Note: Descriptions are shown in the official language in which they were submitted.
ll3aos6
-- 2 --
ARTICLES AND METHODS FOR TREATING FABRICS
Nabil G. Kardouche
BACKGROUN~ ART
The present invention pertains to articles
and met~ods for providing softening and antistatic benefits '
to fabrics, ana especially to the providing of these bene-
fits by treatment of the fabrics in an automatic laundry
dryer. r~ore specifically, damp fabrics are contacted with
a carboxylic acid salt of a long chain tertiary amine in an
automatic clothes dryer and are thereby provided with a
soft, antistatic finish concurrently with the drying
operation. The softening and~antistatic carboxylic acid salt
' : of a long chain tertiary amine is preferably employed in
;'~ 15 combination with a dispensing means adapted for use in an
automatic dryer.
Treatment in an automatic clothes dryer has been
shown to be an effective means for imparting desirable -~
~j~ tactile properties to fabrics. For example, it is becoming
common to soften fabrics in an automatic clothes dryer
~J ~ rather than during the rinse cycle of a laundering operation.
(See Gaiser, U.S. Patent 3,442,692, issued May 6, 1969.)
., .
Fabric "softness" is an expression well-defined
`~ in the art and is usually understood to be that quality of
the treated fabric whereby its handle or texture is
smooth, pliable and fluffy to the touch~ Various chemical
compounds have long been known to possess the ability to
i soften fabrics when applied to them during a laundering
operation, particularly during the rinse cycle.
Fabric softness also connotes the absence of
; static "cling" in the fabrics, and the commonly used cationic
fabric softeners provide both softening and antistatic
., . . .. . . .. ~ . . . . :
~13(~05S
--3--
benefits when applied to fabrics. The imparting of softening/
antistatic benefits to fabrics can also be referred to by the
more generic term, fabric conditioning.
Fatty alkyl cationic antistatic softening compounds and
compositions designed for application to fabrics in an automatic
dryer have been the subject of recent innovations. (See, for
example, Furgal, U.S. Patent 3,634,947, issued January 18, 1972,
and Morton, U.S. Patent 3,686,025, issued August 22, 1972.)
Other fatty materials have been suggested for use as dryer-added
fabric softeners/antistats. (See, for example, Hewitt et al.,
U.S. Patent 3,676,199, issued July 11, 1972, and Zaki et al.,
U.S. Patent 4,022,938, issued May 10, 1977.)
The use of fatty amines and the salts of such amines
as fabric conditioning agents in the washing and rinsing cycles
of an automatic washer, as well as the drying cycle of an auto-
; matic dryer, has been disclosed. (See for example, Blomfield,
U.S. Patent 3,095,373, issued June 25, 1963; Gaiser, U.S.
Patent 3,442,692, issued May 6, 1969; Gaiser, U.S. Patent
3,895,128, issued July 15, 1975; and South African Patent
69/3923.) The use of amines in a dryer context, however, is
accompanied by odor problems and/or softening of the paint used
on interior dryer surfaces. U.S. Patent 4,077,891, Beimesch et
al., issued March 7, 1978, describes formic acid salts of primary
amines as acceptable softeners for use in the dryer in that they
do not produce amine odors and they reduce paint softening
problems. Although the use of formic acid salts of primary
amines provides advantages in odor, paint soften and/or fabric
softening performance over use of the corresponding free amines
or other salts of the amines (such as the hydrochlorides), it is
desired to obtain further improvements in these properties beyond
those which are achieved with the primary amine formates.
~13U056
It is, therefore, an object of the present invention
to provide fabric softening articles for use in automatic
dryers which are superior in odor and/or paint softening
(i.e., less paint softening) and/or fabric softening perform-
ance, compared to similar articles which utilize primary amine
formates as the fabric conditioning agent.
This and o~her objects are obtained herein, as will
be seen from the following disclosure.
Additionally, tertiary amine salts of carboxylic
acids have superior chemical stability, compared to primary
and secondary amine carboxylate salts. For example, primary
and secondary amine carboxylates tend to form amides when
heated, e.g., during processing or use in the dryer. Also,
they absorb carbon dioxide, thereby forming high melting
carbamates which build up as an undesirable residue on
treated fabrics.
DISCLOSURE OF INVENTION
The present invention encompasses an article of
manufacture adapted for use to soften fabrics in an automatic
laundry dryer comprising: (a) a abric softening composition,
which comprises, as its essential ingredient, a carboxylic
acid salt of a tertiary amine having at least one long chain,
as defined hereinafter, and (b) a dispensing means which -~
provides for release of an effective amount of said com-
position to fabrics in the dryer at automatic dryer operating
; temperatures, i.e., 35C-115C.
The invention also encompasses a method for
imparting a sotening and antistatic effect to fabrics in an
automatic clothes dryer comprising tumbling said fabrics
under heat in a clothes dryer with an effective, i.e.,
softening, amount of a composition comprising a carboxylic
acid salt of a tertiary amine.
'
,~
.~ '....... ~
056
-5-
Fabric Softening Compositions
Fabric softening compositions employed herein
contain as their essential component a carboxylic acid salt
of a tertiary amine which has at least one long aliphatic
chain containing from about 12 to about 22 carbon atoms.
Such compositions can also contain a variety of optional
materials.
The tertiary amine salts are a direct product of
the reaction between a tertiary amine and a carboxylic acid.
The tertiary amines utilized in the present
invention have the formula
R
12
Rl - N R3
wherein Rl is a long chain aliphatic group containing from
12 to 22 carbon atoms and R2 and R3 can be the same or
different from each other and are selected from the group
consisting of aliphatic groups containing from 1 to 22
carbon atoms, hydroxyalkyl groups of the formula -R40H
~wherein R4 is an alkylene group of 1 to 3 carbon atoms, and
alkyl ether groups of the formula R50(CnH2nO)m wherein R5
is alkyl or alkenyl of from 1 to 20 carbon atoms or hydrogen,
n is 2 or 3 and m is from 1 to 20. Preferred amines are those
wherein Rl is an aliphatic chain containing from 12 to 22
carbon atoms, R2 is an aliphatic chain of from l to 22
- ~ carbon atoms, and R3 is an aliphatic chain of from l to 3
carbon atoms.
