Title of Invention

PROCESS FOR PRODUCING DRY SOAP/SURFACTANT AND A SYSTEM THEREFOR

Abstract

The present invention relates to a process for producing particulate dry soaps/surfactants, e.g. as noodles, from their respective pastes in particular to a simple and cost-effective process for producing such dried soap/surfactants and to a system for carrying out such a drying process. A process for drying soap or surfacnt pastes, preferably and AOS paste, in which the paste is preheated to a temperature of at least 120°C and then atomised in an atomiser under a vaccum of 35 to 65 mm Hg to produce the dried product.

Full Text

FORM 2 THE PATENTS ACT, 1970 (39 OF 1970) COMPLETE SPECIFICATION (See Section 10) 1. TITLE OF INVENTION PROCESS FOR PRODUCING DRY SOAP/SURFACTANT HINDUSTAN LEVER LIMITED, a company incorporated under the Companies Act, 1913, of Hindustan Lever House, 165/166 Backbay Reclamation, Mumbai -400 020, State of Maharashtra, India and GODREJ SOAPS LIMITED, a company incorporated under the Indian Companies Act of Pirojshanagar, Eastern Express Highway, Vikhroli, Mumbai - 400 079, State of Maharashtra, India, The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed. 6-12-1999 Technical field The present invention relates to a process for producing particulate dry soaps/surfactants, e.g. as noodles, from their respective pastes in particular to a simple and cost-effective process for producing such dried soap/surfactants and to a system for carrying out such a drying process. Background to the Invention Processes in which soaps and/or surfactants, or compositions containing them are granulated and dried are known, whereby the soaps or surfactants are provided in the form of paste starting materials. These conventional paste processing methods utilise capital intensive equipment in the form of a high speed mixer/densifier, the output of which is coupled to a moderate speed mixer/densifier, followed by a drier. Thus, there remains a need to provide a simpler and more cost effective means of processing such pastes. If such a simpler process could be devised, then it would provide a more cost effective route to fully formulated powder products, based on soap or surfactant granules, e.g. anionic surfactant granules. For this purpose, as anionic surfactant, alpha olefin sulphonates (AOS) are of special interest. AOS is a well known anionic surfactant used in a variety of industrial, personal care, and household-cleaning applications. Household applications include use in laundry and hard-surface detergents, and personal care applications include use in soap bars, shampoos and liquid hand soaps. Beneficial attributes of AOS include good cleaning and foaming properties in both soft and hard water, mildness to skin, and rapid biodegradability. 2 Alpha olefin sulphonates are well known to be obtained by direct sulphonation of alpha olefins (AO) of varying chain lengths to form complex mixtures of alkene and hydroxyalkane sulphonate isomers. AOS is usually marketed as approximately 40% active aqueous solutions. For production of low-density powders in spray towers, 40% active aqueous solutions are suitable for use. Also for high active forms of the surfactant in agglomeration and dry blending of detergent powders having high levels of AOS it is known to use AOS in paste form which is subjected to high sheer agglomeration process to achieve such detergent powders. However, such processes require use of special high sheer mixing equipment to transfer the AOS paste into acceptable detergent products. With the increasing market share of compact powder detergents, new high-active forms of AOS which can be utilized in non-tower processes are being commercialized. Various methods have been followed to remove moisture from AOS pastes to obtain AOS in dry form favouring dry mix route of detergent formulation. It is also known to achieve removal of moisture and drying of liquid-surfactant using agitated thin film evaporator consisting of two major assemblies, a jacketed shell precision machined from the inside and a rotor assembly that revolves at high speeds while closely fitting the shell to drive moisture from feed (AOS pastes). The feed enters the shell tangentially and gets spread along the inside periphery by the distributor. The rotor blade tips move with a close clearance from the wall, spread the feed evenly on the heated surface into a thin film and further agitate the film. The heating medium in the jacket supplies the necessary heat for evaporating the volatile component of the feed. The vapor flows counter current to 3 the liquid film and gets cleared in the entrapment separator before leaving through the vapor nozzle. The concentrated product leaves the evaporator bottom through concentrate nozzle. It is also known to dry liquid surfactants using vertical dryer having the rotor blades hinged and rotating at a fixed clearance from the inside of the shell. The feed enters the shell tangentially and gets spread along the inside surface of the shell into a thin film. The hinged rotor blades keep the film under intense agitation preventing any scale formation. The feed progressively passes through different phases like liquid, slurry, paste, wet powder and finally powder of desired dryness. The vapors flow counter current to the solids and pass through a cyclone