Note: Descriptions are shown in the official language in which they were submitted.
WO 92J13934 Pcr/lJS9lJO9453
2~97503
T ~.UNDRY RINSES AND DRYFR SHEETS
Field of Invention
This invention relates to laundry rinses and dryer sheets containing N,N-
dil~ydl-J6~ t~ lw-N~N-di~ L~ ll chloride and an amine oxide.
5 R~ r~l-n~
When fabrics are laundered, it is frequently desirab~e to treat them with fabricsofteners, not only to soften them, but to give them greater bulk, make them easier
to iron, decrease fabric drying time, and reduce static charge. A fabric softener that
is commonly used is N,N-dill.ydllJg~ llow-N,N-djll~ lll chloride
10 (DTMAC), which is both ill~A~ iV~ and effective as a softener but, on the other
hand, has certain ~Pf~ nri~ c~ such as its yellowing and reducing the ~llabilily of
the softened fabrics, having inefficient antistatic activity on polyesters, and dc~ -g
the ~ Labilily of the treated fabrics.
Amine oxides, such as N-alkyl-N,N-dill-~Ll-yh..~ oxides, are also effective
fabric softeners; and they Som~tim~ have advantdges over DTMAC in this regard.
However, when used together with DTMAC, they have either failed to improve the
results obtained with DTMAC alone or have provided results intermediate to thoseobtained with either ~ of the fabric softener alone.
Sllmm~rv of Invention
It has now been found that the use of an N-alkyl-N.N-dilll~,LllyLIlllillc oxide
togetherwithN,N-dilly~ll..~,..,,.lrfh~llr)w-N~N-dill.~dlyl~ lchloridecanprovide
an improved fabric softener product when the fabric softener product is (1) a laundry
rinse which comprises an aqueous solution of a mixture of 25-80% by weight of the
quaternarv ;""""~ l chloride and 75-20% by weight of N-octadecyl-N~N-dilll~lllvlalll-
~5 ine oxide or (~) a laundrv dryer sheet which comprises a flexible absorbent substrate
61.d~d with a mixture of 10-80% by weight of the quaternary ," l, l "~-, l;l ll l l chloride
and 90-20% by weight of an N-alkyl-N,N-di."~Lllyld",i,lc oxide wherein the alkyl is
*
WO 92113934 PCr~lJS9~/09453
?.,r`~9~5Q3 - 2 - ~
octadecyl when the amine oxide constitutes 20-40% of the mixture and otherwise may
be any primary alkyl group containing 8-24 carbons.
Det~ Dffrription
As a~ready ml~ntion~-l, the quaternary ~mm~ni~lm chloride component of the
S fabricsoftenermixtureistheknownN,N-dil~ w-N~N-di~ "~"~-";~
chloride (DTMAC). The DTMAC used in preparing the mixture is generally the
material that is most commonly available, i.e., a 75% paste in an alcohol.
The amine oxide (~ of the mixture is N-octadecyl-N,N-di...~ ....c
oxide or other N-alkyl-N,N-di~ Ll..~l~.lil.c oxide in which the alkyl is a primary alkyl
group contairling 8-24 carbons, preferably 12-18 carbons. The primary allyl group
may be a straight- or branched-chain group, but the preferred oxides are those in which
the primary alkyl group in at least most of the molecules has a straight chain.
Exemplary of these oxides are the N-octyl-, N-decyl-, N-dodecyl-, N t~,.~ccyl-, N-
hexadecyl-, N-octadecyl-, N-eicosyl-, N-docosyl-, and N-tetracosyl-N,N-~
oxides.
Although the amine oxide used in preparing any of the products of the invention
may be a l;UI.~IIliOIlal aqueous solution or a solid amine oxide, such as the amine
oxide dihydrates described in European Patent Application 0401503 and British Patent
Application 2,240,791, it is apt to be preferred to employ an amine oxide in solution
form when the mixture is to be utilized as an aqueou~s solution and other vise to employ
a solid amine oxide.
Except for the fabric softener mixture used, a laundry rinse of the invention
is a conventional rinse which has water as its major ingredient (generally ~:UIIIyli~illg
70-90% by weight of water) and may contain any of the other ill~ di~ typically
used in laundry rinses, e.g., minor amounts of materials such as dyes and perfumes
and ~ s an alcohol, such as ethanol, to prevent phase separation~ as well as
the novel fabric softener mixture. Moreover, the rinse may be prepared as such rinses
are normally prepared except for the use of the novel mixture as the fabric softener:
and conventional t~rhn~ are also suitable for rinsing laundry therewith.
All of the laundry rinses of the invention, reSardless of the particular proportion-
.
WO 92/13934 PCT/US91109453
- 3 -
2~7~
ation of DTMAC and N-octadecyl-N,N-~ l~lh.-~ oxide within the specified ranges,
have the advantage of providing laundered fabrics, such as cotton, with better
rewettability than laundry rinses containing only one component of the fabric softener
- mixture; but optimum rewettability is obtained when the fabric softener is a mixture
5 of about 75% by weight of the .IU~.L~ .y ~mml chloride and about 25% by
weight of the amine oxide. This advantage of the mixtures is lln~yrert~rl since such
synergism is not obtained when other amine oxides, such as N-octyl-N,N-dill,_~ .c
oxide, are used irlstead of the N-octadecyl-N,N-d;~ illc oxide.
