Technical field
[0001] The present invention relates to coating compositions for solid bodies, in particular
to coating compositions for solid bodies in the form of tablets, capsules, micro-tablets,
powders, agglomerates and the like. In particular, it relates to coating compositions
for solid bodies having improved dissolution characteristics together with excellent
strength, surface hardness and storage stability. The coated solid bodies are suitable
for a variety of uses including pharmaceuticals; food and nutrition, such as multi-vitamin
tablets, sweeteners; mouthwash; denture cleaning; general cleaners and disinfectants;
beauty care, for example bathing additives; agriculture, for example fertilizers;
and the like. In the following, however, the invention will be primarily described
in terms of detergent tablets.
Background
[0002] Compositions in tablet form are well known in the art. Tablets hold several advantages
over liquid and particulate composition forms, such as ease of dosing, handling, transportation
and storage. Two main issues can still be improved in tablet formulation: dissolution
rate and tablet strength. The most usual way to make tablets is by compression of
particulate solids usually with a binder. However, a dichotomy exists in that as compression
force is increased, the rate of dissolution of the tablets becomes slower. A low compression
force, on the other hand, improves dissolution but at the expense of tablet strength.
The presence of an external coating can enhance the tablet strength, allowing tabletting
at a reduced compaction force which in turn enhances the speed of disintegration of
a tablet. While tablets without a coating can be entirely effective in use, they usually
lack the necessary surface hardness to withstand the abrasion that is a part of normal
manufacture, packaging and handling. The result is that uncoated tablets can suffer
from abrasion during these processes, resulting in chipped tablets and loss of active
material. Also, especially in the case of highly alkaline compositions, the outer
surface of an uncoated tablet may be aggressive to the skin and even somewhat hazardous
to handle. In such cases, tablet coating is highly desirable. Finally, coating of
tablets is often desired for aesthetic reasons, to improve the outer appearance of
the tablet or to achieve some particular aesthetic effect.
[0003] Coatings for medicinal agents comprising a mixed ester of a lower fatty acid, a dibasic
acid and polyvinyl alcohol are disclosed in JP-B-66 013 996, published on 31
st August 1993. PVA having a degree of polymerisation between 200 and 2000 esterified
with 40-60 mole % with fatty acid and 60-40 mole % with dibasic acid is disclosed.
[0004] Numerous methods of tablet coating have been proposed for detergent tablets. GB-A-983,243
and GB-A-989,638 describe the use of a readily water-soluble organic film forming
polymer as a coating material for detergent tablets to make the tablet resistant to
abrasion and accidental breakage. The polymeric film is formed by spraying the tablet
with an aqueous solution containing between 10 and 25% of polyalcohol and then drying
with forced air, heated air or infra-red rays to harden the coating and evaporate
the solvent.
[0005] GB-A-1,013,686 discloses a detergent tablet surrounded by a coating of an organic
water-dispersible binder selected from of vinyl alcohol homopolymers and copolymers.
[0006] US-A-5,916,866 describes tablets with a coating of a film-forming water-soluble organic
polymer selected from the group consisting of polyethelene glycol, copolymers of vinyl
pyrrolidone and vinyl acetate, and copolymers of maleate and acrylate.
[0007] US-A-4,219,435 discloses a detergent tablet provided with a coating of a hydrated
salt having a melting point in the range from 30°C to 95°C, such coating being applied
to the tablet in the form of a melt.
[0008] Polymer film-coatings as those described in the prior art usually exhibit good mechanical
properties (i.e. strength and elasticity) but they have relatively poor dissolution
characteristics in water. Film coatings can tend to slow down the dissolution rate
of the tablet by opposing water penetration into the tablet core.
[0009] Hydrated salt coatings have a crystalline structure and present a very fast disintegration
rate in contact with water. However, they are relatively weak and brittle due to their
crystalline nature. Therefore, these coatings do not generally provide good tablet
integrity.
[0010] As can be seen from the prior art, there is still a need to provide tablets having,
at one and the same time, good dissolution rate, surface hardness, strength and integrity.
The object of the present invention, therefore, is to provide coated tablets and other
solid forms having good mechanical properties as well as having excellent dissolution
and disintegration characteristics.
Summary of the invention
[0011] In a first embodiment, the present invention provides coating compositions for solid
bodies, such as tablets, comprising an ester formed by the esterification or trans-esterification
product of a compound having an alcohol or ester function with an acid selected from
the group consisting of dicarboxylic acid, polyacid, oligoacid, or mixtures thereof,
wherein the weight ratio of the ester to the unreacted acid is less than 1:3. Preferably
the weight ratio is between 1:100 and 1:5, preferably between 1:50 and 1:10. Preferred
alcohol or ester functional compounds are fully or partly hydrolised polyvinyl alcohol,
or polyvinyl acetate, most preferably having a molecular weight between 10 000 and
200 000, preferably between 20 000 and 100 000.
[0012] In a second embodiment, the present invention provides coating compositions for solid
bodies, such as tablets, comprising the salt formed by the neutralisation product
of an alkali with an acid selected from the group consisting of dicarboxylic acid,
oligoacid, polyacid, or mixtures thereof, wherein the weight ratio of the salt to
the unreacted acid is less than 1:3. Preferably the weight ratio is between 1:100
and 1:5, preferably between 1:50 and 1:10. Preferred alkalis are sodium, potassium,
calcium, or magnesium salts of citrate, acetate or hydroxide.
[0013] According to the invention, the coating compositions comprise a substantially insoluble
dicarboxylic acid and optionally comprises a disintegrant and optionally a component
which is liquid at 25°C.
[0014] The coating compositions of the present invention comprise dicarboxylic acids. Particularly
suitable dicarboxylic acids are selected from the group consisting of oxalic acid,
malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid,
azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic
acid and mixtures thereof. Most preferred is adipic acid.
[0015] Typically, substantially insoluble materials having a melting point below 40 °C are
not sufficiently solid at ambient temperatures and it has been found that materials
having a melting point above about 200 °C are less practicable to use. Preferably,
an acid having a melting point of more than 90°C such as azelaic, sebacic acid, dodecanedioic
acid is used. An acid having a melting point of more than 145°C such as adipic acid
is particularly suitable.
[0016] By "melting point" is meant the temperature at which the material when heated slowly
in, for example, a capillary tube becomes a clear liquid.
[0017] A coating of any desired thickness can be applied. For most purposes, the coating
forms from 1% to 10%, preferably from 1.5% to 5%, of the tablet weight. Tablet coatings
are very hard and provide extra strength to the tablet.
[0018] In order to promote the dissolution of the coated solid body, a disintegrant can
optionally be included in the core and/or the coating. The disintegrant will swell
once in contact with water, helping to break the solid body and/or the coating. Suitable
disintegrants are described in Handbook of Pharmaceutical Excipients (1986) and include
effervescent agents and water-insoluble polymeric disintegrants as well as cation
exchange resins and highly soluble components as described below. Examples of suitable
disintegrants include starch: natural, modified or pregelatinized starch, sodium starch
gluconate; gum: agar gum, guar gum, locust bean gum, karaya gum, pectin gum, tragacanth
gum; croscarmylose Sodium, crospovidone, cellulose, algenic acid and its salts including
sodium alginate, silicon dioxide, clay, ion exchange resins, polymers containing cationic
(e.g. quaternary ammonium) groups, amine-substituted polyacrylates, polymerised cationic
amino acids such as poly-L-lysine, polyallylamine hydrochloride) and mixtures thereof.
Suitable effervescent agents for use herein include perborate, percarbonate, carbonate
and bicarbonate in combination with an inorganic acid such as sulphamic acid or a
carboxylic acid such as citric or maleic acid. Preferred herein is a (bi)carbonate/acid
effervescent system.
