WO2002090475A2

WO2002090475A2 - Shaped solid detergent compositions

Info

Publication number: WO2002090475A2
Application number: PCT/EP2002/005098
Authority: WO
Inventors: Sudhir Achar; Bir Kapoor; Velayudhan Nair Gopa Kumar; Samiran Mahapatra; Devadatta Shivaji Sankholkar
Original assignee: Unilever N.V.; Unilever Plc; Hindustan Lever Ltd
Priority date: 2001-05-03
Filing date: 2002-04-26
Publication date: 2002-11-14
Also published as: AU2002317747A1; PL366839A1; BRPI0209272B1; ZA200307520B; RU2303052C2; PL199102B1; WO2002090475A3; MXPA03009817A; CN1309816C; RU2003134963A; CN1688684A; BR0209272A

Abstract

A shaped detergent composition comprising: 0.5-60% detergent active; 0-90% inorganic particulates; and other conventional ingredients, wherein the external surface of the said shaped detergent composition comprises one or more materials that are substantially water insoluble, said material having melting point greater than 30oC, being adherent to the external surface and capable of being abraded during use.

Description

SHAPED SOLID DETERGENT COMPOSITIONS

The invention relates to shaped solid detergent composition for cleaning hard surfaces or fabric and more particularly the compositions of the invention are suited for manual washing.

Background and Prior art:

Detergent compositions in general for fabric or hard surface cleaning typically comprise a surfactant system whose role is to assist in removal of soil . The surfactant system may predominantly be non-soap surfactants. Various abrasives, fillers, builders, and other ingredients such as colour, perfume, preservatives, etc. may also be incorporated suitably.

Cleaning compositions in the solid form are much cheaper than liquids because of low cost packaging and these are very popular forms in developing countries. Amongst the solid form bars are gaining popularity and growing rapidly in the market of developing countries because of better value delivery. The product dosage in the solid form is easier, it avoids spillage and the product application can be better controlled. Cleaning compositions in the bar form are economically superior to other product forms and the dosage per swipe from the bar is highly controlled. Detergent bars require an acceptable physical strength so that they retain their structural integrity during handling, transport and use. However, detergent bars for fabric and hard surface cleaning are in constant contact with water during usage and subsequent storage and hence get sogged and generally get disintegrated to paste form. The shape and contour of the bar is not retained satisf ctorily. This problem is generally sought to be solved by making suitable changes in the formulation of the bar. Any attempt to harden the bar, if not properly controlled through formulation, can result into a hard product which in use would not release sufficient product for satisfactory cleaning. Therefore, it is a major challenge to ensure that there is no disintegration of the product during use, no wastage of product through mush generation, and yet the product is sufficiently soft to enable the users to pick up the right quantity of product for cleaning.

IN166806 discloses a process for manufacturing detergent bars having good strength and handling properties during transport and use by the incorporation of various dessicants during neutralisation.

09518215 (Ecolab Inc. 1995) discloses an environmentally stable detergent article. The hygroscopic detergent material is made resistant to absorption of ambient humidity or water by introducing a barrier coating onto the detergent. The object of the invention is to obtain a concentrated aqueous detergent for use in washing machines and also to control over-dispensing. The hydrophobic coating is nicked, split, peeled or partially removed to allow dissolution or melting of the coating in a controlled manner.

09955823 (Procter & Gamble, 1999) discloses a non-particulate detergent product that is provided with a core formed by compressing a particulate material comprising a detersive surfactant and a builder having a substantially water-insoluble coating that substantially covers the contoured core in order to provide mechanical strength, shock and chip resistance to the compressed tablet. It is also essential that this coating dissolves under alkaline conditions or is readily emulsified by surfactants.

Description of the Invention: It has now been found possible to formulate firm shaped detergent compositions that are sufficiently soft to enable the user to pick up a suitable quantity of product while cleaning dishes or fabric, and yet do not lose shape or get soggy by water-uptake during use.

