herein is carried out in the following manner. Damp fabrics,
usually containing from about 1 to about 3.5 times their weight of water,
are placed in the drum of an automatic laundry (clothes) dryer. In
practice, such damp fabrics are commonly obtained by laundering, rinsing
and spin-drying the fabrics in a standard washing machine. In a preferred
mode, the present process is carried out by fashioning an article
comprising the substrate-like dispensing means of the type hereinabove
described in releasable combination with a fabric treatment composition.
This article is simply added to a clothes dryer together with the damp
fabrics to be treated. The dryer is then operated in standard fashion to
dry the fabrics, usually at a temperature of from about 50.degree. C. to
about 80.degree. C. for a period from about 10 minutes to about 60
minutes, depending on the fabric load and type. On removal from the dryer,
the dried fabrics have acquired improved perfume benefits and are
softened.
After one treatment in an automatic clothes dryer with an article of the
present invention, the fabrics will have acquired a noticeable perfume
benefit. I.e., more perfume is deposited in the form of
perfume/cyclodextrin complex and, when the fabrics are rewetted, they will
exhibit noticeable perfume odor.
B. Detergent-Compatible Compositions
The other type of fabric conditioning composition useful herein is
detergent-compatible and includes compositions containing softening
particles such as those known in the art, including specifically: U.S.
Pat. No. 3,936,537, Baskerville Jr., issued Feb. 3, 1976, and U.S. Pat.
No. 4,095,946, Jones, issued June 20, 1978, both of which teach the use of
intimate mixtures of organic dispersion inhibitors (e.g., stearyl alcohol
and fatty sorbitan esters) with solid fabric softener to improve the
survival of the softener in the presence of detergent in the washer so
that the softener can act on the fabrics when it is mobilized in the
dryer, and U.S. Pat. No. 4,234,627, Schilling, issued Nov. 18, 1980, which
teaches microencapsulation of fabric softener (The microcapsules survive
the wash and adhere to the fabric surface. They are then ruptured by
subsequent tumbling of the fabric in the dryer, thereby releasing softener
to the fabrics.)
The particles in such detergent-compatible fabric conditioning compositions
comprise at least about 10% of fabric softening agent, preferably cationic
fabric softening agent. For detergent compatibility, the particles often
have a coating as described hereinafter, a sufficiently large particle
size (e.g., a minimum dimension greater than about 5,000 microns), or some
combination of coating and particle size depending upon the identity of
the softener, the other materials in the fabric softening composition,
etc.
The detergent-compatible fabric conditioning composition particles of the
present invention typically comprise an inner core of a fabric
conditioning composition which usually comprises a cationic fabric
softening agent, and, if necessary, an outer coating which protects the
inner core, preferably one which completely surrounds the core and
comprises a substantially water-insoluble material having a melting point
above about 35.degree. C., preferably above about 50.degree. C. By
"substantially water-insoluble" herein is meant having a solubility in
35.degree. C. water of less than about 50 ppm. The particles have
diameters of from about 5 microns to about 15,000 microns, preferably
greater than about 300 microns, and most preferably greater than about 500
microns, with a number average of from about 600 to about 9,000 microns.
The particles typically will be of a generally spherical shape, but can
also have an irregular shape. The particle sizes quoted herein refer to
the largest dimension (diameter or length) of the particle unless
otherwise stated.
The larger, uncoated particles having no dimension less than about 5,000
microns, preferably 10,000 microns, are compatible with detergent
compositions even if uncoated. Such particles are desirable for many
reasons including ease of manufacture. Particles having dimensions that
are less than about 5,000 microns require more or less coating depending
on the size. Particles having maximum dimensions of more than 1,500
microns require less coating for survival. Large, "jumbo" particles are
really practical only when placed in a pouch product as described
hereinafter since segregation and/or loss of the particle during the
laundry process are likely.
