CN1245528A - Coated detergent tablet - Google Patents

Abstract

The present invention relates to tablets comprising a core and a coating, the core being formed by compressing a particulate material, the particulate material comprising surfactant and detergent builder, and the coating comprises dicarboxylic acid. The invention also relates to processes for making the tablets.

Description

Coated detergent tablets

The present invention relates to coated detergent tablets, in particular for use in washing machines, and to a process for the preparation of such coated detergent tablets.

Although detergent compositions in tablet form are generally recommended, no substantial success has been achieved (other than soap bars for body washing) despite several advantages of the product in unit dispersion form. One reason for this is that detergent tablets require a relatively complicated manufacturing process. In particular, it is often desirable to coat the sheet, which further increases the difficulty of production.

While uncoated tablets are fully effective in use, they often lack the necessary surface hardness to resist wear that forms part of normal production, packaging and handling. As a result, uncoated tablets are subject to wear during these processes, causing the tablets to chip and lose active material.

Finally, for aesthetic reasons, the sheet often requires a coating to improve the appearance of the sheet or to achieve some particular aesthetic effect.

There are many processes for coating tablets and most are recommended for use in detergent tablets. However, all of these methods have some disadvantages as described below.

GB-A-0989683, published on 22.4.1965, discloses a granular detergent prepared from a surfactant and an inorganic salt; spraying on water-soluble silicate; and a process for compressing the detergent particles into a tablet which remains in solid form. Finally, polymers that form readily water-soluble organic films (e.g., polyvinyl alcohol) provide a coating that makes the detergent tablet resistant to abrasion and accidental breakage.

EP-A-0002293, published on 13.6.1979, discloses ｃA sheet coating containing halide salts, such as acetates, metaborates, orthophosphates, tartrates and sulfates.

EP-A-0716144, published at 12.6.1996, also discloses laundry detergent tablets with ｃA water-soluble coating which may be an organic polymer comprising acrylic acid/maleic acid copolymer, polyethylene glycol, PVPVA and ｃA sugar.

WO9518215, published on 6.7.1995, provides a water insoluble coating for solid cast pieces. The tablets are provided with a hydrophobic coating comprising a wax, a fatty acid amide and polyethylene glycol.

The prior art does not disclose the use of dicarboxylic acid coating materials for tablets with soft cores prepared by compacting particulate materials.

The present invention provides a process by which nucleated tablets can be made by compacting particulate material containing surfactant and detergent builder and providing the tablets with a thin hard coating so that they can be stored, loaded and transported, but the coating breaks when the tablets are in a washing machine, exposing the soft core, which breaks easily and quickly, releasing the active ingredient into the wash solution.

It is an object of the present invention to provide tablets which disintegrate completely and disperse in alkaline or surfactant-rich solutions, such as washing liquors.

Summary of the invention

The object of the invention is achieved by providing a coating comprising a dicarboxylic acid. Wherein the carbon chain length of the dicarboxylic acid is preferably from C2 to C13.

In one embodiment of the invention, the coating consists essentially of dicarboxylic acid.

In another aspect, the present invention provides a process for preparing a tablet comprising the steps of:

(a) forming a core by compacting a particulate material, the particulate material comprising surfactant and detergent builder;

(b) applying a coating substance to the core, the coating substance being a melt;

(c) solidifying the molten coating substance;

wherein the coating material contains a dicarboxylic acid.

In another embodiment, the present invention provides a process for preparing a tablet comprising the steps of:

(a) forming a core by compacting a particulate material, the particulate material comprising surfactant and detergent builder;

(b) applying a coating substance to the core, the coating substance being soluble in a solvent or water;

(c) allowing the solvent or water to evaporate;

wherein the coating material contains a dicarboxylic acid.

Detailed description of the invention

Tablets coated in the present invention may be prepared by simply mixing the solid components together and compacting the mixture in a conventional tablet press such as those used in the pharmaceutical industry. Any liquid component, such as a surfactant or foam inhibitor, may be added to the solid particulate component in a conventional manner. The preferred main component is used in particulate form.

In particular for laundry tablets, the components, such as auxiliaries and surfactants, can be spray-dried by customary methods and compacted under suitable pressure.

The detergent tablets may be made in any size or shape and may be surface treated according to the invention before coating as desired. Surfactants and adjuvants are included in the core of the tablet and generally constitute a major part of the tablet's cleaning ability. By "adjuvant" is meant all substances capable of removing calcium ions from a solution by ion exchange, complexation, chelation, or precipitation.

The particulate material useful in making the tablets of the present invention may be prepared by any granulation or granulation process. An example of such a process is spray drying (in co-current or counter-current spray drying towers), which generally have a low bulk density, 600g/l or less. The higher density particulate material may 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 mixer). Other suitable methods include fluidized bed processes, compaction processes (e.g., roll compaction), extrusion processes, and all particulate materials prepared by any chemical process, such as flocculation, crystallization precipitation, and the like. The individual particles may also be any other particles, granules, spheres or crystals.