or a wet scrubber. Horizontal dryers are also known to be used where the feed is in the form of a thick slurry, paste or wet powder. A combination of vertical and horizontal dryer produces best results when the feed is dilute and a dry powder is required as an end result. Also known is the process of drying using the Short Path Distillation Unit (SPDU) which operates on principles similar to the Agitated Thin Film Evaporator . However, in the SPDU the rotor cage assembly houses an internal condenser and revolves at moderate speed. The feed enters above the distributor and gets spread into a thin film on the inside surface of the shell. The rollers on the rotor cage gently agitate the film. The product travels down over the heated surface in a very short time while generating vapors. These vapors flow across the rotor and condense on the internally mounted condenser. This short vapor path eliminates pressure drop. The distilled product and the balance bottoms are taken out through separate outlets. 4 However all the above known drying processes involve use of complex machinery which make the processes mechanically cumbersome. The processes are thus cost extensive both in terms of capital investment on machinery and also maintenance requirements. Also such known drying methods are not suitable for working large quantity materials for drying. The need for dry surfactant particles due to its prospective product versatility have led to further innovations in the art of producing dry surfactant products such as the Turbo Tube dryer system. The system involves pre heating the high active surfactant paste and metering to a multi tube, steam-jacketed drying vessel. A high velocity injection system balances the load to each tube. The process achieves about 40% of the total drying during an initial flash evaporation of the paste. After flashing the resultant water vapor propels the detergent paste down the tube at high velocity. The two phase flow providing for increased heat transfer from the steam heated tube wall to the paste resulting in further drying. The dry paste is extruded as small diameter needles and chilled to improve handling properties. Although the above turbo tube drying process of producing dry surfactant in the form of needles do not involve the conventional dryers complications due to absence of any moving parts such as those provided in agitated thin film evaporator, vertical/horizontal dryers and the short path distillation unit discussed above, the same is found to be cost extensive and has limitations in capacity. US-A-4 923 627 discloses process for preparing hard translucent, high moisture soap bars. This process comprises (a) preparing a molten wet kettle soap containing 29 to 32% water, (b) heating the molten wet kettle soap to a temperature of about 190°F, (c) spray drying the molten wet kettle soap in a spray 5 dryer operated at a temperature of 190-230°F (87.8-110°C) under vacuum, (d) extruding the spray dried soap containing 18-25% water to prepare pellets, (e) plodding the pellets in a vacuum plodder, (f) pressing the plodded soap at a temperature of 90 to 100°F (32-38°C) into bars, and (g) recovering the hard translucent high moisture soap bar product. It would be evident from the above that while there is growing demand for powder detergents and the like, simple and cost-effective process for manufacture of soap/surfactant particles, e.g. granules, pellets or noodles which are suitable for incorporation into powder products such as those sold for the washing of fabrics is not known in the art possibly due to difficulty in achieving the desired low moisture content of such products using cost-effective process/system. It is thus the basic object of the present invention to provide a process for producing dry soap/surfactant especially AOS from paste which would be simple, cost effective, energy efficient and safe to carry out. Another object of the present invention is to provide a process for producing dry surfactant in particular AOS as dry noodles from paste. Yet another object of the present invention is to provide a process for producing AOS as dry noodles which would provide for greater flexibility in application and end use of surfactant/AOS. Yet further object is directed to produce AOS in dry noodles from AOS paste which would be easy to handle and transport and would at the same time be storage stable. 6 Yet further object is to provide a system for producing surfactant such as AOS in dry noodle form from paste which would be simple to obtain and easy to operate." Definition of the invention Thus, according to the present invention, there is provided a process for producing dry soap or dry surfactant from a soap paste or from a surfactant paste, the process comprising: (i) pre-heating the soap paste or surfactant paste to a temperature of at least 120°C; and (ii) atomising the pre-heated soap paste or surfactant paste in an atomiser, the atomiser being maintained under vacuum in the range from 35 to 60 mm Hg; whereby the dried soap or surfactant is obtained. Detailed Description of the Invention The paste may comprise one or more soaps and/or one or more (synthetic) detergent surfactants, the latter at least partially (most preferably substantially totally) comprising one or more anionic surfactants. Especially preferred as