Examples of specific tertiary amines are:
.i lauryldimethylamine,
myristyldiethylamine,
stearyldimethylamine,
tallowdimethylamine,
~;j coconutdimethylamine,
dilaurylmethylamine,
distearylmethylamine,
. . ~
; . . .
.
.~
~-
~13COS6
ditallowmethylamine,
oleyl dimethylamine,
dioleyl methylamine,
lauryldi(3-hydroxypropyl)amine,
stearyldi(2-hydroxyethyl)amine,
trilaurylamine,
laurylethylmethylamine,
~',
~ ~ 2 4 lO
C1 8H3 7N
-- (C2H4) loOH
The carboxylic acids have the formula
O
Il ~
R6
wherein R6 can be hydrogen, alkyl, alkenyl, aryl, alkaryl
and aralkyl of 1 to 22 carbon atoms, or substituted alkyl, -
lS alkenyl, aryl, alkaryl, or aralkyl of from l to 22 carbon
j atoms wherein the substituents are selected from the group
consisting of halogen (e.g., Cl or Br), carboxyl, or
hydroxyl. Preferred fatty acids are those wherein R6 is a
long chain, unsubstituted alkyl or alkenyl group of from ll
~-~ 20 to 21 carbon atoms, more preferably 11 to 17 carbon atoms.
Examples of specific carboxylic acids are:
~` ~ formic acid,
acetic acid,
` lauric acid,
myristic acid,
palmitic acid,
~^ stearic acid,
oleic acid,
oxalic acid,
adipic acid,
12-hydroxy stearic acid,
benzoic acid,
;; 4-hydroxy benzoic acid,
'';
,
113(~056
3-chloro benzoic acid,
4-nitro benzoic acid,
4-ethyl benzoic acid,
4-(2-chloroethyl)benzoic acid,
phenylacetic acid,
(4-chlorophenyl)acetic acid,
(4-hydroxyphenyl)acetic acid, and
phthalic acid.
Preferred carboxylic acids are lauric, myristic,
palmitic, stearic, oleic and mixtures thereof.
The amine salt can be formed by a simple addition
reaction, well known in the art, wherein the tertiary amine
is dissolved in a solvent such as methanol, ethanol, propanol,
etc., and the acid is added to the amine solution.
Alternatively, the amine and acid can simply be mixed and
melted together with stirring to form the salt. The molten
amine salt can then be solidified by cooling to room tempera-
ture. The amount of acid should desirably be at least
stoichiometrically eguivalent to the amount of amine since
it is desirable that compositions of the invention be low in
free amine content (the amine salts give better fabric soft-
ening performance than the free amines). If the acid used
to form the amine salt is a polybasic acid (e.g., oxalic
acid), the salt can be monobasic or polybasic, i.e., either
one or more of the acid groups can be utilized to neutralize
~ the amine.
- The formation of amine salts proceeds accordingly to
the following reaction:
,~R6- C - O - H + Rl - 21 - R3 ~ R6 - 1! - O ~1 -- R~
" R 3 _
If the raction is carried out in a lower alcoh
solvent medium, the salt precipitates from solution, and may
~be recovered either by filtration and/or evaporation of the
:'
~ ~ .
,
~13~056
-8-
solvent. Preferably the amine and acid pair used in
preparing amine salts of the present invention should be
chosen so as to produce amine salts having a melting point
within the range of from about 35C to 115C (more prefer-
ably 35C to 85C). Such salts will be solid at roomtemperature but will melt at typical dryer operating tem-
peratures. Amine salts having melting points outside this
range can be used in the present invention by formulating
them into compositions which contain other materials (e.g.,
other softening agents as disclosed hereinafter) so that the
formulated composition has a melting point within the
desired range.
Preferred amine salts for use herein are those
wherein the amine moiety is a C12 to C22 alkyl or alkenyl
dimethyl amine or a di-C12 to C22 alkyl or alkenyl methyl
amine, and the acid moiety is a C12 to C22 alkyl or alkenyl
monocarboxylic acid. The amine and the acid, respectively,
used to form the amine salt will often be of mixed chain
lengths rather than single chain lengths, since these
materials are normally derived from natural fats and oils,
or synthetic processes which produce a mixture of chain
lengths. Also, it is often desirable to utili~e mixtures of
different chain lengths in order to modify the physical or
~ performance characteristics of the softening composition.
`~ 25 Specific preferred amine salts for use in the
present invention are stearyldimethylamine stearate,
stearyldimethylamine myristate, stearyldimethylamine palml-
tate, distearylmethylamine palmitate, distearylmethylamine
laurate, and mixtures thereof. A particularly preferred
` 30 mixture is stearyldimethylamine stearate and distearyl-
: methylamine myristate, in a ratio of 1:10 to 10:1, prefer-
ably about 1:1.
Optional Softening Composition Components
:
Various additives can be used in combination with
the aforedescribed tertiary amine salts in the soften~ng
compositions herein. Although not essential to the inven-
tion herein, certain fabric treating additives are parti
ll3aos6
- 9 -
larly desirable and useful, e.g., perfumes, brightening
agents, shrinkage controllers, spotting agents and the like.
With respect to perfumes, it should be noted that the
tertiary amine salts of the present invention are much more
compatible with conventional perfume components such as
aldehydes, ketones, and esters than are the primary amine
formates described in U.S. Patent 4,077,891, supra.
Additional fabric softener/antistat agents may
also be used in combination with the tertiary amine salts.
These agents are generally nonionic or cationic in nature.