[0019] Examples of optional components which are liquid at 25° are including polyethylene
glycols, thermal oil, silicon oil, esters of dicarboxylic acids, mono carboxylic acids,
paraffin, triacetin, perfumes or alkaline solutions. It is preferred that the structure
of the components which is liquid at 25°C is close to the material forming the crystallised
structure, so that the structure is not excessively disrupted. More preferably, the
crystallised structure is made of adipic acid, the component which is liquid at 25°C
being available under the name Coasol™ from Chemoxy International, being a blend of
the di-isobutyl esters of the glutaric, succinic and adipic acid. The advantage of
the use of this component being the good dispersion in the adipic acid to provide
flexibility. It should be noted that disintegration of the adipic acid is further
improved by the adipate content of Coasol™. Fracture of the coating in the wash can
be improved by adding a disintegrant in the coating.
[0020] A particularly suitable coating composition, for use herein, comprises an acid having
a melting temperature of at least 145°C, such as adipic acid for example, as well
as a clay, such as a bentonite clay for example, whereby the clay is used as a disintegrant
and also to render the structure of adipic acid more favourable for water penetration,
thus improving the dispersion of the adipic acid in a aqueous medium. Preferred are
clays having a particle size of less than 75 µm, more preferably of less than 53 µm,
in order to obtain the desired effect on the structure of the acid. Preferred are
bentonite clays. Indeed the acid has a melting point such that traditional cellulosic
disintegrants undergo a thermal degradation during the coating process, whereas such
clays are found to be more heat stable. Further, traditional cellulosic disintegrant
such as Nymcel™ for example are found to turn brown at these temperatures.
[0021] In preferred embodiments of the invention the solid body is in the form of a single
or multi-phase detergent tablet, i.e., detergent tablets having a single or multi-phase
tablet core. Multi-phases tablets include tablets having multiple layers as well as
tablets having a depression or mould in the main body of the tablet and a compressed
or non-compressed portion contained within the depression or mould. In such embodiments,
the multi-phase tablet can comprises a partial coating which extends across one or
more phases of the core so as to provide differential dissolution or release of the
active components of the core.
[0022] The coating of the solid body is produced according to a process comprising the step
of contacting the body with the coating composition. Preferably the coating composition
comprises little water, and more preferably the coating composition is essentially
anhydrous. Preferred processes include coating baths and shower coatings. The solid
body may be provided with a continuous coating or, alternatively, the solid body may
be coated with a network of fibres, the meshes of which define the pores of the coating.
In the latter case there is provided a coated solid body comprising a core of an active
composition and having a porous water-soluble or dispersible fibre network coating
(sometimes referred to herein as a "net-coating"). Preferably, the net-coating has
an average mesh size in the range from about 5 µm to about 200 µm and preferably from
about 10 µm to about 100 µm. Pore size and mesh size are expressed as the square root
of the cross-sectional area of the pore or mesh in the plane of the coating.
[0023] The objective of the present invention is to provide coated detergent tablets and
other solid bodies with excellent dissolution characteristics as well as excellent
mechanical properties. This is achieved by coating the solid body. The composition
of the invention preferable take the form of a single or multi-phase detergent tablet
and can include one or more active and auxiliary components of detergent tablets as
described in detail below.
[0024] Auxiliary coating materials
[0025] The compositions herein can include an auxiliary coating, between the solid body
and the coating, comprising a crystallised structure. By crystallised, it should be
understood that the coating comprises a material which is solid at ambient temperature
(25°C) and has a structure exhibiting some order. This can be detected typically by
usual crystallography techniques e.g. X-ray analysis, on the material itself. Preferably,
the material forming the crystallised structure does not co-crystallised or only partially
with the optional component which is liquid at 25°C mentioned above. Indeed, it is
preferred that the optional component remains in the liquid state at 25°C in the coating
crystalline structure in order to provide flexibility to the structure and resistance
to mechanical stress. The optional component which is liquid at 25°C may advantageously
have a functionality in the washing of laundry, for example silicone oil which provides
suds suppression benefits or perfume oil.
Highly soluble Compounds
[0026] The compositions herein can further comprise a highly soluble compound. Such a compound
could be formed from a mixture or from a single compound. A highly soluble compound
is defined as follow:
A solution is prepared as follows comprising de-ionised water as well as 20 grams
per litre of a specific compound:
1- 20 g of the specific compound is placed in a Sotax Beaker. This beaker is placed
in a constant temperature bath set at 10°C. A stirrer with a marine propeller is placed
in the beaker so that the bottom of the stirrer is at 5 mm above the bottom of the
Sotax beaker. The mixer is set at a rotation speed of 200 turn per minute.
2- 980 g of the de-ionised water is introduced into the Sotax beaker.
3- 10 s after the water introduction, the conductivity of the solution is measured,
using a conductivity meter.
4- Step 3 is repeated after 20, 30, 40, 50, 1min, 2 min, 5 min and 10 min after step
2.
5- The measurement taken at 10 min is used as the plateau value or maximum value.
The specific compound is highly soluble according to the invention when the conductivity
of the solution reaches 80% of its maximum value in less than 10 seconds, starting
from the complete addition of the de-ionised water to the compound. Indeed, when monitoring
the conductivity in such a manner, the conductivity reaches a plateau after a certain
period of time, this plateau being considered as the maximum value. Such a compound
is preferably in the form of a flowable material constituted of solid particles at
temperatures comprised between 10 and 80°Celsius for ease of handling, but other forms
may be used such as a paste or a liquid.
Example of highly soluble compounds include Sodium di isobutylbenzene sulphonate (DIBS)
or Sodium toluene sulphonate.
Cohesive Effect
[0027] The tablet may comprise a compound having a cohesive effect on the particulate material
of a detergent matrix forming the tablet. The cohesive effect on the particulate material
of a detergent matrix forming the tablet or a layer of the tablet is characterised
by the force required to break a tablet or layer based on the examined detergent matrix
pressed under controlled compression conditions. For a given compression force, a
high tablet or layer strength indicates that the granules stuck highly together when
they were compressed, so that a strong cohesive effect is taking place. Means to assess
tablet or layer strength (also refer to diametrical fracture stress) are given in
Pharmaceutical dosage forms : tablets volume 1 Ed. H.A. Lieberman et al, published
in 1989.
[0028] The cohesive effect is measured by comparing the tablet or layer strength of the
original base powder without compound having a cohesive effect with the tablet or
layer strength of a powder mix which comprises 97 parts of the original base powder
and 3 parts of the compound having a cohesive effect. The compound having a cohesive
effect is preferably added to the matrix in a form in which it is substantially free
of water (water content below 10% (pref. below 5%)). The temperature of the addition
is between 10° and 80°C, more pref. between 10° and 40°C.
[0029] A compound is defined as having a cohesive effect on the particulate material according
to the invention when at a given compacting force of 3000N, tablets with a weight
of 50g of detergent particulate material and a diameter of 55mm have their tablet
tensile strength increased by over 30% (preferably 60 and more preferably 100%) by
means of the presence of 3% of the compound having a cohesive effect in the base particulate
material.
[0030] An example of a compound having a cohesive effect is Sodium di isoalkylbenzene sulphonate.
[0031] When integrating a highly soluble compound having also a cohesive effect on the particulate
material used for a tablet or layer formed by compressing a particulate material comprising
a surfactant, the dissolution of the tablet or layer in an aqueous solution is significantly
increased.
[0032] It should be noted that a composition comprising a highly soluble compound as well
as a surfactant is disclosed in EP-A-0 524 075, this composition being a liquid composition.
[0033] A highly soluble compound having a cohesive effect on the particulate material allows
to obtain a tablet having a higher tensile strength at constant compacting force or
an equal tensile strength at lower compacting force when compared to traditional tablets.
Typically, a whole tablet will have a tensile strength of more than 5kPa, preferably
of more than 10kPa, more preferably, in particular for use in laundry applications,
of more than 15kPa, even more preferably of more than 30 kPa and most preferably of
more than 50 kPa, in particular for use in dish washing or auto dish washing applications;
and a tensile strength of less than 300 kPa, preferably of less than 200 kPa, more
preferably of less than 100 kPa, even more preferably of less than 80 kPa and most
preferably of less than 60 kPa. Indeed, in case of laundry application, the tablets
should be less compressed than in case of auto dish washing applications for example,
whereby the dissolution is more readily achieved, so that in a laundry application,
the tensile strength is preferably of less than 30 kPa.