The particulate matter may be mixed together using any conventional means. Batch mixing is suitable, for example, for concrete mixers, nauta mixers, ribbon mixers or other devices. Optionally the mixing process may be carried out continuously by weighing each component on a conveyor belt, metering them and mixing them in one or several rotating drums or mixers. The liquid may be sprayed onto a mixture of particulate matter, such as a non-ionic surfactant. It is also possible to spray the other liquid components separately onto the mixture of particulate matter or to premix them. For example, a suspension of perfume and optical brightener may be sprayed. Finely divided fluid aids (release agents, such as zeolites, carbonates, silicas) can be added to the particulate material after spraying the non-ionic material, preferably near the end of the process, to produce a less viscous mixture.

The tablets may be prepared by any compaction method, such as tabletting, briquetting or extrusion, preferably tabletting. Suitable apparatus includes a standard single stroke or rotary press (e.g., Courtoy)^®、Korch^®、Manesty^®Or Bonals^®). The tablets prepared according to the invention preferably have a diameter of from 40 mm to 50 mm and a weight of from 25 to 60 g. The compaction pressure used to prepare these tablets need not exceed 5000kN/m²Preferably not more than 3000kN/m²Most preferably not more than 1000kN/m²。

According to the invention, the tablet is coated with a dicarboxylic acid so that the tablet does not absorb moisture, or only absorbs moisture at a very low rate. The coating is strong so that moderate mechanical impact on the sheet during handling, packaging and shipping causes only a very low degree of chipping or rubbing. Finally, the coating is preferably frangible so that the sheet breaks when subjected to strong mechanical impact. In addition, it is advantageous if the coating substance dissolves under alkaline conditions or is easily emulsified by surfactants. This avoids the deposition of insoluble particles or lumps of coating material on the garment. This may be important when a more poorly water soluble dicarboxylic acid is used.

Water Solubility is determined according to ASTM E1148-87, Test protocol entitled "Standard Test methods for measurements of Aqueous solutions".

Suitable coating substances are C2-C13 dicarboxylic acids. Particularly suitable dicarboxylic acids are selected from oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid and brassylic acid and mixtures thereof.

However, whatever the detergent tablets are made from, they are coated according to the invention with a coating substance having a melting point preferably of from 40 ℃ to 200 ℃.

Coating can be carried out in a number of ways. Two preferred coating methods are

a) Coating with a molten substance and b) coating with an aqueous solution of the substance.

In a), the coating material is applied at a temperature above its melting point and cured on the sheet. In b), the coating is applied as a solution and the solvent is dried, leaving an adherent coating. The substantially insoluble material may be applied to the sheet by, for example, spraying or dipping. Typically, when the molten mass is sprayed onto the sheet, it rapidly solidifies, forming an adherent coating. When the sheet is immersed in the molten mass and then removed, it is rapidly cooled again to rapidly solidify the coating mass. It is clear that substantially insoluble materials having a melting point below 40 c do not solidify sufficiently at ambient temperatures and that materials having a melting point above about 200 c have found no practical use. Preferably, the substance melts in the range of 60 to 160 ℃, more preferably 70 to 120 ℃.

"melting point" refers to the temperature at which the substance is slowly heated in, for example, a capillary tube to become a clear liquid.

The thickness of the coating can be any desired thickness according to the invention. In most cases, the coating constitutes from 1% to 10%, preferably from 1.5% to 5%, by weight of the tablet.

The coating of the tablets of the invention is very strong and gives the tablets a particular strength.

In a preferred embodiment of the invention, disintegration of the coating upon washing is improved by the addition of a disintegrant. This disintegrant swells immediately upon contact with water and causes the coating to break into fragments. This improves the dissolution of the coating in the wash solution. This decomposing agent is suspended in the coating melt in an amount of up to 30%, preferably 5 to 20%, most preferably 5 to 10%.

Disintegrants that may be used are described in Handbook of pharmaceutical excipients (1986). Examples of suitable disintegrants include starch: natural, modified or pregelatinized starches, sodium starch gluconate; gum: agar gum, guar gum, locust bean gum, karaya gum, pectin gum, tragacanth gum; croscarmylose sodium, crospovidone, cellulose, carboxymethylcellulose, alginic acid and other salts, including sodium alginate, silica, clays, polypropylene based pyrrolidones, soy polysaccharides, ion exchange resins and mixtures thereof.

Depending on the composition of the raw material and the shape of the pieces, the compaction force employed can be adjusted without affecting the strength (Diamantral frame Stress) and the disintegration time in the washing machine. The process can be used to prepare uniform or layered tablets of any size or shape.

The parametric frame Stress (DFS) represents the strength of the slice, which is determined by the following equation: $=\frac{2F}{\mathrm{\μDt}}$ where F is the maximum force (newtons) that causes loss of tension (fracture) as measured using a VK 200-piece hardness tester supplied by Van Kell industries, Inc. D is the diameter of the sheet and t is the thickness of the sheet.

