[0001] This invention relates to cleaning compositions in the form of tablets for example,
for use in fabric washing or machine dishwashing.
[0002] Detergent compositions in tablet form have advantages over powdered products in that
they do not require measuring and are thus easier to handle and dispense into the
washload.
[0003] Tablets of a cleaning composition are generally made by compressing or compacting
a quantity of the composition in particulate form.
[0004] Tablets comprising two or more separate regions have also been described. For example
WO 01/42416 describes the production of multi-phase moulded bodies comprising a combination
of core moulded bodies and a particulate premix. WO 00/61717 describes a detergent
tablet which is characterised in that at least part of its outer surface is smooth.
WO 00/04129 describes a multi-phase detergent tablet comprising a first phase in the
form of a shaped body having at least one mould therein and a second phase in the
form of a particulate solid compressed within said mould.
[0005] It is an object of the present invention to provide a method to produce cleaning
tablets comprising a smooth phase, wherein the smooth phase has a suitable surface
smoothness and can be produced at high speed at relatively low cost.
[0006] A further objective of the present invention is to.provide a method to produce a
smooth tablet or phase thereof wherein the choice of materials and the manufacturing
method allows the low cost production of tablets of good performance and of good consistency
and texture.
[0007] Although the invention can relate to a single phase smooth tablet, according to a
preferred embodiment of the present invention there is provided a cleaning tablet
which has a plurality of discrete regions with differing compositions, characterised
in that at least one first region of the tablet is a smooth region and at least one
second region of the tablet is a solid region of compacted particulate material.
[0008] One method of producing smooth phases which can be used in cleaning tablets is first
to produce a large quantity e.g. an extruded strand or a log of the material, followed
by partitioning this quantity into smaller quantities for example by cutting.
[0009] A problem with the cutting process of these materials is however that often the cutting
leads to an uneven surface and/or the deformation of the resulting pieces or slices.
[0010] Surprisingly it has been found that the smooth composition can advantageously be
divided into smooth parts for use in cleaning tablets by using a high frequency or
jet cutting process.
[0011] Accordingly in a first aspect the invention relates to a method of producing a cleaning
tablet comprising a smooth phase wherein the preparation of the smooth phase comprises
the step of high-frequency cutting or jet cutting of a cleaning material.
[0012] Preferably the cleaning material comprises from 10 to 90 wt% of non-soap surfactants
and from 0 to 20 wt% of water.
[0013] Preferably tablets (and the smooth phases) of the invention are of cylindrical shape
wherein the two main surfaces (upper side and bottom side) are substantially flat.
Preferably the smooth phases are slices of cleaning material, for example having a
diameter of from 1 to 10 cm (preferably 2 to 6 cm) and a height of from 0.1 to 5 cm
(preferably 0.3 to 1.5 cm).
[0014] As indicated above, tablets of the invention can be single phase tablets, which are
predominantly constituted by the smooth phase as described above. However a preferred
embodiment of the invention relates to a multiphase tablet wherein the smooth phase
is present and additionally one or more other phases are present. Suitably these additional
phases can be smooth or solid. Particularly suitable are solid phases composed of
compacted particulate solids.
[0015] The regions of a multi-phase tablet are possibly separate layers within a tablet.
However, a discrete region of a tablet could also have other forms for example one
or more core(s) or insert(s). In a preferred embodiment the first region is a smooth
layer and the second region is a layer of compacted particulate material. In a further
advantageous embodiment the first region is a core or insert of smooth material embedded
in the second region which is a layer of compacted particulate material.
[0016] If the tablet is a single phase smooth tablet, then preferably the weight of this
tablet will be from 5 to 200 g, more preferably from 10 to 100 g, most preferably
from 15 to 50 g.
[0017] If the tablet is a multi-phase tablet comprising the smooth phase of the invention
then preferably the smooth phase is present as a distinctive region preferably having
a weight of from 2 to 20 grammes, more preferred from 3 to 10 grammes. Preferably
the other phases together have a weight of 10 to 50 grammes, more preferred 15 to
40 grammes.
[0018] For the purpose of this invention the term smooth phase refers to compositions which
are on the one hand solid enough to retain their shape at ambient temperature and
on the other hand smooth in appearance. Smooth textures are generally of low or no
porosity and have -at normal viewing distance- the appearance of a continuous phase
for example as opposed to porous and particulate appearance of a compacted particulate
material.
[0019] It has been found that the use of high frequency cutting or jet cutting processes
to obtain the smooth phase can provide a very attractive appearance to the smooth
phases for example a very smooth appearance and little or no deformation during the
cutting phase.
