U.S. patent application number 10/144912 was filed with the patent office on 2003-03-06 for dishwashing.
This patent application is currently assigned to The Procter & Gamble Company. Invention is credited to Ward, Glenn Steven.
Application Number | 20030045437 10/144912 |
Document ID | / |
Family ID | 26246066 |
Filed Date | 2003-03-06 |
United States Patent
Application |
20030045437 |
Kind Code |
A1 |
Ward, Glenn Steven |
March 6, 2003 |
Dishwashing
Abstract
A method of washing cookware/tableware in an automatic
dishwashing machine having a pre-wash, main-wash and one or more
rinse cycles wherein one or more dishwashing products are dosed
into the one or more rinse cycles and wherein the dosing regime is
such as to provide a rinse cycle concentration factor (C.sub.r) of
at least about 1.3.times.10.sup.4, preferably at least about
1.8.times.10.sup.4 more preferably at least about
2.4.times.10.sup.4 and especially 3.2.times.10.sup.4 ppm min,
wherein C.sub.r is defined as: 1 t r t e c ( t ) t wherein c(t) is
the wash liquor concentration of dishwashing product as a function
of dishwashing time variable t, t.sub.r is the time corresponding
to the start of the first rinse, and t.sub.e is the time
corresponding to the end of the final rinse. The method provides
improved cleaning and finishing of the washed
cookware/tableware.
Inventors: |
Ward, Glenn Steven;
(Newcastle upon Tyne, GB) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY
INTELLECTUAL PROPERTY DIVISION
WINTON HILL TECHNICAL CENTER - BOX 161
6110 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Assignee: |
The Procter & Gamble
Company
Cincinnati
OH
|
Family ID: |
26246066 |
Appl. No.: |
10/144912 |
Filed: |
May 14, 2002 |
Current U.S.
Class: |
510/218 ; 134/18;
134/25.2; 134/29; 510/220; 510/226; 510/233 |
Current CPC
Class: |
C11D 3/3942 20130101;
C11D 17/045 20130101; B65D 85/00 20130101; C11D 17/0073 20130101;
C11D 3/3953 20130101; B65D 77/046 20130101; C11D 11/0023
20130101 |
Class at
Publication: |
510/218 ; 134/18;
134/25.2; 134/29; 510/220; 510/226; 510/233 |
International
Class: |
A47L 015/42; C11D
001/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 14, 2001 |
GB |
0111618.5 |
Apr 9, 2002 |
GB |
0208097.6 |
Claims
What is claimed:
1. A method of washing cookware/tableware in an automatic
dishwashing machine wherein one or more dishwashing products are
dosed into one or more rinse cycles after the main wash and wherein
the dosing regime is such as to provide a rinse cycle concentration
factor (C.sub.r) of at least about 1.3.times.10.sup.4, preferably
at least about 1.8.times.10.sup.4, more preferably at least about
2.4.times.10.sup.4 ppm min and especially 3.2.times.10.sup.4
wherein C.sub.r is defined as: 9 t r t e c ( t ) t wherein c(t) is
the wash liquor concentration of dishwashing product as a function
of dishwashing time variable t, t.sub.r is the time corresponding
to the start of the first rinse, and t.sub.e is the time
corresponding to the end of the final rinse.
2. A method according to claim 1 having two or more rinse cycles
and wherein the dosing regime is such as to provide a pre-final
rinse concentration factor (C.sub.pfr) of at least about
1.0.times.10.sup.3, preferably at least about 3.0.times.10.sup.3,
more preferably at least about 4.0.times.10.sup.3, and especially
at least about 5.0.times.10.sup.3 ppm min, where C.sub.pfr is
defined as: 10 t r t f c ( t ) t wherein t.sub.f is the time
corresponding to the start of the final rinse.
3. A method of washing cookware/tableware in an automatic
dishwashing machine wherein one or more dishwashing products are
dosed into the rinse after the main wash and prior to the final
rinse cycle and wherein the dosing regime is such as to provide a
pre-final rinse concentration factor (C.sub.pfr) of at least about
1.0.times.10.sup.3, preferably at least about 3.0.times.10.sup.3,
more preferably at least about 4.0.times.10.sup.3, and especially
at least about 5.0.times.10.sup.3 ppm min, where C.sub.pfr is
defined as: least about 4.0.times.10.sup.3, and especially at least
about 5.0.times.10.sup.3 ppm min, where C.sub.pfr is defined as: 11
t r t f c ( t ) t wherein t.sub.r is the time corresponding to the
start of the first rinse after the main wash, and t.sub.f is the
time corresponding to the start of the final rinse.
4. A method according to claim 1 wherein two or more dishwashing
products are dosed into the rinse and wherein the dosing regime is
such as to provide a final rinse concentration factor (C.sub.fr) of
at least about 1.2.times.10.sup.3, preferably at least about
5.0.times.10.sup.3, more preferably at least about
1.0.times.10.sup.4 and especially at least about 3.0.times.10.sup.4
ppm min, wherein C.sub.fr is defined as: 12 t f t e c ( t ) t
wherein t.sub.f is the time corresponding to the start of the final
rinse, and t.sub.e is the time corresponding to the end of the
final rinse.
5. A method according to claim 1 wherein the dosage concentration
of the one or more dishwashing products is at least about 1500,
preferably at least about 3000 ppm.
6. A method according to any of claims 1 to 5 wherein the dosing
regime is such as to provide one or more of the following rinse
cycle concentration cofactors: a) an alkali concentration cofactor
(C.sub.r, alk) of at least about 1.0.times.10.sup.3, preferably at
least about 3.0.times.10.sup.3, more preferably at least about
5.0.times.10.sup.3 and especially at least about 1.0.times.10.sup.4
ppm min; b) an acid concentration cofactor (C.sub.r, ac) of at
least about 3.0.times.10.sup.3, preferably at least about
4.0.times.10.sup.3, more preferably at least about
5.0.times.10.sup.3 and specially at least about 1.0.times.10.sup.4
ppm min; c) an active chlorine concentration cofactor (C.sub.r,
chi) of at least about 1.0.times.10.sup.3, preferably at least
about 2.0.times.10.sup.3 and more preferably at least about
4.0.times.10.sup.3 ppm min; d) an active protease concentration
cofactor (C.sub.r, prot) of at least about 30, preferably at least
about 50 and more preferably at least about 100 ppm min; e) an
active amylase concentration cofactor (C.sub.r, amyl) of at least
about 5, preferably at least about 8 and more preferably at least
about 16 ppm min; f) an active pectinase concentration cofactor
(C.sub.r, pect) of at least about 400, preferably at least about
600 and more preferably at least about 1200 ppm min; g) a total
active enzyme concentration cofactor (C.sub.r, enz) of at least
about 35, preferably at least about 60 and more preferably at least
about 120 ppm min; h) an active oxygen concentration cofactor
(C.sub.r, ox) of at least about 400, preferably at least about 600
and more preferably at least about 1200 ppm min; i) a diacyl
peroxide concentration cofactor (C.sub.r, diacyl) of at least about
400, preferably at least about 600 and more preferably at least
about 1200 ppm min; j) an Al.sup.3+ concentration cofactor
(C.sub.r, al) of at least about 500, preferably at least about 750
and more preferably at least about 1500 ppm min; k) a Zn.sup.2+
concentration cofactor (C.sub.r, zn) of at least about 500,
preferably at least about 750 and more preferably at least about
1500 ppm min; l) a surfactant concentration cofactor (C.sub.r,surf)
of at least about, preferably at least about 2.0.times.10.sup.3,
preferably at least about 3.0.times.10.sup.3 and more preferably at
least about 6.0.times.10.sup.3 ppm min; m) a sequestrant or builder
concentration cofactor (C.sub.r, seq) of at least about
2.0.times.10.sup.3, preferably at least about 4.0.times.10.sup.3
and more preferably at least about 8.0.times.10.sup.3 ppm min; n) a
polymeric dispersant concentration cofactor (C.sub.r, disp) of at
least about 4.0.times.10.sup.2, preferably at least about
8.0.times.10.sup.2 and more preferably at least about
1.6.times.10.sup.3 ppm min; o) a silicone concentration cofactor
(C.sub.r, sil) of at least about 3.0.times.10.sup.2, preferably at
least about 6.0.times.10.sup.2 and more preferably at least about
1.2.times.10.sup.3 ppm min; wherein the rinse cycle concentration
cofactor (C.sub.r, aux) for a given detergent auxiliary (aux) is
defined as: 13 t r t e c a u x ( t ) t wherein c.sub.aux(t) is the
wash liquor concentration of the detergent auxiliary as a function
of the dishwashing time variable t.
7. A method of washing cookware/tableware in an automatic
dishwashing machine wherein one or more dishwashing products are
dosed into the rinse after the main wash and prior to the final
rinse cycle and wherein the dosing regime is such as to provide one
or more of the following pre-final rinse concentration cofactors
(C.sub.pfr, aux): a) an alkali concentration cofactor (C.sub.pfr,
alk) of at least about 2.0.times.10.sup.2, preferably at least
about 1.5.times.10.sup.3 and more preferably at least about
2.5.times.10.sup.3 ppm min; b) an acid concentration cofactor
(C.sub.pfr, ac) of at least about 6.0.times.10.sup.2, preferably at
least about 2.0.times.10.sup.3 and more preferably at least about
2.5.times.10.sup.3 ppm min; c) an active chlorine concentration
cofactor (C.sub.pfr, chl) of at least about 200, preferably at
least about 1.0.times.10.sup.3 ppm min; d) an active protease
concentration cofactor (C.sub.pfr, prot) of at least about 6,
preferably at least about 25 ppm min; e) an active amylase
concentration cofactor (C.sub.pfr, amyl) of at least about 1,
preferably at least about 4 ppm min f) an active pectinase
concentration cofactor (C.sub.pfr, pect) of at least about 80,
preferably at least about 300 ppm min; g) a total active enzyme
concentration cofactor (C.sub.pfr, enz) of at least about 7,
preferably at least about 30 ppm min; h) an active oxygen
concentration cofactor (C.sub.pfr, ox) of at least about 80,
preferably at least about 300 ppm min; i) a diacyl peroxide
concentration cofactor (C.sub.pfr, diacyl) of at least about 80,
preferably at least about 300 ppm min; j) an Al.sup.3+
concentration cofactor (C.sub.pfr, al) of at least about 100,
preferably at least about 275 ppm min; k) a Zn.sup.2+ concentration
cofactor (C.sub.pfr, zn) of at least about 100, preferably at least
about 275 ppm min; l) a surfactant concentration cofactor
(C.sub.pfr, surf) of at least about 4.0.times.10.sup.2, preferably
at least about 1.5.times.10.sup.3; m) a sequestrant or builder
concentration cofactor (C.sub.pfr, seq) of at least about
4.0.times.10.sup.2, preferably at least about 2.0.times.10.sup.3
ppm min; n) a polymeric dispersant concentration cofactor
(C.sub.pfr, disp) of at least about 80, preferably at least about
4.times.10.sup.2 ppm min; o) a silicone concentration cofactor
(C.sub.pfr, sil) of at least about 60, preferably at least about
300 ppm min wherein the pre-rinse cycle concentration cofactor
(C.sub.pfr, aux) for a given detergent auxiliary (aux) is defined
as: 14 t r t f c a u x ( t ) t wherein c.sub.aux(t) is the wash
liquor concentration of the detergent auxiliary as a function of
the dishwashing time variable t, t.sub.r is the time corresponding
to the start of the first rinse, and t.sub.f is the time
corresponding to the start of the final rinse.