The invention provides a shaped detergent product which comprises a water-resistant coating that is capable of being abraded from the detergent product during use. Preferably the shaped detergent product is an extruded bar. Preferably the bar comprises an abrasive.

The water-resistant film provided on the product reduces disintegration and deformation of the product during use and also reduces wastage of product by reducing undesired mush formation. The water resistant film is inherent on the product surface and although it gets abraded along with the product during usage, it is capable of maintaining the shape and integrity of the product. The water resistant coating is preferably substantially insoluble in water, even under alkaline conditions.

Detailed Description of the invention

Thus according to the present invention there is provided shaped detergent composition comprising:

0.5-60% detergent active,

0-90% inorganic particulates, and other conventional ingredients, wherein external surfaces of the said shaped detergent article are covered with one or more materials that are substantially water insoluble, said materials having melting point higher than 30°C and being adherent to the external surface but is capable of being abraded during use .

The said materials covering external surfaces of the shaped article are chosen from natural or modified natural polymers or synthetic polymeric material or waxes or a mixture thereof that are substantially water-insoluble and have a melting point higher than 30°C, that are adherent to the external surface but are capable of being abraded during use. More particularly, the said materials may be a mixture of one or more polymers and film-forming diluents selected from natural and synthetic waxes, polysacharides, water-insoluble salts of fatty acids, all having melting point higher than 30°C. Preferably, the said materials comprise 5-25% by weight one or more atactic alpha olefin copolymers and 75-95% by weight a film forming diluent selected from one or more of natural and synthetic waxes having melting point higher than 30°C.

It is particularly preferred that the atactic alpha olefin copolymers are rich in propene or butene monomers .

The synthetic or (modified) natural polymeric material used for the purpose of the invention preferably has molecular weight more than 1600 daltons. When natural or modified natural polymer is used the water vapour permeability coefficient of the said natural or modified

[Cm³ ]Cm] polymers is preferably less than 5000 X 10^"13 [crø²KTp_fll

When synthetic polymer is used the water vapour permeability polymer is preferably less

where [Cm³] = Cm³ (273 , 15K; 1 , 013 X 10⁵ Pa . ) , as outlined in "Polymer Handbook, 1989 , Third edition, Eds . J . Brandrup and E . H. Immergut , (Wiley- Interscience Publication) , page Vl/436 " .

The material covering external surfaces of the detergent article according to the invention preferably has a percentage elongation at break greater than 2% at 25°C. The material covering the external surface of the detergent article is preferably in the form of a film whose thickness is maintained in the range 5-1000 microns and more preferably 10-100 microns and particularly 30 to 60 microns.

The detergent composition useful for fabric or hard surface cleaning may suitably be formulated in the form of a bar which form includes a tablet or compact or a cake. This bar essentially has outer surfaces having one or more water resistant materials thereon preferably having a melting point higher than 30°C. Preferably the material on the outer surface is in the form of a film having thickness of not less than 5 micron that inherently adheres to the outer surface of the contour of the product. The water resistant film is preferably substantially insoluble in water, even under alkaline conditions. Preferably the bar is extruded. Accordingly, a further aspect of the present invention subsists in a process for the manufacture of a detergent bar which comprises the steps of:

(a) extruding a detergent composition to form a detergent bar, and,

(b) providing on outer surfaces of the bar one or more materials that are substantially water insoluble, have melting point higher than 30 °C and together form a water resistant film.

It is especially preferred that the material is a polymerisable photo curable polymeric material .

Water resistant film: The film is made of suitable material that form a water barrier and such that it is inherently adhering to the outer surface of the detergent product. The film is preferably at least 5 microns thick and may be as thick as 1000 microns, preferably 10-100 microns, and more preferably 30-60 microns. The water resistant film is preferably substantially insoluble in water, even under alkaline conditions.