[0020] Preferably the smooth phase is transparent or translucent. Preferably, this means
that the composition has an optical transmissivity of at least 10%, most preferably
20%, still more preferably 30%, through a path length of 0.5 cm at 25° C. These measurements
may be obtained using a Perkin Elmer UV/VIS Spectrometer Lambda 12 or a Brinkman PC801
Colorimeter at a wavelength of 520nm, using water as the 100% standard.
[0021] The transparency or translucency of the compositions according to the invention does
not preclude the composition being coloured, e.g. by addition of a dye, provided that
it does not detract substantially from clarity.
[0022] In an advantageous embodiment of the invention the smooth phase comprises from 20-80
wt% of non-soap surfactants (based on the total weight of said smooth phase), more
preferred from 25 to 75 wt%, most preferred 30 to 70 wt%. It has been found that the
combination of a separate smooth first region and these high surfactant levels provide
very good dispersing and cleaning properties to the tablet.
[0023] Preferably the non-soap surfactants in the first region comprise a combination of
anionic surfactants and non-ionic surfactants in a weight ratio of from 5 : 1 to 1
: 5, more preferred 3 : 1 to 1 : 3, more preferred 2 : 1 to 1: 2. Further surfactants,
for example cationic surfactants may equally be present for example at a level of
0.1 to 10 wt% based on the weight of the smooth part.
[0024] In addition to the non-soap surfactants the smooth region may comprise additional
solid materials such as mineral salts, sugar or structuring soaps for example at a
level of 2 to 90 wt% based on the weight of the smooth part, more preferred from 3
to 70 wt%, most preferred 5 to 40 wt%. Examples of suitable salts are for example
soluble salts such as acetate, citrate, urea. The use of these materials can advantageously
lead to improved structuring and/or improved dissolution properties of the smooth
phase.
[0025] The smooth region of the tablet may also contain diluent materials for example polyethyleneglycol,
dipropyleneglycol, isopropanol or (mono-)propyleneglycol. Preferable the level of
these diluents is from 0 to 40 wt%, more preferred 1 to 20, most preferred from 4
to 15 wt% based on the weight of the smooth phase.
[0026] The smooth phase comprises no or only low levels of water. Preferably the level of
water is less than 20 wt % based on the weight of the smooth phase, more preferred
less than 15 wt%, most preferred from 5 to 12 wt%. Most preferably the smooth phases
are substantially free from water, which means that apart from low levels of moisture
(e.g. for neutralisation or as crystal water) no additional added water is present.
[0027] Preferably the total weight of surfactants in the smooth phase is from 2 to 20 grammes,
more preferred from 3 to 10 grammes.
[0028] Preferably the smooth phase comprises no or only low levels of ingredients such as
builders, bleach activators and bleach materials. Preferably the level of these ingredients
in the smooth phase is less than 5 wt%.
[0029] In a preferred embodiment of the invention the tablet may be a multi-phase tablet
wherein the phases other than the smooth phase as described above comprise no or only
low levels of surfactants. Preferably the level of surfactants in the other phases
is less than 10 wt%(based on the total weight of said phases), more preferred from
0 to 9 wt%, most preferred from 1 to 8 wt%.
[0030] In an advantageous embodiment of the invention the cleaning tablets comprise a first
smooth region (as described above) in combination with a second region of the tablet
which is a solid region, for example prepared by compression of a particulate composition.
[0031] Although the second region may comprise surfactant materials, this region preferably
comprises ingredients of the tablet other than surfactants. Examples of these ingredients
are for example builders, bleach system, enzymes etc. Preferably the builders in the
tablet are predominantly present in the second region. Preferably the bleach system
is predominantly present in the second region. Preferably the enzymes are predominantly
present in the second region. For the purpose of this invention, unless stated otherwise,
the term "predominantly present" refers to a situation wherein at least 90 wt% of
an ingredient is present in the second region, more preferred more than 98 wt%, most
preferred substantially 100 wt%.
[0032] The above description of the tablet has been given with reference to a tablet constituted
by two regions. It will however be understood that each of the regions may be composed
of a limited number of discrete regions. For example the first smooth region may be
a single discrete part of the tablet but may also be a limited number (say 1-5) discrete
smooth parts. Preferably each of these smooth parts are at least 1 gramme, also preferably
each of these smooth parts is substantially of the same composition. If reference
is made to the composition or weight of the first region it is understood that this
concerns the total weight and composition of these smooth parts.