8. A method according to claim 1 wherein two or more dishwashing
products are dosed into the rinse and wherein the dosing regime is
such as to provide one or more of the following final rinse
concentration cofactors: a) an alkali concentration cofactor
(C.sub.fr, alk) of at least about 2.4.times.10.sup.2, preferably at
least about 1.0.times.10.sup.3, more preferably at least about
2.0.times.10.sup.3 and especially about 4.0.times.10.sup.3 ppm min;
b) an acid concentration cofactor (C.sub.fr, ac) of at least about
6.0.times.10.sup.2, preferably at least about 2.5.times.10.sup.3,
more preferably at least about 4.0.times.10.sup.3 and especially
about 8.0.times.10.sup.3 ppm min; c) an active chlorine
concentration cofactor (C.sub.fr, chl) of at least about 200,
preferably at least about 1.0.times.10.sup.3 more preferably at
least about 2.0.times.10.sup.3 ppm min; d) an active protease
concentration cofactor (C.sub.fr, prot) of at least about 6,
preferably at least about 25 more preferably at least about 50 ppm
min; e) an active amylase concentration cofactor (C.sub.fr, amyl)
of at least about 1, preferably at least about 4 more preferably at
least about 8 ppm min f) an active pectinase concentration cofactor
(C.sub.fr, pect) of at least about 80, preferably at least about
300 more preferably at least about 600 ppm min; g) a total active
enzyme concentration cofactor (C.sub.fr, enz) of at least about 7,
preferably at least about 30 more preferably at least about 60 ppm
min; h) an active oxygen concentration cofactor (C.sub.fr, ox) of
at least about 80, preferably at least about 300 more preferably at
least about 600 ppm min; i) a diacyl peroxide concentration
cofactor (C.sub.fr, diacyl) of at least about 80, preferably at
least about 300 more preferably at least about 600 ppm min; j) an
Al.sup.3+ concentration cofactor (C.sub.fr, al) of at least about
100, preferably at least about 275 more preferably at least about
550 ppm min; k) a Zn.sup.2+ concentration cofactor (C.sub.fr, zn)
of at least about 100, preferably at least about 275 more
preferably at least about 550 ppm min; l) a surfactant
concentration cofactor (C.sub.fr, surf) of at least about
4.times.10.sup.2, preferably at least about 1.5.times.10.sup.3 more
preferably at least about 3.0.times.10.sup.3 ppm min; m) a
sequestrant or builder concentration cofactor (C.sub.fr, seq) of at
least about 4.times.10.sup.2, preferably at least about
2.times.10.sup.3 more preferably at least about 4.0.times.10.sup.3
ppm min; n) a polymeric dispersant concentration cofactor
(C.sub.fr, disp) of at least about 80, preferably at least about
4.0.times.10.sup.2 more preferably at least about
8.0.times.10.sup.2 ppm min; o) a silicone concentration cofactor
(C.sub.fr, sil) of at least about 60, preferably at least about 300
more preferably at least about 600 ppm min wherein the final rinse
cycle concentration cofactor (C.sub.fr, aux) for a given detergent
auxiliary (aux) is defined as: 15 t f t e c a u x ( t ) t wherein
c.sub.aux(t) is the wash liquor concentration of the detergent
auxiliary as a function of the dishwashing time variable t, t.sub.f
is the time corresponding to the start of the final rinse, and
t.sub.e is the time corresponding to the end of the final
rinse.
9. A method according to claim 1 wherein the dosing regime is such
as to provide a pre-rinse alkali concentration factor (C.sub.pfr,
alk) of at least 200, preferably at least 1500 ppm min, a pre-rinse
active chlorine concentration factor (C.sub.pfr, chl) of at least
200, preferably at least about 1000 ppm min and a final rinse acid
concentration cofactor (C.sub.fr, ac) of at least about 600,
preferably at least about 2500, more preferably at least about 4000
and especially at least about 8000 ppm min.
10. A method according to claim 1 wherein the rinse liquor at a
point prior to the final rinse has a pH greater than about 10,
preferably greater than about 11.
11. A method according to claim 1 wherein the rinse liquor at a
point during the final rinse has a pH lower than about 8,
preferably lower than about 7.
12. A method according to claim 1 wherein the one or more
dishwashing products are present in the rinse liquor for at least
about 5 min, preferably at least about 10 min, and more preferably
for at least about 15 min.
13. A method according to claim 1 wherein the one or more
dishwashing products are present in the rinse liquor prior to the
final rinse for at least about 5 min, preferably at least about 7.5
min.
14. A method according to claim 1 wherein one or more of the
dishwashing products are delivered into the rinse by means of a
trigger-activated mechanical dosing device.
15. A method according to claim 14 wherein the dosing device is
time-activated or is activated in response to a physical or
chemical trigger such as pH, conductivity, pCa, pNa, temperature,
motion, turbidity, EC etc.
16. A method according to claim 14 wherein a plurality of
dishwashing products are simultaneously dosed into a given rinse
cycle.
17. A method according to claim 14 wherein a plurality of
dishwashing products are dosed into the same or different rinse
cycles at different moments of time.
18. A method according to claim 1 wherein one or more of the
dishwashing products are dosed in liquid form.
19. A method according to claim 1 wherein one or more of the
dishwashing products are dosed in solid form.
20. A method according to claim 19 wherein at least 50% of the
solid delivered into the rinse cycle dissolves in less than about 4
min, preferably less than about 3 min and more preferably less than
about 2 min.
21. A method according to claim 1 wherein one or more of the
dishwashing products comprises a detergency builder, preferably an
organic soluble builder in an amount effective for reducing the
concentration of Ca.sup.2+ in the rinse liquor below about 70 ppm,
preferably below about 35 ppm and more preferably below about 18
ppm expressed as calcium carbonate.
22. A method according to claim 1 wherein one or more of the
dishwashing products comprise a polymeric dispersant wherein the
polymeric dispersant comprises an olefinically unsaturated
carboxylic acid monomer and at least one monomer unit selected from
sulfonated monomers.
23. A method according to claim 22 wherein the concentration of
polymeric dispersant in the rinse liquor is less than about 300,
preferably less than about 200 and more preferably less than about
150 ppm.
24. A method according to claim 1 wherein one or more of the
dishwashing products comprise a wetting agent capable to provide
the rinse liquor with a surface tension of less than about 24 mN/m,
preferably less than about 23 mN/m.
25. A method according to claim 24 wherein the wetting agent is a
siloxane surfactant.
26. A method according to claim 1 wherein one or more of the
dishwashing products comprise a surface substantive modifying
polymer.
27. A method according to claim 26 wherein the surface substantive
modifying polymer is selected from polyvinyl pyrrolidone and
copolymers thereof; especially copolymers of polyvinyl pyrrolidone
with a comonomer selected from vinyl imidazole, acrylic acid,
methacrylic acid and mixtures thereof.
28. A method according to claim 1 wherein one or more of the
dishwashing products comprise a fibrous food degrading enzyme.
29. A method according to claim 28 wherein the fibrous food
degrading enzyme is a pectinase.
30. A method according to claim 28 wherein one or more dishwashing
products provides the rinse liquor with a pH of less than about 7,
preferably less than about 6 as measured at room temperature.
31. A mechanical dosing device for use in an automatic dishwashing
machine and which is adapted to deliver one or more dishwashing
products into the wash liquor according to the dosing regime set
out in claim 1.
Description
[0001] The application is a continuation of patent application GB
0208097.6 filed Apr. 9, 2002, which claims the benefit of GB
0111618.5 filed May 14, 2001, being filed under 35 U.S.C. 120.
TECHNICAL FIELD
[0002] The present invention is in the field of dishwashing, in
particular it relates to methods for the delivery of dishwashing
products into the rinse cycle of an automatic dishwashing machine.
The methods allow for an improved cleaning of tough food residues
and reduction of filming and spotting of the washed articles.
BACKGROUND OF THE INVENTION
[0003] Two of the unsolved problems in the field of automatic
dishwashing are those of cleaning tough food residues and of
preventing filming and spotting of washed articles, especially
glass and plastic articles. Filming and spotting are believed to
occur, among other reasons, due to the formation of insoluble salts
resulting from the combination between the ions generated from the
dishwashing detergent and the ions present in the dishwasher water.
Food soils also play a significant role in causing filming and
spotting. Traditionally, this problem has been ameliorated by the
use of salt in order to soften the water (that is to reduce the
concentration of cations, specially Ca.sup.2+ and Mg.sup.2+) and by
the use of rinse aid containing sequestrant, dispersant and
surfactant which to some extent help to control the hardness of the
ions present in the water and to reduce the surface tension of the
dishwashing liquor, thus avoiding the formation of liquid droplets
and allowing uniform drying of the washed utensils, ameliorating
filming and spotting issues.
[0004] However, some consumers do not use salt or rinse aid or the
water is so hard that salt and rinse aid are not enough to overcome
filming and spotting problems. Moreover, the problem of food soils
and removal of tough food residues still remains a significant
issue.
[0005] Nowadays, dishwashers are designed in such a way as to
deliver approximately from about 2 to about 6 ml of rinse aid at or
towards the end of the final rinse cycle. Sometimes, this amount of
rinse aid is not enough to control filming and spotting, however
dispenser sizes and delivery programs are fixed parameters
determined by dishwashing machine manufacturers and the user has no
control over them. A further restriction which needs to be
considered when formulating a rinse aid composition is the fact
that the rinse aid needs to be stored in the rinse reservoir inside
the dishwasher, usually during many cycles and therefore is subject
to the temperature changes associated with the dishwashing process.
Thus rinse aid compositions need to be very stable in order to
withstand these temperature changes without affecting its physical
form and/or chemical structure. This usually requires the use of
very dilute compositions, which limits even further the amount of
actives that can be delivered into the rinse cycle.
[0006] Some attempts have been made in order to provide controlled
delivery of rinse aid. For example WO-A-00/6684 and WO-A-00/6688
describe a multi-phase tablet comprising a particle which comprises
a core and a coating. The substances present in the core are active
during the rinse cycle and the coating comprises at least one
compound whose solubility increases with a declining concentration
of a specific ion in the surrounding medium. WO-A-99/27067 describe
a multi-phase tablet with a compressed and non-compressed portion
where the non-compressed portion does not dissolve until the rinse
cycle. EP-A-851,024 also describes a multi-phase tablet delivering
actives during the rinse cycle. However, WO '84, WO '88, WO '67 and
EP '24 are capable of delivering only small amount of actives into
the rinse cycle. U.S. Pat. No. 5,453,216 describes the delivery of
actives in the rinse cycle by means of coated particles. The
particles, which are introduced into the pre-wash and into
main-wash cycles, comprise a core comprising an inorganic builder
salt and a waxy coating having a melting point above 65.degree. C.
Particles are said to have a diameter from about 1 to about 2.5 mm.
As such, it seems likely that a large proportion of the particles
will be flushed away with the main wash liquor at the end of the
main wash cycle.
[0007] The majority of automatic dishwashers have wash programs
which last at least one hour but only a relatively small proportion
of the total wash program is devoted to active detersive cleaning
(i.e. the main-wash cycle, which lasts for about 20 min, and
possibly the pre-wash). The remainder of the program is taken up
with one or more post-main wash rinsing cycles. The perfect
dishwashing process able to clean even the toughest residues while
eliminating rinse-related problems such as filming and spotting
within the constraints of current dishwashing machine design, has
still to be developed.
[0008] In view of the above there is still a need for improving
tough food cleaning whilst reducing filming and spotting,
especially in those instances where users wish to avoid or limit
the use of salt and/or rinse aid and in the case of dishwashing
under hard water conditions.
SUMMARY OF THE INVENTION
[0009] An automatic dishwashing operation typically comprises three
or more cycles: a pre-wash cycle, a main-wash cycle and one or more
rinse cycles. In Europe, the pre-wash cycle, when used, is
typically a cold water cycle lasting about 6 or 7 min. In the
main-wash cycle the water comes in cold and is heated up to about
55 or 65.degree. C., the cycle lasting about 20 min. Rinsing
usually comprises two or more separate cycles following the main
wash, the first being cold and lasting between about 2 and 5 min,
the second one starting cold with heat-up to about 65.degree. C. or
70.degree. C. and lasting about 20 min. The dishwashing machine is
filled with cold water at the start of each cycle and emptied at
the end of each cycle through a filter. A typical dishwashing
machine is designed for the delivery of from about 20 to about 40
grams of detergent from the dispenser into the main-wash and from
about 2 to about 6 ml of rinse aid at or towards the end of the
final rinse cycle. In the U.S. the pre-wash may itself be followed
by a separate rinse cycle prior to the main-wash. For purposes of
the invention the term rinse is restricted to rinse cycles
following the main-wash.
[0010] It has now been found that dishwashing performance can be
significantly improved by delivery of one or more detergent
products or components thereof into the rinse following the main
wash, and especially into a rinse cycle prior to the final rinse
and/or into the final rinse, under conditions of concentration and
time such that the rinse cycle concentration factors and cofactors
as herein defined exceed certain minimum values. As used herein,
the term "rinse cycle concentration factor" refers to the integral
of wash liquor concentration of detergent product, treated as a
time-dependent function, over the period of the rinse, i.e. from
the start of the first rinse after the main-wash to the end of the
final rinse. The term "pre-final rinse concentration factor" refers
to the same integral but taken over the period from the start of
the first rinse to the start of the final rinse. The terms "rinse
cycle concentration cofactor" and "pre-final rinse cycle
concentration cofactor" are analogous quantities specified for
individual components of the detergent product, for example,
chlorine bleach, protease, etc. The concentration factors and
cofactors are calculated herein by trapezoidal graphical
integration of the wash liquor concentration function at time
intervals of 1 minute over the appropriate time period.
