Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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CLEANING COMPOSITIONS
10
Field of the invention
E
The present invention relates to cleaning compositions, especially to
thickened
liquid cleaning compositions exhibiting effective cleaning performance and
viscosity.
Background of the invention
Efficient cleaning performance and viscosity of the cleaning compositions are
two
requirements which drive consumer acceptance of cleaning products. Effective
cleaning of surfaces is important, especially on greasy and oily soils and/or
where the composition is thereafter diluted. However viscosity is also a key
factor in the preparation of such a cleaning composition. The viscosity of the
cleaning composition must be high enough to enable the cleaning compositions
to remain on the surface being cleansed for a sufficiently long period of time
to
ensure effective cleaning. Such a requirement is of particular utility in
cleaning
compositions intended to be applied "as is" to non-horizontal structural
surfaces
such as walls, windows and sanitary fittings such as sinks, baths, showers,
wash
basins and WCs. More particularly, viscosities of 10 cps to 4000 cps are
suitable.
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It is therefore an object of the present invention to provide cleaning
compositions
having effective cleaning performance and viscosity.
Thickened cleaning compositions are known in the art. The most commonly
used thickener is a polycarboxylate polymer of high molecular weight i.e. in
the
range of 500 000 to 4 500 000. Furthermore for best results it is preferred
that
the polycarboxylate polymer is cross-linked. EP 834 549 and EP 812 904 both
describe cleaning compositions comprising such polymeric thickeners. However
the Applicant has found disadvantages in the use of such a polymeric
thickeners
in that whilst the polymer provides adequate increase in viscosity, the yield
stress of the composition is also increased. The effect of the increase in
yield
stress is that the composition can become too thick such that it does not
spread
easily on the surface and is therefore difficult to use and/or rinse. In
addition it
has been found that occasionally air bubbles may become trapped in the
composition during manufacture which are difficult to remove and not consumer
acceptable.
The Applicant has now found that the polymeric thickening system described
herein provides thickening of the composition without the disadvantages of the
previously used thickening systems as described above.
Summary of the invention
According to the present invention there is provided a cleaning composition
comprising a polymeric thickening system comprising a polycarboxylate homo or
copolymer having molecular weight in the range of from 500 000 to 4 500 000
and a polycarboxylate homo or copolymer having a molecular weight of from 500
to 10 000.
In another aspect of the invention, there is provided a method for cleaning a
hard
surface by applying on said surface an effective amount of a composition of
the
present invention.
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Detailed description of the invention
Pofymeric Thickening System
The compositions of the present invention comprise a polymeric thickening
system. The benefits of using the polymers described herein versus others
described in the art for example cellulosic polymers such as guar gum or
xanthum gum, are that they are more stable in the presence of bleach
(especially
hypochlorite bleach), provide better thickening efficiency and do not elevate
the
yield stress value to levels that might cause flow problems.
The polymeric thickening system of the present invention comprises at least
two
polycarboxylate polymers; a high molecular weight and a low polycarboxylate
homo or copolymer. By high molecular weight it is meant a polycarboxylate
homo or copolymer having a molecular weight in the range of from 500 000 to 4
500 000, more preferably from 1 000 000 to 4 000 000.
Most preferred high molecular weight polymers for use herein contain from 0.5%
to 4% by weight of a cross-linking agent, wherein the cross-linking agent
tends to
interconnect linear strands of the polymers to form the resulting cross-linked
products. Suitable cross-linking agents include the polyalkenyl polyethers.
Preferred homo- polymers include the poiyacryiate polymers. Preferred
copolymers comprise acrylic acid monomers in combination with other
monomers for malefic acid, malefic anhydride, nethacylic acid, suucinic acid,
vinyl
ester and/or mixtures thereof. Preferred monomers of the homo or copolymeric
species contain a carboxylic group. The molecular weight of the carboxylate
group-containing monomers typically varies from 25 to 200, preferably from 50
to
150, more preferably from 75 to 125. Further, other monomers may be present in
the monomeric mixture, if desired, such as ethylene and propylene, which act
as
diluents.