(Method Pharmaceutical Dosage Forms：Tablets Volume 2 Page213～217)

The rate of disintegration of a detergent tablet can be determined in two ways:

a) in a "VAN KEL" fribilator with a "Vankel Type" drum.

-placing 2 pieces of known weight and D.F.S in a fribilator drum,

-rotating the drum for 20 revolutions,

collect all the product and the remaining tablet pieces in the fribilator drum and sieve out the pieces on a 5 mm sieve and through a 1.7 mm sieve.

-expressed as% of the remainder on a 5 mm sieve and through a 1.7 mm sieve.

The higher the% of material passing 1.7 mm, the better the disintegration.

b) In a washing machine according to the following method

Two pieces of known weight and crushing strength are taken and placed at the bottom of the washing machine (e.g. Bauknecht WA 950).

Place a 3 kg mixed load on the sheet.

Short circulation at 30 ℃ with tap water (procedure 4).

After 5 minutes the cycle was stopped, the washings were checked for undissolved debris, collected and weighed, and the percentage of residue remaining was recorded.

In another embodiment of the invention, the tablet further comprises a foaming agent.

The foaming referred to in the present invention means that bubbles are generated from a liquid as a result of carbon dioxide gas generated by a chemical reaction between a soluble acid raw material and an alkali metal carbonate,

namely, it is

Other examples of acid and carbonate sources and other blowing agent systems can be found in Pharmaceutical Dosage Forms: Tablets Volume 1 pages 287-291.

In addition to the detergent component, a sudsing agent may be added to the tablet mixture. The addition of sudsing agents to detergent tablets increases the speed of tablet disintegration. The amount is preferably from 5 to 20%, most preferably from 10 to 20% by weight of the tablet. Preferably, the foaming agent should be added in the form of agglomerates or compacts of the various particles, rather than as separate particles.

The tablet may have a higher d.f.s due to gas generation by foaming in the tablet and have the same decomposition time as a tablet without the foaming agent. When the d.f.s of the tablet with the blowing agent is the same as the tablet without the blowing agent, the tablet with the blowing agent decomposes faster.

Detergent surfactant

Non-limiting examples of surfactants that can be used in the present invention at concentrations generally from about 1% to 55% by weight include conventional C₁₁-C₁₈Alkyl benzene sulfonates ("LAS") and primary branched and random C₁₀-C₂₀Alkyl sulfates ("AS"), C₁₀-C₁₈A secondary (2, 3) alkyl sulfate of the formula CH₃(CH₂)_x(CHOSO₃ ^-M⁺)CH₃And CH₃(CH₂)_y(CHOSO₃ ^-M⁺)CH₂CH₃Wherein x and (y +1) are integers of at least about 7, preferably at least about 9, M is a water-soluble cation, especially sodium, an unsaturated sulfate, e.g. oleyl sulfate, C₁₀-C₁₈Alkyl alkoxy sulfates ("AEXS", especially the ethoxy sulfate of EO 1-7), C₁₀-C₁₈Alkyl alkoxy carboxylates (especially ethoxy carboxylates of EO 1-5), C₁₀-C₁₈Glycerol ethers, C₁₀-C₁₈Alkyl polyglycosides and their corresponding sulfated polyglycosides, and C₁₂-C₁₈α -sulfonated fatty acid esters if desired, conventional nonionic and zwitterionic surfactants, e.g. C₁₂-C₁₈Alkyl ethoxylates ("AE") include so-called narrow peak alkyl ethoxylates and C₆-C₁₂Alkylphenol alkoxylates (especially ethoxylates and mixed ethoxy/propoxy), C₁₂-C₁₈Betaines and sulfobetaines ("sultaines"), C₁₀-C₁₈Amine oxides and the like may also be included in the above compositions. C may also be used₁₀-C₁₈N-alkyl polyhydroxy fatty acid amides. General examples include C₁₂-C₁₈N-methylglucamide. See WO 9206154. Other saccharide-derived surfactants include N-alkoxy polyhydroxy fatty acid amides, e.g. C₁₀-C₁₈N- (3-methoxypropyl) glucamide. N-propyl to N-hexyl C₁₂-C₁₈Glucosamides can be used for low foamingUse is provided. Also employable are C₁₀-C₂₀Conventional soaps. If high foam is desired, a branched chain C may be used₁₀-C₁₆Soap. Mixtures of anionic and nonionic surfactants are particularly preferred. Other commonly used surfactants are listed in standard articles.

Auxiliary agent

Detergent builders can optionally be included in the compositions of the present invention, which can help control mineral hardness. Inorganic as well as organic auxiliaries can be employed. Builders are commonly used in fabric washing compositions to assist in the removal of particulate soils.

The level of adjuvant may vary over a wide range depending on the end use of the composition.

Inorganic or phosphorus-containing detergent builders include, but are not limited to, the alkali metal, ammonium and alkanolammonium salts of polyphosphoric acid (representative of tripolyphosphates, pyrophosphates, and glassy polymeric metaphosphates), phosphates, phytates, silicates, carbonates (including bicarbonates and sesquicarbonates), sulfates, and aluminosilicates. But in some cases non-phosphate adjuvants are required. It is important that the action of the composition of the invention is surprisingly good, even in the presence of so-called "weak" builders (compared to phosphates), such as citrates, or the so-called "poor aids" that occur with zeolite or phyllosilicate builders.