[0033] Similarly the solid second region may be composed of a limited number (say 1-5) of
solid parts e.g. separate layers in the tablet. Preferably each of these parts has
a weight of at least 10 grammes, also preferably each of the solid parts is substantially
of the same composition. If reference is made to the composition or weight of the
second region it is understood that this concerns the total weight and composition
of these solid parts.
[0034] In addition to the smooth first region and the solid second region the cleaning tablets
of the invention may optionally comprise further regions, for example the tablet may
be partly or wholly coated.
[0035] Cleaning tablets according to the invention are preferably manufactured by firstly
preparing a smooth part. Advantageously the preparation of the smooth phase may include
the heating of the cleaning material followed by cooling. Advantageously the preparation
of the cleaning material may involve extrusion.
[0036] Extrusion processes for washing articles are known, for example WO 01/02532 describes
the extrusion of washing articles with a pressure of less than 10 bar.
[0037] Preferably extrusion processes will involve the forming of an extrudable mass which
is then subsequently extruded from an extrusion device and optionally then partitioned
into parts of the desired size and weight. Optionally the smooth parts may then be
hardened.
[0038] In accordance to the invention the partitioning involves a high frequency cutting
or jet cutting process. Examples of high frequency cutting processes are ultrasonic
cutting and focused energy cutting for example by using focused laser light or ultrasound.
Examples of jet cutting are air or water jet cutting.
[0039] Ultrasonic cutting devices are for example described in EP 783 399 and US 6070509
and generally involve an oscillating cutting device e.g. a vibrating knife. Ultrasonic
cutting machines may for example operate at oscillating frequencies of between 10
and 50 kHz, more preferred 20 to 40 kHz.
[0040] Focused energy cutting generally uses focussed beams of high frequency radiation
such as ultrasound or light (e.g. laser light such as for example from a CO
2 laser). Examples of laser devices for cutting are described in WO 00/48764, EP1083019
and WO 01/38242.
[0041] Jet cutting processes involve the focused application of flows of liquid of gases
for example air or other gases such as CO
2 or nitrogen or liquids such as for example water or propylene glycol. Typically the
pressure of the flow will be from 6.9·10
4 to 6.9·10
5 kPa (10000 to 100000 psi), more preferred 1.38·10
5 to 5.52·10
5 kPa (20000 to 80000 psi), most preferred from 2.07·10
5 to 3.45·10
5 kPa (30000 t0 50000 psi) (1 psi corresponds to 6.9 kPa). Preferably the diameter
of the flow jets is from 0.025 mm to 0.25 mm, more preferred from 0.08 to 0.20 mm,
most preferred from 0.1 to 0.15 mm. Examples of liquid cutting devices are for example
described in WO00/69290 and US4640300. Examples of gas cutting devices are described
in US 4471895. Preferably if air or steam is used as the cutting gas it is used a
elevated temperature of from 50 to 500°C, more preferred from 60 to 250 °C.
[0042] The extrudable mass preferably has before extrusion an initial elevated temperature
for example from 60 to 120°C, more preferred from 70 to 90°C. Preferably the extrudable
mass is during the production of the smooth mass cooled e.g. to a final temperature
of 20°C and then extruded. If extrusion is used this low temperature may for example
be the temperature at the extrusion die for example from 10 to 40, preferably from
15 to 25, most preferred at ambient temperature (20°C).
[0043] After the production and the partitioning of the smooth part the cleaning tablet
of the invention may advantageously be made by a process comprising the steps of:
(a) inserting a particulate composition into a tablet mould
(b) inserting one or more smooth parts into said tablet mould
(c) compression of the particulate composition to form a compressed tablet comprising
discrete regions, wherein the first region is formed by said smooth parts and the
second region is formed by said compressed particulate composition.
[0044] Preferably step (a) takes place before step (b).
[0045] In a preferred embodiment of the invention the particulate composition is pre-compressed
at a force of 0.1 to 20 kN/cm
2 between steps (a) and (b) In another preferred embodiment the particulate composition
is flattened between steps (a) and (b).
[0046] Preferably the (co-)compression of the combination of the smooth and the solid region(s)
takes place at a force of from 0.05 to 20 kN/cm
2. Especially if the solid region has been pre-compressed the co-compression in step
(c) can advantageously be at a force of 0.1- 10 kN/cm
2, more preferred 0.5 to 5 kN/cm
2. If the solid region has not been pre-compressed, the co-compression preferably takes
place at a force of 1- 100 kN/cm
2, more preferred 2-50 kN/cm
2., most preferred 2-10 kN/cm
2.