The material used as the film has a melting point higher than 30°C, and preferably higher than 45°C. At least the surface of the bar which is most likely to be in prolonged contact with water during use will be coated with the water resistant film material. Preferably, all surfaces which are likely to come into such contact will be coated. It will be clear that the top side or working surface of the bar, from which the detergent material is taken or applied to the article to be cleaned, need not necessarily be coated, but preferably the other, non- working, surfaces of the bar are all coated. Film forming materials:

Suitable film forming materials can be comprised of water insoluble materials such as polymers and the combinations thereof, natural and synthetic waxes, polysacharides and water insoluble salts of fatty acids that form inherent film on the outer surfaces of the said detergent composition. The film can also comprise any of the said organic materials together with inorganic materials as diluents/fillers to modify the mechanical properties of the said film.

It is possible to select materials which themselves do not form an adhering film on the surface of the detergent product, but can be made adherent by using another material that has the ability to bind the detergent product and the water resistant material .

Films can be formulated in a liquid solution or dispersion using a solvent or in a heated melt form consisting of single or multiple polymeric/organic materials.

The film composition can be prepared using a composition of polymer (s), various waxes and additives known as tackifiers to improve the adhesive properties of the composition. Appropriate combination of these can be arrived at to provide desired workability and mechanical strength. The said film can be prepared using a base polymer alone depending on the properties of the coating required. The base polymer can be selected from the list below: poly acrylates, poly methylmethacrylate, poly styrenes, poly (ethylene-co-vinyl acetate) , poly (ethylene-co- acrylates) , poly (ethylene-co-methacrylates) , poly (styrene-co- acrylates) , poly olefins, atactic poly α-olefins, poly ethylene, poly propylene, amorphous poly α-olefins, poly imides, nylon, poly vinyl chloride, poly ethylene terephthalate, poly urethanes, epoxy resins.

The natural and synthetic waxes are optionally added to composition to provide application viscosity control in molten state and act towards obtaining less dry tack and erodability. Such waxes can be selected from poly ethylene waxes, fischer tropsch waxes, microcrystalline waxes, paraffin waxes.

Tackifiers and adhesion promoting agents may optionally be added to the composition to increase the cohesive and binding characteristics of the film. These materials can be chosen from the following list: hydrocarbon resins, petroleum C₅-C₉ resins, hydrogenated petroleum resins, aliphatic petroleum resins, alicyclic petroleum resins, coumarine petroleum resins, terpene based resins, stryrene resins, phenol based resins, ester gums, rosins such as gum rosin and wood rosin.

Antioxidants are optionally added to the composition to prevent degradation in the molten state. These antioxidants can be chosen from the following list: phenol base anioxidants such as 2, 6-di-tert .butyl-p-cresol, 2,2^*' -methylenebis- (4-methyl-6-tert- butylphenol) , 4, 4' -butylenebis- (3-methyl-6-tert-butylphenol) , 4, 4' -thiobis- (3-methyl-β-tert-butylphenol) , 2,2' -thiobis- (4- methyl-6-tert-butylphenol) , stearyl-β- (3, 5-di-tert-butyl-4- hydroxyphenol)propionate, tetrakis (methylene-3- (3,5-di- tert .butyl-4-hydroxyphenyl) propionate) methane, triethylene glycol, bis (3- (3-tert .butyl-4-hydroxy-5- methylphenyl) propionate, 1,3, 5-triethyl-2 , 4, 6-tris (3, 5-di-tert- butyl-4-hdroxybenzyl) benzene and 1, 1, 3-tris (2-methyl-5-tert- butylphenol) -butane; amine base antioxidants such as phenyl-α- naphthylamine, phenyl-β-naphthylamine, N-phenyl-N' -cyclohexyl- p-phenylenediamine and N-isopropyl-N' -phenyl-phenylenediamine; phosphorous base antioxidants such as triisodecyl phosphite and 2,2' -methylenebis (4, 6-di-tert-butylphenyl) ocyl phosphite; sulfur- base antioxidants such as 2 , 2 ^r -thiobis (4-methyl-6-tert- butylphenol) ; and hydroquinone antioxidants such as 2,5-di- tert-amylhydroquinone .