[0011] It has also been surprisingly found that the use of liquid
or gel detergent for the main-wash cycle combined with the use of
similar amounts of liquid or gel detergent during the rinse cycle
provides excellent cleaning results with minimum film formation
resulting from hardness/detergent interaction. Without being
bounded by the theory, it is believed that detergents in solid form
(such as powders or tablets) can give rise to the formation of a
film onto the washed articles during the main wash, therefore a
rinse cycle and rinse aid is needed to prevent this film.
Apparently, this film does not occur in the case of liquid or gel
detergent, suggesting that the rinse cycle can be used to achieve
extra cleaning whilst maintaining good rinsing and finishing
performance.
[0012] According to a first aspect of the present invention, there
is provided a method of washing cookware/tableware in an automatic
dishwashing machine having a main-wash, optional pre-wash and one
or more post main-wash rinse cycles wherein one or more dishwashing
products are dosed into the one or more rinse cycles and wherein
the dosing regime is such as to provide a rinse cycle concentration
factor (C.sub.r) of at least about 1.3.times.10.sup.4, preferably
at least about 1.8.times.10.sup.4 more preferably at least about
2.4.times.10.sup.4 and especially at least about 3.2.times.10.sup.4
ppm min, wherein C.sub.r is defined as: 2 t r t e c ( t ) t
[0013] wherein c(t) is the wash liquor concentration of dishwashing
product as a function of dishwashing time variable t, t.sub.r is
the time corresponding to the start of the first rinse, and t.sub.e
is the time corresponding to the end of the final rinse, all times
being measured in min from the start of the dishwashing
operation.
[0014] For calculation purposes, it is assumed that where a
dishwashing product takes less than 1 minute to dissolve or to
disperse substantially to a particle size of less than 53 .mu.m
(270 mesh) after contact with the wash liquor, the product is
considered to dissolve instantaneously and the wash liquor
concentration of the product as function of time simply equates to
the cumulative total of dishwashing product dosed into the wash
liquor as a function of time. This assumption generally applies to
most liquids, gels and paste-type products. Otherwise, the wash
liquor concentration can be determined by means known by the
skilled man in the art. For example, in the case of slowly
dissolving blocks the weight of the block can be monitored at
regular 1 minute time intervals. In the case of powders, samples of
wash solution can be taken at regular 1 minute time intervals and
filtered, the filtered solid being dried and weighed to quantify
the amount of product which is not dissolved, i.e. which does not
pass a 270 mesh filter. Measurements are repeated a sufficient
number of times to obtain a statistical significance (95%
confidence). For the purpose of the present invention it is
suitable to deliver powders having fast dissolution times so they
will have more time to act.
[0015] In a preferred embodiment herein, the dishwashing machine
has two or more rinse cycles and the dosing regime is such as to
provide a pre-final rinse concentration factor (C.sub.pfr) of at
least about 1.0.times.10.sup.3, preferably at least about
3.0.times.10.sup.3, and more preferably at least about
4.0.times.10.sup.3, especially at least about.5.0.times.10.sup.3
ppm min, where C.sub.pfr is defined as: 3 t r t f c ( t ) t
[0016] wherein t.sub.f is the time corresponding to the start of
the final rinse and t.sub.r is as defined above. Achieving a
pre-final rinse concentration factor within the specified range is
important herein for securing an optimum combination of tough food
cleaning and filming/spotting performance.
[0017] Thus, according to another aspect of the present invention,
there is provided a method of washing cookware/tableware in an
automatic dishwashing machine having a main-wash, optional pre-wash
and two or more rinse cycles, wherein one or more dishwashing
products are dosed into the rinse after the main wash and prior to
the final rinse cycle and wherein the dosing regime is such as to
provide a pre-final rinse concentration factor (C.sub.pfr) of at
least about 1.0.times.10.sup.3 preferably at least about
3.0.times.10.sup.3, and more preferably at least about
4.0.times.10.sup.3 and especially at least about.5.0.times.10.sup.3
ppm min, where C.sub.pfr is defined as: 4 t r t f c ( t ) t
[0018] wherein t.sub.r is the time corresponding to the start of
the first rinse, and t.sub.f is the time corresponding to the start
of the final rinse.
[0019] In preferred embodiments two or more dishwashing products
are dosed into the rinse and the dosing regime is such as to
provide a final rinse concentration factor (C.sub.fr) of at least
about 1.2.times.10.sup.3, preferably at least about
5.0.times.10.sup.3 more preferably at least about
1.0.times.10.sup.4 and especially at least about 3.0.times.10.sup.4
ppm min, wherein C.sub.fr is defined as: 5 t f t e c ( t ) t
[0020] wherein t.sub.f is the time corresponding to the start of
the final rinse, and t.sub.e is the time corresponding to the end
of the final rinse.
[0021] In preferred embodiments the dosage concentration of the one
or more dishwashing products delivered into the rinse liquor is
greater than about 1500 ppm, preferably greater than about 2000 ppm
and more preferably greater than about 3000 ppm. Preferably also
the one or more dishwashing products are present in the rinse
liquor for a period of at least about 5 min, preferably at least
about 7 min, more preferably at least about 10 min, and especially
at least about 15 min. It is also preferred that the one or more
dishwashing products are present in the rinse liquor prior to the
final rinse for at least about 2 min, preferably at least about 5
min, more preferably at least about 7.5 min.
[0022] In preferred embodiments the dosing regime is also such as
to provide one or more of the following rinse cycle concentration
cofactors:
[0023] a) an alkali concentration cofactor (C.sub.r, alk) of at
least about 1.0.times.10.sup.3, preferably at least about
3.0.times.10.sup.3, more preferably at least about
5.0.times.10.sup.3 and especially at least about 1.0.times.10.sup.4
ppm min;
[0024] b) an acid concentration cofactor (C.sub.r, ac) of at least
about 3.0.times.10.sup.3, preferably at least about
4.0.times.10.sup.3, more preferably at least about
5.0.times.10.sup.3 and specially at least about 1.0.times.10.sup.4
ppm min;
[0025] c) an active chlorine concentration cofactor (C.sub.r, chl)
of at least about 1.0.times.10.sup.3, preferably at least about
2.0.times.10.sup.3 and more preferably at least about
4.0.times.10.sup.3 ppm min;
[0026] d) an active protease concentration cofactor (C.sub.r, prot)
of at least about 30, preferably at least about 50 and more
preferably at least about 100 ppm min;
[0027] e) an active amylase concentration cofactor (C.sub.r, amyl)
of at least about 5, preferably at least about 8 and more
preferably at least about 16 ppm min;
[0028] f) an active pectinase concentration cofactor (C.sub.r,
pect) of at least about 400, preferably at least about 600 and more
preferably at least about 1200 ppm min;
[0029] g) a total active enzyme concentration cofactor (C.sub.r,
enz) of at least about 35, preferably at least about 60 and more
preferably at least about 120 ppm min;
[0030] h) an active oxygen concentration cofactor (C.sub.r, ox) of
at least about 400, preferably at least about 600 and more
preferably at least about 1200 ppm min;
[0031] i) a diacyl peroxide concentration cofactor (C.sub.r,
diacyl) of at least about 400, preferably at least about 600 and
more preferably at least about 1200 ppm min;
[0032] j) an Al.sup.3+ concentration cofactor (C.sub.r, al,) of at
least about 500, preferably at least about 750 and more preferably
at least about 1500 ppm min;
[0033] k) a Zn.sup.2+ concentration cofactor (C.sub.r, zn) of at
least about 500, preferably at least about 750 and more preferably
at least about 1500 ppm min;
[0034] l) a surfactant concentration cofactor (C.sub.r,surf) of at
least about, preferably at least about 2.0.times.10.sup.3
preferably at least about 3.0.times.10.sup.3 and more preferably at
least about 6.0.times.10.sup.3 ppm min;
[0035] m) a sequestrant or builder concentration cofactor (C.sub.r,
seq) of at least about 2.0.times.10.sup.3, preferably at least
about 4.0.times.10.sup.3 and more preferably at least about
8.0.times.10.sup.3 ppm min;
[0036] n) a polymeric dispersant concentration cofactor (C.sub.r,
disp) of at least about 4.0.times.10.sup.2, preferably at least
about 8.0.times.10.sup.2 and more preferably at least about
1.6.times.10.sup.3 ppm min;
[0037] o) a silicone concentration cofactor (C.sub.r, sil) of at
least about 3.0.times.10.sup.2, preferably at least about
6.0.times.10.sup.2 and more preferably at least about
1.2.times.10.sup.3 ppm min;
[0038] wherein the rinse cycle concentration cofactor (C.sub.r,
aux) for a given detergent auxiliary (aux) is defined as: 6 t r t e
c a u x ( t ) t
[0039] wherein c.sub.aux(t) is the wash liquor concentration of the
detergent auxiliary as a function of the dishwashing time variable
t. In order to calculate C.sub.r, aux samples of the wash liquor
are taken at 1 minute intervals throughout the rinse and the
corresponding concentration of auxiliary is measured using an
appropriate analytical technique. The concentration cofactors are
then determined by trapezoidal graphical integration of wash liquor
concentration of the specified auxiliary at time intervals of 1
minute. Wash liquor concentrations are determined in known manner,
by taking suitably sized aliquots of the wash liquor and performing
conventional analytical techniques on the aliquot. In the case of
enzymes, active enzyme concentration is generally determined by
spectrophotometric or other suitable methods using the substrate,
pH, temperature, buffer and incubation conditions set out in the
manufacturer's product data sheets and related test methods for the
particular enzyme and calibrated against solutions of known
specific and total enzyme activity.
[0040] For example, in the case of amylases, activity through the
wash can be measured by taking 1 ml aliquot every minute. The
aliquot is added to 5 ml of phosphate buffered solution (14.42 g
Na.sub.2HPO.sub.4, 2.59 g KH.sub.2PO.sub.4 in 1 liter of deionised
water, to give a pH of 8.3) and 0.5 ml of 20% w/v sodium sulphite
solution, the mixture is placed in a 37.degree. C. water bath and a
Phadebas tablet (Available from Pharmacia Ltd.) is added, the
mixture is left to incubate for 15 minutes. After 15 minutes the
reaction is stopped by the addition of 1 ml of 1M sodium hydroxide.
The mixture is filtered and the absorbance of the liquor is
measured at 620 nm (using a Pharmacia Biotech Ultropec 2000
spectophotometer) and from here the active enzyme concentration is
read from graphs precalibrated against amylases (such as Termamyl)
of known specific activity in known active concentration
levels.
[0041] In the case of proteases, activity through the wash can be
measured by taking 1 ml aliquot every minute. The aliquot is added
to 0.7 ml of sodium sulphite solution (2.5 g/l), 2 ml of 0.4%
N-N-dimethylcasein solution and 1 ml of 0.65% 2,4,6 trinitro
benzene sulphonic acid solution. The test is carried out at
49.degree. C. and pH 9.0. The absorbance of the liquor is measured
(using a Pharmacia Biotech Ultropec 2000 spectophotometer) and from
here the active enzyme concentration is read from graphs
precalibrated against proteases (such as Savinase) of known
specific activity in known active concentration levels.