[0047] One advantage of the method of the present invention is that the co-compression step
of (c) leads to good adherence of the first region to the second region and avoids
the need of applying an adhesive material between the smooth and solid region. Another
advantage of the method of the invention is that it can be carried out in a normal
tablet press without the need of adaptation of the shape of the pressing surfaces.
[0048] A tablet of this invention may be intended for use in machine dishwashing. Such a
tablet is likely to contain surfactant in a low concentration such as 0.5 to 2 wt%
based on the whole tablet, although higher concentrations ranging up to 10 wt% may
be used. Such will typically contain salts, such as over 60 wt%, often over 85 wt%
of the tablet.
[0049] Water soluble salts typically used in machine dishwashing compositions are phosphates
(including condensed phosphates) carbonates and silicates, generally as alkali metal
salts. Water soluble alkali metal salts selected from phosphates, carbonates and silicates
may provide 60 wt% or more of a dishwashing composition.
[0050] Another preferred possibility is that a tablet of this invention will be intended
for fabric washing. In this event the tablet will be likely to contain at least 2
wt%, probably at least 5 wt%, up to 40 or 50 wt% non-soap surfactant based on the
whole tablet, and from 5 to 80 wt% detergency builder, based on the whole tablet.
[0051] Materials which may be used in tablets of this invention will now be discussed in
more detail.
Surfactant Compounds
[0052] Compositions which are used in tablets of the invention will contain one or more
detergent surfactants. In a fabric washing composition, these preferably provide from
5 to 50% by weight of the overall tablet composition, more preferably from 8 or 9%
by weight of the overall composition up to 40% or 50% by weight. Surfactant may be
anionic (soap or non-soap), cationic, zwitterionic, amphoteric, nonionic or a combination
of these.
[0053] Anionic surfactant may be present in an amount from 0.5 to 50% by weight, preferably
from 2% or 4% up to 30% or 40% by weight of the tablet composition.
[0054] Synthetic (i.e. non-soap) anionic surfactants are well known to those skilled in
the art. Examples include alkylbenzene sulphonates, particularly sodium linear alkylbenzene
sulphonates having an alkyl chain length of C
8-C
15; olefin sulphonates; alkane sulphonates; dialkyl sulphosuccinates; and fatty acid
ester sulphonates.
[0055] Primary alkyl sulphate having the formula
ROSO
3- M
+
in which R is an alkyl or alkenyl chain of 8 to 18 carbon atoms especially 10 to 14
carbon atoms and M
+ is a solubilising cation, is commercially significant as an anionic surfactant. Linear
alkyl benzene sulphonate of the formula
where R is linear alkyl of 8 to 15 carbon atoms and M
+ is a solubilising cation, especially sodium, is also a commercially significant anionic
surfactant.
[0056] Frequently, such linear alkyl benzene sulphonate or primary alkyl sulphate of the
formula above, or a mixture thereof will be the desired anionic surfactant and may
provide 75 to 100 wt% of any anionic non-soap surfactant in the composition.
[0057] In some forms of this invention the amount of non-soap anionic surfactant lies in
a range from 5 to 20 wt% of the tablet composition.
[0058] Soaps for use in accordance to the invention are preferably sodium soaps derived
from naturally occurring fatty acids, for example, the fatty acids from beef tallow.
[0059] Suitable nonionic surfactant compounds which may be used include in particular the
reaction products of compounds having a hydrophobic group and a reactive hydrogen
atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene
oxides, especially ethylene oxide.
[0060] Specific nonionic surfactant compounds are alkyl (C
8-22) phenol-ethylene oxide condensates, the condensation products of linear or branched
aliphatic C
8-20 primary or secondary alcohols with ethylene oxide, and products made by condensation
of ethylene oxide with the reaction products of propylene oxide and ethylene-diamine.
[0061] Especially preferred are the primary and secondary alcohol ethoxylates, especially
the C
9-11 and C
12-15 primary and secondary alcohols ethoxylated with an average of from 5 to 20 moles
of ethylene oxide per mole of alcohol.
[0062] In some fabric washing tablets of this invention, the amount of nonionic surfactant
lies in a range from 4 to 40%, better 4 or 5 to 30% by weight of the whole tablet.
[0063] Many nonionic surfactants are liquids. These may be absorbed onto particles of the
composition.
[0064] In a machine dishwashing tablet the surfactant may be wholly nonionic, in an amount
below 5 wt% of the whole tablet although it is known to include some anionic surfactant
and to use up to 10 wt% surfactant in total.
Detergency Builder
[0065] A composition which is used in tablets of the invention will usually contain from
5 to 80%, more usually 15 to 60% by weight of detergency builder. This may be provided
wholly by water soluble materials, or may be provided in large part or even entirely
by water-insoluble material with water-softening properties. Water-insoluble detergency
builder may be present as 5 to 80 wt%, better 5 to 60 wt% of the composition.