Preferred high molecular weight polycarboxylate polymers for use herein are
the
polyacrylate polymers. Especially preferred polymers are those of the
poiyacrylate type including those sold under the trade names Carbopol~
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(especially Carbopol ~ETD 2691 available form Goodrich), Acrysol~ ICS-1,
Polygel~, and Sokalan~. Preferred poiyacrylate copolymers are those containing
acrylic acid and alkyl (C5-C10) acrylate as monomers, (commercially available
under the tradename Carbopol~ 1623, Carbopol~ 695 from BF Goodrich). Most
preferred are copolymers of acrylic acid and malefic anhydride, (commercially
available under the tradename Polygel~ DB, Polygel~ DV, Polygel~ DA) and
copolymers of acrylic acid and vinyl ester (commercially available under the
tradename Polygel~ DR from 3V Sigma)..
Mixtures of any of the high molecular weight polycarboxylate polymers, herein
before described, may also be used.
The second component of the polymeric thickening system is a low molecular
weight polycarboxylate homo or copolymer. By low molecular weight it is meant
a polycarboxylate polymer having a molecular weight of from 500 to 10 000,
more preferably from 800 to 6000, most preferably from 1000 to 4000.
Preferred low molecular weight homo-polymers are not cross-linked and are most
preferably polyacrylates. Most preferred copolymers comprise acrylic acid in
combination with at least one other type of monomer. An especially preferred
tow molecular weight polymer is Polygel~ W30 available from 3V sigma.
The ratio of high molecular weight to low molecular weight polymer is
preferably
from 50:1 to 1: 10, more preferably from 30:1 to 1:1, most preferably from
10:1
to 5:1.
The compositions of the present invention are shear thinning, meaning
viscosity
is lowered with increasing shear rates. Viscosity is measured using any
currently
available, suitable viscosity measuring equipment. Viscosity of the
composition
is preferably in the range of from 10 cps to 4000 cps, more preferably from 50
to
1000cps, most preferably from 100 to 550cps when measured using a Carrimed
Rheometer at 25 °C and a shear rate of from 10 to 100 s ~'.
The polymeric thickening system is preferably present at a level of from 0.1 %
to
10%, more preferably from 0.5% to 5% and most preferably from 0.7 to 2%.
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Surfactant
A highly preferred, but optional component of the cleaning composition
described
herein is a surfactant. The surfactant may be selected from anionic, non-
ionic,
5 cationic, amphoteric, zwiterionic surfactants or mixtures thereof.
In a preferred aspect of the present invention, the cleaning composition
comprises an anionic surfactant system as described in more detail in the
Applicants copending patent application. The anionic surfactant system
consists
of at least one linear short-chain and one branched long chain anionic
surfactant.
The anionic surfactants are selected from sulphates, suiphonates, alkoxylated
sulphates (preferably propoxylated, more preferably ethoxylated), phosphates
or
mixtures thereof. The short chain surfactants has from 5 to 9 carbon atom
whereas the long chain surfactant has from 10 to 16 carbon atoms.
A preferred short-chain surfactant is C7-9 Empimin available from Albright and
Wilson. A preferred long-chain surfactant is C12-13 branched sulphate based on
Isalchem 123 available from Albright and Wilson.
fn another preferred aspect, the surfactant system additionally comprises a
branched short-chain anionic surfactant. A suitable such anionic surfactant is
2
ethyl hexyl sulphate avaialble from Albright and Wilson under the tradename
Empico10585/A.
Optional components
The compositions according to the present invention may comprise a number of
optional ingredients such as bleaching agents, fatty acids, radical
scavengers,
antimicrobial compounds, builders, chelants, buffers, bactericides, solvents,
enzymes, hydrotropes, colorants, bleach activators, soil suspenders, dye
transfer
agents, brighteners, anti dusting agents, dispersants, dye transfer
inhibitors,
pigments, perfumes and dyes:
A highly preferred optional ingredient according to the present invention is a
hypochlorite bleaching agent, preferably an alkali metal hypochlorite.
Advantageously, the compositions of the invention are stable in the presence
of
this bleaching agent. Although alkali metal hypochlorites are preferred other
hypochlorite compounds may also be used herein and can be selected from
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calcium and magnesium hypochlorite. A preferred alkali metal hypochlorite for
use herein is sodium hypochlorite. Compositions according to the present
invention may comprise hypochlorite bleaching agents such that the content of
active chlorine in the compositions is from 0.1 % to 4%, preferably from 0.5%
to
2% by weight.
