Note: Descriptions are shown in the official language in which they were submitted.
; , , CA 02232473 1998-03-17
570-8
DRYER-ACTIVATED FABRIC CONDITIONING
AND ANTISTATIC CO~POSITIONS
TECHNICAL FIELD
The present disclosure relates to dryer-activated
softening products, compositions and processes for making
same.
TECHNICAL BACKGROUND
Textile softening compositions are generally delivered
either in the wash cycle or during the drying-cycle. In a
dryer-added softener, the softening composition is normally
provided on a substrate (e.g., sheet or sponge). Heat from
the dryer causes release of the softening composition from the
substrate.
Uneven release of the softening composition from the
substrate during the drying cycle is not uncommon among dryer-
activated softeners which are presently commercially
available. The result may be unsatisfactory softening and/or
unsatisfactory antistatic performance. It would be desirable
to provide a dryer-activated softener product that achieves a
more uniform delivery of the softening composition.
SUMMARY OF THE INVENTION
Dryer-activated fabric softening compositions and
articles have been discovered. When the compositions are
- applied to a substrate, the resulting articles exhibit
improved delivery of the composition from the substrate and/or
improved antistatic effects. These compositions and/or
articles comprise a blend of nonionic and cationic surfactantc
exhibiting a broad trough endotherm between about room
temperature and about 60~C. Particularly useful blends
contain at least about 40~ by weight cationic surfactant with
the balance of the blend being one or more nonionic:
surfactants. Preferred cationic surfactants for making the
blend are quartenary compounds of the ~ormula:
CA 02232473 1998-03-17
Rl- Nl - R3 (I)
R4 X~
wherein R1 is selected from the group consisting of C12 - C24
O Z
// /
aliphatic groups, and Rs(C)m(-OCH-CH2)~- groups wherein m=0 or
1, n=1 to 6 and Z is selected from the group consisting of
hydrogen, and C1 to C6 alkyl or alkylene group, and Rs is Cl~-C23
aliphatic;
R2 and R3 can be the same or different and are
indlvidually selected from the group consisting of Rl, Cl-C6
aliphatic groups, and oxyalkylene or polyoxyalkylene groups of
similar or dissimilar naturei
R4 is a Cl-C4 alkyl; and
X~ is any compatible anion, examples of which
include, but are not limited to halogen, methylsulfate,
ethylsulfate, acetate, carbonate, nitrate, phosphate and
methylcarbonate.
The softener compositions described herein are
preferably applied to a substrate. In use, the impregnated
and/or coated substrate is placed in the dryer with clothes or
other textiles to be dried and softened. Due to the broad
trough endotherm, a relatively uniform release of softener
composition is achieved throughout the drying cycle. The
compositions described herein provide excellent antistatic
activity.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 graphically depicts static charge and weight
loss both as a function of time for the dryer-activated
softening product of E~ample 1.
Figure 2 is a DSC curve for the product of Example 1.
Figure 3 graphically depicts static charge and weight
CA 02232473 1998-03-17
loss both as a function of time for the dryer-activated
softening product of Example 2.
Figure 4 is a DSC curve for the product of Example 2.
Figure 5 graphically depicts static charge and weight
loss both as a function of time fo~ the dryer-activated
softening product of the Comparative Example.
Figure 6 is a DSC curve for the product of the
Comparative Example.
DETAILED DESCRIPTION OF PREFERRED EMBO~IMENTS
Fabric softening compositions and articles having
improved delivery from a substrate and/or antistatic effects
are described herein for use in an automatic clothes dryer.
The compositions comprise a blend of cationic and nonionic
surfactants. The surfactant blend exhibits, as indicated by
Differential Scanning Calorimetry, a broad trough endotherm
between about room temperature and about 60~C. The trough
minimum preferably corresponds to a temperature in the range
between about 45~C and about 55~C. Surfactant blends
exhibiting such heat absorption characteristics achieve a
relatively even release of the softening composition during a
typical drying cycle, thereby providing desirable and improved
softening and antistatic effects.