(1) The Fabric Softener
Typical cationic fabric softeners useful in the detergent-compatible fabric
conditioning compositions herein include those that have been described
hereinbefore with respect to the substrate articles and include quaternary
ammonium salts of the formula
[R.sub.1 R.sub.2 R.sub.3 R.sub.4 N]+Y-
wherein one or two of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 groups is an
organic radical containing a group selected from a C.sub.12 -C.sub.22
aliphatic radical or an alkylphenyl or alkylbenzyl radical having from 10
to 16 carbon atoms in the alkyl chain, the remaining groups being selected
from C.sub.1 -C.sub.4 alkyl, C.sub.2 -C.sub.4 hydroxyalkyl and cyclic
structures in which the nitrogen atom in the above formula forms part of
the ring, and Y constitutes an anionic radical such as halide, nitrate,
bisulfate, methylsulfate, ethylsulfate and phosphate, to balance the
cationic charge.
In the context of the above definition, the hydrophobic moiety (i.e., the
C.sub.12 -C.sub.22 aliphatic, C.sub.10 -C.sub.16 alkyl phenol or
alkylbenzyl radical) in the organic radical R.sub.1 or R.sub.2 can be
directly attached to the quaternary nitrogen atom or can be indirectly
attached thereto through an amide, ester, alkoxy, ether, or like grouping.
The quaternary ammonium compounds useful in detergent compatible
compositions herein include both water-soluble compounds and substantially
water-insoluble compounds which are dispersible in water. For example,
imidazolinium compounds of the structure
##STR1##
wherein R is a C.sub.16 to C.sub.22 alkyl group, possess appreciable water
solubility, but can be utilized in the present invention.
The following are representative examples of quaternary ammonium softening
compounds suitable for use in the detergent-compatible compositions of the
present invention. All the quaternary ammonium compounds listed can be
included in the present invention, but the compilation of suitable
quaternary compounds hereinafter is only by way of example and is not
intended to be limiting of such compounds. Dioctadecyldimethylammonium
methylsulfate is an especially preferred fabric softening compound for use
herein, by virtue of its high antistatic, as well as fabric softening
activity; ditallowalkyldimethylammonium methylsulfate is equally preferred
because of its ready availability and its good antistatic activity; other
useful di-long chain quaternary compounds are dicetyldimethylammonium
chloride, didocosyldimethylammonium chloride, didodecyldimethylammonium
chloride, ditallowalkyldimethylammonium bromide, dioleoyldimethylammonium
methylsulfate, ditallowalkyldiethylammonium chloride,
ditallowalkyldipropylammonium bromide, ditallowalkyldibutylammonium
fluoride, cetyldecylmethylethylammonium chloride,
bis-[ditallowalkyldimethylammonium] bisulfate,
tris-[ditallowalkyldimethylammonium] phosphate,
1-methyl-1-tallowamidoethyl-2-tallowimidazolinium methylsulfate, and the
like. Particularly preferred quaternary ammonium fabric softening
compounds are ditallowalkyldimethylammonium chloride (DTDMAC) and
ditallowalkyldimethylammonium methylsulfate. The fabric softener core of
the coated particles of the invention comprises from about 70% to about
98% and most preferably about 85% to about 97% of the particle. All
percentages herein are "by weight" unless otherwise indicated.
The quaternary ammonium softener compounds used in this invention in both
substrate articles and detergent-compatible compositions can be prepared
in various ways well-known in the art and many such materials are
commercially available. The quaternaries are often made from alkyl halide
mixtures corresponding to the mixed alkyl chain lengths in fatty acids.
For example, the ditallowalkyl quaternaries are made from alkyl halides
having mixed C.sub.14 -C.sub.18 chain lengths. Such mixed di-long chain
quaternaries are useful herein and are preferred from a cost standpoint.
The anionic group which can be the counter-ion in the quaternary compounds
useful herein is typically a halide (e.g., chloride or bromide), nitrate,
bisulfate, ethylsulfate, or methylsulfate. The methylsulfate and chloride
ions are the preferred counter-anions from an availability standpoint;
while the methylsulfate anion is most preferred because of its
minimization of corrosive effects on the automatic clothes dryers in which
it is used.