all or part of any anionic surfactant component are alpha olefin sulphonates, especially having an average carbon atom content of C12-C14. Other anionic surfactants are well known to those skilled in the art. Examples include alkylbenzene sulphonates, particularly linear alkylbenzene sulphonates having an alkyl chain length of C8-C15 primary and secondary alkylsulphates, particularly C8-C15 primarily alkyl sulphates; alkyl ether sulphates; alkyl xylene 7 sulphonates; dialkyl sulphosuccinates; and fatty acid estersulphonates. Sodium salts are generally preferred. Preferably, following the above process it is possible to provide dry soap/surfactant in the form of noodles from soap/surfactant paste. A preferred embodiment for forming such noodles comprises : pre-heating the soap/surfactant paste to a temperature of 120 - 170°, followed by subjecting the same to atomization in an atomizer, said atomizer maintained in vacuum of 35 - 60 mm Hg to thereby provide dried soap/surfactant; extruding at least once the thus dried soap/surfactant paste to provide the soap/surfactant in the form of dry noodles. In accordance with one preferred embodiment, the process of the invention involves producing dry AOS noodles from AOS paste comprising : pre-heating the AOS to a temperature of 120 - 170°C followed by subjecting the same to atomization in an atomizer maintained in vacuum of 35 - 60 mm Hg to provide the dried surfactant, and extruding the thus dried surfactant through an extruder/plodder at least once to provide dried noodles of AOS. Optionally, one or more filler materials such as alkali metal (e.g. sodium) carbonates, silicates, sulphates or aluminosilicates may be incorporated in the paste, e.g. to structure the final product. The total amount of filler material is preferably no more than 5wt%, most preferably no more than 1wt% of the paste. However, it is especially preferred for filler materials to be substantially omitted. In fact, apart from the soap and/or surfactant and the water, the total amount of other 8 components in the paste is preferable no more than 5wt%, most preferably no more than 1wt%, especially substantially Owt%. It is preferable to incorporate one or more anti-tac (layering) agents such as talc, aluminosilicate or boric acid prior to the process of extrusion. Such materials are optionally included in a weight ratio from 1:5 to 1:20 of layering agent: product prior to addition of the layering agent. Preferably, the paste is preheated to 135-150°C more preferably 140-145°C and pumped to the atomizer using a positive displacement pump at a rate of 1 to 2 MT/ Hr. The back pressure on the paste at the inlet to the atomizer is selected to be 2-8 kg/cm2 preferably 3-6 kg/cm2 and more preferably 4 to 4.5 kg/cm2. In accordance with another aspect of the present invention, there is provided a process for producing dry surfactant noodles such as dry surfactant/AOS noodles comprising : pre-heating the AOS paste to a temperature of 120 - 170°C followed by subjecting the same to atomization in an atomizer maintained in vacuum of 35 - 60 mm Hg. to provide the dried surfactant; extruding at least once the thus dried surfactant through an extruder/plodder to provide dried noodles of said AOS ; cooling the noodles while passage through said extruder/plodder by circulating chilled water through the plodder cooling jacket. Preferably the said extruder/plodder cooling jacket is circulated with chilled water having inlet temperature of 5-15°C preferably 8-12°C. 9 By way of such cooling the dry noodle output from the atomizer which has a temperature in the range of 25-55°C preferably 30-50°C is cooled down to 25-35°C preferably 25-30°C. Advantageously, the noodles thus obtained after cooling to 25-30°C are re-plodded in an extruder/plodder similar to the one previously used. The temperature of noodles at the outlet after re-plodding is 30-50X which are again cooled to 30-35°C. The thus cooled dry AOS noodles are preferably packed in HDPE bags stitched and stored for transportation. Thus, by way of the above preferred process of the invention, AOS paste of 18 to 36% moisture preferably 24 to 30% can be dried on an atomizer maintained in vacuum preferably 45 - 55 mm Hg to a moisture content of only about 1-15%, preferably 6-12% and more preferably 7-9%. In accordance with a further aspect of the present invention, there is provided a system for producing dried surfactant/soap noodles comprising : a pre heating unit to preheat the surfactant/soap ; an atomizer adapted to be maintained under vacuum ; means to feed said surfactant/soap into said atomizer; and extruder/plodder means to provide the said dried noodles of soap/surfactant. Preferably, the atomizer nozzle is selected to have a diameter in the range of 4 -15 mm preferably 8-15 mm and more preferably 10-12 mm. 10 The extruder/plodder can be a compressed mechanical plodder preferably a twinworm plodder having a cooling jacket adapted for circulation of chilled water there through. It is thus possible by way of the present invention to provide for a simple and cost effective method of producing dry soap/surfactant from pastes thereof especially dry AOS in the form of noodles from AOS paste which would favour achieving flexibility and versatility in application/end uses of the surfactant/AOS. The process utilizes