Examples of silicate builders are alkali metal silicates, especially those of SiO₂∶Na₂Silicates and layered silicates with a ratio of O between 1.6: 1 and 3.2: 1, such as the layered sodium silicates described by h.p. rieck in US4664839 entitled 5/12 1987. NaSKS-6 is a trade name for crystalline layered silicates supplied by Hoechst (generally abbreviated as "SKS-6"). Unlike zeolite promoters, the NaSKS-6 silicate promoter does not contain aluminum. NaSKS-6 is delta-Na₂SiO₅A layered silicate in its form. It can be prepared, for example, by the processes described in DE-A-3417649 and DE-A-3742043 in Germany. SKS-6 is a highly preferred layered silicate for use in the present invention, but other such layered silicates, such as those of the formula NaMSi_xO_2x+1.yH₂O, where M is sodium or hydrogen, x is a number from 1.9 to 4, preferably 2, y is a number from 0 to 20, preferably 0, may be used in the present invention various other layered silicates from Hoechst include NaSKS-5, NaSKS-7 and NaSKS-11, e.g., in the α, β and γ forms₂SiO₅(NaSKS-6 form) is the most preferred for the present invention. Other silicates are also effective, such as magnesium silicate, which acts as a crispening agent in granular formulations, as a stabilizing agent for oxygen bleaches and as a stabilizerIs a component of a foam suppressing system.

Examples of carbonate assistants are alkaline earth and alkali metal carbonates, as disclosed, for example, in german patent 2321001 on 11/15/1973.

Aluminosilicate builders are effective in the present invention. Aluminosilicate builders are important in most of the high-performance particulate detergent compositions currently on the market, and also as an important builder component in liquid detergent compositions. Aluminosilicate builders include those having the general formula:

Mz(zAlO₂)_y·xH₂o wherein z and y are integers of at least 6, the molar ratio of z to y is in the range of 1.0 to about 0.5, and x is an integer from about 15 to about 264.

Effective aluminosilicate ion exchange materials are commercially available. These aluminosilicates may be crystalline or amorphous in structure, and may be naturally occurring aluminosilicates or synthetic. A process for the preparation of aluminosilicate ion exchange materials is disclosed in U.S. Pat. No. 3,85669 to Krummel et al, 1976, 10/12. Preferred synthetic crystalline aluminosilicate ion exchange materials useful in the present invention may be employed named zeolite a, zeolite p (b), zeolite MAP and zeolite X. In a particularly preferred embodiment, the crystalline aluminosilicate ion exchange material has the general formula:

Na₁₂[(AlO₂)₁₂(SiO₂)₁₂].xH₂o wherein x is a number from about 20 to about 30, especially about 27. This material is known as zeolite a. In the present invention, dehydrated zeolite (x is 0 to 10) may be used. Preferred are aluminosilicates having particles of about 0.1 to 10 microns in diameter.

Organic detergent builders suitable for the purposes of the present invention include, but are not limited to, various polycarboxylate compounds. As used herein, "polycarboxylate" refers to compounds having a plurality of carboxylic acid groups, preferably at least 3 carboxylate groups. Polycarboxylate adjuvants can generally be added to the composition in the acid form, but also in the form of neutralized salts. When in salt form, alkali metal salts, such as sodium, potassium and lithium or alkoxide salts are preferred.

Included in the polycarboxylate adjuvants are various classes of active materials. One important class of polycarboxylate adjuvants includes ether polycarboxylates, including oxydisuccinates, as disclosed in berg. US3128287 entitled to US 4/7 in 1964 and in Lamberti et al US3635830 entitled to US 1/18 in 1972. See also the "TMS/TDS" adjuvant of US4663071, Bush et al, entitled 5.5.5.1987. Suitable ether polycarboxylates also include cyclic compounds, particularly alicyclic compounds, such as disclosed in US3923679, 3835163, 4158635, 4120874 and 4102903.

Other useful detergent builders include ether hydroxypolycarboxylates, copolymers of maleic anhydride with ethylene or vinyl methyl ether, 1, 3, 5-trihydroxybenzene-2, 4, 6-trisulfonic acid and carboxymethyloxysuccinic acid, polyacetic acids such as the various alkali metal, ammonium and substituted ammonium salts of ethylenediaminetetraacetic acid and nitrilotriacetic acid, and polycarboxylates such as mellitic acid, succinic acid, oxydisuccinic acid, polymaleic acid, benzene-1, 3, 5-tricarboxylic acid, carboxymethyloxysuccinic acid and soluble salts thereof.

Citrate builders, such as citric acid and soluble salts thereof (especially sodium salts), are particularly important polycarboxylate builders for high-performance liquid detergent formulations because they are renewable raw materials and are available for their biodegradability. Citrate salts may also be used in the particulate composition, particularly in combination with zeolite and/or layered silicate builders. Oxydisuccinates are also particularly effective in these compositions and combinations.