The softener compositions, e.g., the core composition of the coated
particles, can consist entirely of cationic fabric softeners and the
silica particles described hereinafter. The softener composition, e.g.,
core, will generally comprise at least 10%, usually from about 10% to
about 90%, preferably from about 20% to about 60%, fabric softening agent,
preferably cationic fabric softener, and from about 0.5% to about 60%,
preferably from about 1% to about 50%, more preferably from about 5% to
about 40% of perfume-cyclodextrin complex as described hereinafter.
Optionally, and preferably, the composition can contain additional
materials besides the perfume/cyclodextrin complexes described
hereinafter, including auxiliary fabric softening agents (e.g., smectite
clay, fatty alcohols and fatty amine(s), such as ditallowmethyl amine or
1-tallowamidoethyl-2-tallowimidazoline), soil release agents, fabric
brighteners, etc. Additional disclosure of materials which can be applied
to fabrics along with cationic fabric softening agents in a laundry dryer
and, therefore, can be part of the core composition of the particles
herein, are disclosed in U.S. Pat. Nos. 4,073,996, Bedenk et al., issued
Feb. 14, 1978; 4,237,155, Kardouche, issued Dec. 2, 1980; and 4,421,792,
Rudy et al., issued Dec. 20, 1983, all incorporated herein be reference.
(2) The Coating Materials
The preferred coating materials used in the coated particles are
substantially water-insoluble materials, typically (but not necessarily)
selected from waxy materials such as paraffinic waxes, microcrystalline
waxes, animal waxes, vegetable waxes, saturated fatty acids and fatty
alcohols having from 12 to 40 carbon atoms in their alkyl chain, and fatty
esters such as fatty acid triglycerides, fatty acid esters of sorbitan and
fatty acid esters of fatty alcohols, or from substantially water-insoluble
polymers. Typical specific suitable waxy coating materials include lauric,
myristic, palmitic, stearic, arachidic and behenic acids, stearyl and
behenyl alcohol, microcrystalline wax, beeswax, spermaceti wax, candelilla
wax, sorbitan tristearate, sorbitan tetralaurate, tripalmitin, trimyristin
and octacosane. A preferred waxy material is stearyl alcohol.
Examples of water-insoluble polymeric materials which can be used for the
coating of the particles herein are cellulose ethers such as ethyl, propyl
or butyl cellulose; cellulose esters such as cellulose acetate,
propionate, butyrate or acetate-butyrate; ureaformaldehyde resins,
polyvinyl chloride, polyvinylidene chloride, polyethylene, polypropylene,
polyacrylates, polymethacrylates, polymethyl-methacrylates and nylon. Such
materials and their equivalents are described in greater detail in any
conventional handbook of synthetic organic plastics, for example, in
Modern Plastics Encyclopaedia Volume, Vol. 62, No. 10A (for 1985-1986) at
pages 768-787, published by McGraw-Hill, N.Y. (October 1985), incorporated
herein by reference. A preferred polymeric material is ethyl cellulose.
The polymeric coating materials can be plasticized with known plasticizing
agents such as phthalate, adipate and sebacate esters, polyols (e.g.,
ethylene glycol), tricresyl phosphate, castor oil and camphor. These
polymeric coatings are preferred for the superior protection they provide.
The coating surrounds the cationic fabric softener core and is present in
an amount of from about 2% to about 30%, preferably from about 3% to about
15% by weight of the particle.
The coating material can comprise a mixture of waxy coating materials and
polymeric coating materials. In such mixtures the waxy coating material
will typically comprises from about 70% to about 90% of the mixture and
the polymeric material about 30% to about 10%.
Typically, the coating material will have a hardness which corresponds to a
needle penetration value of about 0.6 mm or less, and preferably less than
about 0.1 mm, as measured by ASTM Test D-1321, modified by using a 100 g
weight instead of a 50 g weight. The test is performed at
25.degree.-27.degree. C. In the case of polymeric coating materials,
sample preparation is accomplished by dissolving the polymer in a volatile
solvent and then evaporating the solvent after the polymer solution has
been placed in the test container. For waxy coating materials, sample
preparation is done by melting the sample and the solidifying it in the
test container in the manner set forth in the ASTM method.