Another optional component of the present invention is an alkali metal salt of
a
Cg-C1g fatty acid. Said fatty acids are used as suds suppressors. Suitable
fatt~~
acids for use herein can be any Cg-C1 g fatty acid, preferably fully
saturated,
preferably a sodium, potassium or lithium salt, more preferably the sodium
salt.
Suitable fatty acids may be selected from caprylic acid, capric acid, lauric
acid,
myristic acid, palmitic acid, stearic acid and mixtures of fatty acids
suitably
hardened, derived from natural sources such as tallow, coconut oil, ground oil
and babassu oil. Other suitable suds suppressors include C10-18 alkoxylated
capped alcohols. Most preferably however the suds suppressor consists of a
mixture of fatty acid, preferably coconut fatty acid (e.g. Prifac 5900
available from
Unichem) and alkoxylated capped alcohol, preferably C12-14 ethoxy butoxy
methyl ether (e.g. Plurafac LF231 available from BASF). Compositions
according to the present invention comprise from 0.1~% to 2%, preferably less
than 0.6% by weight of the composition of fatty acids.
A further optional component of the present invention is a radical scavenger.
Said radical scavengers are used as stabilisers. A suitable radical scavenger
for
use herein is the aromatic molecule containing a carboxylic group ring
substitution. Suitable examples of radical scavengers for use herein include
the
meta and para-chlorobenzoic acid, benzoic acid, meta- ortho- and para-
methoxybenzoic acid, meta nitrobenzoic acid, para bromobenzoic acid, salicylic
acid, 5-sulphosalicylic acid, 3,5-dimethyl salicylic acid and paratoluic acid.
Of the
above materials, ortho-methoxybenzoic acid is preferred. Compositions
according to the present invention comprise from 0.01 % to 1.5% by weight,
preferably from 0.1 % to 0.8% by weight and more preferably from 0.2% to 0.5%
by weight of the composition of radical scavengers.
An optional requirement of the compositions according to the present invention
is
that the pH is greater than 10, preferably greater than 11, more preferably
greater than 12. This is achieved by the addition of from 0.4% to 2% of a
caustic
alkali. Suitable caustic alkalis for use herein include sodium and potassium
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hydroxide. Compositions according to the present invention comprising
hypochlorite preferably have a pH greater than 12 for hypochlorite stability.
The compositions according to the present invention are preferably aqueous and
preferably comprise from 80% to 95%, more preferably from 85% to 90% of
water.
The compositions according to the present invention are prepared by methods
well known in the art such as the methods described in GB 1 329 086 with the
exception of the polymer being pre-dispersed in an acidic water solution of pH
3
and then neutralised up to pH 7 before starting adding the other components.
The compositions according to the present invention can then be prepared by
mixing all of the ingredients in a non-metallic apparatus at room temperature
or in
warm water. If fatty acid is used, it is melted before being added to the
mixture.
Preferably, the surfactant blend is first prepared by adding the short chain
surfactant to the long chain surfactants. Other optionals such as perfume and
the
alkali metal hypochlorite are then added whilst stirring. Colourants, if
present, are
added after all the other ingredients have been mixed.
The compositions according to the present invention preferably have a
viscosity
of from 10 cps to 4000 cps, more preferably from 50 cps to 2000 cps, most
preferably from 150 cps to 1000 cps measured with a Carrimed Rheometer at a
temperature of 25°C and a shear rate of 15-100 s-1. Where the
composition is in
a sprayed form, the viscosity of said spraying compositions is preferably of
from
15 cps to 40 cps.
The compositions of the present invention may be used for a variety of
cleaning
purposes such as cleaning hard surfaces whereby said compositions thickened
nature results in longer adhesion to the surface than non-thickened
compositions. By "hard surface" it is meant herein any surface like bathroom,
sanitary fittings such as sinks, showers, wash basins and WCs, kitchen, sinks,
cooker tops, table tops, refrigerators, walls, windows and the like.
Packaging form of the compositions
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The compositions herein may be packaged in a variety of suitable detergent
packaging known to those skilled in the art. The liquid compositions herein
may
desirably be packaged in manually operated spray dispensing containers, which
are usually made of synthetic organic polymeric plastic materials.