The most common type of cationic softener/
antistate materials are the cationic nitrogen-containing
compounds such as quaternary ammonium compounds having one
or two straight-chain organic groups of at least eight
carbon atoms. Preferably, they have one or two such groups
of from 12 to 22 carbon atoms. Preferred cation-active
softener compounds include the quaternary ammonium
softener/antistat compounds corresponding to the formula
~ R ~
wherein R7 is an a liphatic group of from 1 to 22 carbon
atoms; R8 is an aliphatic group having from 12 to 22 carbon
atoms; Rg and Rlo are each alkyl groups of from 1 to 3
carbon atoms; and X is an anion selected from halogen,
acetate, phosphate, nitrate and methyl sulfate radicals.
Because of their excellent softening efficacy and
ready availability, preferred cationic softener/antistate
compounds which can be optionally included in the composi-
tions herein are the dialkyl dimthyl ammonium methyl
sulfates, wherein the aliphatic groups have from 12 to 22
carbon atoms and are derived from long-chain fatty acids,
such as hydrogenated tallow. As employed herein, aliphatic
113W56
--10-
is intended as including unsaturated compounds such as are
present in aliphatic groups derived from naturally
occurring fatty oils. The term "tallow" refers to fatty
aliphatic groups derived from tallow fatty acids. Such
fatty acids give rise to quaternary softener compounds
wherein R7 and R8 have predominantly from 16 to 18 carbon
atoms. The term "coconut" refers to fatty acid groups from
coconut oil fatty acids. The coconut R7 and R8 groups
have from about 8 to 18 carbon atoms and predominate
in C12 to C14 alkyl groups. Representative examples of ~1
quaternary softeners for use herein include tallow trimethyl
ammonium chloride; ditallow dimethyl ammonium chloride;
ditallow dimethyl ammonium methyl sulfate; dihexadecyl
dimethyl ammonium chloride; di(hydrogenated tallow) dimethyl
ammonium chloride; dioctadecyl dimethyl ammonium chloride;
dieicosyl dimethyl ammonium chloride; didocosyl dimethyl
ammonium chloride; di(hydrogenated tallow) dimethyl ammonium
methyl sulfate; dihexadecyl diethyl ammonium chloride:
dihexadecyl dimethyl a~monium acetate; ditallow dipropyl a~m~nium phosphate;
ditall w dimethyl ammonium nitrate; di(coconut-alkyl) dimethyl ammonium
An especially preferred class of quaternary
ammonium softener/antistats correspond to the formula
I R
111
CH3 N CH3 X
L 12
wherein Rll and R12 are each straight chain aliphatic groups
of from 12 to 22 carbon atoms and X is halogen, e.g.,
chloride or methyl sulfate. Especially preferred are
ditallow dimethyl ammonium methyl sulfate (or chloride) and
di(hydrogenated tallow-alkyl) dimethyl ammonium methyl
sulfate (or chloride~ and di(coconut-alkyl) dimethyl
ammonium methyl sulfate (or chloride), these compounds
113~0S6
--11--
being preferred from the standpoint of good softening
properties and ready availability.
Other suitable cation-active softener/antistat
compounds which can optionally be included in the compositions
herein are the quaternary imidazolinium salts. Preferred
salts are those conforming to the formula
+
- H H O
H - C C - H ll X
N N - C2H4 - I C 16
L Cl 13 R14
R15 --
wherein R13 is an alkyl containing from 1 to 4, preferably
from 1 to 2 carbon atoms, R14 is an alkyl containing from
1 to 4 carbon atoms or a hydrogen radical, R15 is an alkyl
containing from 1 to 22, preferably at least 15 carbon atoms
or a hydrogen radical, R16 is an alkyl containing from 8 to
22, preferably at least 15 carbon atoms, and X is an anion,
preferably methysulfate or chloride ions. Other suitable
anions include those disclosed with reference to the
cationic quaternary ammonium fabric antistat/softeners
described hereinbefore. Paxticularly preferred are those
imidazolinium compounds in which both R15 and R16 are
alkyls of from 12 to 22 carbon atoms, e.g., l-methyl-l-
[(stearoylamide)ethyl]-2-heptadecyl-4,5-dihydroimidazolinium
methyl sulfate; 1-methyl-1-[(palmitoylamide)ethyl]-2-
octadecyl-4,5-dihydroimidazolinium chloride and l-methyl-l-
E (tallowamide)ethyl]-2-tallow-imidazolinium methyl sulfate.
Other cationic quaternary ammonium fabric
softener/antistats which are useful herein include, for
example, alkyl (C12 to C22)-pyridinium chlorides, alkyl
(C12 to C22)-alkyl (Cl to C3)-morpholinium chlorides, and
~uaternary derivatives of amino acids and amino esters.
.~
1~3~C~S6
-12~
Nonionic fabric softener/antistat materials
include a wide variety of materials including fatty esters,
fatty alcohols and their derivatives, diamine compounds and
the like. One preferred type of nonionic fabric antistat/
softener material comprises the esterified cyclic dehydration
products of sorbitol, i.e., sorbitan esters. See U.S. Patent
4,022,938, Zaki et al., issued May 10, 1977.
Sorbitan mono- and di-esters of lauric, myristic,
palmitic, stearic, and behenic acids are particularly
useful herein for conditioning the fabrics being treated. `
Mixed sorbitan esters, e.g., mixtures of the foregoing
esters, and mixtures prepared by esterifying sorbitan with
fatty acid mixtures such as the mixed tallow and hydrogenated
palm oil fatty acids, are useful herein and are economically
attractive. Unsaturated C10 -C18 sorbitan esters, e.g.,
sorbitan mono-oleate, usually are present in such mixtures.
It is to be recognized that all sorbitan esters, and mixtures
thereof, which are essentially water-insoluble and which have
fatty hydrocarbyl "tails," are useful fabric antistat/softener
materials in the context of the present invention.