[0066] Alkali metal aluminosilicates are strongly favoured as environmentally acceptable
water-insoluble builders for fabric washing. Alkali metal (preferably sodium) aluminosilicates
may be either crystalline or amorphous or mixtures thereof, having the general formula:
0.8 - 1.5 Na
2O.Al
2O
3. 0.8 - 6 SiO
2. xH
2O
[0067] These materials contain some bound water (indicated as "xH2O") and are required to
have a calcium ion exchange capacity of at least 50 mg CaO/g. The preferred sodium
aluminosilicates contain 1.5-3.5 SiO
2 units (in the formula above). Both the amorphous and the crystalline materials can
be prepared readily by reaction between sodium silicate and sodium aluminate, as amply
described in the literature.
[0068] Suitable crystalline sodium aluminosilicate ion-exchange detergency builders are
described, for example, in GB 1429143 (Procter & Gamble). The preferred sodium aluminosilicates
of this type are the well known commercially available zeolites A and X, the novel
zeolite P described and claimed in EP 384070 (Unilever) and mixtures thereof.
[0069] Conceivably a water-insoluble detergency builder could be a layered sodium silicate
as described in US 4664839.
NaSKS-6 is the trademark for a crystalline layered silicate marketed by Hoechst (commonly
abbreviated as "SKS-6"). NaSKS-6 has the delta-Na
2SiO
5 morphology form of layered silicate. It can be prepared by methods such as described
in DE-A-3,417,649 and DE-A-3,742,043. Other such layered silicates, such as those
having the general formula NaMSi
xO
2x+1.yH
2O wherein M is sodium or hydrogen, x is a number from 1.9 to 4, preferably 2, and
y is a number from 0 to 20, preferably 0 can be used.
[0070] Water-soluble phosphorous-containing inorganic detergency builders, include the alkali-metal
orthophosphates, metaphosphates, pyrophosphates and polyphosphates. Specific examples
of inorganic phosphate builders include sodium and potassium tripolyphosphates, orthophosphates
and hexametaphosphates.
[0071] Non-phosphorous water-soluble builders may be organic or inorganic. Inorganic builders
that may be present include alkali metal (generally sodium) carbonate; while organic
builders include polycarboxylate polymers, such as polyacrylates, acrylic/maleic copolymers,
and acrylic phosphonates, monomeric polycarboxylates such as citrates, gluconates,
oxydisuccinates, glycerol mono- di- and trisuccinates, carboxymethyloxysuccinates,
carboxymethyloxymalonates, dipicolinates and hydroxyethyliminodiacetates.
[0072] At least one region (preferably the second region) of a fabric washing tablet preferably
include polycarboxylate polymers, more especially polyacrylates and acrylic/maleic
copolymers which can function as builders and also inhibit unwanted deposition onto
fabric from the wash liquor.
Bleach System
[0073] Tablets according to the invention may contain a bleach system in at least one region
of a tablet, preferably in the second region. This preferably comprises one or more
peroxy bleach compounds, for example, inorganic persalts or organic peroxyacids, which
may be employed in conjunction with activators to improve bleaching action at low
wash temperatures. If any peroxygen compound is present, the amount is likely to lie
in a range from 10 to 25% by weight of the composition.
[0074] Preferred inorganic persalts are sodium perborate monohydrate and tetrahydrate, and
sodium percarbonate, advantageously employed together with an activator. Bleach activators,
also referred to as bleach precursors, have been widely disclosed in the art. Preferred
examples include peracetic acid precursors, for example, tetraacetylethylene diamine
(TAED), now in widespread commercial use in conjunction with sodium perborate; and
perbenzoic acid precursors. The quaternary ammonium and phosphonium bleach activators
disclosed in US 4751015 and US 4818426 (Lever Brothers Company) are also of interest.
Another type of bleach activator which may be used, but which is not a bleach precursor,
is a transition metal catalyst as disclosed in EP-A-458397, EP-A-458398 and EP-A-549272.
A bleach system may also include a bleach stabiliser (heavy metal sequestrant) such
as ethylenediamine tetramethylene phosphonate and diethylenetriamine pentamethylene
phosphonate.
[0075] As indicated above, if a bleach is present and is a water-soluble inorganic peroxygen
bleach, the amount may well be from 10% to 25% by weight of the composition.