[0034] This allows to produce tablets or layers which have a solidity and mechanical resistance
comparable to the solidity or mechanical resistance of traditional tablets while having
a less compact tablet or layer thus dissolving more readily. Furthermore, as the compound
is highly soluble, the dissolution of the tablet or layer is further facilitated,
resulting in a synergy leading to facilitated dissolution for a tablet according to
the invention.
Tablet Manufacture
[0035] The tablet may comprise several layers. For the purpose of manufacture of a single
layer, the layer may be considered as a tablet itself.
[0036] Detergent tablets can be prepared simply by mixing the solid ingredients together
and compressing the mixture in a conventional tablet press as used, for example, in
the pharmaceutical industry. Preferably the principal ingredients, in particular gelling
surfactants, are used in particulate form. Any liquid ingredients, for example surfactant
or suds suppressor, can be incorporated in a conventional manner into the solid particulate
ingredients.
[0037] In particular for laundry tablets, the ingredients such as builder and surfactant
can be spray-dried in a conventional manner and then compacted at a suitable pressure.
Preferably, the tablets according to the invention are compressed using a force of
less than 100000N, more preferably of less than 50000N, even more preferably of less
than 5000N and most preferably of less than 3000 N. Indeed, the most preferred embodiment
is a tablet suitable for laundry compressed using a force of less than 2500N, but
tablets for auto dish washing may also be considered for example, whereby such auto
dish washing tablets are usually more compressed than laundry tablets.
[0038] The particulate material used for making a tablet can be made by any particulation
or granulation process. An example of such a process is spray drying (in a co-current
or counter current spray drying tower) which typically gives low bulk densities 600g/l
or lower. Particulate materials of higher density can be prepared by granulation and
densification in a high shear batch mixer/granulator or by a continuous granulation
and densification process (e.g. using Lodige® CB and/or Lodige® KM mixers). Other
suitable processes include fluid bed processes, compaction processes (e.g. roll compaction),
extrusion, as well as any particulate material made by any chemical process like flocculation,
crystallisation sentering, etc. Individual particles can also be any other particle,
granule, sphere or grain.
[0039] The components of the particulate material may be mixed together by any conventional
means. Batch is suitable in, for example, a concrete mixer, Nauta mixer, ribbon mixer
or any other. Alternatively the mixing process may be carried out continuously by
metering each component by weight on to a moving belt, and blending them in one or
more drum(s) or mixer(s). Non-gelling binder can be sprayed on to the mix of some,
or all of, the components of the particulate material. Other liquid ingredients may
also be sprayed on to the mix of components either separately or premixed. For example
perfume and slurries of optical brighteners may be sprayed. A finely divided flow
aid (dusting agent such as zeolites, carbonates, silicas) can be added to the particulate
material after spraying the binder, preferably towards the end of the process, to
make the mix less sticky.
[0040] The tablets may be manufactured by using any compacting process, such as tabletting,
briquetting, or extrusion, preferably tabletting. Suitable equipment includes a standard
single stroke or a rotary press (such as Courtoy®, Korch®, Manesty®, or Bonals®).
The tablets prepared according to this invention preferably have a diameter of between
20mm and 60mm, preferably of at least 35 and up to 55 mm, and a weight between 25
and 100 g. The ratio of height to diameter (or width) of the tablets is preferably
greater than 1:3, more preferably greater than 1:2. The compaction pressure used for
preparing these tablets need not exceed 100000 kN/m
2, preferably not exceed 30000 kN/m
2, more preferably not exceed 5000 kN/m
2, even more preferably not exceed 3000kN/m
2 and most preferably not exceed 1000kN/m
2. Tablets usually have a density of at least 0.9 g/cm
3, more preferably of at least 1.0 g/cm
3, and preferably of less than 2.0 g/cm
3, more preferably of less than 1.5 g/cm
3, even more preferably of less than 1.25 g/cm
3 and most preferably of less than 1.1 g/cm
3.
Multi layered tablets are typically formed in rotating presses by placing the matrices
of each layer, one after the other in matrix force feeding flasks. As the process
continues, the matrix layers are then pressed together in the precompression and compression
stages stations to form the multilayer layer tablet. With some rotating presses it
is also possible to compress the first feed layer before compressing the whole tablet.
Hydrotrope compound
[0041] A highly soluble compound having a cohesive effect may be integrated to a detergent
tablet, whereby this compound is also a hydrotrope compound. Such hydrotrope compound
may be generally used to favour surfactant dissolution by avoiding gelling. A specific
compound is defined as being hydrotrope as follows (see S.E. Friberg and M. Chiu,
J. Dispersion Science and Technology, 9(5&6), pages 443 to 457, (1988-1989)):
1. A solution is prepared comprising 25% by weight of the specific compound and 75%
by weight of water.
2. Octanoic Acid is thereafter added to the solution in a proportion of 1.6 times
the weight of the specific compound in solution, the solution being at a temperature
of 20°Celsius. The solution is mixed in a Sotax beaker with a stirrer with a marine
propeller, the propeller being situated at about 5mm above the bottom of the beaker,
the mixer being set at a rotation speed of 200 rounds per minute.
3. The specific compound is hydrotrope if the the Octanoic Acid is completely solubilised,
i.e . if the solution comprises only one phase, the phase being a liquid phase.
[0042] The hydrotrope compound is preferably a flowable material made of solid particles
at operating conditions between 15 and 60° Celsius.
[0043] Hydrotrope compounds include the compounds listed thereafter:
A list of commercial hydrotropes could be found in McCutcheon's Emulsifiers and Detergents
published by the McCutcheon division of Manufacturing Confectioners Company. Compounds
of interest also include:
1. Nonionic hydrotrope with the following structure:
where R is a C8-C10 alkyl chain, x ranges from 1 to 15, y from 3 to 10.
2. Anionic hydrotropes such as alkali metal aryl sulfonates. This includes alkali
metal salts of benzoic acid, salicylic acid, bezenesulfonic acid and its many derivatives,
naphthoic acid and various hydroaromatic acids. Examples of these are sodium, potassium
and ammonium benzene sulfonate salts derived from toluene sulfonic acid, xylene sulfonic
acid, cumene sulfonic acid, tetralin sulfonic acid, naphtalene sulfonic acid, methyl-
naphtalene sulfonic acid, dimethyl naphtalene sulfonic acid and trimethyl naphtalene
sulfonic acid.
Other examples include salts of dialkyl benzene sulfonic acid such as salts of di-isopropyl
benzene sulfonic acid, ethyl methyl benzene sulfonic acid, alkyl benzene sulfonic
acid with an alkyl chain length with 3 to 10, (pref. 4 to 9), linear or branched alkyl
sulfonates with an alkyl chain with 1 to 18 carbons.
3. Solvent hydrotropes such as alkoxylated glycerines and alkoxylated glycerides,
esters slakoxylated glycerines, alkoxylated fatty acids, esters of glycerin, polyglycerol
esters. Preferred alkoxylated glycerines have the following structure:
where I, m and n are each a number from 0 to about 20, with l+m+n = from about 2
to about 60, preferably from about 10 to about 45 and R represents H, CH3 or C2H5
Preferred alkoxvlated glycerides have the following structure
where R1 and R2 are each CnCOO or -(CH2CHR3-O)I-H where R3 = H, CH3 or C2H5 and I is a number from 1 to about 60, n is a number from about 6 to about 24.
4. Polymeric hvdrotropes such as those described in EP636687:
where E is a hydrophilic functional group,
R is H or a C1-C10 alkyl group or is a hydrophilic functional group;
R1 is H a lower alkyl group or an aromatic group,
R2 is H or a cyclic alkyl or aromatic group.