[0042] Preferred herein from the viewpoint of achieving optimum
tough food cleaning and rinsing/finishing performance are wash
processes wherein certain active components are delivered into the
rinse prior to the final rinse. Thus, according to another aspect
of the invention, there is provided a method of washing
cookware/tableware in an automatic dishwashing machine having a
main-wash, optional pre-wash and two or more rinse cycles, wherein
one or more dishwashing products are dosed into the rinse after the
main wash and prior to the final rinse cycle and wherein the dosing
regime is such as to provide one or more of the following pre-final
rinse concentration cofactors (C.sub.pfr, aux):
[0043] a) an alkali concentration cofactor (C.sub.pfr, alk) of at
least about 2.0.times.10.sup.2, preferably at least about
1.5.times.10.sup.3 and more preferably at least about
2.5.times.10.sup.3 ppm min;
[0044] b) an acid concentration cofactor (C.sub.pfr, ac) of at
least about 6.0.times.10.sup.2, preferably at least about
2.0.times.10.sup.3 and more preferably at least about
2.5.times.10.sup.3 ppm min;
[0045] c) an active chlorine concentration cofactor (C.sub.pfr,
chl) of at least about 200, preferably at least about
1.0.times.10.sup.3 ppm min;
[0046] d) an active protease concentration cofactor (C.sub.pfr,
prot) of at least about 6, preferably at least about 25 ppm
min;
[0047] e) an active amylase concentration cofactor (C.sub.pfr,
amyl) of at least about 1, preferably at least about 4 ppm min
[0048] f) an active pectinase concentration cofactor (C.sub.pfr,
pect) of at least about 80, preferably at least about 300 ppm
min;
[0049] g) a total active enzyme concentration cofactor (C.sub.pfr,
enz) of at least about 7, preferably at least about 30 ppm min;
[0050] h) an active oxygen concentration cofactor (C.sub.pfr, ox)
of at least about 80, preferably at least about 300 ppm min;
[0051] i) a diacyl peroxide concentration cofactor (C.sub.pfr,
diacyl) of at least about 80, preferably at least about 300 ppm
min;
[0052] j) an Al.sup.3+ concentration cofactor (C.sub.pfr, al) of at
least about 100, preferably at least about 275 ppm min;
[0053] k) a Zn.sup.2+ concentration cofactor (C.sub.pfr, zn) of at
least about 100, preferably at least about 275 ppm min;
[0054] l) a surfactant concentration cofactor (C.sub.pfr, surf) of
at least about 4.0.times.10.sup.2, preferably at least about
1.5.times.10.sup.3;
[0055] m) a sequestrant or builder concentration cofactor
(C.sub.pfr, seq) of at least about 4.0.times.10.sup.2, preferably
at least about 2.0.times.10.sup.3 ppm min;
[0056] n) a polymeric dispersant concentration cofactor (C.sub.pfr,
disp) of at least about 80, preferably at least about
4.times.10.sup.2 ppm min;
[0057] o) a silicone concentration cofactor (C.sub.pfr, sil) of at
least about 60, preferably at least about 300 ppm min;
[0058] wherein the pre-rinse cycle concentration cofactor
(C.sub.pfr, aux) for a given detergent auxiliary (aux) is defined
as: 7 t r t f c a u x ( t ) t
[0059] wherein c.sub.aux(t) is the wash liquor concentration of the
detergent auxiliary as a function of the dishwashing time variable
t, t.sub.r is the time corresponding to the start of the first
rinse, and t.sub.f is the time corresponding to the start of the
final rinse.
[0060] In other preferred embodiments, two or more dishwashing
products are dosed into the rinse and the dosing regime is such as
to provide one or more of the following final rinse concentration
cofactors:
[0061] a) an alkali concentration cofactor (C.sub.fr, alk) of at
least about 2.4.times.10.sup.2, preferably at least about
1.0.times.10.sup.3, more preferably at least about
2.0.times.10.sup.3 and especially about 4.0.times.10.sup.3 ppm
min;
[0062] b) an acid concentration cofactor (C.sub.fr, ac) of at least
about 6.0.times.10.sup.2, preferably at least about
2.5.times.10.sup.3, more preferably at least about
4.0.times.10.sup.3 and especially about 8.0.times.10.sup.3 ppm
min;
[0063] c) an active chlorine concentration cofactor (C.sub.fr, chl)
of at least about 200, preferably at least about 1.0.times.10.sup.3
more preferably at least about 2.0.times.10.sup.3 ppm min;
[0064] d) an active protease concentration cofactor (C.sub.fr,
prot) of at least about 6, preferably at least about 25 more
preferably at least about 50 ppm min;
[0065] e) an active amylase concentration cofactor (C.sub.fr, amyl)
of at least about 1, preferably at least about 4 more preferably at
least about 8 ppm min
[0066] f) an active pectinase concentration cofactor (C.sub.fr,
pect) of at least about 80, preferably at least about 300 more
preferably at least about 600 ppm min;
[0067] g) a total active enzyme concentration cofactor (C.sub.fr,
enz) of at least about 7, preferably at least about 30 more
preferably at least about 60 ppm min;
[0068] h) an active oxygen concentration cofactor (C.sub.fr, ox) of
at least about 80, preferably at least about 300 more preferably at
least about 600 ppm min;
[0069] i) a diacyl peroxide concentration cofactor (C.sub.fr,
diacyl) of at least about 80, preferably at least about 300 more
preferably at least about 600 ppm min;
[0070] j) an Al.sup.3+ concentration cofactor (C.sub.fr, al) of at
least about 100, preferably at least about 275 more preferably at
least about 550 ppm min;
[0071] k) a Zn.sup.2+ concentration cofactor (C.sub.fr, zn) of at
least about 100, preferably at least about 275 more preferably at
least about 550 ppm min;
[0072] l) a surfactant concentration cofactor (C.sub.fr, surf) of
at least about 4.times.10.sup.2, preferably at least about
1.5.times.10.sup.3 more preferably at least about
3.0.times.10.sup.3 ppm min;
[0073] m) a sequestrant or builder concentration cofactor
(C.sub.fr, seq) of at least about 4.times.10.sup.2, preferably at
least about 2.times.10.sup.3 more preferably at least about
4.0.times.10.sup.3 ppm min;
[0074] n) a polymeric dispersant concentration cofactor (C.sub.fr,
disp) of at least about 80, preferably at least about
4.0.times.10.sup.2 more preferably at least about
8.0.times.10.sup.2 ppm min;
[0075] o) a silicone concentration cofactor (C.sub.fr, sil) of at
least about 60, preferably at least about 300 more preferably at
least about 600 ppm min;
[0076] wherein the final rinse cycle concentration cofactor
(C.sub.fr, aux) for a given detergent auxiliary (aux) is defined
as: 8 t f t e c a u x ( t ) t
[0077] wherein c.sub.aux(t) is the wash liquor concentration of the
detergent auxiliary as a function of the dishwashing time variable
t, t.sub.f is the time corresponding to the start of the final
rinse, and t.sub.e is the time corresponding to the end of the
final rinse.
[0078] In an especially preferred embodiment, the dosing regime is
such as to provide a pre-rinse alkali concentration factor
(C.sub.pfr, alk) of at least about 200, preferably at least about
1500 ppm min, a pre-rinse active chlorine concentration factor
(C.sub.pfr, chl) of at least about 200, preferably at least about
1000 ppm min, and a final rinse acid concentration cofactor
(C.sub.fr, ac) of at least about 600, preferably at least about
2500, more preferably at least about 4000 and especially at least
about 8000 ppm min.
[0079] Preferably also, the dosing regime is such that the rinse
liquor at a point prior to the final rinse has a pH greater than
about 10, preferably greater than about 11; and at a point during
the final rinse has a pH lower than about 8, preferably lower than
about 7.
[0080] Preferably the one or more dishwashing compositions are
delivered into the rinse by means of a trigger-activated mechanical
dosing device designed to achieve the requisite concentration
factors and cofactors. Suitable for use herein are dosing devices
which contain sufficient dishwashing product for a single
dishwashing rinse cycle or for a plurality of dishwashing rinse
cycles, in the same or different dishwashing operations. Any device
capable of storing and dosing one or more dishwashing products at
pre-determined times in the rinse cycle is suitable for use herein.
The device keeps the dishwashing product/s enclosed until a
pre-determined time at which the product/s is/are released, usually
by opening of one or more outlets of the device. The outlet opening
time can be controlled by any mechanism known in the art, such as
for example a timer, a shape memory alloy, a shape memory polymer,
a sensor which detects stimulus from the wash liquor (pH,
conductivity, pCa, pNa, temperature, motion, turbidity, etc) or
some other means capable of providing a physical or chemical
trigger.
[0081] The device can contain only one compartment or a plurality
of compartments for the storage of one or more products. Where
there are products containing mutually incompatible ingredients,
such products are normally placed in different compartments in the
device. For example, it is useful to have separate compartments
when bleach and bleach activator are to be delivered into the rinse
or when bleach and enzymes are to be delivered into the rinse.
Different products can be dosed at the same time or at different
times in order to optimise the cleaning and finishing benefits in
the dishwashing process.
[0082] Other ways to deliver the dishwashing products into the
rinse cycle are for example a slow-release block, a single or
multi-compartment sachet with sensitive seals (pH, temperature,
ionic strength, etc), a single or multi-compartment porous sachet
with a pore-occluding coating (sensitive to pH, temperature, ionic
strength, etc) or a single or multi-compartment water permeable
sachet comprising an encapsulated dishwashing product (sensitive to
pH, temperature, ionic strength, etc).
[0083] In preferred embodiments, at least one and preferably all of
the dishwashing products is/are in liquid or gel form. In the case
of solid form products, preferably at least 50% of the solid
delivered into the rinse cycle dissolves in less than about 4 min,
preferably less than about 3 min, more preferably less than about 2
min and even more preferably less than about 1 min.
[0084] In a highly preferred embodiment one or more of the
dishwashing products comprises a detergency builder, preferably an
organic soluble builder in an amount effective to reduce the
concentration of Ca.sup.2+ in the rinse liquor below about 70 ppm
expressed as calcium carbonate, preferably below about 35 ppm and
more preferably below about 18 ppm. Such a low Ca.sup.2+
concentration is beneficial not only for the washed
dishware/tableware but also for the heating element of the
dishwasher. The Ca.sup.2+ in the rinse liquor can be measured using
for example atomic absorption.
[0085] Without wishing to be bound by the theory, it is believed
that a film can be left on the dishware/tableware after the main
wash. It has also been found that this film can be dissolved by
very soft water, i.e., water containing less than about 70 ppm,
preferably less than about 35 ppm and more preferably less than
about 18 ppm of Ca.sup.2+, a level which may not be attained even
with the use of a salt softening system. Herein the soft water is
obtained by the use of soluble builders in appropnate
concentrations and concentration factors and cofactors. Among the
suitable organic soluble builders for use herein are organo
aminophosphonic acid, organo diphosphonic acid, carboxylic acid and
polycarboxylic acid and their salts and complexes. Preferred for
use herein are ethane 1-hydroxy-1,1-diphosphonic acid (HEDP) and
citric acid or their salts.
[0086] In another preferred embodiment one or more of the
dishwashing products comprises a polymeric dispersant, highly
preferred herein being a polymeric dispersant which comprises an
olefinically unsaturated carboxylic acid monomer and at least one
monomer unit selected from sulfonated monomers. The polymeric
dispersant is effective in suspending the film that is formed on
the dishware/tableware after the main wash cycle. Preferred for use
herein are tetrapolymers of 4-sulfophenol methallyl ether, sodium
methallyl sulfonate, acrylic acid and methyl methacrylate.
[0087] Preferably the concentration of polymeric dispersant in the
rinse liquor is less than about 300, preferably less than about
200, more preferably less than about 150 ppm and even more
preferably less than about 100 ppm.
[0088] Spotting in plasticware after the dishwashing process is a
common feature produced as consequence of uneven drying of the
water from the surface of the ware after the rinsing step. To help
minimize spotting one or more of the dishwashing products
preferably comprises a wetting agent capable of providing the rinse
liquor with a surface tension of less than about 24 mN/m,
preferably less than about 23 mN/m and even more preferably less
than about 21 mN/m. The low surface tension of the wash liquor
allows for sheeting of the water, avoiding the spotting in
plasticware. Preferred wetting agents for use herein are siloxane
surfactants especially trisiloxanes.
[0089] Also preferred for use herein from the viewpoint of reducing
spotting is a chlorine bleaching agent. Chlorine bleach greatly
improves cleaning performance of the automatic dishwashing
operation, in particular it remove stains left by tea, coffee or
fruit juices. Chlorine bleach is also very good in the removal of
protein films from dishware/tableware caused by soil food or by
enzymes deposition. Additionally chlorine bleach is an excellent
sanitizer and germicide.
[0090] In another embodiment one or more of the dishwashing
products comprises a surface substantive modifying polymer. Surface
substantive modifying polymers suitable for use herein are selected
from polyvinyl pyrrolidone and copolymers thereof; especially
copolymers of polyvinyl pyrrolidone with a comonomer selected from
vinyl imidazole, acrylic acid, methacrylic acid, N-oxide and
mixtures thereof.