The film composition can also be prepared using ultra-violet (UV) cure formulation involving acrylate based oligomers, monomers and photo-initiaters. Typical oligomers can be selected from the group: urethane acrylate, polyester acrylate, polyether acrylate, poly butadiene acrylate and epoxy acrylate and their combinations to achieve the desired film properties. Descriptions of such oligomers are presented in "N.S. Allen, M. A. Johnson, P. Oldring (ed.) and M. S. Salim, Chemistry & Technology of UV&EB-Curing Formulations for Coatings, Inks & Paints, Vol. 2, SITA Technology, London 1991". Monomers can be chosen from the mono, di, tri, tetra and penta functional acrylates with various aliphatic or aromatic backbones. Typical examples of monomers include tripropylene glycol diacrylate (TPGDA) , 1,6 hexanediol diacrylate (HDDA) , propoxylated3 glyceryl triacrylate (GPTA) , Isobornyl acrylate, 2-phenoxy ethyl acrylate (2-PEA) , Tridecyl acrylate (TDA) , ethoxylated nonyl phenol acrylate (EONPA) , ethoxylated pentaerythritol tetraacrylate (EOPETA) , ehtoxylated bisphenol A diacrylate (EOBPADA) , trimethylolpropane trimethacrylate (TMPTA) & triacrylate, allyl methacrylate, stearyl acrylate & methacrylate, 1,3 butylene glycol dimethacrylate, ethylene glycol dimethacrylate, cyclohexyl methacrylate, glycidyl methacrylate, isodecyl acrylate, isooctyl acrylate, polyethelene acrylate. Customary photoinitiators include aromatic ketone compounds, such as benzophenone, alkylbenzo- phenones, Michler's ketone, anthrone, halogenated benzophenones, 2 , 4, 6-trimethylbenzoyldiphenylphosphine oxide, phenylglyoxylic esters, anthraquinone and its derivatives, benzil ketals, hydroxyalkylphenones, etc. can be used for polymerization initiation. Mixtures of these compounds may also be employed.

The film forming material can also include as additives: inorganic materials such as talc, silica, china clay, oxides, carbonates and chlorides of alkali or alkaline earth metals or transition metals and preferably they are salts of calcium or magnesium or zinc .

Methods of film formation:

The detergent composition is provided with the water resistant material by any of the following methods. The shaped detergent article may be first prepared and then the surface is coated with the water resistant material by using any conventional process. Such processes include applying the coating material in molten condition such as by dipping the detergent article in the coating melt or spraying the coating melt on the article, followed by cooling to solidify the coating material. Such processes also include applying the coating material as a solution in a suitable solvent, again such as by dipping or spraying, followed by evaporating the solvent in known ways. Specific kinds of film forming coating material may also be applied in a monomeric or oligomeric form whereafter the material is further reacted on the surface of the detergent article to form the water resistant film. Such processes are known as heat-, Ultra Violet or Electron Beam curing. Coating may also be applied using an intermediate when the water resistant material does not adhere to the product . Furthermore, the coating may be co-extruded with the detergent article. Detergent Actives :

The detergent compositions according to the invention will preferably comprise detergent actives that may be soap or non- soap surfactants and generally chosen from anionic, nonionic, cationic, zwitterionic detergent actives or mixtures thereof. Suitable examples of detergent-active compounds are compounds commonly used as surface-active agents given in the well-known textbooks: "Surface Active Agents" Vol.l, by Schwartz & Perry, Interscience 1949, Vol.2 by Schwartz, Perry & Berch, Interscience 1958; in the current edition of "McCutcheon ' s Emulsifiers and Detergents" published by Manufacturing Confectioners Company; or in "Tenside-Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981.

The total amount of detergent active compound to be employed in the detergent composition of the invention will preferably be from 5-30% by weight of the composition.