The preferred alkyl sorbitan ester fabric softener/
antistat materials herein comprise sorbitan monolaurate,
sorbitan monomyristate, sorbitan monopalmitate, sorbitan
monostearate, sorbitan monobehenate, sorbitan dilaurate,
sorbitan dimyristate, sorbitan dipalmitate, sorbitan
distearate, sorbitan dibehenate, and mixtures thereof, the
mixed coconutalkyl sorbitan mono- and di-esters and the
mixed tallowalkyl sorbitan mono-and di-esters. The tri-
and tetra-esters of sorbitan with lauric, myristic,
palmitic, stearic and behenic acids, and mixtures thereof,
are also useful herein.
Another useful type of nonionic fabric softener/
antistat material encompasses the substantially water-
insoluble compounds chemically classified as fatty alcohols.
Mono-ols, di-ols, and poly-ols having the requisite melting
113~5~
-13-
points and water-insolubility properties set forth above
are useful herein. Such alcohol-type fabric conditioning
materials also include the mono- and di-fatty glycerides
which contain at least one "free" OH group.
All manner of water-insoluble, high melting
alcohols (including mono- and di-glycerides), are useful
herein, inasmuch as all such materials are, to some extent,
fabric substantive. Of course, it is desirable to use those
materials which are relatively colorless, so as not to alter
the color of the fabrics being treated. Toxicologically
acceptable materials which are safe for use in contact with
skin should be chosen.
A preferred type of unesterified alcohol useful
herein includes the higher melting members of the so-called
fatty alcohol class. Although once limited to alcohols
obtained from natural fats and oils, the term "fatty
alcohols" has come to mean those alcohols which correspond
to the alcohols obtainable from fats and oils, and all
such alcohols can be made by synthetic processes. Fatty
alcohols prepared by the mild oxidation of petroleum
products are useful herein.
Another type of material which can be classified
as an alcohol and which can be employed as an optional
softener/antistat material in the înstant invention encom-
passes various esters of polyhydric alcohols. Such"ester-alcohol" materials which have a melting point
within the range of about 35C to 100C and which are sub-
stantially water-insoluble can be employed herein when
they contain at least one free hydroxyl group, i.e., when
they can be classified chemically as alcohols.
The alcoholic di-esters of glycerol useful herein
include both the 1,3-di-glycerides and the 1,2-di-glycerides.
In particular, di-glycerides containing two C8-C20,
preferably Cl0-C18, alkyl groups in the molecule are
useful fabric conditioning agents.
Nonlimiting examples of ester-alcohols useful
herein include: Glycerol-1,2-dilaurate; glycerol-1,3-
, . .
1130056
~14~
dilaurate;glycerol-l, 2-dimyristate;glycerol-i/3-dimyris-
tate; glycerol-1,2-dipalmitate;glycerol-1,3-dipalmitate;
glycerol-1,2-distearate and glycerol-1,3-distearate. Mixed
glycerides available from mixed tallowalkyl fatty acids,
i.e., 1,2-ditallowalkyl glycerol and 1,3-ditallowalkyl
glycerol, are economically attractive for use herein. The
foregoing ester-alcohols are preferred for use herein due
to their ready availablity from natural fats and oils.
Mono- and di-ether alcohols, especially the
C10-C18 di-ether alcohols having at least one free -OH
group, also fall within the definition of alcohols useful
as optional fabric softener/antistat materials herein. The
ether-alcohols can be prepared by the classic Williamson
ether synthesis. As with the ester-alcohols, the reaction
conditions are chosen such that at least one free,
unetherified -OH group remains in the molecule.
Ether-alcohols useful herein include glycerol-l,
2-dilauryl ether; glycerol-1,3-distearyl ether; and
butane tetra-ol-1,2,3-trioctanyl ether.
While not essential, liquids which serve as a
carrier for the softening agents and other materials can
also be employed as part of the softening compositions
herein. Such liquids can be used, for example, to more
evenly impregnate an absorbent substrate with the softening
composition when such an absorbent substrate is employed
(as discussed hereinafter) as the dispensing means for the
instant compositions. When a ligui~ carrier is so used,
it should preferably be inert or stable with the fabric
softeners. Moreover, a liquid carrier used in substrate
impregnation should be substantially evaporated at room
temperatures, and the residue (i.e., the softening agent
and other optional materials) should then be sufficiently
hardened so as not to run or drip off the substrate, or
cause the substrate to stick together when folded.
Isopropyl alcohol or isopropyl alcohol/water mixtures are
the preferred liquid carriers for substrate impregnation
.
r
113(~056
. . . l.;
- 15 -
purposes. Methanol, ethanol, acetone, ethylene glycol,
propylene glycol, alcohol ethoxylate nonionic surfactants
and/or liquified fluorocarbons such as dichlorofluoroethane
and dichlorodifluoromethane can also be used as carriers
either for dispensing the softening compositions in the
dryer, for introducing the softening compositions into the
dryer dispensing means or for facilitating release of the
softening compositions from the dryer dispensing means.
~ Clays can be added to the compositions of the
invention in an amount of from about 0.5% to about 50% of
the total composition. See U.S. Patent 4,073,996, Bedenk
et al., issued February 14, 1978. Clay promotes even release
of the softening composition from substrate-type dispensing
means ~such as woven or nonwoven cloth sheets) thereby mini-
mizing any tendency to stain the treated fabrics which mightbe caused by uneven transfer of softener to them. Smectite
clays axe ~arti~ularly prçferrçd clays for use herein. An
example of a smectite clay is"Gelwhite GP' which is
marketed by Georgia Kaolin Co. Another additive which can
be used to promote even release of the softener composi-
tion from a substrate-ty~e dispensing means is a mixture
of about 1.5%"Carbopol"resin (B. F. Goodrich Co.) and 4
glycerine, based on the total weight of the composition.
Other additives can include anticreasing agents,
finishing agents, fumigants, lubricants, fungicides, and
sizing agents. Specific examples of useul additives dis-
closed herein can be found in any current Year Book of
the American Association of Textile Chemists and Colorists.
Any additive used should be compatible with the softening
agents.