The surfactant blend contains at least one cationic
surfactant. Suitable cationic surfactants are quaternary
ammonium compounds of the formula:
R1- N+- R3 . (I)
R4 X~
3s wherein Rl is selected from the group consisting of Cl2 - C24
- ~ CA 02232473 1998-03-17
O Z
// /
aliphatic groups, and Rs(C)m(-OC~-C~2)~- groups wherein m=0 or
1, n=1 to 6 and Z is selected from the group consisting of
hydrosen, and Cl to C6 alkyl or alkylene group, and Rs is C11-C2
aliphatic;
R2 and R~ can be the same or different and are
individually selected from the group consisting of R1, C1-C
aliphatic groups, and oxyalkylene or polyoxyalkylene groups of
similar or dissimilar nature;
R4 is a Cl-C4 alkyl; and
X~ is any compati~le anion, examples of which
include, but are not limited to halogen, methylsulfate,
ethylsulfate, acetate, carbonate, nitrate, phosphate and
methylcar~onate.
Suitable quaternary compounds include, but are not
limited to dihydrogenated tallow dimethyl ammonium methyl
sulfate, ditallow dimethyl ammonium methyl sulfate,
dihydrogenated palm dimethyl ammonium methyl sulfate, dipalm
dimethyl ammonium methyl sulfate and mixtures thereof.
The cationic surfactants can be blended with nonionic
surfactants to ~roduce surfactant blends. Any conventional
nonionic surfactant can be blended with the above-described
cationic surfactant, provided the blend exhibits a broad
trough endotherm between about room temperature and about
60OC. In a preferred embodiment a blend of non-ionic
surfactants is employed.
Suitable nonionic surfactants include the r@action
products of alkylene oxide with hydrophobic groups. By way of
example, ethylene oxide or propylene oxide can be reacted with
fatty acids, fatty alcohols or alkylphenols. As other
examples, fatty acid alkanolamides, glycerol esters (e.g.,
glycerol monostearate or fatty alcohols (e.g., stearyl
alcohol)) can be used as the nonionic surfactant. Other
specific examples of suitable nonionic surfactants include:
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a. the condensation product of 1 mole of a saturated or
unsaturated, straight or branched chained aliphatic alcoh
having from about 10 to about 24 carbon atoms with from about
1 to about 40 moles of alkylene oxide, preferably from about
3 to about 20 moles of alkylene oxide, and still more
preferably from about 4 to about 10 moles of alkylene oxide;
b. the condensation product of 1 mole of a saturated or
unsaturated, straight or branched chain aliphatic carboxylic
acid having from about 10 to about 24 carbon atoms with from
about 1 to about 50 moles of alkylene oxide, preferably from
3 to about 20 moles of alkylene oxide, and still more
preferably from about 4 to about 10 moles of alkylene oxide;
c. aliphatic carboxylic acids containing from about 12
to about 30 carbon atomsi
d. aliphatic alcohols having from about 16 to about 30
carbon atoms;
e. the condensation product of 1 mole of an alkyl
phenol, wherein the alkyl chain has from about eight to about
18 carbon atoms, with from about 2 to about 50 moles of
alkylene oxide, preferably from about 4 to about 35 moles of
alkylene oxide, and still more preferably from about 6 to
about 15 moles of alkylene oxide;
f. glycerides, selected from the group consisting of
monoglycerides, diglycerides, triglycerides and mixtures
thereof;
g. amides, selected from the group consisting of:
i. propyl amide,
ii. N-methyl amides having an acyl chain length of
from about 10 to about 15 carbon atoms,
iii. oleamide,
iv. amides of ricinoleic acid,
v. N-isobutyl amides of pelargonic, capric,
undecanoic, or lauric acids,
vi. N-(2-hydroxylethyl) amides having a carbon
chain length of from about six to about 10
CA 02232473 1998-03-17
carbon atoms,
vii. pentylanilide,
- vii. anilides having a carbon chain length of from
about seven to about 12 carbon atoms,
ix. N-cyclopentyllauramide ard N-cyclo-
pentylstearamide, and
x. glucose amides; and
h. the condensation product of 1 mole of a primary or
secondary amine containing at least 12 carbon atoms with from
1 to about 100 moles of alkylene oxide, preferably from about
3 to about 50 moles of alkylene oxide, and still more
preferably from about 4 to about 25 moles of alkylene oxide.
Fatty acid ethoxylates and triglycerides are particularly
useful nonionic surfactants. Most preferred are ~thofat~
18/14 (an Akzo Nobel ethoxylate) and Pristerene3 4911 (a fatty
acid from Unichema).
