Note: Descriptions are shown in the official language in which they were submitted.
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LAVATORY CLEANSING COMPOSITIONS
Technical Field
This invention is concerned with lavatory cleansing blocks
which may be used to clean and/or perfume the flush water of
a lavatory or urinal.
Background to the Invention
The use of toilet blocks to impart cleansing and/or other
components to the flush water of a lavatory or urinal is
well known. Such compositions may, for example, be immersed
in the water of a lavatory or held under the rim of a
toilet, in a suitable holder, for intermittent contact of
the solid material with flush water. For convenience these
two approaches will be referred to herein respectively as
`cistern-blocks' and `rim-blocks'
In recent years it has become commonplace for toilet blocks
to contain a halogen release agent or other bleaching agent.
From EP 0206725 it is clear that halogen release agents are,
by their nature, powerful chemically reactive species,
serving as halogenating or oxidising agents and it is
consequently difficult to incorporate bleach-sensitive
components such as perfumes and dyestuffs into blocks which
contain bleaching agents.
Toilet blocks in which two incompatible components are
separated by placing them in different phases of the toilet
block are described in EP 0 101 402 (Henkel).
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We have found that with dual phase toilet one phase tends to
dissolve faster than the other phase leading to a disparity
in the dosing of the ingredients in the final flushes of the
toilet.
Brief Description of the Invention
We have determined that improved toilet blocks can be
formulated in which the problem of uneven dissolution
between the phases of a multiphase block can be mitigated.
Accordingly, the present invention provides a lavatory
cleansing block comprising at least two phases one phase
(phase 1) comprising a water insoluble salt as at least 50
wt% of the salt present within that phase and a second phase
(phase 2) comprising a perfume and a water soluble salt such
that the salts in both phases have the same anion.
The invention also relates to a process for producing the
toilet blocks, described in the above paragraph, the process
comprising the step of co-extruding the two phases to form a
block.
Detailed Description of the Invention
In order that the invention may be further understood the
following description details preferred and optional
features of the invention.
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Salts
The present invention preferably relates to a dual phase
block.
Phase 1 of the block comprises a water insoluble salt as at
least 50 wt% of the salt present, in the context of the
present invention water insoluble salt refers to salts
having a maximum solubility parameter of 0.05 gram per 100cc
of water at 25 C .
The second phase (Phase 2) of the block comprises a perfume
and a water soluble salt. The term water soluble salt
refers to salts having a solubility parameter of at least
0.5 gram per 100cc of water at 0 C, more preferably greater
than 1 gram per 100 cc of water. The salts in both phases
should have the same anion.
Other salts with differing anions may also be present within
each phase. However, it is highly preferable if phase 1
does not contain a water soluble salt having the same anion
as the water insoluble salt.
The total level of water soluble salt having the same anion
as the water insoluble salt within phase 2 is from 1 to 10
wt% of the total level of ingredients present in phase 2.
It is preferred if phase 2 further comprises a water
insoluble salt having the same anion as the water soluble
salt. More preferably the ratio of water soluble salt and
the water insoluble salt both having the same anion within
phase 2 of the toilet block is from 5:1 t 1:5. Most
preferably the ratio of water soluble salt and the water
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insoluble salt both having the same anion within phase 2 of
the toilet block is from 3:2 to 2:3.
A preferred water soluble salt for use with the present
invention is sodium carbonate.
A preferred water insoluble salt for use with the present
invention is calcium carbonate.
The total level of water insoluble salt in phase 1 is from 1
to 10 wt% of the total level of ingredients present in phase
1.
Blocks according to the present invention comprise 5 to 50
wt% to by weight of salt as a sum of the total ingredients
of both phases inclusive of the anion present, more
preferably 10-30 wt%.
Alcohol Ethoxylate
The toilet blocks according to the invention may include an
alcohol ethoxylate. The alcohol ethoxylate preferably used
in the present invention is ethoxylated with 8 or less moles
of alkylene oxide, more preferably the alcohol ethoxylate is
ethoxylated with 5 or less moles of alkylene oxide.
Preferably the alcohol ethoxylate has a carbon chain length
of C8 to C22, more preferably from C8 to C16
Preferably the alcohol ethoxylate is branched.
It is preferred if the alcohol ethoxylate has an H.L.B of 12
or less, more preferably an HLB of 10 or less, most
preferably of 8 or less.
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The alcohol ethoxylate should preferably have a cloud point
of less than 65 when measured in water at a 1% solution.