A laundry dryer sheet of the invention may be prepared by the w...~ iolldl
I0 technique of soaking an absorbent flexible substrate with an aqueous mixture of the
fabric softener mixture, pressing the resultant soaked sheet to remove any excess
surfactant, and then drying it. However, it is preferably prepared by coating anabsorbent flexible substrate with a molten mixture of the fabric softener ~ u~ . .r . ,t~
and then solidifying the mixture.
In preparing a laundry dryer sheet from a molten fabric softener mixture, it
is ~u..._.u.,-~L to conduct the process by soaking the absorbent flexible substrate in
a molten mixture of the fabric softener ~r,...l..".. -~ thus coating and inherently
i.ll~.~6.l~li.lg it with the surfactants; passing the soaked sheet between two rollers,
as in a roller press, to remove any excess surfactant; and allowing the remaining
surfactant to solidify.
The absorbent flexible substrate used in preparing the dryer sheets may be any
of the substrates typically employed in making such sheets. since the only IC.IUilC.~
for the substrate is that it be an absorbent material in sheet form. For example. it
may be a sponge, paper, or woven or non-woven cloth, especially a non-woven cloth
made from fibers or filaments of a material such as wool, silk, jute, hemp, cotton, linen,
sisal, ramie, rayon, cellulose esters, vinyl polymers, polyamides, and polyesters. A
particularly desirable substrate is a sheet of non-woven pol~,Lll~ c terephthalate
cloth.
All of the laundry dryer sheets of the invention in which the fabric softener
is a mixtuFe of 50-80% by weight of DTMAC and 50-20% by weight of N-octadecyl-
N,N-di~ lllillc oxide have the advantage of being able to impart greater softness
WO 92/13934 PCrIUS91/09453
9~ 3 _ --
to laundered fabrics, such as cotton, than can be achieved when either componentof the mixture is used alone as the fabric softener. However, optimum reults areachieved when the fabric softener is a mixture of about 75~o by weight of DTMAC
and about ~5~o by weight of the amine oxide.
The laundry dryer sheets in which the fabric softener is a mr~ture of 10-60~c
by weight of DTMAC and 9040~o by weight of any of the ilrul~ ", l~ d N-alkyl-N,N-
dimethylami..e oxides have the advantage of leading to the reduction of static charge
buildup on laundered polyester fabrics or laundry batches ~.:UIII~ illV at least some
polyester fabric when they are used in the drying step. In this case, optimum results
10 are obtained when the fabric softener is a mr~ture of about 50% by weight of DTMAC
and about 50% by weight of the amine oxide.
The following examples are given to illustrate the invention and are not intended
as a limitation thereo Unless otherwise specified, quantities m~nti~npd in the
examples are quantities by weight.
F~MpLE I
Fivemedium-gradecottonterryclothtowelsweresubjectedtofourwash/rinse/-
dryer cycles in which the rinses were aqueous solutions of N-octadecyl-N,N-d;.l,~Ll~rla.ll-
ine oxide (AO-18) and/or N,N-dillydl~ w-N,N 1' t~ .r' chloride
(DTMAC). The treated towels were then tested for 1. .._L~ y in accordance with
20 CSMA test protocol Method D-13D by cutting the towels into strips measuring 5 x
6 inches (12.7 x 15.2 cm), marking each of the strips one c~ t~l Erom the narrowedgeandloweringitintoaO.01%RhodamineBdyebathforsixminutes,andrecording
the distance of dye movement at the end of that time in centimeters. The amountsof AO-18 and DTMAC used in the fabric softener and the re~ults of the rewettability
25 tests are shown in the Table following the examples.
EXAMPLE Il
Fifty cotton hand-towels were washed on medium loading for 30 minutes in
the presence of 37.5g of an anionic laundry detergent and divided into five groups
of ten towels. each group then being loaded into an automatic dryer and dried for
WO 92/13934 PClllJS91~09453
60 minutes on "normal" at about 65 C in the presence of a polyester dryer sheet having
a lg loading of softener l,UIII~ lg AO-18 and/or DTMAC. The softness of the dried
towels was then evaluated by a panel of evaluators who ranked them from 5 (softest)
to 1 (least soft). The amounts of AO-18 and DTMAC used in the fabric softener and
5 lhe results of the softness test are shown in the Table following the examples.
FXAMPJ F ITT
A laundry batch composed of 23% polyester fabric, 46% cotton/polyester fabric,
and 31% cotton fabric was washed on medium loading for 30 minutes in the presence
of an anionic laundry detergent and then separated into five identical sub-batches.
10 Each sub-batch was loaded into an automatic dryer, a polyester dryer sheet havirtg
a lg loading of AO-18 and/or DTMAC fabric softener was placed into each of the
automatic dryers on top of the sub-batch, and the sub-batch was then dried for 60
minutes on "normal" at about 65 C The antistatic activity of the fabric softener in
eachdryersheetwasthen~ t.~rmin~din~,vlval.~ewithCSMAtestprotocolMethod
15 D-13F by removing the separate pieces of laundered fabric from the dryer, dropping
them into a Faraday cage, and recording the initial voltage -- the test being performed
on a day when the relative humidity was 50% at 22 C The amounts of AO-18 and
DTMAC used in the fabric softener and the results of the softness test are shown in
the Table following the examples.
'~o AQ ~ )TMAC~ ~ve Movement (cm~ ir ('l~r (kV)
Overall
1000 '.8 2 7 3.8 13
7525 4.0 7 5 1.2 13
~550 50 4.~ ~ 33 1.5 0.1
~5 75 4 8 . 3.6 3.1 1.7
O 100 1.6 3.0 '.8 1.7
,~.
.