[0091] Preferably, the one or more dishwashing products provides
the final rinse liquor with a pH of less than about 10, preferably
less than about 9 and even more preferably less than about 8 as
measured at room temperature.
[0092] In another embodiment one or more of the dishwashing
products comprises a fibrous food degrading enzyme. The addition of
fibrous food degrading enzyme is especially valuable for the
cleaning of the machine itself. Usually after the dishwashing
process there can be a lot food residues left over in the filter
and other parts of the dishwashing machine. The use of machine
cleaner products is known in the art, however, these usually
necessitate running the machine empty. The present method allows
for the simultaneous cleaning of dishware/tableware and the
dishwashing machine interior. Suitable fibrous food degrading
enzymes for use herein include pectinases and are normally employed
at a pH of less than about 7, preferably less than about 6 as
measured at room temperature.
DETAILED DESCRIPTION OF THE INVENTION
[0093] The present invention envisages a dishwashing method based
on the use of one or more rinse cycles to provide chemical cleaning
after the main wash and/or to improve finishing of the
dishware/tableware by delivering high amounts of actives into the
rinse. The actives are preferably delivered early into the rinse
and preferably prior to the final rinse so as to provide both tough
food cleaning benefits and finishing benefits at one and the same
time. Embodiments in which one or more dishwashing products are
delivered prior to the final rinse and one or more dishwashing
products are thereafter delivered into the final rinse are also
highly preferred. According to preferred embodiments of the
invention, the dishwashing products are delivered by means of
purpose-built dosing devices. Suitable dosing devices allow for the
storage of the dishwashing products in one or more compartments and
for simultaneous or sequential dosing of the products in one or
more cycles, wherein the products are in solid, liquid, gel or
paste form.
[0094] The method of the invention also envisages the use of
products comprising chlorine bleach, organic soluble builders and
polymeric dispersants to reduce filming and spotting; the use of
products comprising wetting agents to facilitate uniform drying and
the use of surface substantive modifying polymers to improve the
finishing of dishware/tableware.
[0095] Finally, the method of the invention also envisages the use
of products comprising fibrous food degrading enzymes which
contribute to the cleaning of the machine itself.
[0096] The dishwashing products can be delivered using any suitable
device capable of delivering a predetermined amount of product at a
predetermined time. For example, a dosing device suitable for use
herein comprises a housing with at least one opening wherein the
opening is removably closed by a cover. Inside the housing, the
dosing device comprises at least one product compartment for
storing the product to be dosed. The compartment can have any
suitable shape sufficient to ensure easy and complete release of
its contents. The device can be electrically operated, in which
case the device would also comprise at least one compartment for
storing electromechanical components. While the dosing device can
have any suitable shape, a preferred one is made out of two
hemispheres, one comprising at least one product compartment for
containing at least one product to be released, and the other
hemisphere comprising an electromechanical compartment containing
the power supply, at least one sensor, actuator systems and a
microchip for driving a logic control program.
[0097] By sensor is meant a chip or similar electronic device which
detects a stimulus in the dosing device's environment, for example
in the wash water (such as pH, temperature, ionic strength, etc).
Preferably, the sensor is directly coupled to a microchip which
transforms the stimulus into an electric impulse which is then sent
to the actuator. The sensor is housed in the electromechanical
compartment of the device and secured for example with brackets and
screws. The microchip which is preferably integrated to the sensor
itself is an electronic circuit which runs a basic program, so
called logic control program. The logic control program integrates
different parameters of the wash which are sensed in the medium
(i.e. the wash water), and also integrates the type of product that
needs to be released and the desired rinse cycle concentration
factors, in order to calculate at what time(s) during the rinse,
said products must be released. The specific construction of the
electronic circuit of the microchip will be appropriately chosen by
a person skilled in the art.
[0098] The sensor structure and construction is adapted to the
stimulus to be detected, and the choice of the appropriate sensor
construction will be easily determined by a person skilled in the
art. One dosing device suitable for use herein comprises at least
one sensor, such that it can react to at least one stimulus present
in its environment. It will be appreciated that the more stimuli
said device detects, the more accurate the product dosing and/or
release will be.
[0099] The dosing device can alternatively be controlled by means
of memory shape alloys or polymers, which properties are determined
by temperature.
[0100] By dosing device is meant a device with which it is possible
to measure the right amount of product to be released during the
rinse cycle, for example depending on the wash conditions,
including but not limited to the amount of items to be washed, the
composition of the washing environment (for instance the wash
water), the nature of the product which is used for the wash, the
required rinse cycle concentration factors, etc.
[0101] The dosing can be done by the user her/himself with
instructions as to the requisite dosing regime. For example, this
can be done by using the size of the device's compartment to
measure the right amount of product to be released at a requisite
part of the rinse. In this case, the device comprises a means, for
example dosing line-up marks, that will help the user chose the
right amount of product. Alternatively, the user can introduce a
cartridge of product into the dosing device, said cartridge
containing a predetermined amount of product, e.g. for one or
several wash(es).
[0102] Alternatively, the dosing is done by the device itself,
which is constructed so that at least one compartment can be opened
and closed again during the wash. In this case, the compartment
does not comprise line-up marks, the user fills it completely
before the wash. During the rinse cycle, the dosing device first
opens to release product, then senses or calculates when the
concentration of product is sufficient and finally closes to
prevent over-dosing of the product. In this case, the concentration
sensing can be done by checking one component which is a
characteristic of the product to being released, for example, the
level of bleach can be sensed, in case the product to be released
is bleach. The skilled person will be able to determine which
compound must be sensed, depending on which product is released. Of
course, a corresponding and suitable sensor must be integrated to
the dosing device in this case, and the control logic program must
be adapted accordingly.
[0103] Preferably, the dosing device comprises a means to enable it
to stand on a flat surface, for example on a table. This means can
be for example a flat portion of the housing, an outside surface or
a stand. Alternatively, in the case of power operated device, the
electronic components which are the heaviest part of said device
are located in the bottom portion of said device, so that when the
device is put on a flat surface, it always stays in the upright
position. Once activated, the dosing device most preferably stays
as a single unite, so that the user does not have to remove more
than one portion of the device from the dishwashing machine.
[0104] The materials used for the housing and the cover might be of
any type, and they may be made out of one or several materials.
Preferred materials for the housing and the cover are synthetic
materials, for example plastic or rubber, so as to be resistant to
liquids and/or temperature variations. It is highly preferred that
once closed, the dosing device be liquid-tight. Of course, all
materials used in the dosing device should be chosen such that they
resist the conditions of use. Preferably, they are heat resistant
so as to withstand the dish-washing temperatures. Examples of hard
materials include but are not limited to polypropylene (PP),
polycarbonate (PC), copolymers of butadiene and styrene, and the
like.
[0105] The housing and the cover are preferably made by injection
molding. In case they are made out of more than one material,
co-injection molding process will be preferred, where applicable,
since it is less expensive than molding several insert portions
separately and then assembling them. For instance, co-injection
molding can be used for the housing, to make it out of hard
plastic, with some portions made out of a non-slipping rubber
material. It is preferred that at least some portions of the dosing
device's outer surface (including housing and cover) are made out
of a rubber-like material, which will help to prevent noise.
Preferably, the dosing device is secured to the walls of the
dishwashing machine, for example by means of a magnet or by
adhesive means.
[0106] In the case of a power-operated device, the dosing device
comprises at least one means for storing energy and releasing it,
such that the contents of said dosing device is released at a given
predetermined time during the rinse cycle. It is preferred that the
dosing device also comprises at least one sensor which is linked to
the means, to determine when the environment, for example the wash
water, requires that the dosing device be opened and the product
released. Also preferably, the dosing device comprises an actuator
which is linked to the cover, so as to activate the opening of said
cover during the wash. Finally, the dosing device further comprises
a microchip that monitors the data received from the sensors, and
gives a signal to the actuator to open said dosing device at the
right time during the wash cycle, in order to meet the required
concentration factors and cofactors.
[0107] The dosing device is preferably portable, that is to say
that it is not too bulky and heavy and can easily be handheld and
manipulated by a user for in-house usage. Its dimensions must be
such that it can be put into a dishwasher. Preferably, its greatest
outer dimension does not exceed 20 cm. Also preferably, its overall
weight does not exceed 5 kg when empty, more preferably, it does
not exceed 2.5 kg when empty, even more preferably its weight is
not more than 1 kg when empty.
[0108] The dosing device for use herein is preferably self
contained. By self contained is meant that the dosing device, once
filled with product and closed, can work independently from any
other device. Particularly, it comprises its own power source, and
all means necessary to determine properly the right time its
contents needs to be released, only by sensing its external
environment. Alternatively, the power can be transmitted via a coil
transmitter, which receives electricity via a remote generator. The
sensing and/or microchip means can also be provided as a separate
unit with signals for actuating the dosing device being transmitted
by Bluetooth or some other wireless communication device.
[0109] Alkali materials for use herein are any materials capable of
providing the dishwashing liquor with a pH above 7, preferably
above 8, more preferably above 10 and even more preferably above
11. Preferred for use herein are caustic agents such as alkali
hydroxides, especially sodium hydroxide, potassium hydroxide and
mixtures therefore.
[0110] Acidic materials for use herein are any materials capable of
providing the dishwashing liquor with a pH below 7, preferably
below 6, more preferably below 5 and even more preferably below 4.
Suitable for use herein are organic acids, for example carboxylic
acids, such as citric and succinic acids, polycarboxylic acids,
such as polyacrylic acid and also acetic acid boric acid, malonic
acid, their derivatives and mixtures thereof. Also suitable for use
herein are inorganic acids and their salts, especially useful are
salt of inorganic acids containing a cation which plays a role in
the dishwashing process as for example aluminium. Preferred for use
herein is aluminium sulphate, which provides the dishwashing
liquior with an adequate pH and provides glass care benefits.
[0111] Organic Soluble Builder
[0112] Organic soluble builders for use herein are capable of
reducing the concentration of Ca.sup.2+ below about 4 ppm,
preferably below about 2 ppm and more preferably below 1 ppm. The
organic soluble builder is preferably present at a level of from
about 1 to about 80%, preferably from about 5 to about 70% and more
preferably from about 10 to about 60% by weight of the
composition.
[0113] Suitable for use herein are organo aminophosphonic acid or
one of its salts or complexes. By organo aminophosphonic acid
component it is meant herein an organic compound comprising at
least one phosphonic acid group, and at least one amino group. The
organo aminophosphonic acid component may be present in its acid
form or in the form of one of its salts or complexes with a
suitable counter cation, and reference herein to the acid component
implicitly includes reference to the salts or complexes. Preferably
any salts/complexes are water soluble, with the alkali metal and
alkaline earth metal salts/complexes being especially
preferred.
[0114] Suitable organo aminophosphonic acid components for use
herein include the amino alkylene poly (alkylene phosphonic acids)
and nitrilo trimethylene phosphonic acids. Preferred are diethylene
triamine penta (methylene phosphonic acid) and hexamethylene
diamine tetra (methylene phosphonic acid).
[0115] A preferred component of the dishwashing products used
herein is an organo diphosphonic acid or one of its salts or
complexes. Said organo diphosphonic acid may act in combination
with the organo aminophosphonic acid component to further enhance
the prevention of calcium deposit formation. By organo diphosphonic
acid it is meant herein an organo diphosphonic acid which does not
contain nitrogen as part of its chemical structure. This definition
therefore excludes the organo aminophosphonates.
[0116] The organo diphosphonic acid component may be present in its
acid form or in the form of one of its salts or complexes with a
suitable counter cation. Preferably any salts/complexes are water
soluble, with the alkali metal and alkaline earth metal
salts/complexes being especially preferred. The organo diphosphonic
acid is preferably a C1-C4 diphosphonic acid, more preferably a C2
diphosphonic acid, such as ethylene diphosphonic acid, or most
preferably ethane 1-hydroxy-1,1-diphosphonic acid (HEDP).
[0117] Suitable water-soluble carboxylate or polycarboxylate
builders include carboxylic and polycarboxylic acids their salts
and complexes. The carboxylate or polycarboxylate builder can be
momomeric or oligomeric in type although monomeric polycarboxylates
are generally preferred for reasons of cost and performance.
Monomeric and oligomeric builders can be selected from acyclic,
alicyclic, heterocyclic and aromatic carboxylates.