The amounts of some additives (e.g., perfume and
brighteners) that are generally used in combination with
the softening agents are small, being in the range of from
0~01~ to 10% by weight of the softening composition. Other
additives such as the optional antistat/softener agents
and liquid carriers can be present in larger amounts. Such
*Trademark
**Trademark for a water-soluble resin
~ .
~1300S6
-16-
optional and/or liquid carrier materials can be present in fabric
softening compositions to the extent of from about 0.01%
to 50% or more by weight of the softening composition.
All percentages herein are "by weight" unless specified
otherwise.
A highly preferred softening composition herein
contains from about 5% to 100% (preferably 50~ to 100%) by
weight of the composition of the essential acid salt of a
tertiary amine and from about 0% to 95% (preferably 0% to
50%) by weight of the composition of an optional softener~
antistat agent. Preferred optional softener/antistatic
agents are ditallow dimethyl ammonium methyl sulfate, ~ -
sorbitan monostearate and mixtures of these materials.
Highly preferred mixtures are those wherein the ratios of
lS the two are in the range of about 80/20 to about 20/80.
A liquid carrier, if used, will,of course, be
present in the softening composition in relatively large
amounts, especially if the presence of such a carrier is
useful in dispensing the softening composition in the dryer
(in an aerosol device, for example).
Dispensing Means
The tertiary amine acid salt-containing softening
compositions can be employed by simply adding a measured
amount into the dryer, e.g., as liquid dispersion. However,
in a preferred embodiment, the softening composition is pro-
vided as part of an article of manufacture in combination
with a dispensing means which effectively releases the
composition in an automatic clothes dryer. Such dispensing
means can be designed for singls usage or for multiple uses.
One such article comprises a sponge material
releasably enclosing enough softener composition to impart
effectively fabric softness during the treating of
several loads of clothes. This multi-use article can be
made by filling a hollow sponge with about 20 grams of
.. ~
~13C056
- 17 -
the softening composition. In use, the composition melts
and leaches out through the pores of the sponge to soften
fabrics. Such a filled sponge can be used to treat several
loads of fabrics in conventional dryers, and has the
advantage that it can remain in the dryer after use and
is not likely to be misplaced or lost.
Another article comprises a cloth or paper bag
releasably enclosing the composition and sealed with a
melt of the composition, which is subsequently hardened to
for~ a heat-sensitive seal. The action and heat of the
dryer melt the seal, thereby opening the bag and releasing
the salt to perform its softening function.
Still another article comprises an aerosol
cannister containing the above-described sof~ening compo-
sitions under pressure. The compositions can be dispensed
from this aerosol article onto the interior surface of the
cold dryer drum prior to the addition of fabrics in the
manner more fully described in Rudy et al., U.S. Patent
3,650,816, issued March 21, 1972,
Other devices and articles suitable for dispensing
the softening material into automatic dryers include those
described in Dillarstone, U.S. Patent 3,736,668, issued
June 5, 1973; Compa et al., U.S. Patent 3,701,202, issued
October 31, 1972; Furgal, U.S. Patent 3,634,947, issued
January 18, 1972; Hoeflin, U.S. Patent 3,633,538, i~sued
January 11, 1972; and Rumsey, U.S. Patent 3,435,537, issued
April 1, 1969. See also Murphy et al., U.S. Patent
4,085,052, issued April 18, 1978.
A highly preferred article herein comprises the
tertiary amine salt-containing composition releasably
affixed to a sheet of paper or woven or nonwoven cloth
substrate or a sheet of foamed plastic such as polyurethane.
When such an article is placed in an automatic laundry
dryer, the heat and tumbling action of the dryer removes
~,,,,~ .
,:
~13~0S6
-18-
the composition from the substrate and deposits it on
the fabrics.
The sheet conformation has several advantages.
For example, effective amounts of the composition for use
in conventional dryers can be easily sorbed onto and into
the sheet substrate by a simple dipping or padding process.
Thus, the user need not measure the amount of composition
necessary to obtain fabric softness. Additionally, the
', ~3
~? ~
1~3C0~6
" -- 19 --
flat configuration of the sheet provides a large surface
area which results in efficient release of the softener
materials onto fabrics by the tumbling action of the dryer.
The water-insoluble paper, or woven or nonwoven
substrates used in the articles herein can have a dense,
or more preferably, open or porous structure. Examples of
suitable materials which can be used as substrates herein
include paper, woven cloth, and nonwoven cloth. The term --
"cloth" herein means a woven or nonwoven substrate for the
articles of manufacture, as distinguished from the term
"fabric" which encompasses the clothing fabrics being
dried in an automatic dryer.
Highly preferred paper, woven, or ~onwoven
"absorbent" substrates useful herein are fully disclosed
in Morton, U.S. Patent 3,686,025, issued August 22, 1972.
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) of from 2 to 25 times its
weight of water.
Determination of absorbent capacity values is
made by using the capacity testing pxocedures described in
U.S. Federal Specifications UU-T-595b, modified as follows:
tl) tap water is used instead of distilled water;
(2~ the specimen is immersed or 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., kraft or bond
having a basis weight of about 32 pounds per 3,000 square
. .
p~ ,
, ., . .. , . ~ , , . . . . . ~ ., .
:~13~0~6
i ~s/ ~
. - 20 -
feet -52 kg. per 1000 sq. meters) has an absorbent capacity
of 3.5 to 4; commercially available household one-ply towel- -
ing 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 2 tends to cause too rapid release of the soft-
ening agent fr~m the substrate resulting in several disad-
vantages, one of which is uneven softening of the fabrics.
Using a substrate with an absorbent capacity over 25 is
undesirable, inasmuch as too little of the softening agent
is released to soften the fabrics in optimal fashion during
a normal drying cycle. If the substrate is a woven or
nonwoven cellulosic cloth or paper, rather than a foamed
plastic material, the absorbency should preferably be in the
range of 2 to 15, most preferably between 5 and 7. For
foamed plastics, the absorbency is preferably in the range
of from about 15 to about 22.