Preferably, the level of alcohol ethoxylate within the block
is less than 5 wt% of the total weight of the block. More
preferably the alcohol ethoxylate is in a separate phase to
the perfume (that is phase 1). It is advantageous if the
level of alcohol ethoxylate is from 0.5 to 6 wt % of the
weight of the total composition (i.e. both phases), more
preferably from 1.5 to 4 wt% of the weight of the total
composition.
Bleaching Agents
Typically the blocks comprise up to 50% by weight of a at
least sparingly water soluble bleaching agent. Typically
levels of bleaching agents are 2-30% wt on product. For the
purposes of the present specification the term bleaching
agent is used to mean both a bleaching agent and a precursor
which produces a bleaching agent unless the context demands
otherwise.
Suitable bleaching agents active-halide and active-oxygen
bleaching agents, particularly the so-called `halogen
release agents'.
Chlorine bleaching agents are preferred. Suitable water-
soluble, active chlorine, bleaching agents used in
accordance with the invention include chlorinated
cyanurates, phthalimides, p-toluene sulphonamides,
azodicarbonamides, hydantoins, glycoluracils, amines and
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melamines. The alkali metal salts of cyanurates are
preferred.
A particularly preferred bleaching agent is sodium
dichlorocyanurate (NaDCCA). The bleaching agent is
typically present in an amount of 10-30% and most preferably
at around 25%. Oxidan DCN/WSG (TM) ex Sigma has been found
to be a suitable bleaching agent.
In a particularly preferred embodiment of the invention the
bleach resides in the same phase as the water insoluble salt
(phase 1).
Anionic Surfactant
Preferably, the composition will also contain a surfactant
component which is anionic in nature. This surfactant
serves to provide a cleansing and foaming effect.
Suitable anionic surface active agents include alkali metal
or ammonium alkylaryl sulphonates (especially alkyl benzene
sulphonates), alkane sulphonates, alkyl sulphates and
sarcosinates.
We have determined that improved foaming properties are
sometimes obtained by the use of a surfactant system which
comprises primary alkyl sulphate (PAS) together with other
anionic surfactants. Preferably the present invention
provides a lavatory block comprising 1-15% wt (more
preferably 1-5% wt) of a primary alkyl sulphate and 15-50%wt
(more preferably 30-50%wt) of other anionic surfactants. We
have determined that the use of this mixed surfactant system
is advantageous in that it reduces the stickiness of the
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block during manufacture. The blocks with 1-5% PAS show
improved wear characteristics.
Preferably the other anionic surfactants are sulphonates.
Suitable sulphonates include alkyl benzene sulphonate (ABS).
It is believed that the combination of relatively low levels
of PAS together with higher levels of ABS promotes the
foaming and the perfume delivery from the block.
The total amount of surfactant when present, may lie within
wide limits. In practice, the surfactant will generally be
for 10 to 70% by weight of the composition, but more
preferable that surfactant comprises from 20 to 50% by
weight thereof.
Process Aids
As will be described in further detail below extrusion is
the preferred method of manufacture. Optionally, the blocks
according to the invention further comprise a processing aid
to assist in extrusion. Suitable processing aids include
oils (including both mineral and silicone oils), esters
(other than those derived from ethylenically unsaturated
carboxyl group containing monomers), alcohol ethoxylates and
polybutene.
Perfume
Preferably, the blocks comprise 2-15%wt of a hydrophobic
oily liquid perfume. The blocks more preferably comprise,
2-10%, more preferably 3-6% wt of the perfume. Levels of
around 4% wt perfume are particularly preferred. This oily
perfume is typically of the kind described in the European
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patent application EP 167,210. It will be understood that
the liquid oily perfume must be stable in the presence of
the water-soluble, active chlorine, bleaching agent.
Suitable oily perfumes can be easily selected by testing
them in combination with the water-soluble, active chlorine,
bleaching agent.
In some instances, the toilet block may comprise two
perfumes in this case it is preferable if the perfume
present in each phase is at least 80 wt% of the total
perfume present in that phase. More preferably different
perfumes are present in phases.
Examples of suitable bleach-stable perfumes are Verdeo- 898,
Bonanza" 048 and Ponderosa" 431 all ex IFF, and LB 132 ex
Quest. Particularly preferred perfumes are Icebreaker Super
Mod, Oxygen Supra Mod, Motebianco Supra and lemonfit Supra
(all TM) ex Givaudan Roure.
Minors
Minor components will generally be present but are optional.
These include colouring agents, and/or whiteners. These
materials should be chosen such that they are compatible
with the bleaching agent and do not react therewith to a
significant extent. Titanium dioxide is an acceptable
whitener. Levels of colouring agents and/or whiteners as
typically below 5% wt.