While the cationic and nonionic surfactants can be
blended in any proportion that provides the desired endotherm,
particularly useful compositions contain at least about 40~ by
weight of the cationic surfactant. In particularly useful
embodiments, two or more nonionic surfactants are blended with
the cationic surfactant in making the softening composition.
The manner of preparing the surfactant blend and applying
the blend to a substrate is not critical. In a typical
preparation, cationic surfactant is produced in a diluant or
neat, such that the temperature is maintained preferably
between 45~C and 150~C or at a temperature sufficient to
maintain liquidity during quaternization. The concen~ration
of quaternary at this point could range anywhere from 40~ to
100~ tby weight). After quaternization, the concentration of
nonionic can be adjusted to the desired level by adding the
liquified nonionic to the cationic or vice versa. When the
quaternization is performed, a non-ionic surfactant or a blend
of non-ionic surfactants can be utilized as a diluent to
maintain liquidity of the reaction mixture. The benefit of
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such procedure is that the non-ionic surfactant or blend of
non-ionic surfactants need not be removed from the final
product, as it becomes an integral component thereof.
Alternatively, organic solvents can be used as diluents during
the quaternization. However, it is desirable to remove such
solvents to a level of below l~ and more preferably to a level
of below 0.5~ prior to use as a tumble dryer sheet active
because of flammability and possible health considerations.
Typically, short chain aliphatic alcohols (for example, C1 to
C6 alcohols such as ethanol, propanol, isopropanol or butanol
and the like) can be employed as the diluent.
Optional components which can be included in the
softening compositions described herein include soil re~ease
agents, perfume components (e.g. free perfume or
cyclodextrin/perfume complexes), stabilizers (including
antioxidants and reductive agents), colorants, preservatives,
optical brighteners, opacifiers, anti-shrinkage agents,
antiwrinkle agents, fabric crisping agents, spotting agents,
germicides, fungicides, anti-corrosion agents, antifoam agents
and the like.
In particularly useful embodiments, the softening
compositions described herein are incorporated into articles
of manufacture. Representative articles are those that are
adapted to soften fabrics in an automatic laundry dryer, such
25as the types disclosed in U.S. Pat. Nos. 3,989,631; 4,055,248;
4,073,996; 4,022,938i 4,764,289; 4,808,086; 4,103,047;
3,736,668; 3,701,202; 3,634,947; 3,633,538; 3,435,537 and
4,000,340, all of said patents being incorporated he-rein by
reference.
30In a preferred substrate article embodimeht, the
softening compositions described herein are provided as an
article of manufacture in combination with a dispensing means
such as a flexible substrate which e fec~ively releases the
composition in an automatic laundry (clothes) dryer. Such
dispensing means can be designed for single usage or for
CA 02232473 1998-03-17
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 effectivè amount
typically provides sufficient fabric softening/antistatic
composition for at least one treatment of a minimum load in an
automatic laundry dryer. Amounts of fabric softening
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 20 g, most preferably from about 1 g to about 10 g.
Highly preferred paper, woven or nonwoven "absorbent"
substrates useful herein are fully disclosed in U.S. Pat. No.
153,686,025, 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
20retain a liquid) from 4 to 12, preferably 5 to 7, times its
weight of water.
Another article comprises a sponge material releasably
enclosing enough fabric softening composition to effectively
impart antistatic effect and/or softness benefits during
several cycles of drying clothes. This multi-use article can
be made by filling a hollow sponge with about 20 grams of the
fabric softening composition described herein.
Once applied to the substrate, the fabric softening
composition described herein can be applied to fabric to
provide softening and/or antistatic effects to fabric in an
automatic laundry dryer. Generally, the method of using the
compositions described herein comprises: commingling pieces of
damp fabric by tumbling said fabric under heat in an automatic
clothes dryer with an effective amount of the fabric softening
composition. The composition preferably has a melting point
~ CA 02232473 1998-03-17
greater than about room temperature (e.g., about 35~C) and the
composition is flowable at dryer operating temperatures.
The following are nonlimiting examples of the instant
articles, methods and compositions of the present invention.
Exam~le 1
In this example a composition comprising roughly 50~ cf
dihydrogenated tallow dimethyl ammonium methyl sulfate in
combination with 25~ stearic acid and 25~ ethoxylated stearic
acid (4 moles of ethylene oxide) is evenly distributed on a
polyester nonwoven substrate for use in the tumble dryer. A
typical method for accomplishing this is to place the active
onto a warm temperature-controlled surface and place the non-
woven substrate sheet on top. The active is then spread using
a rolling device and applying a fixed amount of downward force
during the rolling.