Also suitable for use in the detergent compositions of the present invention are 3, 3-dicarboxy-4-oxa-1, 6-adipate and related compounds disclosed in US4566984 to which Bush was entitled on 28.1.1986. Effective succinic acid auxiliary agents include C₅-C₂₀Alkyl and alkenyl succinic acids and salts thereof. A particularly preferred compound of this type is dodecenylsuccinic acid. Specific examples of succinates include: lauryl succinate, myristyl succinate, palmityl succinate, and 2-dodecenyl succinate (preferably) 2-pentadecenyl succinate and the like. Lauryl succinate is a preferred adjuvant in this class and is described in EP86200690.5/0200263 published on 5.11.1986.

Other suitable polycarboxylates are disclosed in US4144226 published by Crutchfield et al on 1979 at 13.3 and US3308067 entitled by Diehl on 1967 at 3.7. See also US3723322 to Diehl.

Fatty acids, e.g. C₁₂-C₁₈Monocarboxylic acids may also be added to the composition, either alone or in combination with the above-mentioned adjuvants, in particular citrate and/or succinate adjuvants, to impart additional adjuvant activity. Such use of fatty acids will generally reduce foaming, which will depend on the formulator.

In the case of phosphorus-based adjuvants, and in particular in stick formulations for hand-washing operations, various alkali metal phosphates, such as the known sodium tripolyphosphates, sodium pyrophosphates and sodium orthophosphates, can be used. Phosphonate builders such as ethane-1-hydroxy-1, 1-diphosphonate and other known phosphonates may also be employed (see, e.g., US3159581, 3213030, 3422021, 3400148 and 3422137).

Bleaching agent

The detergent compositions of the present invention may optionally contain a bleaching agent or a bleaching composition comprising a bleaching agent and one or more bleach activators. When included, the bleaching agent will be present in an amount of from about 1% to about 30%, more preferably from about 5% to 20% of the detergent composition, especially for use in fabric laundering. If included, the amount of bleach activator is typically from about 0.1% to about 60%, more typically from about 0.5% to about 40%, of the bleach composition containing the bleach plus bleach activator.

The bleaching agent employed in the present invention may be any of those presently known or to be known in detergent compositions which may be used for fabric cleaning, hard surface cleaning or other cleaning purposes. They include oxygen bleaches, as well as other bleaching agents. Perborate bleaches such as sodium perborate (e.g., mono-or tetrahydrate) may be used in the present invention.

Other classes of non-limiting bleaching agents include percarboxylic acid bleaching agents and salts thereof. Suitable examples of such agents include magnesium monoperoxyphthalate hexahydrate, magnesium meta-chloroperbenzoate, 4-nonylamino-4-oxoperoxybutyric acid, and diperoxydodecanedioic acid. These bleaches are disclosed in US4483781, entitled by Hartman at 20/11 1984, US740446, entitled by Burns et al at 3/6 1985, EP0133354, issued by Bank et al at 20/2 1985, and US4412934, entitled by Chung et al at 1/11 1983. Highly preferred bleaching agents also include 6-nonylamino-6-oxoperoxyhexanoic acid, as described in US4634551 by Burns et al, entitled 1/6 in 1987.

Peroxygen bleaches may also be employed. Suitable peroxy bleach compounds include sodium carbonate peroxyhydrate and equivalent amounts of "percarbonate" bleach, sodium pyrophosphate peroxyhydrate, urea peroxyhydrate and sodium peroxide. Persulfate bleach (e.g., OXONE commercially produced by DuPont) may also be used.

Preferred percarbonate bleach compositions contain dry particles having an average particle size in the range of from about 500 microns to about 1000 microns, no more than about 10% by weight of said particles being less than about 200 microns, and no more than about 10% by weight of said particles being greater than about 1250 microns. Optionally, the percarbonate may be coated with silicate, borate or water soluble surfactants. Percarbonate can come from various industrial sources, such as FMC, Solvay and Tokai Denka.

Mixtures of bleaching agents may also be employed.

Peroxygen bleaches, perborates, percarbonates, and the like are preferably used in combination with bleach activators, which may be prepared in situ (i.e., during the wash) in an aqueous solution of the peroxyacid corresponding to the bleach activator. Various non-limiting examples of active agents are disclosed in US4915854 and US4412934, which Mao et al have acquired rights in 4/10 1990. Typically nonanoyloxybenzene sulfonate (NOBS) and Tetraacetylethylenediamine (TAED) actives, and mixtures thereof may also be employed. See US4634551 for other types of bleaching and active agents.

Highly preferred amide derived bleach activators are of the formula:

R¹N(R⁵)C(O)R²c (O) L or R¹C(O)N(R⁵)R²C(O)L

Wherein R is¹Is an alkyl radical having from about 6 to 12 carbon atoms, R²Is containing about 1 to 6 carbon atomsAlkylene of (A), R⁵Is hydrogen or an alkyl, aryl or alkaryl group containing from 1 to 10 carbon atoms and L is any leaving group used. A leaving group is any group that is displaced from the bleach activator as a result of the nucleophilic action of the perhydrolyzed anion on the bleach activator. Preferably the leaving group is benzenesulfonate.