Other Detergent Ingredients
[0076] The detergent tablets of the invention may also contain (preferably in the second
region) one of the detergency enzymes well known in the art for their ability to degrade
and aid in the removal of various soils and stains. Suitable enzymes include the various
proteases, cellulases, lipases, amylases, and mixtures thereof, which are designed
to remove a variety of soils and stains from fabrics. Examples of suitable proteases
are Maxatase (Trade Mark), as supplied by Gist-Brocades N.V., Delft, Holland, and
Alcalase (Trade Mark), and Savinase (Trade Mark), as supplied by Novo Industri A/S,
Copenhagen, Denmark. Detergency enzymes are commonly employed in the form of granules
or marumes, optionally with a protective coating, in amount of from about 0.1% to
about 3.0% by weight of the composition; and these granules or marumes present no
problems with respect to compaction to form a tablet.
[0077] The detergent tablets of the invention may also contain (preferably in the second
region) a fluorescer (optical brightener), for example, Tinopal (Trade Mark) DMS or
Tinopal CBS available from Ciba-Geigy AG, Basel, Switzerland. Tinopal DMS is disodium
4,4'bis-(2-morpholino-4-anilino-s-triazin-6-ylamino) stilbene disulphonate; and Tinopal
CBS is disodium 2,2'-bis-(phenyl-styryl) disulphonate.
[0078] An antifoam material is advantageously included (preferably in the second region),
especially if a detergent tablet is primarily intended for use in front-loading drum-type
automatic washing machines. Suitable antifoam materials are usually in granular form,
such as those described in EP 266863A (Unilever). Such antifoam granules typically
comprise a mixture of silicone oil, petroleum jelly, hydrophobic silica and alkyl
phosphate as antifoam active material, absorbed onto a porous absorbed water-soluble
carbonate-based inorganic carrier material. Antifoam granules may be present in an
amount up to 5% by weight of the composition.
[0079] It may also be desirable that a detergent tablet of the invention includes an amount
of an alkali metal silicate, particularly sodium ortho-, meta- or disilicate. The
presence of such alkali metal silicates at levels, for example, of 0.1 to 10 wt%,
may be advantageous in providing protection against the corrosion of metal parts in
washing machines, besides providing some measure of building and giving processing
benefits in manufacture of the particulate material which is compacted into tablets.
[0080] A tablet for fabric washing will generally not contain more than 15 wt% silicate.
A tablet for machine dishwashing will often contain more than 20 wt% silicate. Preferably
the silicate is present in the second region of the tablet.
[0081] Further ingredients which can optionally be employed in a region of a fabric washing
detergent of the invention tablet (preferably the second region) include anti-redeposition
agents such as sodium carboxymethylcellulose, straight-chain polyvinyl pyrrolidone
and the cellulose ethers such as methyl cellulose and ethyl hydroxyethyl cellulose,
fabric-softening agents; heavy metal sequestrants such as EDTA; perfumes; and colorants
or coloured speckles.
[0082] Further ingredients which can optionally be used in tablets of the invention, preferably
in the second region are dispersing aids. Examples of suitable dispersing aids are
water-swellable polymers (e.g. SCMC) highly soluble materials (e.g. sodium citrate,
potassium carbonate or sodium acetate) or sodium tripolyphospate with preferably at
least 40% of the anhydrous phase I form.
Particle Size and Distribution
[0083] The second region of a detergent tablet of this invention, is a preferably a matrix
of compacted particles.
[0084] Preferably the particulate composition has an average particle size in the range
from 200 to 2000 µm, more preferably from 250 to 1400 µm. Fine particles, smaller
than 180 µm or 200 µm may be eliminated by sieving before tableting, if desired, although
we have observed that this is not always essential.
[0085] While the starting particulate composition may in principle have any bulk density,
the present invention is especially relevant to tablets made by compacting powders
of relatively high bulk density, because of their greater tendency to exhibit disintegration
and dispersion problems. Such tablets have the advantage that, as compared with a
tablet derived from a low bulk density powder, a given dose of composition can be
presented as a smaller tablet.
[0086] Thus the starting particulate composition may suitably have a bulk density of at
least 400 g/l, preferably at least 500 g/l, and perhaps at least 600 g/l.
[0087] Tableting machinery able to carry out the manufacture of tablets of the invention
is known, for example suitable tablet presses are available from Fette and from Korch.
[0088] Tableting may be carried out at ambient temperature or at a temperature above ambient
which may allow adequate strength to be achieved with less applied pressure during
compaction. In order to carry out the tableting at a temperature which is above ambient,
the particulate composition is preferably supplied to the tableting machinery at an
elevated temperature. This will of course supply heat to the tableting machinery,
but the machinery may be heated in some other way also.