The polymer typically has a molecular weight of between about 1000 and 1000000.
5. Hydrotrope of unusual structure such as 5-carboxy-4-hexyl-2-cyclohexene-1-yl octanoic
acid (Diacid®)
Use of such compound in the invention would further increase the dissolution rate
of the tablet, as a hydrotrope compound facilitates dissolution of surfactants, for
example. Such a compound could be formed from a mixture or from a single compound.
Tensile Strength
[0044] For the purpose of measuring tensile strength of a layer, the layer may be considered
as a tablet itself.
[0045] Depending on the composition of the starting material, and the shape of the tablets,
the used compacting force may be adjusted to not affect the tensile strength, and
the disintegration time in the washing or dishwashing machine. This process may be
used to prepare homogenous or layered tablets of any size or shape.
[0046] For a cylindrical tablet, the tensile strength corresponds to the diametrical fracture
stress (DFS) which is a way to express the strength of a tablet or layer, and is determined
by the following equation :
[0047] Where F is the maximum force (Newton) to cause tensile failure (fracture) measured
by a VK 200 tablet hardness tester supplied by Van Kell industries, Inc. D is the
diameter of the tablet or layer, and t the thickness of the tablet or layer. For a
non round tablet, πD may simply be replaced by the perimeter of the tablet.
(Method Pharmaceutical Dosage Forms : Tablets Volume 2 Page 213 to 217). A tablet
having a diametral fracture stress of less than 20 kPa is considered to be fragile
and is likely to result in some broken tablets being delivered to the consumer. A
diametral fracture stress of at least 25 kPa is preferred.
[0048] This applies similarly to non cylindrical tablets, to define the tensile strength,
whereby the cross section normal to the height of the tablet is non round, and whereby
the force is applied along a direction perpendicular to the direction of the height
of the tablet and normal to the side of the tablet, the side being perpendicular to
the non round cross section.
Tablet Dispensing
[0049] The rate of dispensing of a detergent tablet can be determined in the following way:
Two tablets, nominally 50 grams each, are weighed, and then placed in the dispenser
of a Baucknecht® WA9850 washing machine. The water supply to the washing machine is
set to a temperature of 20 °C and a hardness of 21 grains per gallon, the dispenser
water inlet flow-rate being set to 8 l/min. The level of tablet residues left in the
dispenser is checked by switching the washing on and the wash cycle set to wash program
4 (white/colors, short cycle). The dispensing percentage residue is determined as
follows:
The level of residues is determined by repeating the procedure 10 times and an average
residue level is calculated based on the ten individual measurements. In this stressed
test a residue of 40 % of the starting tablet weight is considered to be acceptable.
A residue of less than 30% is preferred, and less than 25% is more preferred.
[0050] It should be noted that the measure of water hardness is given in the traditional
"grain per gallon" unit, whereby 0.001 mole per litre = 7.0 grain per gallon, representing
the concentration of Ca
2+ ions in solution.
Effervescent agent
[0051] Detergent tablets may further comprise an effervescent agent.
[0052] Effervescency as defined herein means the evolution of bubbles of gas from a liquid,
as the result of a chemical reaction between a soluble acid source and an alkali metal
carbonate, to produce carbon dioxide gas,
[0053] Further examples of acid and carbonate sources and other effervescent systems may
be found in : (Pharmaceutical Dosage Forms : Tablets Volume 1 Page 287 to 291).
[0054] An effervescent agent may be added to the tablet mix in addition to the detergent
ingredients. The addition of this effervescent agent to the detergent tablet improves
the disintegration time of the tablet. Preferably the effervescent agent should be
added as an agglomerate of the different particles or as a compact, and not as separated
particles.
[0055] Due to the gas created by the effervescency in the tablet, the tablet can have a
higher D.F.S. and still have the same disintegration time as a tablet without effervescency.
When the D.F.S. of the tablet with effervescency is kept the same as a tablet without,
the disintegration of the tablet with effervescency will be faster.
[0056] Further dissolution aid could be provided by using compounds such as sodium acetate
or urea. A list of suitable dissolution aid may also be found in Pharmaceutical Dosage
Forms: Tablets, Volume 1, Second edition, Edited by H.A. Lieberman et all, ISBN 0-8247-8044-2.
Detersive surfactants
[0057] Surfactant are typically comprised in a detergent composition. The dissolution of
surfactants is favoured by the addition of the highly soluble compound.
[0058] Nonlimiting examples of surfactants useful herein typically at levels from about
1% to about 55%, by weight, include the conventional C
11-C
18 alkyl benzene sulfonates ("LAS") and primary, branched-chain and random C
10-C
20 alkyl sulfates ("AS"), the C
10-C
18 secondary (2,3) alkyl sulfates of the formula
[0059] CH
3(CH
2)
x(CHOSO
3-M
+) CH
3 and CH
3 (CH
2)
y(CHOSO
3-M
+) CH
2CH
3 where x and (y + 1) are integers of at least about 7, preferably at least about 9,
and M is a water-solubilizing cation, especially sodium, unsaturated sulfates such
as oleyl sulfate, the C
10-C
18 alkyl alkoxy sulfates ("AE
XS"; especially EO 1-7 ethoxy sulfates), C
10-C
18 alkyl alkoxy carboxylates (especially the EO 1-5 ethoxycarboxylates), the C
10-18 glycerol ethers, the C
10-C
18 alkyl polyglycosides and their corresponding sulfated polyglycosides, and C
12-C
18 alpha-sulfonated fatty acid esters. If desired, the conventional nonionic and amphoteric
surfactants such as the C
12-C
18 alkyl ethoxylates ("AE") including the so-called narrow peaked alkyl ethoxylates
and C
6-C
12 alkyl phenol alkoxylates (especially ethoxylates and mixed ethoxy/propoxy), C
12-C
18 betaines and sulfobetaines ("sultaines"), C
10-C
18 amine oxides, and the like, can also be included in the overall compositions. The
C
10-C
18 N-alkyl polyhydroxy fatty acid amides can also be used. Typical examples include
the C
12-C
18 N-methylglucamides. See WO 9,206,154. Other sugar-derived surfactants include the
N-alkoxy polyhydroxy fatty acid amides, such as C
10-C
18 N-(3-methoxypropyl) glucamide. The N-propyl through N-hexyl C
12-C
18 glucamides can be used for low sudsing. C
10-C
20 conventional soaps may also be used. If high sudsing is desired, the branched-chain
C
10-C
16 soaps may be used. Mixtures of anionic and nonionic surfactants are especially useful.
Other conventional useful surfactants are listed in standard texts.
Non gelling binders
[0060] Non gelling binders can be integrated in detergent compositions to further facilitate
dissolution.
[0061] If non gelling binders are used, suitable non-gelling binders include synthetic organic
polymers such as polyethylene glycols, polyvinylpyrrolidones, polyacrylates and water-soluble
acrylate copolymers. The handbook of Pharmaceutical Excipients second edition, has
the following binders classification: Acacia, Alginic Acid, Carbomer, Carboxymethylcellulose
sodium, Dextrin, Ethylcellulose, Gelatin, Guar gum, Hydrogenated vegetable oil type
I, Hydroxyethyl cellulose, Hydroxypropyl methylcellulose, Liquid glucose, Magnesium
aluminum silicate, Maltodextrin, Methylcellulose, polymethacrylates, povidone, sodium
alginate, starch and zein. Most preferable binders also have an active cleaning function
in the laundry wash such as cationic polymers, i.e. ethoxylated hexamethylene diamine
quaternary compounds, bishexamethylene triamines, or others such as pentaamines, ethoxylated
polyethylene amines, maleic acrylic polymers.
[0062] Non-gelling binder materials are preferably sprayed on and hence have an appropriate
melting point temperature below 90°C, preferably below 70°C and even more preferably
below 50°C so as not to damage or degrade the other active ingredients in the matrix.