[0118] Suitable carboxylates containing one carboxy group include
lactic acid, glycolic acid and ether derivatives thereof as
disclosed in Belgian Patent Nos. 831,368, 821,369 and 821,370.
Polycarboxylates containing two carboxy groups include succinic
acid, malonic acid, (ethylenedioxy) diacetic acid, maleic acid,
diglycolic acid, tartaric acid, tartronic acid and fumaric acid and
their water-soluble salts, as well as the ether carboxylates
described in German Offenlegenschrift 2,446,686, and 2,446,687 and
U.S. Pat. No. 3,935,257 and the sulfinyl carboxylates described in
Belgian Patent No. 840,623. Polycarboxylates containing three
carboxy groups include, in particular, water-soluble citrates,
aconitrates and citraconates as well as succinate derivatives such
as the carboxymethyloxysuccinates described in British Patent No.
1,379,241, lactoxysuccinates described in British Patent No.
1,389,732, and aminosuccinates described in Netherlands Application
7205873, and the oxypolycarboxylate materials such as
2-oxa-1,1,3-propane tricarboxylates described in British Patent No.
1,387,447. Citric acid and citrates are highly preferred for use
herein.
[0119] Polycarboxylates containing four carboxy groups include
oxydisuccinates disclosed in British Patent No. 1,261,829,
1,1,2,2-ethane tetracarboxylates, 1,1,3,3-propane tetracarboxylates
and 1,1,2,3-propane tetracarboxylates.
[0120] Polycarboxylates containing sulfo substituents include the
sulfosuccinate derivatives disclosed in British Patent Nos.
1,398,421 and 1,398,422 and in U.S. Pat. No. 3,936,448, and the
sulfonated pyrolysed citrates described in British Patent No.
1,439,000.
[0121] Alicyclic and heterocyclic polycarboxylates include
cyclopentane-cis,cis,cis-tetracarboxylates, cyclopentadienide
pentacarboxylates, 2,3,4,5-tetrahydrofuran-cis, cis,
cis-tetracarboxylates, 2,5-tetrahydrofuran-cis-dicarboxylates,
2,2,5,5-tetrahydrofuran-tetracarboxylates,
1,2,3,4,5,6-hexane-hexacarboxy- lates and carboxymethyl derivatives
of polyhydric alcohols such as sorbitol, mannitol and xylitol.
Aromatic polycarboxylates include mellitic acid, pyromellitic acid
and the phthalic acid derivatives disclosed in British Patent No.
1,425,343.
[0122] Of the above, the preferred polycarboxylates are
hydroxycarboxylates containing up to three carboxy groups per
molecule, more particularly citrates, especially sodium
citrate.
[0123] Polymeric Dispersant
[0124] Preferably, polymeric dispersants are used in a level of
from about 50 to about 200 ppm, preferably from about 70 to 120 ppm
in the rinse liquor. Suitable polymers comprise from about 50 to
about 99% by weight, preferably from about 70 to about 98%, most
preferably from about 75 to about 95% by weight of an olefinically
unsaturated carboxylic acid monomer and from about 1% to about 50%,
preferably from about 2 to about 30%, most preferably from about 5
to about 25% by weight of at least one monomer unit selected from
the group consisting of
[0125] (a) copolymerizable sulfonated monomers,
[0126] (b) copolymerizable nonionic monomers or
[0127] (c) mixtures of (a) and (b).
[0128] The olefinically unsaturated carboxylic acid monomer for use
herein is intended to include aliphatic, branched or cyclic, mono-
or dicarboxylic acids, the alkali or alkaline earth metal or
ammonium salts thereof, and the anhydrides thereof. Useful
olefinically unsaturated acids of this class include acrylic acid
comonomers typified by acrylic acid itself, methacrylic acid,
ethacrylic acid, alpha-chloro-acrylic acid, alpha-cyano acrylic
acid, beta methyl-acrylic acid (crotonic acid), alpha-phenylacrylic
acid, beta-acryloxy propionic acid, sorbic acid, alpha-chloro
sorbic acid, angelic acid, cinnamic acid, p-chloro cinnamic acid,
beta-styryl acrylic acid (1-carboxy-4-phenyl butadiene-1,3),
itaconic acid, maleic acid, citraconic acid, mesaconic acid,
glutaconic acid, aconitic acid, fumaric acid, and
tricarboxyethylene.
[0129] For the polycarboxylic acid monomers, an anhydride group is
formed by the elimination of one molecule of water from two
carboxyl groups located on the same polycarboxylic acid molecule.
Preferred carboxylic monomers for use in this invention are the
monoolefinic acrylic acids having a substituent selected from the
class consisting of hydrogen, halogen and hydroxyl groups,
monovalent alkyl radicals, monovalent aryl radicals, monovalent
aralkyl radicals, monovalent alkaryl radicals and monovalent
cycloaliphatic radicals. As used herein, (meth) acrylic acid is
intended to include acrylic acid and methacrylic acid. Preferred
unsaturated carboxylic acid monomers are acrylic and methacrylic
acid, more preferably acrylic acid.
[0130] Examples of sulfonate monomers (a) include, but not limited
to, allyl hydroxypropanyl sulfonate ether, allylsulfonic acid,
methallylsulfonic acid, styrene sulfonic acid, vinyl toluene
sulfonic acid, acrylamido alkane sulfonic acid, allyloxybenzene
sulfonic acid, 2-alkylallyloxybenzene sulfonic acid such as
4-sulfophenol methallyl ether, and the alkali or alkaline earth
metal or ammonium salts thereof.
[0131] The copolymerizable nonionic monomers (b) are vinyl or allyl
compounds selected from the group consisting of C1-C6 alkyl esters
of (meth)acrylic acid, acrylamide and the C1-C6 alkyl-substituted
acrylamides, the N-alkyl-substituted acrylamides and the
N-alkanol-substituted acrylamides, N-vinyl pyrrolidone or any other
vinyl amide. Also useful are the C1-C6 alkyl esters and C1-C6 alkyl
half-esters of unsaturated vinylic acids, such as maleic acid and
itaconic acid.
[0132] Preferred nonionic monomers are selected from the group
consisting of methyl (meth)acrylate, mono- and dimethyl maleate,
mono- and di-ethyl itaconate, and (meth)allyl acetates, propionates
and valerates. Particularly preferred is methyl methacrylate. Minor
amounts of crosslinking monomers such as diallyl maleate, alkylene
bisacrylarnide and triallyl cyanurate may also be employed
herein.
[0133] The average molecular weight of the polymers ranges from
1500 to 250,000, preferably from 5,000 to 100,000.
[0134] A suitable example of polymeric dispersant include, but are
not limited to a tetrapolymer of 4-sulfophenol methallyl ether,
sodium methallyl sulfonate, acrylic acid and methyl methacrylate.
The monomer unit, sulfophenol methallyl ether, has a formula
(I):
CH2.dbd.C(CH3)CH2OC6H4SO3M (I)
[0135] where M represents hydrogen, alkali metal, alkaline earth
metal or ammonium ions.
[0136] Other suitable examples of polymeric dispersant include, but
are not limited to, a copolymer of acrylic acid and 4-sulfophenol
methallyl ether; a copolymer of acrylic acid and
2-acrylamido-2-methylpropane sulfonate; a terpolymer of acrylic
acid, 2-acrylamido-2-methylpropane sulfonate and sodium styrene
sulfonate; a copolymer of acrylic acid and vinyl pyrrolidone; and a
copolymer of acrylic acid and acrylamide. Preferably, the polymer
is the tetrapolymer of 4-sulfophenol methallyl ether, sodium
methallyl sulfonate, acrylic acid and methyl methacrylate.
[0137] Preferred commercial available copolymers include:
Alcosperse 240, Aquatreat AR 540 and Aquatreat MPS supplied by Alco
Chemical; Acumer 3100 and Acumer 2000 supplied by Rohm & Haas;
Goodrich K-798, K-775 and K-797 supplied by B F Goodrich; ACP 1042
supplied by ISP technologies Inc.; and polyacrylic acid/acrylamide
supplied by Aldrich. A particularly preferred copolymer is
Alcosperse 240 supplied by Alco Chemical.
[0138] Wetting Agent
[0139] Wetting agents suitable for use herein are surfactants and
include anionic, amphoteric, zwitterionic, nonionic and semi-polar
surfactants. Preferred nonionic surfactants include silicone
surfactants, such as Silwet copolymers, preferred Silwet copolymers
include Silwet L-8610, Silwet L-8600, Silwet L-77, Silwet L-7657,
Silwet L-7650, Silwet L-7607, Silwet L-7604, Silwet L-7600, Silwet
L-7280 and mixtures thereof. Preferred for use herein is Silwet
L-77.
[0140] Surface Substantive Modifying Polymer
[0141] Preferably the surface substantive polymer is selected from
the group consisting of homo and copolymers of polyvinyl
pyrrolidone (PVP), suitable levels for use herein are from about
0.001 to about 10%, preferably from about 0.01 to about 1% by
weight of the dishwashing product and at from about 1 to about 200,
preferably from about 20 to about 100 ppm in the rinse liquor. In
general terms such homo and copolymers can have an average
molecular weight (eg as measured by light scattering) in the range
from about 1,000 to about 5,000,000, preferably from about 5,000 to
about 500,000. In addition, preferred copolymers comprise at least
about 5%, most preferably at least about 15%, especially at least
about 40% by weight thereof of the comonomer. Highly preferred
comonomers include aromatic monomers such as vinyl imidazole and
carboxylic monomors such as acrylic acid and methacrylic acid.
[0142] PVP preferred for use herein has an average molecular weight
of from about 2,500 to about 400,000, preferably from about 5,000
to about 200,000, more preferably from about 5,000 to about 50,000,
and most preferably from about 5,000 to about 15,000. Suitable
polyvinylpyrrolidones are commercially available from ISP
Corporation, New York, N.Y. and Montreal, Canada under the product
names PVP K-15 (viscosity molecular weight of 10,000), PVP K-30
(average molecular weight of 40,000), PVP K-60 (average molecular
weight of 160,000), and PVP K-90 (average molecular weight of
360,000). PVP K-15 is also available from ISP Corporation. Other
suitable polyvinylpyrrolidones which are commercially available
from BASF Corporation include Sokalan HP 165 and Sokalan HP 12.
Other polyvinylpyrrolidones known to persons skilled in the
detergent field, see for example EP-A-262,897 and EP-A-256,696, are
also suitable.
[0143] A particularly preferred copolymer of polyvinyl pyrrolidone
is N-vinylimidazole N-vinylpyrrolidone (PVPVI) polymers available
from for example BASF under the trade name Luvitec VP155K18P.
Preferred PVPVI polymers have an average molecular weight of from
about 1,000 to about 5,000,000, more preferably from 5,000 to
2,000,000, even more preferably from about 5,000 to about 500,000
and most preferably from about 5,000 to about 15,000. Preferred
PVPVI polymers comprise at least 45%, preferably at least 50%
N-vinylimidazole monomers. Another suitable PVP copolymer is a
quaternized PVPVI, for example, the compound sold under the
tradename Luvitec Quat 73W by BASF.
[0144] Other suitable copolymers of vinylpyrrolidone for use in the
compositions of the present invention are copolymers of
polyvinylpyrrolidone and acrylic acid or methacrylic acid.
[0145] Fibrous Food Degrading Enzyme
[0146] Suitable enzymes for use herein include enzyme which acts to
break down pectic bondings. Preferably incorporated into the
dishwashing product at a level of from 0.0001% to 2%, preferably
from 0.0005% to 0.5%, more preferably from 0.001% to 0.05% active
enzyme by weight of dishwashing product and at about 10 to about
200, preferably from about 40 to about 150 ppm in the wash
liquor.
[0147] Preferred for use herein is polygalacturanase enzyme. By
polygalacturanase enzyme it is meant herein any enzyme which acts
to break down pectic substances by cleaving the glycosidic bonds
between galacturonic acid molecules. Pectic substances may be found
in plant tissues, and are common constituents of fruit juices such
as orange, tomato and grape juices. Pectic substances contain
galacturonic acids and/or their derivatives.
[0148] Pectic substances include pectins and pectic acids. Pectins
are, in general, polymers made up of chains of galacturonic acids
joined by alpha-1-4 glycosidic linkages. Typically, in natural
pectins approximately two-thirds of the carboxylic acid groups are
esterified with methanol. Partial hydrolysis of these methyl esters
gives low methoxyl pectins, which tend to form gels with calcium
ions. Complete methyl ester hydrolysis gives pectic acids. are not
polygalacturanase.