[0089] The size of a tablet will suitably range from 10 to 160 grams, preferably from 15
to 60 g, depending on the conditions of intended use, and whether it represents a
dose for an average load in a fabric washing or dishwashing machine or a fractional
part of such a dose. The tablets may be of any shape. However, for ease of packaging
they are preferably blocks of substantially uniform cross-section, such as cylinders
or cuboids. The overall density of a tablet preferably lies in a range from 1040 or
1050g/l up to 1600g/l.
Example 1
[0090] 7 kg of anionic surfactant (Dobanic acid 103 ex Shell) and 6kg of nonionic surfactant
(Lutensol AO7 ex BASF) were mixed and neutralised to a pH of 9 using a 50% NaOH solution.
[0091] 10 wt% (based on the weight of neutralised blend) of C16/C18 soap fatty acid was
added. 5 to 10 wt% (based on the weight of neutralised blend) dipropylene glycol (ex
Vopak) was also added to the mixture. The mixture was further neutralised with a 50%
NaOH solution to a pH of 11.
[0092] After neutralisation to pH of 11, the mixture was pumped into a sequence of 2 stainless
steel tubes by a Maag Sinox P7 pump or a piston pump, type SIBa HK 05016SST4000M000
ex Prominent, Vleuten (NL). Both tubes were double jacketed. The first tube was 2.5m
long and had an inner diameter of 73mm. The second tube was 1.5m long and had an inner
diameter of 45mm. The tubes were connected by a 10cm long pipe.
[0093] The mixture was pumped into the tubes at a temperature of 85°C at a throughput of
4 kg/hr. The first tube was cooled using a water bath at 40°C. The second tube was
cooled using a 50:50 weight mixture of ethylene glycol and water. The coolant temperature
was -15°C. The material coming out of the second tube had a temperature of about 20°C
and was collected and divided into bars of around 0.5m.
[0094] After storage the bars can for example be cut into slices of 5 grammes each by using
a laser cutting device (CO
2 laser) an acoustic knife (oscillating at 25kHz) a water jet (operating at 25000 psi
and with a diameter of 0.1 mm).
[0095] The use of high frequency or jet cutting leads to a very smooth finished surface
of the smooth phase.
Example II: multi-phase tablets
[0096] A detergent powder was made of the following composition by pregranulating the granule
ingredients, followed by post-dosing the rest of the ingredients
Ingredient |
Parts by weight |
Granules |
|
Na-las |
1.1 |
Nonionic 7EO |
0.5 |
C12 soap |
0.1 |
NaAc.3aq |
0.3 |
Zeolite A24 |
2.4 |
Light soda ash |
0.4 |
Moisture/minors |
0.4 |
Post-dose |
|
EAG (17% silicone) |
3.0 |
Fluorescer (15%) |
2.2 |
STP |
62.4 |
Na-disilicate (80%) |
3.8 |
TAED (83%) |
4.3 |
Percarbonate |
16.9 |
Dequest 2047 |
1.9 |
Minors/ enzymes/colour |
to 100 |
[0097] Smooth parts of 5 gramme were prepared as in example 1
[0098] The tablets were made in 2 different ways:
(I) 20 grammes of the powder are inserted into a 45 mm die of a tabletting machine,
optionally followed by a flattening step, followed by addition of a single smooth
part on top of the powder bed. After addition of the smooth onto the powder bed or
flattened powder, the whole material is compressed at 30kN into a single tablet, followed
by ejection of the tablet. This results in a tablet with a smooth part embedded in
the cleaning tablet. The density of the powdered region is 1.5 kg/l, the density of
the smooth part is 1.0 kg/l. The height of the smooth part after compression is 3.4
mm, of the powdered part 11 mm.
(II) Another way of making a tablet with compressed smooth part is to put a single
smooth part as above onto 20 grammes of the (optionally pre-compressed at 4 kN) powdered
composition in a die of 45 mm diameter followed by a final compression step at 30
kN. During the final compression step, the smooth part flows by the compaction forces
to form a 3.4 mm smooth layer adhered on top of the particulate layer. The density
of the powdered region is 1.5 kg/l, the density of the smooth part is 1.0 kg/l. The
height of the powdered part after compression is 11 mm.
1. Verfahren zur Herstellung einer eine glatte Phase umfassenden Reinigungstablette,
wobei die Herstellung der glatten Phase den Schritt von Hochfrequenzschneiden oder
Strahlschneiden eines Reinigungsmaterials umfasst.
2. Verfahren nach Anspruch 1, wobei das Reinigungsmaterial 10 bis 90 Gewichtsprozent
Nichtseifentenside und 0 bis 20 Gewichtsprozent Wasser umfasst.