Most preferred are non-aqueous liquid binders (i.e. not in aqueous solution) which
may be sprayed in molten form. However, they may also be solid binders incorporated
into the matrix by dry addition but which have binding properties within the tablet.
[0063] It is preferred that gelling binders, such as nonionic surfactants are avoided in
their liquid or molten form. Nonionic surfactants and other gelling binders are not
excluded from the compositions, but it is preferred that they be processed into the
detergent tablets as components of particulate materials, and not as liquids.
Builders
[0064] Detergent builders can optionally be included in the compositions herein to assist
in controlling mineral hardness. Inorganic as well as organic builders can be used.
Builders are typically used in fabric laundering compositions to assist in the removal
of particulate soils.
[0065] The level of builder can vary widely depending upon the end use of the composition.
[0066] Inorganic or P-containing detergent builders include, but are not limited to, the
alkali metal, ammonium and alkanolammonium salts of polyphosphates (exemplified by
the tripolyphosphates, pyrophosphates, and glassy polymeric meta-phosphates), phosphonates,
phytic acid, silicates, carbonates (including bicarbonates and sesquicarbonates),
sulphates, and aluminosilicates. However, non-phosphate builders are required in some
locales. Importantly, the compositions herein function surprisingly well even in the
presence of the so-called "weak" builders (as compared with phosphates) such as citrate,
or in the so-called "underbuilt" situation that may occur with zeolite or layered
silicate builders.
[0067] Examples of silicate builders are the alkali metal silicates, particularly those
having a SiO
2:Na
2O ratio in the range 1.6:1 to 3.2:1 and layered silicates, such as the layered sodium
silicates described in U.S. Patent 4,664,839, issued May 12, 1987 to H. P. Rieck.
NaSKS-6 is the trademark for a crystalline layered silicate marketed by Hoechst (commonly
abbreviated herein as "SKS-6"). Unlike zeolite builders, the Na SKS-6 silicate builder
does not contain aluminum. NaSKS-6 has the delta-Na
2SiO
5 morphology form of layered silicate. It can be prepared by methods such as those
described in German DE-A-3,417,649 and DE-A-3,742,043. SKS-6 is a highly preferred
layered silicate for use herein, but 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 herein. Various other layered
silicates from Hoechst include NaSKS-5, NaSKS-7 and NaSKS-11, as the alpha, beta and
gamma forms. As noted above, the delta-Na
2SiO
5 (NaSKS-6 form) is most preferred for use herein. Other silicates may also be useful
such as for example magnesium silicate, which can serve as a crispening agent in granular
formulations, as a stabilizing agent for oxygen bleaches, and as a component of suds
control systems.
[0068] Examples of carbonate builders are the alkaline earth and alkali metal carbonates
as disclosed in German Patent Application No. 2,321,001 published on November 15,
1973.
[0069] Aluminosilicate builders are useful in the present invention. Aluminosilicate builders
are of great importance in most currently marketed heavy duty granular detergent compositions,
and can also be a significant builder ingredient in liquid detergent formulations.
Aluminosilicate builders include those having the empirical formula:
M
z(zAlO
2)
y]·xH
2O
wherein z and y are integers of at least 6, the molar ratio of z to y is in the range
from 1.0 to about 0.5, and x is an integer from about 15 to about 264. Useful aluminosilicate
ion exchange materials are commercially available. These aluminosilicates can be crystalline
or amorphous in structure and can be naturally-occurring aluminosilicates or synthetically
derived. A method for producing aluminosilicate ion exchange materials is disclosed
in U.S. Patent 3,985,669, Krummel, et al, issued October 12, 1976. Preferred synthetic
crystalline aluminosilicate ion exchange materials useful herein are available under
the designations Zeolite A, Zeolite P (B), Zeolite MAP and Zeolite X. In an especially
preferred embodiment, the crystalline aluminosilicate ion exchange material has the
formula:
Na
12[(AlO
2)
12(SiO
2)
12]·xH
2O
wherein x is from about 20 to about 30, especially about 27. This material is known
as Zeolite A. Dehydrated zeolites (x = 0 - 10) may also be used herein. Preferably,
the aluminosilicate has a particle size of about 0.1-10 microns in diameter.
Organic detergent builders suitable for the purposes of the present invention include,
but are not restricted to, a wide variety of polycarboxylate compounds. As used herein,
"polycarboxylate" refers to compounds having a plurality of carboxylate groups, preferably
at least 3 carboxylates. Polycarboxylate builder can generally be added to the composition
in acid form, but can also be added in the form of a neutralized salt. When utilized
in salt form, alkali metals, such as sodium, potassium, and lithium, or alkanolammonium
salts are preferred.
Included among the polycarboxylate builders are a variety of categories of useful
materials. One important category of polycarboxylate builders encompasses the ether
polycarboxylates, including oxydisuccinate, as disclosed in Berg, U.S. Patent 3,128,287,
issued April 7, 1964, and Lamberti et al, U.S. Patent 3,635,830, issued January 18,
1972. See also "TMS/TDS" builders of U.S. Patent 4,663,071, issued to Bush et al,
on May 5, 1987. Suitable ether polycarboxylates also include cyclic compounds, particularly
alicyclic compounds, such as those described in U.S. Patents 3,923,679; 3,835,163;
4,158,635; 4,120,874 and 4,102,903.
Other useful detergency builders include the ether hydroxypolycarboxylates, copolymers
of maleic anhydride with ethylene or vinyl methyl ether, 1, 3, 5-trihydroxy benzene-2,
4, 6-trisulphonic acid, and carboxymethyloxysuccinic acid, the various alkali metal,
ammonium and substituted ammonium salts of polyacetic acids such as ethylenediamine
tetraacetic acid and nitrilotriacetic acid, as well as polycarboxylates such as mellitic
acid, succinic acid, oxy-disuccinic acid, polymaleic acid, benzene 1,3,5-tricarboxylic
acid, carboxymethyloxysuccinic acid, and soluble salts thereof.
Citrate builders, e.g., citric acid and soluble salts thereof (particularly sodium
salt), are polycarboxylate builders of particular importance for heavy duty liquid
detergent formulations due to their availability from renewable resources and their
biodegradability. Citrates can also be used in granular compositions, especially in
combination with zeolite and/or layered silicate builders.
[0070] Oxydisuccinates are also especially useful in such compositions and combinations.
[0071] Also suitable in the detergent compositions of the present invention are the 3,3-dicarboxy-4-oxa-1,6-hexanedioates
and the related compounds disclosed in U.S. Patent 4,566,984, Bush, issued January
28, 1986. Useful succinic acid builders include the C
5-C
20 alkyl and alkenyl succinic acids and salts thereof. A particularly preferred compound
of this type is dodecenylsuccinic acid. Specific examples of succinate builders include:
laurylsuccinate, myristylsuccinate, palmitylsuccinate, 2-dodecenylsuccinate (preferred),
2-pentadecenylsuccinate, and the like. Laurylsuccinates are the preferred builders
of this group, and are described in European Patent Application 86200690.5/0,200,263,
published November 5, 1986.
[0072] Other suitable polycarboxylates are disclosed in U.S. Patent 4,144,226, Crutchfield
et al, issued March 13, 1979 and in U.S. Patent 3,308,067, Diehl, issued March 7,
1967. See also Diehl U.S. Patent 3,723,322.
[0073] Fatty acids, e.g., C
12-C
18 monocarboxylic acids, can also be incorporated into the compositions alone, or in
combination with the aforesaid builders, especially citrate and/or the succinate builders,
to provide additional builder activity. Such use of fatty acids will generally result
in a diminution of sudsing, which should be taken into account by the formulator.
[0074] In situations where phosphorus-based builders can be used, and especially in the
formulation of bars used for hand-laundering operations, the various alkali metal
phosphates such as the well-known sodium tripolyphosphates, sodium pyrophosphate and
sodium orthophosphate can be used. Phosphonate builders such as ethane-1-hydroxy-1,1-diphosphonate
and other known phosphonates (see, for example, U.S. Patents 3,159,581; 3,213,030;
3,422,021; 3,400,148 and 3,422,137) can also be used.
