Note: Descriptions are shown in the official language in which they were submitted.
CA 02248093 l998-09-03
W O 97/47721 PCT~EP97/02501
IMPROVEMENTS RELATING TO
~AVATORY CLEANING BLOCKS
~echnlcal Field
The present invention relates to lavatory blocks including
those which are intended, in use, to be located under the
rim of a lavatory bowl or urinal such that, during a
flushing cycle, water from the cistern flows over the
block thereby dissolving a portion of the block. Such
blocks are generally known in the art as ~rim blocks' and
will be referred to as such or simply as 'blocks~ herein.
The invention also relates to so-called 'in-cistern~
blocks which sit in the cistern of a lavatory or urinal
and slowly dissolve in the water contained therein.
Backqround to the Invention
Lavatory blocks produce foam, often produce a pleasing
odour and can have germicidal properties. These
germicidal properties can be due to the presence of
bleaching species such as the so-called Ichlorine release
agents', other oxygen bleaches such as peroxides and non-
bleaching species such as ~uaternary ammonium compounds or
halogated materials which do not release hypohalous acids
in use.
~ WO 92/03532 (Jeyes) discloses that rim blocks generally
comprise a surfactant component and a solubility retarding
component or 'fillerl. Typically, the surfactant
component is an anionic surfactant which is present at a
level of 5-85% by weight of the block.
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W O 97t47721 PCT~EP97102501
A number of different anionic surfactant systems are known
for rim blocks. These comprise mixtures of two or more of
primary alkyl sulphate (PAS), alkyl sulphates (AS) which
may be branched, secondary alkyl sulphates (SAS) alkyl
ether sulphates (AES) and alkyl benzene sulphonates (LAS)
or the essentially pure surfactant materials. US 4874536
discloses that AS/LAS mixtures can be used in blocks which
are free of oxygen bleaching species. WO 95/11958
discloses the use of PAS/AES mixtures again in bleach-free
blocks. WO 96/14392 discloses the use of PAS/LAS mixtures
in bleach-free blocks. EP 0619367 discloses the presence
of PAS/LES in bleach-free blocks. EP 0184416 discloses
LAS/PAS in bleach free-blocks. GB 2169612 LAS/PAS in
bleach-free blocks. GB 2178442 discloses the use of
LAS/PAS mixtures in blocks which comprise two halogen
bleaching agents.
EP 0462643 (Unilever) discloses how blocks which comprise
halogen bleaching agents can be improved by the
incorporation therein of an oily liquid perfume component.
We have found that one problem with these bleach/perfume
blocks is that the presence of the bleaching agent
requires that relatively high levels of the perfume are
present for moderate term stability. Moreover the
bleaching agent also replaces a portion of the filler
which is typically present. The presence of the perfume
and bleach leads to a Isticky~ block which can be
difficult to produce using the extrusion technique which
is commonplace in manufacture of these blocks.
It also is advantageous that a block should produce a
copious foam when first installed, i.e. during the first
50-80 flushes and continue to produce copious foam during
a significant part of the lifetime of the block.
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WO97/47721 PCT~P97/02501
Brief Descri~tion o~ the Invention
We have determined that improved foaming properties and/or
a lack or reduction of stickiness in bleach and perfume
containing blocks are obtained by the use of a particular
surfactant system which comprises primary alkyl sulphate
(PAS) together with alkyl benzene sulphonate (LAS) at
specified levels.
Accordingly the present invention provides a lavatory
block comprising:
a) 2-15%wt of oily liquid perfume structurant,
b) 2-30%wt of halogen bleaching agent,
c) 3-15%wt of primary alkyl sulphate, and,
d) 15-50%wt of alkyl benzene sulphonate.
Without wishing to limit the invention by reference to any
theory of operation, it is believed that the PAS and LAS
form a phase which can adsorb some of the perfume present
and prevent the development or expression of stickiness.
This facilitates the manufacture of blocks by the process
in which the mixture is extruded into a bar which is then
cut into individual blocks. It also is believed that the
combination of PAS together with ABS promotes the foaming
and the perfume delivery from the block.
Accordingly a further aspect of the present invention
subsists in the use of 3-15%wt primary alkyl sulphate and
15-50%wt of alkyl benezene sulphonate to reduce stickiness
in a process for the manufacture of a lavatory block
comprising 2-15%wt of oily li~uid perfume and 2-30% of
halogen bleaching agent.