Accordingly,
the present invention also encompasses liquid cleaning compositions of the
invention packaged in a spray dispenser, preferably in a trigger spray
dispenser.
indeed, said spray-type dispensers allow to uniformly apply to a relatively
large
area of a surface to be cleaned the liquid cleaning compositions suitable for
use
according to the present invention; thereby contributing to the cleaning
properties
of said compositions. Such spray-type dispensers are particularly suitable to
clean vertical surfaces. Surprisingly, the spraying of a liquid composition
containing a polycarboxyiate polymer, contrary to compositions which do not
contain the poiycarboxylate polymer, has been seen beneficial for preventing
ors
reducing inhalation of the composition by the user as said composition is_
sprayed.
The present advantage is preferably observed where the cleaning composition is
as defined hereinbefore. Accordingly, the use of a poiycarboxyiate polymer in
a
liquid cleaning composition is provided, said composition being in a sprayed
form, for preventing or reducing inhalation of said composition by the user as
said composition is sprayed. Preferably, the liquid cleaning composition is as
defined hereinbefore.
Suitable spray-type dispensers to be used according to the present invention
include manually operated foam trigger-type dispensers sold for example by
Specialty Packaging Products, Inc. or Continental Sprayers, Inc. These types
of
dispensers are disclosed, for instance, in US-4,701,311 to Dunnining et al.
and
US-4,646,973 and US-4,538,745 both to Focarracci. Particularly preferred to be
used herein ace spray-type dispensers such as T 8500~ or T 8900~
commercially available from Continental Spray International or T 8100~
commercially available from Canyon, Northern Ireland. In such a dispenser the
liquid composition is divided in fine liquid droplets resulting in a spray
that is
directed onto the surface to be treated. Indeed, in such a spray-type
dispenser
the composition contained in the body of said dispenser is directed through
the
spray-type dispenser head via energy communicated to a pumping mechanism
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by the user as said user activates said pumping mechanism. More particularly,
in
said spray-type dispenser head the composition is forced against an obstacle,
e.g. a grid or a cone or the like, thereby providing shocks to help atomise
the
liquid composition, i.e. to help the formation of liquid droplets.
The present invention further encompasses a method for cleaning a hard surface
by applying on said surface an effective amount of a composition of the
invention. The said composition may be applied in its neat form or after
having
been diluted with water. Preferably said composition is.diluted up to 200
times its
weight of water, preferably into 50 to 150 times its weight of water and more
preferably 75 to 95, before it is applied to said surface. When the
composition is
diluted prior to use (to reach a total active level in the order of 1.2%), the
composition will still advantageously provide effective cleaning performance.
In
the preferred embodiment of the method of the present invention wherein sail
composition is applied to a hard-surface to be cleaned in its diluted form, it
may_
not be necessary to rinse the surface after the composition has been applied.
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Examples
The examples provided below are not intended to be limiting and merely provide
an example of the sort of formulation that is envisaged by the Applicant. All
amounts are listed in % weight of the total composition.
IA B C
w/w % w/w % w/w
Hi h MW of mer #1 1.0 - 1.0
Low MW of mer 0.1 0.1 0.1
Hi h MW of mer #2 ~ - I 1.5 -
Heptyl-nonyl sulfate 1.5 1.5 I 3.0
Em imin LN from A&W
Capped nonionic alcohol - - 0.1
Plurafac LF231 from BASF
Coconut fatty acid - - 0.1
Prifac 5900 from Unichema
2 ethyl-hexyl sulfate 1.5 1.5 -
Em icol 0585/A from A8~W
C12-C13 branched sulfate1.0 1.0 1.0
based on Isalchem123
Citrus Bleach PCMF erfume0.3 0.3 0.2
H ochlorite 1.0 1.0 1.0
Caustic 1.0 1.0 1.0
Green d a 0.0058 0.0058 0.0058
Periodic acid 0.01 0.01 0.01
Sodium silicate 0.4 0.4 0.4
Demineralized water Balance Balance Balance
High MW polymer #1 is Polygel DR from 3Vsigma
High MW polymer #2 is Carbopol ETD2691 from Goodrich
Low MW polymer is Polygel W30 from 3Vsigma