Bleach
[0075] The detergent compositions herein may optionally contain bleaching agents or bleaching
compositions containing a bleaching agent and one or more bleach activators. When
present, bleaching agents will typically be at levels of from about 1% to about 30%,
more typically from about 5% to about 20%, of the detergent composition, especially
for fabric laundering. If present, the amount of bleach activators will typically
be from about 0.1% to about 60%, more typically from about 0.5% to about 40% of the
bleaching composition comprising the bleaching agent-plus-bleach activator.
[0076] The bleaching agents used herein can be any of the bleaching agents useful for detergent
compositions in textile cleaning, hard surface cleaning, or other cleaning purposes
that are now known or become known. These include oxygen bleaches as well as other
bleaching agents. Perborate bleaches, e.g., sodium perborate (e.g., mono- or tetra-hydrate)
can be used herein.
[0077] Another category of bleaching agent that can be used without restriction encompasses
percarboxylic acid bleaching agents and salts thereof. Suitable examples of this class
of agents include magnesium monoperoxyphthalate hexahydrate, the magnesium salt of
metachloro perbenzoic acid, 4-nonylamino-4-oxoperoxybutyric acid and diperoxydodecanedioic
acid. Such bleaching agents are disclosed in U.S. Patent 4,483,781, Hartman, issued
November 20, 1984, U.S. Patent Application 740,446, Burns et al, filed June 3, 1985,
European Patent Application 0,133,354, Banks et al, published February 20, 1985, and
U.S. Patent 4,412,934, Chung et al, issued November 1, 1983. Highly preferred bleaching
agents also include 6-nonylamino-6-oxoperoxycaproic acid as described in U.S. Patent
4,634,551, issued January 6, 1987 to Burns et al.
[0078] Peroxygen bleaching agents can also be used. Suitable peroxygen bleaching compounds
include sodium carbonate peroxyhydrate and equivalent "percarbonate" bleaches, sodium
pyrophosphate peroxyhydrate, urea peroxyhydrate, and sodium peroxide. Persulfate bleach
(e.g., OXONE, manufactured commercially by DuPont) can also be used.
[0079] A preferred percarbonate bleach comprises dry particles having an average particle
size in the range from about 500 micrometers to about 1,000 micrometers, not more
than about 10% by weight of said particles being smaller than about 200 micrometers
and not more than about 10% by weight of said particles being larger than about 1,250
micrometers. Optionally, the percarbonate can be coated with silicate, borate or water-soluble
surfactants. Percarbonate is available from various commercial sources such as FMC,
Solvay and Tokai Denka.
[0080] Mixtures of bleaching agents can also be used.
[0081] Peroxygen bleaching agents, the perborates, the percarbonates, etc., are preferably
combined with bleach activators, which lead to the in situ production in aqueous solution
(i.e., during the washing process) of the peroxy acid corresponding to the bleach
activator. Various nonlimiting examples of activators are disclosed in U.S. Patent
4,915,854, issued April 10, 1990 to Mao et al, and U.S. Patent 4,412,934. The nonanoyloxybenzene
sulfonate (NOBS) and tetraacetyl ethylene diamine (TAED) activators are typical, and
mixtures thereof can also be used. See also U.S. 4,634,551 for other typical bleaches
and activators useful herein.
[0082] Highly preferred amido-derived bleach activators are those of the formulae:
R
1N(R
5)C(O)R
2C(O)L or R
1C(O)N(R
5)R
2C(O)L
wherein R
1 is an alkyl group containing from about 6 to about 12 carbon atoms, R
2 is an alkylene containing from 1 to about 6 carbon atoms, R
5 is H or alkyl, aryl, or alkaryl containing from about 1 to about 10 carbon atoms,
and L is any suitable leaving group. A leaving group is any group that is displaced
from the bleach activator as a consequence of the nucleophilic attack on the bleach
activator by the perhydrolysis anion. A preferred leaving group is phenyl sulfonate.
Preferred examples of bleach activators of the above formulae include (6-octanamido-caproyl)oxybenzenesulfonate,
(6-nonanamidocaproyl)oxybenzenesulfonate, (6-decanamido-caproyl)oxybenzenesulfonate,
and mixtures thereof as described in U.S. Patent 4,634,551, incorporated herein by
reference.
Another class of bleach activators comprises the benzoxazin-type activators disclosed
by Hodge et al in U.S. Patent 4,966,723, issued October 30, 1990, incorporated herein
by reference. A highly preferred activator of the benzoxazin-type is:
[0083] Still another class of preferred bleach activators includes the acyl lactam activators,
especially acyl caprolactams and acyl valerolactams of the formulae:
wherein R
6 is H or an alkyl, aryl, alkoxyaryl, or alkaryl group containing from 1 to about 12
carbon atoms. Highly preferred lactam activators include benzoyl caprolactam, octanoyl
caprolactam, 3,5,5-trimethylhexanoyl caprolactam, nonanoyl caprolactam, decanoyl caprolactam,
undecenoyl caprolactam, benzoyl valerolactam, octanoyl valerolactam, decanoyl valerolactam,
undecenoyl valerolactam, nonanoyl valerolactam, 3,5,5-trimethylhexanoyl valerolactam
and mixtures thereof. See also U.S. Patent 4,545,784, issued to Sanderson, October
8, 1985, incorporated herein by reference, which discloses acyl caprolactams, including
benzoyl caprolactam, adsorbed into sodium perborate.
Bleaching agents other than oxygen bleaching agents are also known in the art and
can be utilized herein. One type of non-oxygen bleaching agent of particular interest
includes photoactivated bleaching agents such as the sulfonated zinc and/or aluminum
phthalocyanines. See U.S. Patent 4,033,718, issued July 5, 1977 to Holcombe et al.
If used, detergent compositions will typically contain from about 0.025% to about
1.25%, by weight, of such bleaches, especially sulfonate zinc phthalocyanine.
If desired, the bleaching compounds can be catalyzed by means of a manganese compound.
Such compounds are well known in the art and include, for example, the manganese-based
catalysts disclosed in U.S. Pat. 5,246,621, U.S. Pat. 5,244,594; U.S. Pat. 5,194,416;
U.S. Pat. 5,114,606; and European Pat. App. Pub. Nos. 549,271A1, 549,272A1, 544,440A2,
and 544,490A1; Preferred examples of these catalysts include Mn
IV2(u-O)
3(1,4,7-trimethyl-1,4,7-triazacyclononane)
2(PF
6)
2, Mn
III2(u-O)
1(u-OAc)
2(1,4,7-trimethyl-1,4,7-tnazacyclononane)
2-(ClO
4)
2, Mn
IV4(u-O)
6(1,4,7-triazacyclononane)
4(ClO
4)
4, Mn
IIIMn
IV4(u-O)
1(u-OAc)
2-(1,4,7-trimethyl-1,4,7-triazacyclononane)
2(ClO
4)
3, Mn
IV(1,4,7-trimethyl-1,4,7-triazacyclononane)-(OCH
3)
3(PF
6), and mixtures thereof. Other metal-based bleach catalysts include those disclosed
in U.S. Pat. 4,430,243 and U.S. Pat. 5,114,611. The use of manganese with various
complex ligands to enhance bleaching is also reported in the following United States
Patents: 4,728,455; 5,284,944; 5,246,612; 5,256,779; 5,280,117; 5,274,147; 5,153,161;
and 5,227,084.
As a practical matter, and not by way of limitation, the compositions and processes
herein can be adjusted to provide on the order of at least one part per ten million
of the active bleach catalyst species in the aqueous washing liquor, and will preferably
provide from about 0.1 ppm to about 700 ppm, more preferably from about 1 ppm to about
500 ppm, of the catalyst species in the laundry liquor.