As noted above, suitable materials which can be
....
used as a substrate in the invention herein include, among
others, sponges, paper, and woven and nonwoven cloth, all
having the necessary absorbency requirements defined above.
; The preferred substrates-of the softening compositions
herein are cellulosic, polyester or polyester~cellulosic
blends, particularly mu}ti-ply paper and nonw~ven cloth.
4 A more detailed description of multi-ply paper
and nonwoven cloth materials which are suitable for use as
substrates in dryer-added fabric softener articles of the
type herein is given in U.S. Patent 4,022,938, Zaki et al.,
30 issued May 10, 1977. See
especially Col. 11 to Col. 13 of said patent.
The preferred fabric softening articles of the
present invention are structured to be compatible with
conventional laundry dryer designs. While it is preferred
- 35 to employ the articles of the present invention in an
automatic laundry dryer, other equivalent machines can be
employed, and in some instances, heat and drying air may
be omitted for part or all of the cycle. Genexally, how-
........ .. ...... . .. .. . .. .. ..
.. . .. . .. . .
113(~056
- 21 -
.. .
ever, hea-ted air will be employed and such air will be
circulated frequently in the dryer. Normally, there are ~ -
from about 5 to 50 volume changes of drying air in the
dryer drum per minute and the air moves at about 125 to
175 cubic feet per minute (3.5-to 4.9 cu. meters per minute).
These changing volumes of air create a drawing or suction
effect which can, especially with small fabric loads, cause
an item such as a sock, handkerchief or the like, or a
fabric conditioning article, to be disposed on the surface -_
of the air outlet of the dryer. A usual load of fabrics of
from about 4 to about 12 pounds (l.8 to 5.4 kilograms1 dry
weight will fill from about lO~ to a~out 70~ of the volume
of most dryers and will normally pose little difficulty. A
sufficient number of tumbling items will normally be present
to prevent any item from being drawn to the exhaust outlet,
or to cause the item to be removed from the outlet in the
event the item does become drawn against it. In the event,
a fabric softening article is caused to be disposed in
relation to the air exhaust outlet in such a manner as to
cause blockage of passing air, undesirable temperature
increases can result. In the case of fabric softening
articles prepared from the normally solid or waxy softeners-
such as the amine salts herein, which soften or melt undar
conditions of heat, the article may tend to adhere to an
exhaust outlet.
The problem of blockage can be sol~ed by providing
openings in the article in the manner described in two U.S.
patents to A. R. McQueary, U.S. Patent 3,944,694 and U.S.
Patent 3,956,556, issued March 16, 1976, and May ll, l976,
respectively~ More
specifically, as described in these patents, slits or holes
are cut through the substrate.
Article Manufacture
The articles herein comprise tertiary amine
salt-containing softener compositions in combination with
any dispensing means suita~le for releasing the soLtening
- . :
. --~
~A`
.. . . ... ... ~
`.
113(~056
composition to the fabric load at temperatures encountered
in automatic laundry dryers. Preferred articles herein are
those wherein the softening composition is releasably affixed
to an absorbent substrate as an impregnate or as a coating.
The impregnation or coating can be accomplished in any
convenient manner, and many methods are known in the art.
For example, the softening composition, in liquid form, can
be sprayed onto a substrate or can be added to a wood-pulp
slurry from which the substrate is manufactured.
Impregnating, rather than coating, the substrate
with the softener composition is highly preferred for optimal
softening with minimal fabric staining. The term "coating"
connotes the adjoining of one substance to the external
surface of another; "impregnating" is intended to mean
the permeation of the entire substrate structure, internally
as well as externally. One factor affecting a given sub-
strate's absorbent capacity is its free space. Accordingly,
when a softening composition is applied to an absorbent
substrate, it penetrates into the free space; hence, the
substrate is deemed impregnated. The free space in a
substrate of low a~sorbency, such as a one-ply kraft or
bond paper, is very limited; such a substrate, is therefore,
deemed "dense." Thus, while a small portion of the
softening composition penetrates into the limited free space
available in a dense substrate, a rather substantial bal-
ance of the softener composition does not penetrate and
remains on the surface of the substrate so that it is
deemed a coating. The difference between coating and impreg-
nation is believed to explain why the softener-impregnated
sheet substrates of the invention herein substantially
reduce the staining of fabrics observed when a softener-
coated dense substrate is utilized.
In one method of making the preferred softener-
impregnated absorbent sheet substrate, a softener compo-
sition containing a tertiary amine salt, alone or withthe optional additives, is applied to absorbent paper or
nonwoven cloth by a method generally known as "padding."
The softening composition is preferably applied in liquid
form to the substrate. Thus, the softener composition,
which is normally solid at room temperature should first
be melted and/or solvent treated with one of the liquid
113(3056
-23-
carriers mentioned hereinbefore. Methods of melting the
softener composition and/or for treating the softener
composition with a solvent are known and can easily be
done to provide a satisfactory softener-treated substrate.
In another preferred method, the softener compo-
sition, in liquified form, is placed in a pan or trough
which can be heated to maintain the softener composition
in liquid form. The liquid softener composition contains
any of the desired optional additives. A roll of absorbent
paper (or cloth) is then set up on an apparatus so that it
can unroll freely. As the paper or cloth unrolls, it
travels downwardly and, submersed, passes through the pan
or trough containing the liquid softener at a slow enough
speed to allow sufficient impregnation. The absorbent
paper or cloth then travels upwardly and through a pair
of rollers which remove excess bath liquid and provide
the absorbent paper or cloth with about 1 to about 12
grams of the softening composition per 100 sq. inches to 150
sq. inches (645 to 968 sq. cm.) of substrate sheet. The
impregnated paper or cloth is then cooled to room tempera-
ture, after which it can be folded, cut or perforated at
uniform lengths, and subsequently packaged and/or used.