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W O97/47721 PCT~EP97/02501
Detailed Descri~tion of the Invention
The preferred ratio of the primary alkyl su~phate and the
alkyl benzene sulphonate is 1:1 to 1:5 in terms of
PAS:LAS, most preferably around 1:3 in terms of PAS:LAS.
Particularly suitable materials are PAS with an average
alkyl chain length of C10-C16 and alkyl benzene sulphonate
with an average alkyl chain length of C10-C16.
Preferably the blocks according to the invention contain
less than 5%wt of other surfactant components and more
preferably the blocks are free of other surfactant
components.
Optionally, the blocks according to the invention further
comprise a processing aid to further assist in extrusion.
Suitable processing aids include oils (including both
mineral and silicone oils), esters (e.g. methyl
decanoate), liquid ketones (e.g. 2-decanone), li~uid
tertiary alcohols (e.g 2-methyl hexan 2-ol) and
polybutene. One suitable processing aid is an alkoxylated
alcohol. It is preferred that the alkoxylated alcohol is
an ethoxylated alcohol. When present the preferred level
of alkoxylated alcohol is 0.75-2%wt. The preferred ethoxy
chain length is 40-60 with an average ethoxy chain length
of around 50 being preferred. Suitable materials include
Empilan KM 50/KF (TM) ex. Albright ~ Wilson. Another
suitable process aid is a PEG monostearate. PEG 4000
Monostearate (100%) ex DAC is a suitable raw material.
Advantageously, the blocks according to the invention are
free of this processing aid.
Typically, blocks according to the present invention
comprise 0 to 50% by weight of an inert and/or electrolyte
filler. Preferably blocks contain 5-50%wt of filler.
Suitable fillers include ionic (soluble) fillers and inert
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WO 97147721 rcT~ps7lo2sol
(insoluble) fillers. Suitable fillers include one or more
of urea, sodium, magnesium and calcium carbonates, sodium
chloride, borax, talc and sodium, magnesium and calcium
sulphates. Preferred ionic fillers include sodium
sulphate. It has been found advantageous to include at
least sparingly soluble salts of the metals barium,
cadmium, copper, iron, manganese or nickel so as to modify
the in-use lifetime of the block.
Preferred inert fillers include calcium carbonate.
Typical levels of total filler range from 20-50%wt on
product in total. Preferred levels of filler are 10-20%wt
on product of ionic filler and 10-20~ on product of inert
filler. It is particularly preferred to use an
approximately 50:50 mixture of sodium sulphate and calcium
carbonate as the filler. Typical levels in product are
13-17%wt of each of calcium carbonate and sodium sulphate.
It is generally preferred that for in-cistern blocks the
inert filler is absent to prevent residues on block
dissolution.
Where the inert filler is sparingly soluble, such as with
calcite, it has been found useful to employ an inert
filler with a narrow cut large particle size such that
dissolution and re-precipitation of the calcite is
minimised. Where inert filler is present, Calcitec SG
(TM) has been found to be a suitable material.
Suitable halogen bleaching agents are those which are at
least sparingly soluble in water. The active 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 melamines. Other
chlorine release agents such as calcium hypochlorite may
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be employed. The alkali metal salts of cyanurates are
preferred.
A particularly preferred bleaching agent comprises at
least one N-chlorinated cyanuric acid derivative, more
preferably sodium dichlorocyanurate (NaDCCA). The
bleaching agent is preferably present in an amount of 10
to 25% by weight, most preferably at around 15%wt. Oxidan
DCN/WSG (TM) ex Sigma has been found to be a suitable
bleaching agent.
Preferably, the blocks comprise 4-10% by weight of the
perfume. Levels of 5-8% perfume are particularly
preferred. This is most preferably the liquid oily
perfume structurant of the ~ind described in the European
patent application EP 167210. It will be understood that
the liquid oily perfume must be stable in the presence of
the particular water-soluble, active chlorine, bleaching
agent selected. It is believed that substituted
~uinolines, cedryl methyl ether and cineole are all
suitably stable perfume components.
Suitable commercially available oily perfumes can be
easily selected by testing them in combination with the
water-soluble, active chlorine, bleaching agent. 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, Montebianco Turbo7 and
Lemonfit Supra (all TM) ex Givaudan Roure.
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. We have
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W O 97/47721 PCT~EP97/02501
determined that 'Sudangelb 150' (TM) ex. Sandoz is an
acceptable colouring agent as are Colanyl Green (TM) ex
Hoechst and Dispers Blue (TM) ex BASF. Titanium dioxide is
an acceptable whitener. A further optional minor
component is a foam-boosting surfactant such as an amine
oxide.