Preferred examples of bleach activators having the above general formula include (6-octanoylamide-hexanoyl) oxybenzene-sulfonate, (6-nonanoylamino-hexanoyl) oxybenzene-sulfonate, (6-decanoylamino-hexanoyl) oxybenzene-sulfonate and mixtures thereof, which are described in US4634551, which is incorporated herein by reference.

Other classes of bleach activators include benzoxazines disclosed in US4966723 issued by Hodge et al on 1990, 30.10.4, which is incorporated herein by reference. Highly preferred benzoxazine-based active agents are:

yet another preferred class of bleach activators includes acyl lactam activators, particularly acyl caprolactams and acyl valerolactams of the general formula:

wherein R is⁶Is hydrogen or an alkyl, aryl, alkoxyaryl or alkylaryl group containing from 1 to about 12 carbon atoms. Highly preferred lactam actives 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. Pat. No. 4,45784 to Sanderson, entitled 10/8/1985, incorporated herein by reference, which discloses acyl caprolactams absorbed in sodium perborateIncluding benzoyl caprolactam.

Bleaching agents other than oxygen bleaching agents are also known in the art and may be used in the present invention. One particularly effective class of non-oxygen bleaches includes photoactivated bleaches such as sulfonated zinc and/or aluminum phthalocyanine. See US4033718 entitled to holcomb et al, 5/7 1977. If employed, detergent compositions typically contain from about 0.025% to about 1.25% by weight of such bleaching agents, especially zinc phthalocyanine sulfonates.

If desired, the bleaching compound may be catalyzed by a manganese compound. Such compounds are known in the art and include, for example, manganese-based catalysts, which are disclosed in US5246621, US5244594, US5194416, US5114606 and EP549271a1, 549272a1, 544440a2 and 544490a 1; preferred examples of these catalysts include Mn^IV ₂(u-O)₃(1, 4, 7-trimethyl)-1, 4, 7-triazacyclononane)₂(PF₆)₂、Mn^III ₂(u-O)₁(u-OAc)₂(1, 4, 7-trimethyl-1, 4, 7-triazacyclononane)₂-(ClO₄)₂、Mn^IV ₄(u-O)₆(1, 4, 7-triazacyclononane)₄(ClO₄)₄、Mn^IIIMn^IV ₄(u-O)₁(u-OAc)₂- (1, 4, 7-trimethyl-1, 4, 7-triazacyclononane)₂(ClO₄)₃、Mn^IV(1, 4, 7-trimethyl-1, 4, 7-triazacyclononane) - (OCH₃)₃(PF₆) And mixtures thereof. Other metal-based bleach catalysts include those disclosed in US4430243 and US 5114611. The use of manganese with various complex ligands to promote bleaching is also disclosed in US4728455, 5284944, 5246612, 5256779, 5280117, 5274147, 5153161 and 5227084 below.

Indeed, and not by way of limitation, the compositions and methods of the present invention can be adapted to have at least one part per million concentration of active bleach catalyst species in the aqueous wash liquor, and preferably from about 0.1ppm to about 700ppm, more preferably from about 1ppm to about 500ppm, of catalytic species in the laundry liquor.

Enzyme

The formulations of the present invention may contain enzymes for a wide range of fabric laundering applications, including the removal of soils, for example, protein-, carbohydrate-or triglyceride-based soils, and for the prevention of dye transfer and for fabric restoration. Enzymes that may be added include proteases, amylases, lipases, cellulases, peroxidases, and mixtures thereof. Other types of enzymes may also be added. They may be of any origin, such as vegetable, animal, bacterial, fungal and yeast origin. However, their selection is based on several factors, such as pH-activity and or optimum stability, thermal stability, stability to active detergents, auxiliaries and the like. In this case, bacterial or fungal enzymes are preferred, such as bacterial amylases and proteases and fungal cellulases.

Enzymes are typically added in amounts of up to about 5 mg, usually about 0.01 to 3 mg, of active enzyme per gram of composition. It is also to be noted that: the compositions of the invention generally contain from about 0.001 to 5%, preferably from 0.01 to 1% by weight of industrially produced enzymes. Proteases are generally present in such industrial formulations in an amount sufficient to have an activity of 0.005 to 0.1 daltons (Anson) units (AU) per gram of the composition.

Examples of suitable proteases are subtilisins, which are prepared from specific genera of Bacillus subtilis and Bacillus licheniformis. Another suitable protease is prepared from the genus Bacillus with the maximum activity in the pH range of 8-12, developed and sold as ESPERASE by Novo Industries A/S. The preparation of this and similar enzymes is described in GB1243784 to Novo. Commercially available proteolytic enzymes suitable for removing protein-based stains include ALCALASE and SAVINASE supplied by Novo Industries A/S (Denmark) and MAXATASE supplied by International Bio-Synthesis, Inc. (the Netherlands). Other enzymes include protease A (see EP130756, published on 9.1.1985) and protease B (see EP87303761.8, 28.4.1987 and EP130756, Bott et al, published on 9.1.1985).