The rollers used resemble "squeeze rolls" used
by those in the paper and paper-making art; they can be
made of hard rubber or steel. Preferably, the rollers are
adjustable, so that the opening between their respective
surfaces can be regulated to control the amount of the
softener composition liquid on the paper or cloth.
In applying the softener composition to the
absorbent substrate, the amount of softener composition
(excluding any solvent which may have been used in the pro-
cess) impregnated into or coated onto the absorbent-substrate
is conveniently in the weight ratio range of from about
}0:1 to 0.5:1 based on the ratio of total softener compo-
sition to dry, untreated substrate (fiber plus binder).
Preferably, the ratio of softener composition to dry,
untreated substrate ranges from about 5:1 to about 1:1,
most preferably from about 3:1 to 1:1. As noted above, the
softening composition can contain from 5% to 100% of the
tertiary amine salt softening agent.
Following application of the liquified softener
~
.~
1~3(~
-24-
composition, the articles are held at room temperature
until the softener composition solidifies. The resulting
dry articles, prepared at the softener composition: substrate
ratios set forth above, remain flexible; the sheet articles
are suitable for packaging in rolls. The sheet articles
can optionally be slitted or punched to provide a non-
blocking aspect (as described previously) a~ any convenient
time during the manufacturing process.
The most highly preferred articles herein are
those where the softener composition is releasably affixed
to a woven or nonwoven cloth substrate Of the type disclosed
hereinabove having an absorbent capacity of from about 2
to about 15. A highly preferred substrate for such an
article has an absorbent capacity of from about 5 to 7.
The most highly preferred substrate for the articles com-
prises a water-laid or air-laid nonwoven cloth consisting
essentially of cellulosic fibers, said fibers having a
length of about 3/16 inch to about 2 inches and a denier
from about 1.5 to about 5, said fibers being at least
partially oriented haphazardly, and adhesively bonded
together with a binder-resin. Such water-laid or air-
laid nonwoven cloths can easily be prep~red having the
preferred absorbent capacities set forth above.
The most highly preferred articles herein are
those wherein the flexible substrate is provided with
openings sufficient in size and number to reduce restric-
tion by said article of the flow of air through the auto-
matic dryer. Articles wherein the openings comprise a
plurality of rectilinear slits extending along one dimension
of the æubstrate, especially those wherein the slits extend
to within 1 inch from at least one edge of said dimension of
the substrate, articles wherein the slits comprise a plur-
ality of curvilinear slits in a continuous pattern of U-
shaped or C-shaped slits, and articles wherein the openings
comprise circular holes, are highly preferred herein.
It is most convenient to provide an article in the
form of a nonblocking sheet substrate having the physical
parameters noted hereinabove, said substrate having an area
of from about 50 sq. in. to about 200 sq. in. (322 sq. cm.
to 1290 sq. cm.), containing from about 1.5 grams to about
7.5 grams of the softening composition releasably impreg-
113~0~6
-25-
nated in said substrate. The articles are provided with
openings such as the holes or slits described hereinabove,
said openings comprising from about 0.5% to about 75%, pref-
erably 5% to about 40~, of the area of the article, said
openings being so disposed as to provide a nonblocking
effect.
Usage
In the method aspect of this invention the ter-
tiary amine salt-containing softening compositions are used
in an effective amount to soften and condition fabrics in
an automatic laundry dryer. The effective, i.e., softening
and static-controlling, amount of the composition used in
the manner of this invention will depend somewhat on the `-
type of fabric being treated and the dampness of the sur-
rounding atmosphere. For example, it is well known that
under conditions of low humidity, static control in fabrics
is somewhat more difficult to achieve than under conditions
of high humidity.
For most purposes, the composition is applied to
fabrics at a rate of about 0.01 gram to about 12 grams,
preferably 1 gram to about 4 grams, per 5 lbs. (2.25 kg.) of
fabrics on a dry fabric weight basis. Higher usage rates
can be employed, if desired, but can result in an unde-
sirable greasy feel on the fabrics.
The method herein is carried out in the following
manner. Damp fabrics, usually containing from about 1 to
about 1.5 times their weight of water, are placed in the
drum of an automatic clothes dryer. In practice, such
damp fabrics are commonly obtained by laundering, rinsing
and spin-drying the fabrics in a conventional washing machine.
The amine salt either alone or in combination with other
additives is simply spread uniformly over all fabric sur-
; faces, for example, by sprinkling an amine salt-containing
composition onto the fabrics from a shaker device.
Alternatively, the amine salt-containing compositions can
be sprayed into the dryer containing the fabrics or onto
the dryer drum. The dryer is then operated in standard
fashion to dry the fabrics, usually at a temperature from
35C to 115C (more typically from about 50C to about 85C)
for a period from about 10 minutes to about 60 minutes,
~13(~0S6
-26-
depending on the fabric load and type. On removal from the
dryer, the dried fabrics are softened. Moreover, the fabrics
instantaneously sorb a minute quantity of water which in-
creases the electrical conductivity of the fabric surfaces,
thereby quickly and effectively dissipating static charge.
In a preferred mode, the present process is
carried out by fashioning an article comprising the sub-
strate-like dispensing means of the type hereinabove
described in releasable combination with a tertiary amine
salt-containing softener composition. This article is
simply added to a clothes dryer together with the damp
fabrics to be treated. The heat and tumbling action of the
revolving dryer drum evenly distributes the softener
composition over all fabric surfaces, and dries the fabrics.
The amine salts herein also perform well as fabric
softeners when added to the rinse cycle of a typical washing
operation. Thus, articles of the invention can be added to
the rinse water. Alternatively, an aqueous concentrate con-
taining from about 5~ to 10% by weight amine salt can be pre-
pared and sufficient amount of this concentrate can be added
to the rinse water to produce a concentration of from about
30 to about 60 ppm amine salt in the rinse water. Also the
amine salts herein are more compatible with anionic deter-
gents than conventional quaternary ammonium softeners, and
thus can be added, at levels of from about 30-60 ppm, direct-
ly to the wash cycle of a typical washing operation, thereby
softening the fabrics at the same time they are being washed.