[0149] Other pectic enzymes for use herein include, for example,
the pectin methylesterases which hydrolyse the pectin methyl ester
linkages, and the pectin transeliminases or lyases which act on the
pectic acids to bring about non-hydrolytic cleavage of alpha-4
glycosidic linkages to form unsaturated derivatives of galacturonic
acid.
[0150] Polygalacturanase enzymes herein include naturally derived
polygalacturanase enzymes and any variants obtained by, for
example, genetic engineering techniques. Any such variants may be
specifically designed with regard to the optimization of
performance efficiency in the detergent compositions of the
invention. For example, variants may be designed such that the
stability of the enzyme to commonly encountered components of such
compositions is increased. Alternatively, the variant may be
designed such that the optimal pH or temperature performance range
of the enzyme variant is tailored to suit the particular detergent
application.
[0151] Polygalacturanase enzymes may be derived from plants,
especially fruits, and from fungal sources. A common fungal source
is provided by certain strains of the Aspergillus Niger group.
Commercially available pectic enzymes tend to be mixtures of pectic
enzymes of the pectin methylesterase, polygalacturonase and pectin
lyase types; therefore further purification to isolate
polygalacturanase enzymes substantially free of other pectic enzyme
using standard enzyme purification techniques is required.
Polygalacturanase can be isolated from these commercial mixtures by
standard protein separation methods that are well known in the
art.
[0152] Preferably, the polygalacturanase is obtained through
recombinant DNA techniques wherein the genetic material coding only
for polygalacturanase is isolated from a natural host and
transferred into a suitable production organism, like Aspergillus
Niger, Aspergillus Orayze, or Bacillus Subtilus for subsequent
fermentation, recovery, and purification of the polygalacturanase
protein.
[0153] Commercially available pectic enzymes include those sold
under the Pectinex AR tradename by Novo Industries A/S, those sold
under the Rapidase tradename by International Bio-Synthetics (a
division of Gist-Brocades BV), those sold under the Cytolase
tradename by Genencor International, and those sold under the
tradename, Clarex by Solvay Enzymes. Such enzymes may be used
following purification isolate polygalacturanase enzymes
substantially free of other pectic enzyme. Preferred are pectic
enzyme compositions consisting essentially of polygalacturanase
enzymes
[0154] Surfactant
[0155] In the methods of the present invention surfactant can be
used as part of a dishwashing product. For use herein the detergent
surfactant is preferably low foaming by itself or in combination
with other components (i.e. suds suppressers). Surfactants suitable
herein include anionic surfactants such as alkyl sulfates, alkyl
ether sulfates, alkyl benzene sulfonates, alkyl glyceryl
sulfonates, alkyl and alkenyl sulphonates, alkyl ethoxy
carboxylates, N-acyl sarcosinates, N-acyl taurates and alkyl
succinates and sulfosuccinates, wherein the alkyl, alkenyl or acyl
moiety is C.sub.5-C.sub.20, preferably C.sub.10-C.sub.18 linear or
branched; cationic surfactants such as chlorine esters (U.S. Pat.
No. 4,228,042, U.S. Pat. No. 4,239,660 and U.S. Pat. No. 4,260,529)
and mono C.sub.6-C.sub.16 N-alkyl or alkenyl ammonium surfactants
wherein the remaining N positions are substituted by methyl,
hydroxyethyl or hydroxypropyl groups; low and high cloud point
nonionic surfactants and mixtures thereof including nonionic
alkoxylated surfactants (especially ethoxylatesu derived from
C.sub.6-C.sub.18 primary alcohols), ethoxylated-propoxylated
alcohols (e.g., BASF Poly-Tergent.RTM. SLF18), epoxy-capped
poly(oxyalkylated) alcohols (e.g., BASF Poly-Tergent.RTM.
SLF18B--see WO-A-94/22800), ether-capped poly(oxyalkylated) alcohol
surfactants, and block polyoxyethylene-polyoxypropylene polymeric
compounds such as PLURONIC.RTM., REVERSED PLURONIC.RTM., and
TETRONIC.RTM. by the BASF-Wyandotte Corp., Wyandotte, Mich.;
amphoteric surfactants such as the C.sub.12-C.sub.20 alkyl amine
oxides (preferred amine oxides for use herein include
lauryldimethyl amine oxide and hexadecyl dimethyl amine oxide), and
alkyl amphocarboxylic surfactants such as Miranol.TM. C2M; and
zwitterionic surfactants such as the betaines and sultaines; and
mixtures thereof. Surfactants suitable herein are disclosed, for
example, in U.S. Pat. No. 3,929,678, U.S. Pat. No. 4,259,217,
EP-A-0414 549, WO-A-93/08876 and WO-A-93/08874. Surfactants are
typically present at a level of from about 0.2% to about 30% by
weight, more preferably from about 0.5% to about 10% by weight,
most preferably from about 1% to about 5% by weight of dishwashing
product and at about 10 to about 2000, preferably from about 20 to
about 1000 ppm of the wash liquor. Preferred surfactant for use
herein are low foaming and include low cloud point nonionic
surfactants and mixtures of higher foaming surfactants with low
cloud point nonionic surfactants which act as suds suppresser
therefor.
[0156] Inorganic Builder
[0157] In addiction to the organic soluble builder described
hereinabove inorganic builders can also be comprised in the
products used herein. Suitable inorganic builders include
crystalline layered silicates (EP-A-0164514 and EP-A-0293640) and
aluminosilicates inclusive of Zeolites A, B, P, X, HS and MAP. The
builder is typically present at a level of from about 1% to about
80% by weight, preferably from about 10% to about 70% by weight,
most preferably from about 20% to about 60% by weight of
dishwashing product and at from about 10 to about 2000, preferably
from about 100 to about 1000 ppm of the wash liquor.
[0158] Amorphous sodium silicates having an SiO.sub.2:Na.sub.2O
ratio of from 1.8 to 3.0, preferably from 1.8 to 2.4, most
preferably 2.0 can also be used herein although highly preferred
from the viewpoint of long term storage stability are compositions
containing less than about 22%, preferably less than about 15%
total (amorphous and crystalline) silicate.
[0159] Enzyme
[0160] Additionally or in place of the fibrous food degrading
enzymes described hereinabove other enzymes can also be comprised
in the products used herein. Enzymes suitable herein include
bacterial and fungal cellulases such as Carezyme and Celluzyme
(Novo Nordisk A/S); peroxidases; lipases such as Amano-P (Amano
Pharmaceutical Co.), M1 Lipase.sup.R and Lipomax.sup.R
(Gist-Brocades) and Lipolase.sup.R and Lipolase Ultra.sup.R (Novo);
cutinases; proteases such as Esperase.sup.R, Alcalase.sup.R,
Durazym.sup.R and Savinase.sup.R (Novo) and Maxatase.sup.R,
Maxacal.sup.R, Properase.sup.R and Maxapem.sup.R (Gist-Brocades);
and .alpha. and .beta. amylases such as Purafect Ox Am.sup.R
(Genencor) and Termamyl.sup.R, Ban.sup.R, Fungamyl.sup.R,
Duramyl.sup.R, and Natalase.sup.R (Novo); and mixtures thereof.
Enzymes are preferably added herein as prills, granulates, or
cogranulates at levels typically in the range from about 0.1 to
about 2000, preferably from about 1 to about 1000, more preferably
from about 3 to about 300 mg of active enzyme per 100 g of
dishwashing product, determined according to the supplier's
specific activity data for the particular enzyme. The total enzyme
level is typically at least about 50, preferably at least about 100
and more preferably at about 150 mg/100 g or product, or at least
about 2, preferable at least about 4 and more preferably at least
about 6 ppm of wash liquor.
[0161] Bleaching Agent
[0162] Bleaching agents suitable herein include chlorine and oxygen
bleaches, especially inorganic perhydrate salts such as sodium
perborate mono-and tetrahydrates and sodium percarbonate optionally
coated to provide controlled rate of release (see, for example,
GB-A-1466799 on sulfate/carbonate coatings), preformed organic
peroxyacids and mixtures thereof with organic peroxyacid bleach
precursors and/or transition metal-containing bleach catalysts
(especially manganese or cobalt) and organic peroxides. Inorganic
perhydrate salts are typically incorporated at levels in the range
from about 1% to about 40% by weight, preferably from about 2% to
about 30% by weight and more preferably from abut 5% to about 25%
by weight of dishwashing product. Peroxyacid bleach precursors
preferred for use herein include precursors of perbenzoic acid and
substituted perbenzoic acid; cationic peroxyacid precursors;
peracetic acid precursors such as TAED, sodium acetoxybenzene
sulfonate and pentaacetylglucose; pernonanoic acid precursors such
as sodium 3,5,5-trimethylhexanoyloxybenzene sulfonate (iso-NOBS)
and sodium nonanoyloxybenzene sulfonate (NOBS); amide substituted
alkyl peroxyacid precursors (EP-A-0170386); and benzoxazin
peroxyacid precursors (EP-A-0332294 and EP-A-0482807). Bleach
precursors are typically incorporated at levels in the range from
about 0.5% to about 25%, preferably from about 1% to about 10% by
weight of product while the preformed organic peroxyacids
themselves are typically incorporated at levels in the range from
0.5% to 25% by weight, more preferably from 1% to 10% by weight of
product. Bleach catalysts preferred for use herein include the
manganese triazacyclononane and related complexes (U.S. Pat. No.
4,246,612, U.S. Pat. No. 5,227,084); Co, Cu, Mn and Fe
bispyridylamine and related complexes (U.S. Pat. No. 5,114,611);
and pentamine acetate cobalt(III) and related complexes(U.S. Pat.
No. 4,810,410). Organic peroxides suitable for use herein include
diacyl and tetraacylperoxides, especially dibenzoyl peroxide.
[0163] Low Cloud Point Non-Ionic Surfactants and Suds
Suppressers
[0164] The suds suppressers suitable for use herein include
nonionic surfactants having a low cloud point. "Cloud point", as
used herein, is a well known property of nonionic surfactants which
is the result of the surfactant becoming less soluble with
increasing temperature, the temperature at which the appearance of
a second phase is observable is referred to as the "cloud point"
(See Kirk Othmer, pp. 360-362). As used herein, a "low cloud point"
nonionic surfactant is defined as a nonionic surfactant system
ingredient having a cloud point of less than 30.degree. C.,
preferably less than about 20.degree. C., and even more preferably
less than about 10.degree. C., and most preferably less than about
7.5.degree. C. Typical low cloud point nonionic surfactants include
nonionic alkoxylated surfactants, especially ethoxylates derived
from primary alcohol, and
polyoxypropylene/polyoxyethylene/polyoxypropylene (PO/EO/PO)
reverse block polymers. Also, such low cloud point nonionic
surfactants include, for example, ethoxylated-propoxylated alcohol
(e.g., BASF's Poly-Tergent.RTM. SLF18) and epoxy-capped
poly(oxyalkylated) alcohols (e.g., BASF's Poly-Tergent.RTM. SLF18B
series of nonionics, as described, for example, in U.S. Pat. No.
5,576,281).
[0165] Preferred low cloud point surfactants are the ether-capped
poly(oxyalkylated) suds suppresser having the formula: 1
[0166] wherein R.sup.1 is a linear, alkyl hydrocarbon having an
average of from about 7 to about 12 carbon atoms, R.sup.2 is a
linear, alkyl hydrocarbon of about 1 to about 4 carbon atoms,
R.sup.3 is a linear, alkyl hydrocarbon of about 1 to about 4 carbon
atoms, x is an integer of about 1 to about 6, y is an integer of
about 4 to about 15, and z is an integer of about 4 to about
25.