Enzymes
[0084] Enzymes can be included in the formulations herein for a wide variety of dish or
fabric laundering purposes, including removal of protein-based, carbohydrate-based,
or triglyceride-based stains, for example, and for the prevention of refugee dye transfer,
and for fabric restoration. The enzymes to be incorporated include proteases, amylases,
lipases, cellulases, and peroxidases, as well as mixtures thereof. Other types of
enzymes may also be included. They may be of any suitable origin, such as vegetable,
animal, bacterial, fungal and yeast origin. However, their choice is governed by several
factors such as pH-activity and/or stability optima, thermostability, stability versus
active detergents, builders and so on. In this respect bacterial or fungal enzymes
are preferred, such as bacterial amylases and proteases, and fungal cellulases.
[0085] Enzymes are normally incorporated at levels sufficient to provide up to about 5 mg
by weight, more typically about 0.01 mg to about 3 mg, of active enzyme per gram of
the composition. Stated otherwise, the compositions herein will typically comprise
from about 0.001% to about 5%, preferably 0.01%-1% by weight of a commercial enzyme
preparation. Protease enzymes are usually present in such commercial preparations
at levels sufficient to provide from 0.005 to 0.1 Anson units (AU) of activity per
gram of composition.
[0086] Suitable examples of proteases are the subtilisins which are obtained from particular
strains of B. subtilis and B. licheniforms. Another suitable protease is obtained
from a strain of Bacillus, having maximum activity throughout the pH range of 8-12,
developed and sold by Novo Industries A/S under the registered trade name ESPERASE.
The preparation of this enzyme and analogous enzymes is described in British Patent
Specification No. 1,243,784 of Novo. Proteolytic enzymes suitable for removing protein-based
stains that are commercially available include those sold under the tradenames ALCALASE
and SAVINASE by Novo Industries A/S (Denmark) and MAXATASE by International Bio-Synthetics,
Inc. (The Netherlands). Other proteases include Protease A (see European Patent Application
130,756, published January 9, 1985) and Protease B (see European Patent Application
Serial No. 87303761.8, filed April 28, 1987, and European Patent Application 130,756,
Bott et al, published January 9, 1985).
[0087] Amylases include, for example, α-amylases described in British Patent Specification
No. 1,296,839 (Novo), RAPIDASE, International Bio-Synthetics, Inc. and TERMAMYL, Novo
Industries. The cellulase usable in the present invention include both bacterial or
fungal cellulase. Preferably, they will have a pH optimum of between 5 and 9.5. Suitable
cellulases are disclosed in U.S. Patent 4,435,307, Barbesgoard et al, issued March
6, 1984, which discloses fungal cellulase produced from Humicola insolens and Humicola
strain DSM1800 or a cellulase 212-producing fungus belonging to the genus Aeromonas,
and cellulase extracted from the hepatopancreas of a marine mollusk (Dolabella Auricula
Solander). suitable cellulases are also disclosed in GB-A-2.075.028; GB-A-2.095.275
and DE-OS-2.247.832. CAREZYME (Novo) is especially useful.
Suitable lipase enzymes for detergent usage include those produced by microorganisms
of the Pseudomonas group, such as Pseudomonas stutzeri ATCC 19.154, as disclosed in
British Patent 1,372,034. See also lipases in Japanese Patent Application 53,20487,
laid open to public inspection on February 24, 1978. This lipase is available from
Amano Pharmaceutical Co. Ltd., Nagoya, Japan, under the trade name Lipase P "Amano,"
hereinafter referred to as "Amano-P." Other commercial lipases include Amano-CES,
lipases ex Chromobacter viscosum, e.g. Chromobacter viscosum var. lipolyticum NRRLB
3673, commercially available from Toyo Jozo Co., Tagata, Japan; and further Chromobacter
viscosum lipases from U.S. Biochemical Corp., U.S.A. and Disoynth Co., The Netherlands,
and lipases ex Pseudomonas gladioli. The LIPOLASE enzyme derived from Humicola lanuginosa
and commercially available from Novo (see also EPO 341,947) is a preferred lipase
for use herein.
Peroxidase enzymes are used in combination with oxygen sources, e.g., percarbonate,
perborate, persulfate, hydrogen peroxide, etc. They are used for "solution bleaching,"
i.e. to prevent transfer of dyes or pigments removed from substrates during wash operations
to other substrates in the wash solution. Peroxidase enzymes are known in the art,
and include, for example, horseradish peroxidase, ligninase, and haloperoxidase such
as chloro- and bromo-peroxidase. Peroxidase-containing detergent compositions are
disclosed, for example, in PCT International Application WO 89/099813, published October
19, 1989, by O. Kirk, assigned to Novo Industries A/S.
[0088] A wide range of enzyme materials and means for their incorporation into synthetic
detergent compositions are also disclosed in U.S. Patent 3,553,139, issued January
5, 1971 to McCarty et al. Enzymes are further disclosed in U.S. Patent 4,101,457,
Place et al, issued July 18, 1978, and in U.S. Patent 4,507,219, Hughes, issued March
26, 1985, both. Enzyme materials useful for liquid detergent formulations, and their
incorporation into such formulations, are disclosed in U.S. Patent 4,261,868, Hora
et al, issued April 14, 1981. Enzymes for use in detergents can be stabilized by various
techniques. Enzyme stabilization techniques are disclosed and exemplified in U.S.
Patent 3,600,319, issued August 17, 1971 to Gedge, et al, and European Patent Application
Publication No. 0 199 405, Application No. 86200586.5, published October 29, 1986,
Venegas. Enzyme stabilization systems are also described, for example, in U.S. Patent
3,519,570.
[0089] Other components which are commonly used in detergent compositions and which may
be incorporated into detergent tablets include chelating agents, soil release agents,
soil antiredeposition agents, dispersing agents, suds suppressors, fabric softeners,
dye transfer inhibition agents and perfumes.
[0090] The compounds disclosed above for a product are advantageously packed in a packaging
system.
A packaging system may be formed from a sheet of flexible material. Materials suitable
for use as a flexible sheet include mono-layer, co-extruded or laminated films. Such
films may comprise various components, such as poly-ethylene, poly-propylene, poly-styrene,
poly-ethylene-terephtalate. Preferably, the packaging system is composed of a poly-ethylene
and bi-oriented-poly-propylene co-extruded film with an MVTR of less than 5 g/day/m
2. The MVTR of the packaging system is preferably of less than 10 g/day/m
2, more preferably of less than 5 g/day/m
2. The film (2) may have various thicknesses. The thickness should typically be between
10 and 150 µm, preferably between 15 and 120 µm, more preferably between 20 and 100
µm, even more preferably between 25 and 80 µm and most preferably between 30 and 40
µm.
A packaging material preferably comprises a barrier layer typically found with packaging
materials having a low oxygen transmission rate, typically of less than 300 cm
3/m
2/day, preferably of less than 150 cm
3/m
2/day, more preferably of less than 100 cm
3/m
2/day, even more preferably of less than 50 cm
3/m
2/day and most preferably of less than 10 cm
3/m
2/day. Typical materials having such barrier properties include bi oriented polypropylene,
poly ethylene terephthalate, Nylon, poly(ethylene vinyl alcohol) , or laminated materials
comprising one of these, as well as SiOx (Silicium oxydes), or metallic foils such
as aluminium foils for example. Such packaging material may have a beneficial influence
on the stability of the product during storage for example.
[0091] Among the packing method used are typically the wrapping methods disclosed in WO92/20593,
including flow wrapping or over wrapping. When using such processes, a longitudinal
seal is provided, which may be a fin seal or an overlapping seal, after which a first
end of the packaging system is closed with a first end seal, followed by closure of
the second end with a second end seal. The packaging system may comprise re-closing
means as described in WO92/20593. In particular, using a twist, a cold seal or an
adhesive is particularly suited. Indeed, a band of cold seal or a band of adhesive
may be applied to the surface of the packaging system at a position adjacent to the
second end of the packaging system, so that this band may provide both the initial
seal and re-closure of the packaging system. In such a case the adhesive or cold seal
band may correspond to a region having a cohesive surface, i.e. a surface which will
adhere only to another cohesive surface. Such re-closing means may also comprise spacers
which will prevent unwanted adhesion. Such spacers are described in WO 95/13225, published
on the 18
th of May 1995. There may also be a plurality of spacers and a plurality of strips of
adhesive material. The main requirement is that the communication between the exterior
and the interior of the package should be minimal, even after first opening of the
packaging system. A cold seal may be used, and in particular a grid of cold seal,
whereby the cold seal is adapted so as to facilitate opening of the packaging system.