Amylases include, for example, the α -lipase described in UK patent 1296839(Novo), RAPIDASE, International Bio-Synthesis, Inc., and TERMAMYL, Novo industries.

Cellulases usable in the present invention include cellulases of bacteria and fungi. Preferably the desired pH is between 5 and 9.5. Suitable cellulases are disclosed in US4435307, Barbesgoard et al, 3/6 1984, which discloses fungal cellulases prepared from Humicola insolens or pythium DSM1800 or cellulases 212-prepared from fungi belonging to the genus aeromonas and cellulases extracted from the liver pancreas of ship maggots (dolabella auricula Solander). Suitable cellulases are also disclosed in GB-A-2075028, GB-A-2095275 and DE-OS-2247832. CAREZYME (Novo) is particularly effective.

Suitable lipases for use in washing applications include those prepared from microorganisms of the genus Pseudomonas, e.g., Pseudomonas stutzeri ATCC19.154, as disclosed in GB 1372034. Lipase can also be found in Japanese patent application No. 5320487 published on 24/2 of 1978. Such lipases are supplied by Amano Pharmaceutical co. Other suitable industrial lipases include Amano-CES, a lipase produced by Chromobacter viscosum, such as Chromobacter viscosum, i.e., Chromobacter viscosum var. lipolyticum NRRLB 3673, supplied by Toyo Jozo Co.Tagata, Japan; and other Chromobacter viscosum lipases supplied by U.S. Biochemical Corp. and Disoynth Co. of the Netherlands, as well as lipases prepared from Pseudomonas gladioli. LIPOLASE enzyme derived from Humicola lanuginosa and produced industrially by Novo (see EP341947) is here a preferred lipase.

Peroxidase enzymes may be used in combination with oxygen sources such as percarbonates, perborates, persulfates, hydroxides, etc. They can be used for "solution bleaching", i.e. to prevent dye transfer or transfer of pigments from a substrate to other substrates present in the wash solution during the wash process. Peroxidases are known in the art and include, for example, horseradish peroxidase, ligninase and haloperoxidase, such as chloro-or bromo-peroxidase. Detergent compositions containing peroxidase are disclosed in PCT application WO89/099813, entitled to Novo Industries A/S by O.Kirk at 10/19 1989.

The range of enzymatic materials and methods for their incorporation into synthetic detergent compositions are described in US3553139, entitled McCarty et al, 1971, month 1, day 5. Enzymes are also disclosed in US4101457 by Place et al, entitled 7/18 in 1978, and US4507219, entitled 26/3 in 1985, by Hughes. Enzymes useful in liquid detergent formulations and methods of incorporating them into such formulations are disclosed in US4261868 entitled by Hora et al at 4/14 1981. Enzymes used in detergents can be stabilized by various techniques. Enzyme stabilization techniques are disclosed and are typically found in Gedge et al, US3600319, entitled 8/17, 1971, and EP199405 and EP86200586.5, Venegas, 10/29, 1986. Enzyme stabilization systems are also described, for example, in US 3519570.

Other components which may be used in detergent compositions and which may be incorporated into the detergent tablets of the present invention include sequestrants, soil release agents, soil redeposition prevention agents, dispersants, brighteners, suds suppressors, fabric softeners, dye transfer inhibitors and perfumes.

Examples

	Example 1	Example 2
			Anionic agglomerates	25.00	20.00
Nonionic agglomerate	5.53	4.42
			Bleach active agglomerates	5.69	4.55
Phthalocyanine zinc sulfonate capsule	0.03	0.02
			Foam inhibitor	3.23	2.58
Dried zeolite	6.30	5.04
			Layered silicate	13.69	10.95
Dye transfer inhibitor agglomerates	0.13	0.10
			Perfume capsule	0.23	0.18
Nonionic paste-like spray body	5.43	4.34
			Fluorescent agent	0.26	0.21
Sodium carbonate	4.68	3.74
			Sodium percarbonate	19.78	15.86
HEDP sodium salt	0.79	0.63
			Soil release polymers	0.18	0.14

Perfume	0.33	0.26
			Protease enzyme	0.86	0.69
Cellulase enzymes	0.25	0.20
			Lipase enzyme	0.21	0.17
Amylase	0.70	0.56
Adipic acid	6.70	6.70
			Foaming compact	-	18.66
Total amount of	100.00	100.00

The anionic agglomerates contained 38% anionic surfactant, 22% zeolite and 40% carbonate.

The non-ionic agglomerates contained 26% non-ionic surfactant, 48% zeolite and 26% carbonate.

The bleach activator agglomerates contained 81% TAED, 17% acrylic acid/maleic acid copolymer (in acid form) and 2% water.

The phthalocyanine zinc sulfonate capsules have 10% activity.