Blocks according to the present invention are manufactured
by an extrusion process as known in the art: i.e. the
ingredients are mixed to form a dough, which is then
extruded into a rod or bar which is cut into blocks of
suitable lengths. As used herein the term block is not
intended to limit the shape of the eventual product. For
rim-blocks the rod is generally cut into lengths which are
long relative to their diameter and for cistern blocks the
rod is cut into lengths which are short relative to their
diameter. Preferably the blocks are extruded as a single
composition, to give a homogenous block.
Rim blocks according to the present invention are
typically used in a cage which is adapted to be suspended
from the rim of the toilet bowl in such a manner that
flush water flows over and through the cage when the
cistern of the toilet is discharged. A particularly
preferred embodiment of the present invention comprises a
block according to the claims appended hereto in
combination with a cage which retains the block, said cage
being provided with a hook for attachment of the cage to
the rim of a toilet bowl.
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W O97/47721 PCT~EP97/02501
Particularly preferred compositions are:
4-15%wt primary alkyl sulphate
15-50%wt alkyl benzene sulphonate
2-30%wt at least one N-chlorinated cyanuric acid
derivative, preferably NaDCCA
10-50%wt Sodium sulphate, calcium carbonate or a
mixture thereof,
2-15%wt Perfume
0-5%wt Colour and/or optical brightener
In order that the invention may be further understood it
will be described hereafter by way of the following non-
limiting examples.
ExamPles
The components listed in Table 1 below were mixed in the
proportions specified and extruded in the form of a bar
which was then cut into blocks. All proportions are given
in weight % as throughout the specification unless stated
otherwise. Examples 1-2 and 4 are embodiments of the
invention and example 3 is a comparative example.
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WO 97/47721 PCT~EP97/02501
The following materials were used:
Nonionic Empilan KM 50/KF (TM, ex. Albright and
Wilson)
Process Aid PEG 4000 Monostearate (100%) ex DAC
Anionics (ABS) Nansa HS 80/GPF (TM, ex. Albright and
Wilson)
~PAS) Empicol LZ-V (TM, ex. Albright and
Wilson)
10 Bleaching agent Oxidan DCN/WSG (TM, ex Sigma).
Ionic Filler Sodium Sulphate
Inert Filler Calcium Carbonate (Calcitec SG lTM]
ex. Mineraria Sacilese~
15 Perfume (Montebianco Turbo 7 [TM] ex. Givaudan Roure) was
present at 6.5-7%, whitener (titanium dioxide) when
present at 0.071 and colour (Colanyl Green ex. Hoechst) at
0.024% or less.
Compositions are given in the upper part of table 1 while
foam height results obtained from toilet flushing
experiments with formulations 1-4 are given in the lower
part. In the foam height results the figure given is the
foam height in cm which is attained directly after the
flush.
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W O 97/47721 PCTAEP97/02501
-- 10 --
Table 1
Example 1 ¦ 2 ¦ 3 ¦ 4
Composition
Bleaching agent 15 15 15 15
Ionic Filler 15 15 10.2 15.98
Inert Filler 7.3 14.5 4.36 14.7
Perfume 6.5 6.5 6.5 6.5
Colour 0. 024 0.024 0.024 0.024
Whitener - - O. 07
Process Aid - - 1.0
Nonionic - - 3.0
PAS 10 10 - 10
ABS 35 30 47.8 30
Water to 100 to 100 to 100 to 100
Results
Flush Foam Height
1 2.4 2.5 1.0 2.5
3.3 3.5 1.5 3.5
3.4 3.5 3.0 3.5
4.0 4.0 3.0 4.0
4.0 4.0 3.0 4.4
105 4.5 4.5 3.3 5.0
150 4-7 4-7 3-3 5.0
210 4.5 4.5 3.2 4.6
250 4.0 4.0 3.0 4.5
300 3.5 3.5 3.0 4.0
350 3.0 3.0 2.0 3.5
400 2.5 2.5 2.0 2.8
500 2.0 2.0 1.3 2.0
600 0.5 0.5 0.5 0.5
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From the results given in table 1 it can be seen that
blocks which contain a conventional surfactant system
(comparative example 3) have a significantly lower level
of foam than blocks which contain PAS (examples 1-2 and
4). Empirical observation during the manufacturing
process indicated that far less stickiness, as assessed by
the operator, was observed during the manufacture of
blocks according to examples 1,2 and 4 than during
manufacture of 'standard~ blocks according to example 3.
.