The function of the coating which surrounds the fabric softener is to
prevent the softener from becoming dissolved and/or dispersed in the wash
water when the particles are present during the wash step of a laundry
process, and thereby prevent interaction between the fabric softener and
the detergent. During the washing and rinsing of the fabrics, a
substantial amount of the particles adhere to, or become entrapped within
folds of the fabrics. When the fabrics are dried in a heated automatic
clothes dryer (typically at temperatures of about 65.degree. to 85.degree.
C.), the coating and the fabric softener core composition melt, thereby
permitting the softener to spread throughout the fabric load and soften
the fabrics. The coating materials are disclosed in the copending U.S.
patent application of Wierenga et al, for DETERGENT COMPATIBLE, DRYER
RELEASED FABRIC SOFTENING/ANTISTATIC AGENTS, Ser. No. 058,449, filed June
5, 1987.
If the softener particles will survive the conditions of use and be
available in the clothes dryer, a coating is not required.
If the particles are incorporated directly into a loose granular detergent
composition, it is preferred that the particle size of the softener
particles be similar to the particle size of the detergent granule in
order to minimize segregation. This will typically be in the range of from
about 500 to about 1,500 microns. Softener particles which are smaller in
size than the detergent granules can be agglomerated to form larger
particles to match the particle size of the detergent granules into which
they will be incorporated. The agglomeration can be accomplished by using
water-soluble or dispersible materials such as polyvinyl alcohol, sodium
carboxymethyl cellulose, gelatin and polyoxyethylene waxes. The
agglomerates disintegrate when the detergent composition is added to
water. Methods and agglomerating agents for agglomeration of fabric
softener particles are described in U.S. Pat. No. 4,141,841, McDanald,
issued Feb. 27, 1979, incorporated by reference herein.
Desirable additives to such detergent-compatible compositions include
silica particles which have a diameter of from about 0.001 micron to
about 15 microns. The silica particles, when they have a diameter of
greater than about one micron and are present at a level of at least about
4% in said dryer-activated fabric softening compositions, can provide
protection against staining. It is also often desirable that silica gel
particles be used in softener compositions to maintain the desired
viscosity range, e.g., from about 5,000 to about 30,000 mPas, preferably
from about 8,000 to about 20,000 mPas, of the softener when it is in the
molten form, while improving the aesthetic character of any subsequent
noticeable softener deposits on fabric by acting as a visual "masking"
adjuvant. The desired level of silica gel particles in solid softener
compositions, including the substrate articles described hereinbefore, is
from about 2% to about 15%, preferably from about 4% to about 12% . The
preferred particle size that is desired for softener compositions is from
about 1 micron to about 15 microns, preferably from about 2 microns to
about 6 microns.
(3) Preparation of Particles
In preparing the optional coated softener particles of the invention, the
solid fabric softener composition and any visual "masking" adjuvant (MA),
which are to be the core of the particles, are formed into particles
having a size of from about 5 microns to about 15,000 microns. This can be
accomplished, for example, by milling the solid softener composition or be
melting the composition, mixing the MA into the resulting melt, and
spraying the melt through appropriate sized nozzles into an atmosphere
having a temperature below the melting point of the softener, thereby
forming the softener-composition/MA mixture into solid particles.
The particles of softener-composition/MA can then be coated with coating
material which is typically either melted or dissolved in a volatile
solvent. The coating can be done at a temperature which is below the
melting point of the softener composition, and the coated particles are
then cooled (or the solvent is evaporated) to solidify the coating. The
coating is typically applied in a fluidized bed type apparatus. A suitable
type of apparatus is that described in U.S. Pat. No. 3,196,827, Wurster et
al., issued July 27, 1965, incorporated by reference herein. In this
apparatus, solid softener core particles are suspended in an air stream
which caries them in a smooth cyclic flow past the coating nozzle, which
sprays them with fluid coating material. Air atomizes and expels the
coating fluid through the coating nozzle. The atomized coating fluid
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