Examples
[0092]
i) A detergent powder of composition A (see table 1) was prepared as follows: all
the particulate materials of composition A were mixed together in a mixing drum to
form a homogenous particulate mixture. During the mixing the binder was sprayed on.
Table 1.
Detergent base powder composition |
|
Composition A (%) |
Anionic agglomerates 1 |
22.266 |
Anionic agglomerates 2 |
9.115 |
Cationic agglomerates |
4.675 |
Nonionic agglomerates |
6.15 |
Citric acid |
4.67 |
Layered silicate, SKS-6® |
9.757 |
Sodium percarbonate |
12.266 |
Bleach activator agglomerates |
6.093 |
Sodium carbonate |
10.986 |
EDDS / Sulphate particle |
0.495 |
Tetrasodium salt of Hydroxyethane Diphosphonic acid |
0.82 |
Soil release polymer |
0.363 |
Fluorescer |
0.23 |
Soap powder |
1.4 |
Suds suppressor |
2.8 |
Polyethylene glycol, Pluriol 4000® dry add |
2 |
Protease |
0.967 |
Lipase |
0.35 |
Cellulase |
0.152 |
Amylase |
1.134 |
Perfume |
0.561 |
Binder: |
|
Sodium Di Iso Propyl Benzene Sulphonate |
0.75 |
Lutensit KHD 96® |
0.75 |
Polyethylene glycol, Pluriol 1000® |
0.39 |
Polyethylene glycol, Pluriol 4000® |
0.86 |
Anionic agglomerates 1 comprises 40% AS/AE3S; 27% Zeolite A; 12% sodium carbonate;
9% maleic/acrylic copolymer; the balance being moisture and minor ingredients, impurities
etc. |
Anionic agglomerates 2 comprises 20% AS/AE3S; 20 LAS; 28% Zeolite A; 20% sodium carbonate;
the Cationic agglomerates comprises 20% quaternary ammonium compound; 64% Zeolite
A; 10% sodium sulphate; the balance being moisture and minor ingredients, impurities
etc. |
Nonionic agglomerates comprises 24% alkyl ethoxylate (AE7); 11% Zeolite A; 20% sodium
carbonate; 36% sodium acetate; the balance being moisture and minor ingredients, impurities
etc. |
Bleach activator agglomerates comprises 81% TAED; 17% acrylic/maleic copolymer and
2% water. |
Suds suppressor comprises 11.5% silicone oil; 4.5% hyfac; 13% TAE80 and 71% starch. |
Fluorescer comprises 87% Brightener 47 (81% active) and 13% Brightener 49 (100% active). |
ii) Core tablets were made using the particulate mixture described in i). The particulate
mixture was poured into the hoppers of a Single Punch Rotary Gepa press or Bonals
press having round 4.5 cm diameter dies or 42X42 cm square dies and compressed at
1.5kN or the required force to obtain core tablets with an average tablet weight of
about 42.5g, average tablet hardness of about 2-3Kp's and average tablet density of
about 1030g/l.
iii) The coating of the core tablets was done as following: the adipic acid is heated
in a thermostatic bath at 160-180°C with gentle stirring until molten. The rest of
the ingredients are added slowly, in a continuous step, to the coating bath as powder
or as a 10-60% w/w aqueous solution. The round core tablets are dipped into the homogeneous
liquid molten coating system and immediately allowed to cool in an aluminum tray and
circulating cool air. The square core tablets are coated via dipping and showering
with the molten coating system followed by a cooling stage with cool air. Gentle mixing
is kept during the whole coating process. The coated tablets will have an average
tablet weight of 45g with an average coating weight of about 2.5g. Typical coating
batch sizes are of 1.0 Kg and 10Kg.
iv) The tablet hardness of the coated tablets was used to evaluate the resistance
towards manufacturing and transport forces. Tablet hardness was measured at least
2hr after the tablets were coated via a Van Kel-200 tablet hardness tester and reported
in Kilo-Points (Kp) as an average of 6-10 individual measurements.
v) The disintegration test is conducted in water at 8°C and reported as the time in
seconds that it takes for the coated tablet to disintegrate. The test is conducted
in a 1L glass beaker containing 600ml water. The disintegration values are reported
as an average of 4-6 individual measurements.
vi) The reference is prepared with core tablets coated only with 96.5% Adipic Acid
and 3.5% Sulphonated Polystyrene/Divynylbenzene copolymer (average of about 8% cross-linking
level) following the coating procedure described in paragraph iii. The coating compositions
containing alcohol, ester or alkali function compounds used to increase the hardness
of the coated tablet are shown in Table 2. The tablet hardness results are reported
as the hardness increase in % compared to the hardness of the reference [(Kp example-
Kp reference)X100 /Kp reference]. The disintegration performance is compared to a
target disintegration (<30 sec). The results are shown in Table 3.
Table 2.
Coating Compositions |
Example→ |
Ref. |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
Adipic Acid |
96.5 |
95.0 |
93.5 |
96.0 |
96.0 |
86.5 |
95.0 |
95.0 |
95.0 |
95.0 |
95.75 |
SPS/DVB copolymer |
3.5 |
3.5 |
3.5 |
3.5 |
3.5 |
3.5 |
3.5 |
3.5 |
3.5 |
3.5 |
3.5 |
Opadry® AMB |
--- |
1.5 |
3.0 |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
PVA MW≈22,000 |
--- |
--- |
--- |
0.5 |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
PVA MW≈100,000 |
--- |
--- |
--- |
--- |
0.5 |
--- |
--- |
--- |
--- |
--- |
--- |
Erkol® V03/240 |
--- |
--- |
--- |
--- |
--- |
10.0 |
--- |
--- |
--- |
--- |
--- |
Erkopol® B17 |
--- |
--- |
--- |
--- |
--- |
--- |
1.5 |
--- |
--- |
--- |
--- |
Potassium Acetate |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
1.5 |
--- |
--- |
--- |
Potassium Citrate |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
1.5 |
--- |
--- |
Calcium Citrate Tetrahydrate |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
1.5 |
--- |
Sodium Hydroxide |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
--- |
0.75 |
SPS/DVB stands for Sulphonated Polystyrene/Divynylbenze copolymer (average of 8% DVB
crosslinking level). |
Opadry® AMB is a mixture of Polyvinyl Alcohol, talc, titanium dioxide, xanthan gum
and lecithin. |
PVA stands for Polyvinyl Alcohol material having molecular weights of about 22,000
(degree of polymerisation=500 and degree of hydrolisis=97.5-99.5 mol%) and about 100,000
molecular weight (degree of polymerisation=2000, degree of hydrolisis=86-89 mol%). |
Erkol® V03/240 is Polyvinyl Alcohol from Erkol with saponification number = 220-260
mg KOH/g and degree of hydrolisis= 74.7-79.3 mol %. |
Erkopol® B17 is Polyvinyl Acetate from Erkol with viscosity grade of 2.5-3.5 cps measured
as a 10% solution in Ethyl Acetate at 20°C. |
The Sodium Hydroxide was added as 50% w/w aqueous solution. |
Table 3.
Tablet hardness and disintegration performance |
Example→ |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
hardness gain vs reference (% increase) |
28% |
152% |
25% |
15% |
133% |
16% |
23% |
28% |
18% |
38% |
disintegration (<30 sec) |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
% hardness increase = (Kp example- Kp reference) X 100 /Kp reference |