Abrasives : The detergent compositions according to the invention preferably comprise solid insoluble abrasive. Suitable abrasives can be selected from, particulate zeolites, calcites, dolomites, feldspar, silicas, silicates, other carbonates, aluminas, bicarbonates, borates, sulphates and polymeric materials such as polyethylene. There can be an abrasive system with more than a single type of abrasive to achieve a balanced abrasive property. It has been shown that combination of abrasives of different hardness in a formulation provide significant benefits in some of the user properties. Abrasive may also be included in the coating to assist in its initial removal on the side where the detergent composition is being applied to the article to be cleaned. Detergency Builders:

Detergency builders / alkaline buffer salts are preferably used in the detergent compositions. They are preferably inorganic and suitable builders include, for example, alkali metal aluminosilicates (zeolites) , sodium carbonate, sodium tripolyphosphate (STPP) , tetrasodium pyrophosphate (TSPP) , and combinations of these. Builders/ alkaline buffer salts are suitably used in an amount ranging from 2 to 15% by wt, preferably from 5 to 10% by wt .

Other Ingredients :

Other ingredients such as fillers, solvents, amines, perfumes, colouring agents, flourescers, enzymes can also be used in the formulation, for example, in an amount up to 10 wt%.

The invention will now be illustrated by the following non- limiting examples.

Examples :

A detergent composition useful for washing dishes, having a formulation as described in Table 1 was used for the demonstration of the invention. The bar was not covered with any water resistant material (Example 1) , in Example 2, the bar was covered with a film of 40 micron thick made of poly(methacrylonitrile-co-styrene) -50/50 ratio that had a

permeability coefficient greater than 1000X10^"13 that

is greater than preferred for the present invention. In Examples 3-5 the composition of the film was. a mixture comprising of 25% by weight of amorphous poly-α-olefin and 75% by weight of microcrystalline wax melted together at temperature of 150°C and the permeability coefficient was below

which is according to the invention. The thickness of the film was less than 5 microns (Example 3), greater than 1000 microns (Example 4) and was 40 microns in Example 5. In Examples 2-5 the bars were covered with a film on all sides except the surface which is used for picking up the product for use.

Determination of bar integrity:

The bars according to Examples 1 to 5 were tested by a trained panel for a period of 1 week for washing dishes under controlled simulated consumer usage conditions. The panellists gave a score on a 0 to 10 scale where 0 refers to very low disintegration and deformation and 10 very high disintegration and deformation. Similarly, the panellists gave a score on a 0 to 10 scale where 0 refers to very high economy and 10 very low economy in use .

The bar was also tested by immersing the portion covered by the film in water for 2 hours and determining the bar loss to solution after two hours. The data are presented in Table 2.

Fig la to lc. Show the bar characteristics before and during use.

Fig la refers to an unused sample

Fig lb refers to examples 5, that is according to the invention

Fig lc refers to Example 1, the control sample Table 1

Table 2

* The shell is too thick to be abraded and leads to poor economy.

The data show that the bars according to the invention are economical as the bar loss to solution is very low and also as per scores given by the panellists. The control bars and bars with a film less than 5 microns thick get deformed significantly and when the film is greater than 1000 microns the film does not get abraded during use and leaves a shell . This also leads to poor economy and is not preferred by the user because of the inconvenience in product pick up and for aesthetic reasons. Coating with microcrystalline wax:

The bars were prepared by extruding the detergent formulation given in table 1. The bars were coated with the hot melt coating composition by dipping the bar for 3-5 seconds in a bath containing the composition at 150°C. The excess of the coating material was allowed to drip into the bath and the coated bar was allowed to cool to room temperature. The details of the composition of the coating materials are described in Table 3.

The bars were analysed for various properties by the following method.