3. Verfahren nach Anspruch 1, wobei die Reinigungstablette eine glatte Einphasentablette
mit einem Gewicht von 5 bis 200 g, bevorzugter 10 bis 100 g, besonders bevorzugt 15
bis 35 g, ist.
4. Verfahren nach Anspruch 1, wobei die Reinigungstablette eine Mehrphasentablette ist,
die eine glatte Phase als einen unterscheidbaren Bereich mit einem Gewicht von 2 bis
20 g, bevorzugter 3 bis 10 g, umfasst.
5. Verfahren nach Anspruch 1, wobei die Hochfrequenzschneideverfahren aus Ultraschallschneiden
und gerichtetem Energieschneiden ausgewählt sind.
6. Verfahren nach Anspruch 5, wobei die Ultraschallschneidevorrichtung bei Frequenzen
zwischen 10 und 50 kHz, bevorzugter 20 bis 40 kHz, arbeitet.
7. Verfahren nach Anspruch 5, wobei das gerichtete Energieschneiden gerichtete Strahlen
von Ultraschall oder Licht, vorzugsweise Laserlicht, anwendet.
8. Verfahren nach Anspruch 1, wobei das Strahlschneiden die gerichtete Anwendung von
Flüssigkeitsströmen, wie beispielsweise Wasser oder Propylenglycol, beinhaltet.
9. Verfahren nach Anspruch 1, wobei das Strahlschneiden die gerichtete Anwendung von
Gasströmen, wie beispielsweise Luft, Dampf oder Stickstoff, beinhaltet.
10. Verfahren nach Anspruch 8 oder 9, wobei der Druck des Stroms 6,9 · 104 bis 6,9 · 105 kPa (10000 bis 100000 psi), bevorzugter 1,38 · 105 bis 5,52 · 105 kPa (20000 bis 80000 psi), besonders bevorzugt 2,07 · 105 bis 3,45 · 105 kPa (30000 bis 50000 psi), ist, und der Durchmesser der Ströme 0,025 mm bis 0,25
mm, bevorzugter 0,08 bis 0,20 mm, besonders bevorzugt 0,1 bis 0,15 mm, ist.
1. Procédé de production d'une pastille détergente comprenant une phase lisse, dans lequel
la préparation de la phase lisse comprend l'étape de découpe à haute fréquence ou
de découpe au jet d'un matériau détergent.
2. Procédé selon la revendication 1, dans lequel le matériau détergent comprend de 10
à 90 % en poids de tensioactifs non savonneux et de 0 à 20 % en poids d'eau.
3. Procédé selon la revendication 1, dans lequel la pastille détergente est une pastille
lisse monophase ayant un poids de 5 à 200 grammes, de préférence de 10 à 100 grammes,
mieux encore de 15 à 35 grammes.
4. Procédé selon la revendication 1, dans lequel la pastille détergente est une pastille
multiphases comprenant la phase lisse en tant qu'une région distincte ayant un poids
de 2 à 20 grammes, mieux de 3 à 10 grammes.
5. Procédé selon la revendication 1, dans lequel les processus de découpe à haute fréquence
sont sélectionnés parmi la découpe aux ultrasons et la découpe par énergie focalisée.
6. Procédé selon la revendication 5, dans lequel l'appareil de découpe aux ultrasons
fonctionne à des fréquences entre 10 et 50 kHz, mieux de 20 à 40 kHz.
7. Procédé selon la revendication 5, dans lequel la découpe par énergie focalisée utilise
des faisceaux focalisés d'ultrasons ou de lumière, de préférence de lumière laser.
8. Procédé selon la revendication 1, dans lequel la découpe au jet met en oeuvre l'application
focalisée de flux de liquides, tels que par exemple de l'eau ou du propylène glycol.
9. Procédé selon la revendication 1, dans lequel la découpe au jet met en oeuvre l'application
focalisée de flux de gaz, tels que par exemple de l'air, de la vapeur ou de l'azote.
10. Procédé selon la revendication 8 ou 9, dans lequel la pression du flux est de 6,9
. 104 à 6,9 . 105 kPa (10000 à 100000 psi), de préférence de 1,38 . 105 à 5,52 . 105 kPa (20000 à 80000 psi), mieux encore de 2,07 . 105 à 3,45 . 105 kPa (30000 à 50000 psi), et le diamètre des flux est de 0,025 mm à 0,25 mm, de préférence
de 0,08 à 0,20 mm, mieux encore de 0,1 à 0,15 mm.