The suds suppressor contained 11.5% silicone oil (supplied by Dow Corning) and 88.5% starch.

The layered silicate contained 78% SKS-6 supplied by Hoechst, 22% citric acid.

The dye transfer inhibitor agglomerate contained 21% PVNO/PVPVI, 61% zeolite and 18% carbonate.

The perfume capsules contained 50% perfume and 50% starch.

The non-ionic paste spray contained 67% C12-C15 AE5 (alcohol containing an average of 5 ethoxy groups per molecule), 24% N-methylglucamide and 9% water.

The foamed compacts contained 54.5% sodium bicarbonate and 45.5% citric acid.

All of the particulate materials of example 1 except the dried zeolite were mixed in a mixing drum to produce a homogeneous particulate mixture that was sprayed during mixing. After spraying, dusting was carried out with dry zeolite.

The first set of tablets was prepared by adding about 37.5 grams of the mixture to a circular mold 4.5 cm in diameter and compaction pressure of 0.5kN, or about30N/cm²Tablets having a height of about 2.2cm and a density of about 1.1g/cc were made. The tensile strength of the sheet was 3.5 kPa.

Adipic acid is heated to 170 ℃ in a thermostatic bath with appropriate stirring until molten. The molten product was a clear liquid. The sheet prepared as above was then immersed in a liquid to produce a final coated sheet having a total weight of 40.2 g and a tensile strength of 6.5 kPa.

With a compaction pressure of 1kN, or about 63N/cm²A second set of tablets was prepared, made into tablets having a height of about 2.0cm, a density of about 1.2g/cc, and a tensile strength of 9.0 kPa.

After coating with adipic acid, the weight of the tablets was 40.2 grams and the tensile strength was 15.5 kPa.

With a compaction pressure of 1.5kN, or about 95N/cm²To prepare a third set of tablets, made into tablets having a height of about 1.9cm, a density of about 1.3g/cc, and a tensile strength of 12.9 kPa.

After coating with adipic acid, the weight of the tablets was 40.2 grams and the tensile strength was 19.5 kPa.

Example 2

Mixing was carried out as in example 1 and the foamer granules were added to the mixing drum after dusting to produce the final mixture.

Tablets were pressed and coated as described in example 1.

Using 1kN, or about 63N/cm²Compaction pressure of (A) A first set of tablets was prepared to produce tablets having a height of about 2.2cm, a density of about 1.1g/cc, and a tensile strength of 4.5 kPa.

After coating with adipic acid, the weight of the tablets was 40.2 grams and the tensile strength was 10.4 kPa.

With a compaction pressure of 1.5kN, or about 95N/cm²A second set of tablets was prepared, made into tablets having a height of about 2.1cm, a density of about 1.2g/cc, and a tensile strength of 8.5 kPa.

After coating with adipic acid, the weight of the tablets was 40.2 grams and the tensile strength was 14.5 kPa.

With a compaction pressure of 2.5kN, or about 160N/cm²To prepare a third set of tablets, made into tablets having a height of about 2.0cm, a density of about 1.2g/cc, and a tensile strength of 15.7 kPa.

After coating with adipic acid, the weight of the tablets was 40.2 grams and the tensile strength was 21.3 kPa.

Example 1 was repeated, replacing the adipic acid by glutaric acid. Glutaric acid was heated to 120 ℃ in a constant temperature bath with appropriate stirring until molten. The final tensile strengths of the three sets of sheets were 10.4kPa, 17.3kPa, and 22.5kPa, respectively.

Example 2 was repeated, replacing the adipic acid by glutaric acid. Glutaric acid was heated to 120 ℃ in a constant temperature bath with appropriate stirring until molten. The final tensile strengths of the three sets of sheets were 11.3kPa, 16.9kPa, and 23.0kPa, respectively.

Similar results were obtained by replacing the adipic acid in example 1 or 2 with any of azelaic acid, suberic acid or sebacic acid.

Claims (6)

1. A tablet having a core and a coating, wherein the core is formed by compressing a particulate material, the particulate material comprising surfactant and detergent builder, characterised in that the coating comprises a dicarboxylic acid.

2. A tablet according to claim 1 wherein the carbon chain length of the dicarboxylic acid is from C2 to C13.

3. A tablet according to claim 1 wherein the coating material consists essentially of dicarboxylic acid.

4. A method of making a tablet comprising the steps of:

(a) forming a core by compacting a particulate material, the particulate material comprising surfactant and detergent builder;

(b) applying a coating substance to the core, the coating substance being a melt;

(c) solidifying the molten coating substance;

characterized in that the coating material contains a dicarboxylic acid.

5. A process according to claim 4, wherein the coating substance or the mixture of coating substances has a melting point of from 40 ℃ to 200 ℃.

6. A method of making a tablet comprising the steps of:

(a) forming a core by compacting a particulate material, the particulate material comprising surfactant and detergent builder;

(b) applying a coating substance to the core, the coating substance being soluble in a solvent or water;

(c) allowing the solvent or water to evaporate;

characterized in that the coating material contains a dicarboxylic acid.