The following are nonlimiting examples of the
instant articles and methods.
EXAMPLE I
P aration of Tertiar Amine Salts
rep Y
Several tertiary amine salts of the present
; invention were made according to the following procedure~
The amine was placed in a glass vessel. An amount
of the desired acid, calculated to be stoichiometrically
equivalent to the amount of amine was added to the amine and
the mixture was stirred at 65C to 77C for approximately
10 minutes, thereby forming the amine salt. The amine salt
was then solidified by cooling it to room temperature.
Stearyldimethylamine hydrochloride was also pre-
113(~056
-27-
pared. This compound was made by adding a stoichiometric
amount of 37~ aqueous HCl to stearyldimethylamine at room
temperature. The resulting thick paste was then spread
on a heated metal plate (about 90C-100C) to complete the
reaction and drive off the water.
Preparation of Fabric Softe_ n~_Articles
Fabric softening articles comprising a rayon
nonwoven fabric substrate (having a weight of 1.52 grams
per 639 sq. cm.) and an amine salt softening agent were
prepared in the following manner.
The substrate was passed through a trough con-
taining the melted softener and then was drawn between a
pair of rollers to squeeze off the excess molten softener.
The treated substrate was then cooled to room temperature
to solidify the softener, cut into 22.86 cm. x 27.94 cm.
sheets, and six evenly-spaced parallel slits were then cut
into each sheet within about 2.54 cm. of opposite ends of
the sheets. The softener was present on the sheets at a
weight ratio of about 2.1 to 1 softener:substrate.
In the case of stearyldimethylamine hydrochloride,
the salt was applied to the substrate at room temperature
in a 50/50 methanol/chloroform solvent mixture. The solvent
mixture was then evaporated from the substrate.
FABRIC SOFTENING PEP~ORN~NCE
The fabric softening performance of the above-
described articles was evaluated in a Seaxs "Kenmore" Electric
Dryer (on the standard 45 minutes timed cycle, 50C-70C),
using a previously washed standardi~ed mixed fabric load,
which contained four terry cloth towels as fabric softness
test pieces. The mixed fabric load was washed in a Sears
"Kenmore" Washer with the recommended amount of CHEERR
~ETEgGENT (77 grams in 64.3 liters of water) and subjected
to a warm water rinse before treatment in the dryer.
Fabric softening was evaluated on the four terry
cloth towels from the respective test loads, using as
controls, a similar set of fabrics which was unsoftened,
and sets which had been softened in rinse application of
DOWNYR fabric softener and in a dryer application of
BOUNCER fabric softener. These two trademarked products
*Trademark
~r
.
l~3aos6
-28-
are both products of The Procter & Gamble Company. DOWNY
is a liquid fabric softener marketed for use in the rinse cycle,
and BOUNCE is a softener-impregnated web sheet article
marketed for use in the dryer. The softness evaluation was
done by round robin paired comparison grading by a panel of
three judges who assigned numerical softness difference
scores to the graded pairs on a scale of 0 to 4, where 0 is
"no difference" and 4 is "a whole lot softer." A computer-
ized analysis of variance program summarized the individual
treatment scores. The results were mathematically "normal-
ized" by adjusting the panel score obtained on the unsoftened
fabrics to "0" and making an adjustment of the same magnitude
to the scores obtained on the fabrics for each of the other
treatments. A difference of about 0.3 to 0.4 panel score
units between treatments is statistically significant. By
using the "0" normalization technique noted above, it is
possible to make valid comparisons between treatments which
have not been directly compared against each other in the
same test run.
The release weight of softening composition from
the nonwoven softening article to fabrics was determined by
comparing the weight of the article before and after use,
and calculating the weight % of composition which was removed
from the article.
Results on several amine salts of the invention
and on an amine hydrochloride salt are shown in the following
table.
TA9LE I
Meltin~ Softness Percent
Amine Salt Point _C Panel ScoreRelease
Stearyldimethyl-
amine hydrochloride 104 0.9 20
Stearyldimethyl- O
amine stearate 58 2.1 91
Stearyldimethyl-
amine formate 42 2.3 97
Stearyldimethyl- O
amine myristate 35 2.3 96
40 Stearyldimethyl- O
amine palmitate 49 2.3 95
.
113(~056
-29-
Meltin~ Softness Percent
Amine Salt Point C Panel Score Release
Ditallowmethyl-
amine myristate 48 1.8 93
Ditallowmethyl-
amine laurate 34 1.7 98
Ditallowmethyl-
amine palmitate 53 1.4 89
~itallowmethyl-
amine stearate 57 1.4 92
BOUNCEl _ 1.2 65
DOWNY2 - 2.6
Softener is an 80/20 mixture of
sorbitan monostearate/ditallowdi-
methylammonium methylsulfate.
Softener is distearyldimethylammonium
chloride.
EXAMPLE II
An article of the invention utilizing the
following softening composition is prepared.
Amine salt 89%
"Gelwhite" GP clay 8
Perfume 3
100%
The amine salt is a 40/60 mixture of stearyldi-
methylamine stearate ana ditallowmethylamine myristate.
The individual amine salts are prepared according to the
procedure in Example I. The amine salts are heated to a
temperature of 66C to 77C and mixed together. The
clay is added to this liquid mixture and dispersed in the
mixture via high-shear mixing. The perfume is then blended
into the mixture. The hot li~uid mixture is then applied
to a nonwoven rayon substrate in the manner described in
Example I to produce a softener composition: substrate ratio
of 2.1:1. The treated substrate is then cut into 27.94 x
27.94 cm. sheets and slitted in the manner described in
- ,~
~13~056
-30-
Example I. This article, when added to a five-pound load of
fabrics in a laundry dryer, which is operated at about 66C
for 45 minutes, produces excellent fabric softening and
antistatic benefits.
:
::
. ~
. . ., . ~ . . .. . .