1. Coat adhesion: The coat adhesion was measured by assessing the ease at which the coated film could be peeled off from the detergent bar surface. A rating of 1 to 5 was given. Rating of 1 represents excellent adhesion of the coating on to the bar surface where the film could not be peeled off from the bar surface, while a rating of 5 represents poor adhesion and the coated film could be easily peeled off from the bar surface . 2. Bar intergitys The bar integrity was measured by the procedure described earlier.

Table 3

Table 4

The data presented in Table 4 show that a detergent bar having an external surface with microcrystalline wax either alone or in combination with poly olefins leads to superior adherence to the bar and also maintains bar integrity.

Coating with modified natural polymers:

The bars were prepared by extruding the detergent formulation given in table 1. The bars were coated with a solution of cellulose derivatives. Example 9 cellulose acetate, example 10 was cellulose nitrate, and example 11 was ethyl cellulose and was compared with the uncoated bar Example 1. Table 5

The data presented in Table 5 show that the modified natural polymers with permeability coefficient less than 5000 are useful in maintaining the bar integrity.

Claims

1. A shaped detergent composition comprising: 0.5-60% detergent active; 0-90% inorganic particulates; and other conventional ingredients, wherein external surfaces of the said shaped detergent composition are covered with one or more materials that are substantially water-insoluble, said materials having melting point higher than 30°C, being adherent to the external surface and capable of being abraded during use .

2. A shaped detergent composition as claimed in claim 1 wherein the said materials are chosen from natural or modiefied natural or synthetic polymeric material or waxes or mixtures thereof

3. A shaped detergent composition as claimed in claims 1 or 2 wherein said material is chosen from natural or modified natural polymers with water vapour permeability coefficient

wherein [Cm³] is = Cm³(273,15K; 1,013 X 10⁵ Pa) ^•

4. A shaped detergent composition as claimed in claims 1 or 2 wherein the said material is chosen from synthetic polymers with water vapour permeability coefficient less than 1000 X

[Cm³]Cm] ^10~13 |θw²EϊPαl ^{here± [}Cro³] = Cm³⁽273,15K; 1,013 X 10⁵ Pa).

5. A shaped detergent composition as claimed in anyone of the preceding claims wherein the said polymeric material has molecular weight more than 1600 daltons.

6. A shaped detergent composition as claimed in anyone of the preceding claims wherein the said material is a mixture of one or more polymers and film forming diluent selected from one or more of natural and synthetic waxes, polysacharides, water insoluble salts of fatty acids having melting point higher than 30°C.

7. A shaped detergent composition as claimed in anyone of the preceding claims wherein the said material comprises 5-25% by weight one or more atactic alpha olefin polymers and 75- 95% by weight a film forming diluent selected from one or more of natural and synthetic waxes having melting point higher than 30°C.

8. A shaped detergent composition as claimed in claims 6 wherein the atactic alpha olefin polymers are rich in propene or butene monomer.

9. A shaped detergent composition as claimed in any preceding claims wherein external surface of the composition is covered by a film having a percentage elongation at break greater than 2% at 25°C.

10. A shaped detergent composition as claimed in any preceding claim 8 wherein the said film has a thickness in the range 5-1000 microns

11. A shaped detergent composition as claimed in claim 10 wherein the thickness of the film is between 10-100 microns .

12. A shaped detergent composition as claimed in claim 11 wherein the thickness of the film is between 30 to 60 microns .

13. A process for the manufacture of a shaped detergent composition as claimed in claim 1 which comprises the steps of :

(a) extruding a detergent composition in a shaped form; and

(b) providing on the outer surface of the composition one or more materials that are substantially water insoluble and have melting point above 30 °C.

14. A process for the manufacture of a shaped detergent composition as claimed in claim 13 wherein the said material is a heat-, ultra violet or electron beam polymerisable or curable polymeric material .

15. A process as claimed in claims 13-14 wherein the shaped detergent composition is in the form of a bar or tablet or compact or cake .

16. A shaped detergent composition substantially as herein described with reference to the examples .

17. A process for the manufacture of a shaped detergent composition substantially as herein described with reference to the examples.