The sheets loaded with approximately 1.5 grams of
active were then evaluated using the standard protocol for
evaluating tumble dryer sheet effectiveness in a tumble dryer.
A sheet was added with the wet fabric (roughly 7.0 lbs of
mixed fabric/garments). The electric tumble dryer was set to
"high~ and was allowed to tumble for up to 70 minutes without
a cool-down cycle. Static charge measurements were made at 5
minute intervals on a pair of women~s, polyester fabric pants.
Measurements were made using a hand-held Simco~ static charge
voltmeter. Additionally, measurements were made of the tumble
dryer sheet to determine the release of active from the non-
woven during the drying process. Graphs of static charge as
a function of time and weight loss from the sheet as a
function of time are shown in Figure 1. Also to get a better
understanding of the amount of charge being accumulated in the
tumble dryer as a function of time the point charge data was
integrated to yield a value which could be described as the
total ~Ipower~l developed during the drying process. This
values give a relatively good value for making comparisons of
effectiveness of different tumble dryer treatments. Since it
CA 02232473 1998-03-17
ls desired that the addition of the tumble dryer sheet will
result in decreased amounts of static charge development, the
lower the value of the "power" the more effective the
sheet/treatment. The amount of active available for release
is approximately 1.5 grams. The effectiveness on reducing
static charge and the total amount of material being released
into the drying fabric is measured periodically. The amount
of static charge values and the weight of product released
into the tumbling fabric is shown graphically in ~igure l as
a function of drying time. The DSC of the active of Example
1 is shown in Figure 2.
Example 2
A nonwoven substrate carrying 1.5 grams of a composition
containing 40~ dihydrogenated tallow dimethyl ammonium methyl
sulfate, 30~ stearic acid and 30~ ethoxylated stearic acid (4
moles of ethylene oxide) is prepared and tested as in the
previous ~xample A plot of the static charge and release of
actives into the fabric as a function of time is shown in
Figure 3. Figure 4 shows a plot of the DSC for this material.
Com~arative ExamPle
For comparison a typical commercial composition of dryer sheet
active (Armosoft~ DA-3 a tradename of Akzo Nobel Chemicals
Inc.) is distributed evenly on a polyester nonwoven substrate
of dimension 9"xll". This sheet was loaded so that the amount
of product available for transfer was 1.5 grams. Measurements
of static charge and product transferred from the nonwoven are
made for comparison with data from the previous examples. The
data is graphically shown in Figure 5. The amount of static
charge accumulated during the latter half of the drying cycle
increases significantly. Also, there is a less even~ release
of actives from the dryer sheet than in previous examples.
A DSC of the Armosoft DA-3 is shown in Figure 6. The DSC
curves of the materials in Examples 1-2, show a broad
endotherm, or single minimum trough which had a minimum in the
region of 50-60~C. In contrast, the DSC of Armosoft DA-3 of
CA 02232473 1998-03-17
the Comparative Example, there are two distinct troughs and
minima for the composition indicating that the material does
not soften evenly over the course of the drying/heating. This
also indicates a propensity for the material being released to
have a different composition over the drying history.
The foIlowing Table I summarizes data from the foregoing
Examples and compares the integrals of static charge as a
function of time. The integrals of Examples 1-2 are all of
significantly lower values for the materials herewith falling
under the teachings of the present disclosure, as compared
with that of a typical dryer sheet active as represented by
the Comparative Example.
Table I
PRODUCT INTEGRAL OF AVG. STATIC AVG.~ WEIGHT
STATI~ CHARGE ~ 70 RELEASED FROM
MINS. (kV) SHEET @ 70
MINS
Comparative 720.75 0.955 81.67
Example
Example 1 206.00 0.027 92.8
Example 2 293.50 0.313 87.87
As the foregoing examples show, the compositions
described herein provide a more even application of softening
and antistatic properties over the entire drying cycle. These
results are most easily seen by comparing the two peak DSC
curves of conventional compositions which indicate uneven
release of the composition, and the broad trough endotherm
shown in a DSC curve of compositions in accordance wi-th this
disclosure.
Modifications and variations of the compositions and
processes described herein are possible in light of the above
teachings. It is therefore to be understood that changes may
be made in particular embodiments described which are within
the full intended scope of the invention as defined by the
claims.