[0167] Other low cloud point nonionic surfactants are the
ether-capped poly(oxyalkylated) having the formula:
R.sub.IO(R.sub.IIO).sub.nCH(CH.sub.3)OR.sub.III
[0168] wherein, R.sub.I is selected from the group consisting of
linear or branched, saturated or unsaturated, substituted or
unsubstituted, aliphatic or aromatic hydrocarbon radicals having
from about 7 to about 12 carbon atoms; R.sub.II may be the same or
different, and is independently selected from the group consisting
of branched or linear C.sub.2 to C.sub.7 alkylene in any given
molecule; n is a number from 1 to about 30; and R.sub.III is
selected from the group consisting of:
[0169] (i) a 4 to 8 membered substituted, or unsubstituted
heterocyclic ring containing from 1 to 3 hetero atoms; and
[0170] (ii) linear or branched, saturated or unsaturated,
substituted or unsubstituted, cyclic or acyclic, aliphatic or
aromatic hydrocarbon radicals having from about 1 to about 30
carbon atoms;
[0171] (b) provided that when R.sup.2 is (ii) then either: (A) at
least one of R.sup.1 is other than C.sub.2 to C.sub.3 alkylene; or
(B) R.sup.2 has from 6 to 30 carbon atoms, and with the further
proviso that when R.sup.2 has from 8 to 18 carbon atoms, R is other
than C.sub.1 to C.sub.5 alkyl.
[0172] Other suitable components herein include organic polymers
having dispersant, anti-redeposition, soil release or other
detergency properties invention in levels of from about 0.1% to
about 30%, preferably from about 0.5% to about 15%, most preferably
from about 1% to about 10% by weight of composition. Preferred
anti-redeposition polymers herein include acrylic acid containing
polymers such as Sokalan PA30, PA20, PA15, PA10 and Sokalan CP10
(BASF GmbH), Acusol 45N, 480N, 460N (Rohm and Haas), acrylic
acid/maleic acid copolymers such as Sokalan CP5 and
acrylic/methacrylic copolymers. Preferred soil release polymers
herein include alkyl and hydroxyalkyl celluloses (U.S. Pat. No.
4,000,093), polyoxyethylenes, polyoxypropylenes and copolymers
thereof, and nonionic and anionic polymers based on terephthalate
esters of ethylene glycol, propylene glycol and mixtures
thereof.
[0173] Heavy metal sequestrants and crystal growth inhibitors are
suitable for use herein in levels generally from about 0.005% to
about 20%, preferably from about 0.1% to about 10%, more preferably
from about 0.25% to about 7.5% and most preferably from about 0.5%
to about 5% by weight of product, for example diethylenetriamine
penta (methylene phosphonate), ethylenediamine tetra(methylene
phosphonate) hexamethylenediamine tetra(methylene phosphonate),
ethylene diphosphonate, hydroxy-ethylene-1,1-diphosphonate,
nitrilotriacetate, ethylenediaminotetracetate,
ethylenediamine-N,N'-disuccinate in their salt and free acid
forms.
[0174] The products used herein can contain a corrosion inhibitor
such as organic silver coating agents in levels of from about 0.05%
to about 10%, preferably from about 0.1% to about 5% by weight of
product (especially paraffins such as Winog 70 sold by Wintershall,
Salzbergen, Germany), nitrogen-containing corrosion inhibitor
compounds (for example benzotriazole and benzimadazole--see
GB-A-1137741) and Mn(II) compounds, particularly Mn(II) salts of
organic ligands in levels of from about 0.005% to about 5%,
preferably from about 0.01% to about 1%, more preferably from about
0.02% to about 0.4% by weight of the product.
[0175] Other suitable components herein include colorants,
water-soluble bismuth compounds such as bismuth acetate and bismuth
citrate at levels of from about 0.01% to about 5%, enzyme
stabilizers such as calcium ion, boric acid, propylene glycol and
chlorine bleach scavengers at levels of from about 0.01% to about
6%, lime soap dispersants (see WO-A-93/08877), suds suppressors
(see WO-93/08876 and EP-A-0705324), polymeric dye transfer
inhibiting agents, optical brighteners, perfumes, fillers and
clay.
[0176] Solvents
[0177] Solvents that can be used herein include: i) alcohols, such
as benzyl alcohol, 1,4-cyclohexanedimethanol, 2-ethyl-1-hexanol,
furfuryl alcohol, 1,2-hexanediol and other similar materials; ii)
amines, such as alkanolamines (e.g. primary alkanolamines:
monoethanolamine, monoisopropanolamine, diethylethanolamine, ethyl
diethanolamine; secondary alkanolamines: diethanolamine,
diisopropanolamine, 2-(methylamino)ethanol; ternary alkanolamines:
triethanolamine, triisopropanolamine); alkylamines (e.g. primary
alkylamines: monomethylamine, monoethylamine, monopropylamine,
monobutylamine, monopentylamine, cyclohexylamine), secondary
alkylamines: (dimethylamine), alkylene amines (primary alkylene
amines: ethylenediamine, propylenediamine) and other similar
materials; iii) esters, such as ethyl lactate, methyl ester, ethyl
acetoacetate, ethylene glycol monobutyl ether acetate, diethylene
glycol monoethyl ether acetate, diethylene glycol monobutyl ether
acetate and other similar materials; iv) glycol ethers, such as
ethylene glycol monobutyl ether, diethylene glycol monobutyl ether,
ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
diethylene glycol monomethyl ether, diethylene glycol monoethyl
ether, propylene glycol butyl ether and other similar materials; v)
glycols, such as propylene glycol, diethylene glycol, hexylene
glycol (2-methyl-2, 4 pentanediol), triethylene glycol, composition
and dipropylene glycol and other similar materials; and mixtures
thereof.
[0178] Liquid dishwashing products containing low quantities of low
molecular weight primary or secondary alcohols such as methanol,
ethanol, propanol and isopropanol can be usedherein. Other suitable
carrier solvents used in low quantities includes glycerol,
propylene glycol, ethylene glycol, 1,2-propanediol, sorbitol and
mixtures thereof.
EXAMPLES
[0179] Abbreviations used in Examples
[0180] In the examples, the abbreviated component identifications
have the following meanings:
1 FN3 Protease available from Genencor Natalase Amylase from Novo
Nordisk A/S Pectinase Ultra SP Pectinase available from Novo
Nordisk A/S Plurafac 400 C.sub.13-C.sub.15 mixed
ethoxylated/propoxylated fatty alcohol with an average degree of
ethoxylation of 3.8 and an average degree of propoxylation of 4.5,
available from BASF C.sub.14 AO Tetradecyl dimethyl amine oxide
ACNI Alkyl capped non-ionic surfactant of formula C.sub.9/11
H.sub.19/23 EO.sub.8- cyclohexyl acetal Alcosperse 240
PAA/MMA/SPEM/SME polymer available from Alco Chemical Citric acid
Citric acid HEDP Ethane 1-hydroxy-1,1-diphosphonic acid Silwet 77
Siloxane surfactant available from Ckwitko PVNO
Poly-4-vinylpyridine N-oxide available from BASF STPP Sodium
tripolyphosphate KOH Potassium hydroxide NaGH Sodium hydroxide
DCICA Dichloroisocyanuric acid (Sodium Salt) Percarbonate Sodium
percarbonate of the nominal formula
2Na.sub.2CO.sub.3.3H.sub.2O.sub.2 Silicate 3:2 Amorphous Sodium
Silicate (SiO.sub.2:Na.sub.2O ratio = 3:2) SLF18 Low foaming
surfactant available from BASF Polygel DKP Dipotassium phosphate
gel available from 3V Inc. Water De-ionised water
[0181] In the following examples all levels are quoted as parts by
weight.
Examples 1 to 8
[0182] A load of dishware/tableware is placed into a Bosch Siemens
6032 dishwashing machine having a 5 liters wash water capacity. The
load comprises different soils and different substrates: lasagne
baked for 2 hours at 140.degree. C. on Pyrex, lasagne cooked for 2
hours at 150.degree. C. on stainless steel, potato and cheese
cooked for 2 hours at 150.degree. C. on stainless steel, egg yolk
cooked for 2 hours at 150.degree. C. on stainless steel and sausage
cooked for 1 hour at 120.degree. C. followed by 1 hour at
180.degree. C. A Fairy tablet (available from Procter & Gamble)
is placed in the dispenser for delivery in the main wash. 20 ml of
the compositions of examples 1 to 8 are introduced into a dosing
device as previously described which is secured to one of the
dishwasher internal walls. The dosing device is programmed in such
a way as to open and deliver the product at the start of the first
rinse cycle. The dishwashing machine is operated in its normal
55.degree. C. program. The rinse cycle concentration factor is
3.times.10.sup.4 ppm min for each example. The washing method
provided excellent removal of cooked-on, baked-on and burnt-on food
soils as well as excellent shine, filming and spotting
performance.
2 Example 1 2 3 4 5 6 7 8 FN3 1.9 1.9 1.9 2 1.5 2 1 Natalase 5.75
5.75 5.75 4 5 6 4 Pectinase 2 2 5 Plurafac 400 1.8 1 2 1.5 2 C14A0
2 2 1 1.5 ACM 0.5 1 1 0.5 Alcosperse 240 5 4 Citric acid 25 25 30
HEDP 20 18 22 Silwet 77 1 0.1 0.1 0.5 0.5 0.2 PVNO 0.1 0.1 0.1 0.1
0.2 Perfume 1 0.5 0.5 1 0.3 0.4 0.2 0.8 Dye 0.3 0.4 0.2 0.4 0.2 0.4
0.05 0.1 Water up to 100
Examples 9 to 12
[0183] A load of dishware/tableware is placed into a Bosch Siemens
6032 dishwashing machine having a 5 liters wash water capacity. The
load comprises different soils and different substrates: lasagne
baked for 2 hours at 140.degree. C. on Pyrex, lasagne cooked for 2
hours at 150.degree. C. on stainless steel, potato and cheese
cooked for 2 hours at 150.degree. C. on stainless steel, egg yolk
cooked for 2 hours at 150.degree. C. on stainless steel and sausage
cooked for 1 hour at 120.degree. C. followed by 1 hour at
180.degree. C. 20 ml of the compositions of examples 9 to 12 are
placed in the dispenser for delivery in the main wash. 20 ml of the
compositions of examples 9 to 12 are introduced into a dosing
device as previously described which is secured to one of the
dishwasher internal walls. The dosing device is programmed in such
a way as to open and deliver the product at the start of the first
rinse cycle. The dishwashing machine is operated in its normal
55.degree. C. program. The rinse cycle concentration factor is
3.times.10.sup.4 ppm min for each example. The washing method
provided excellent removal of cooked-on, baked-on and burnt-on food
soils as well as excellent shine, filming and spotting
performance.
3 Example 9 10 11 12 STPP 28.00 28.00 28.00 28.00 KOH 5.30 5.30
5.30 5.30 Silicate 3:2 1.0 1.0 1.0 1.0 Polygel DKP 0.55 0.55 0.55
0.55 SLF18 1.25 1.25 C.sub.16 AO 0.40 0.40 ACNI 3.00 3.00 Water up
to 100
Examples 13 to 16
[0184] A load of dishware/tableware is placed into a Bosch Siemens
6032 dishwashing machine having a 5 liters wash water capacity. The
load comprises different soils and different substrates: lasagne
baked for 2 hours at 140.degree. C. on Pyrex, lasagne cooked for 2
hours at 150.degree. C. on stainless steel, potato and cheese
cooked for 2 hours at 150.degree. C. on stainless steel, egg yolk
cooked for 2 hours at 150.degree. C. on stainless steel and sausage
cooked for 1 hour at 120.degree. C. followed by 1 hour at
180.degree. C. A Fairy tablet (available from Procter & Gamble)
is placed in the dispenser for delivery in the main wash. Dual
compartment pouches comprising 5 g of composition A (examples 13 to
16) in a cold water soluble compartment and 10 g of composition B
(examples 13 to 16) in a hot water soluble compartment are
introduced into a dosing device as previously described which is
secured to one of the dishwasher internal walls. The dosing device
is programmed in such a way as to open and deliver the pouches at
the start of the first rinse cycle. The pouches are designed to
deliver composition A into the pre-final rinse cycle and
composition B into the final rinse cycle. The dishwashing machine
is operated in its normal 55.degree. C. program. The pre-final
rinse cycle concentration factor is 5.times.10.sup.3 ppm min and
the final rinse cycle concentration factor is 2.times.10.sup.4 ppm
min for each example. The washing method provided excellent removal
of cooked-on, baked-on and burnt-on food soils as well as excellent
shine. Examples 13 to 16 were repeated but delivering compositions
A and B into the pre-final rinse and final rinse cycles
respectively by means of the dosing device herein described.
Excellent results were obtained.
4 Example 13 14 15 16 Composition A NaOH 50 30 50 30 DCICA 50 70
Percarbonate 50 70 Composition B Citric acid 88 87 92 97 SLF18 10
11 7 Perfume 2 2 1 3
* * * * *