Further enhancement of the product may be obtained by the
additional use of chelating agent, sequestrant or water-
softening agent such as ethylene diamine tetra-acetic acid
or a derivative thereof, nitrolotriacetic acid, phosphonates
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of polyphosphates, metasilicates, boroheptonates, s.s-
thylene-diamino disuccinate, dipicolinic acid, 2-
phosphonobutane-1,2,4-tricarboxylic acid, or lower molecular
weight polymeric materials capable of inhibiting crystal
growth. Further reducing agents, such as alkali metal
metabisulphates may be present to assist in the reduction of
staining due to metals such as iron.
Typically, one phase of the blocks according to the present
invention comprise 1-15% wt, more preferably 2-10% of a
dyestuff on a carrier. It is preferable if the other phase
of the block is totally coloured. In both cases it is
preferable if the dye is water soluble.
Polymers
A water-insoluble, gelling polymers may be used in
compositions of the invention, these are polycarboxylic
acids derived from one or more ethylenically unsaturated
carboxyl group-containing monomers, especially ethylenically
unsaturated carboxylic acids such as acrylic acid or maleic
acid.
Suitable polymers include polyacrylic acid, polymaleic
anhydride and copolymers of either of the aforementioned
with ethylene, styrene and methyl vinyl ester. If present it
is preferred that the polymer is cross-linked. Polygel DB
(TM) ex 3V Sigma, a cross-linked high molecular weight
polyacrylate, has been found to be a suitable material at an
inclusion level of around 2-3%wt.
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Process
Compositions in accordance with the invention may be
produced by a variety of routes. For example, they may be
prepared by a so-called "hot-melt" process comprising
melting the fusible constituents of each phase of the block
followed by adding the other components, and subsequently
casting the melt into moulds or are formed into the desired
final shape by a compression technique, i.e., a technique
involving the steps of forming a mixture of the ingredients
of the compositions and then compressing that mixture into
the desired shape. The two phases so formed are then
compressed together.
An especially preferred process is an extrusion process in
which mixtures of the components of each phase are co-
extruded into a solid bar or rod which is subsequently cut
into pieces of the desired size.
It may be noted that when the compositions of the invention
are used as free-standing lavatory cleansing blocks, these
suitably have a weight from 30 to 150 gms. When extruding a
solid composition it is generally advantageous, as noted
above, that some lubricant component or process aid be
present to facilitate extrusion. The weight of each phase is
preferably approximately the same as each other
(approximately in this context meaning that the weight of
each phase varies within 20% from each other, more
preferably within 10%).
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Compositions in accordance with the invention may also be
formed into the final desired shape by a tabletting
technique.
As used herein the term block is not intended to limit the
shape of the eventual product. For cistern blocks the rod
is cut into lengths which are short relative to their
diameter.
The invention also provides a method of cleaning a lavatory
or urinal using a block of a composition in accordance with
the invention.
In order that the invention may well be understood, the
following Examples are given by way of illustration only.
Examples of the invention are illustrated by a number,
comparative Examples are illustrated by a letter.
Examples
Toilet blocks were formed by an extrusion process in which
the mixture of the components of each phase were co-extruded
as a plastified mass through an aperture to form a billet
and said billet is cut into tablets of appropriate size.
The toilet blocks had the following formulation:
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wt% of total block
Example
A 1 2
Phase 1
ABS 15 15 15
PAS2 6 6 6
NaDCCA 11.25 11.25 11.25
CaCO3 4.4 4.4 4.4
Na2SO4 4.3 . 4. 3 4.3
Alcohol ethoxylate 2E0 - - 3
Minors to 50 wt%
Phase 2
ABS 17.4 17.4 17.4
PAS 2.5 2.5 2.5
CaCO3 11.3 9.2 5.1
Na2SO4 9. 8 9.8 9. 8
Na2CO3 - 2.2 5.3
Perfume 3.5 3.5 3.5
Minors to 50 wtt
ABS1 Nansa" HS 80/L ex Albright & Wilson
PAS2 PAS-Empicoll` LZ-V ex Albright & Wilson
Coloured granules sodium carbonate ex Crosfield
Alcohol ethoxylate 2E05 Loradac- 2-24 2E0 ex DAC.
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The in-use lifetime of each block was measured by placing in
a toilet, flushing 250 times and measuring the residual
weight of the block.
Example Phase A of original Phase B % of
block remaining original block
remaining
A 0 40
1 0 35
2 0 20
It can thus be seen that the disparity between the two
phases of the toilet block is less with the blocks of the
invention.