simple and cost effective gadgets which is convenient and easy to operate and can be used for producing dried soap/surfactant noodles of varying capacity and bulk. Importantly, the process and system of drying soap/surfactant of the invention is safe and favour convenient operation detergent dry mix technique. The dry noodles of soap/surfactant thus obtained by way of the invention apart from favouring vertical end uses will also be convenient to handle, transport and for storage. The noodles prepared as above may be incorporated with other ingredients, especially solid ingredients, to formulate a full detergent powder composition, e.g. in the manner disclosed in WO-A-98/54287 and WO-A-98/54289. For example, they may be admixed with a conventional substantially fully formulated composition, e.g. made by a spray drying or mechanical non-spray drying process. Optionally, one or more other ingredients may be dosed separately to this mixture. This is a convenient way of increasing the total detergent content of such a composition. Alternatively, the noodles may be mixed with plural other components to form a fully formulated detergent composition by a multi-adjunct approach. 11 The total final composition may then contain two or more surfactants, especially anionic and/or nonionic surfactants, and/or one or more detergency builders such as sodium tripolyphosphate and/or sodium aluminosilicate. Other usual detergent composition components also may be included, e.g. selected from bleaches and bleach systems, enzymes, fluorescers, soil release agents, antifoams and the like, and mixtures thereof. The present invention will now be explained in more detail by the following non-limiting examples. Examples Example 1 C14-C16 alpha olefin sulphonate was converted to a paste by admixture with water to a total moisture content of 22% by weight. The paste was preheated to 150°C and pumped at a rate of 1.5MT/hr to a vacuum atomizer where it was atomised at a reduced pressure of 50mm Hg. The back pressure on the paste at the inlet to the atomiser was 4.3kg/cm2. The atomiser nozzle was 10mm diameter. The resultant product was found to have a moisture content of 8wt%. The atomised product was admixed with 7wt% of sodium aluminosilicate layering agent, based on its weight before addition of the layering agent. The product was then extruded through a twinworm extruder/plodder having a cooling jacket through which water was circulated at 10°C. The resultant noodles emerged at a temperature of 40°C, were cooled at 30°C and then pre-plodded in an identical plodder to emerge again at a temperature of 40°C and cooled once more to 30°C. 12 After storage, the noodles were incorporated in a fully formulated product as follows: A base powder B was prepared by dosing the listed components into a high¬speed Fukae batch granulator and granulating. The sodium LAS in the base powder was prepared by in situ neutralisation of LAS acid with sodium carbonate. The materials were granulated until powder with good particle size was obtained. Ingredients wt%] Base Powder B STP 42.6 NaLAS 27.4 Sodium carbonate 27.0 Impurities & Moisture 3.0 The base powder B was then mixed with the noodles prepared as above to give a final detergent composition. Formulation Base powder B 60.4 AOS noodles 34.1 Granular sodium carbonate 5.5 13 WE CLAIM: 1. A process for producing dry soap/surfactant from a soap/surfactant paste comprising: (i) preheating the soap /surfactant to a temperature of from 120°C to 170°C; and (ii) atomizing the preheated soap/surfactant paste in an atomizer such that the back pressure on the preheated paste at the inlet of the atomizer is in the range of 2 to 8 kg/cm2, the atomizer being maintained in vacuum in the range from 35 to 60 mm Hg; whereby the dried soap/surfactant is obtained such that it has a moisture content of 1-15%. 2. A process as claimed in claim 1 wherein the soap/surfactant paste is preheated to a temperature of at least 135°C preferably at least 140°C. 3. A process as claimed in anyone of claims 1 or 2 wherein the soap/surfactant paste is preheated to a temperature not in excess of 180°C preferably not in excess of 170°C. 4. A process as claimed in anyone of preceding claims wherein the surfactant is an anionic surfactant. 5. A process as claimed in claim 4 wherein the anionic surfactant is alpha olefin sulphonate, preferably having an average carbon atom content of C12 - Ci6 more preferably Cn - C14. 6. A process as claimed in anyone of preceding claims wherein the soap/surfactant paste used has a moisture content of more than 15 wt% preferably more than 18 wt% more preferably more than 20 wt%. 14 7. A process as claimed in anyone of preceding claims wherein the soap/surfactant paste used has a moisture content of 18 to 40 wt% preferably 20 to 30 wt% more preferably 24to30wt%. 8. A process as claimed in anyone of preceding claims wherein the dried soap/surfactant thus produced has a moisture content of about 1 to 15 wt% preferably 6 to 12 wt% more preferably 7 to 9 wt%. 9. A process as claimed in anyone of claims 1 to 8 wherein the paste optionally incorporates up to 5% of one or more filler material selected from alkali metal carbonates, silicates, sulphates or aluminosilicates. 10. A process as claimed in anyone of preceding claims comprising obtaining the dried soap/surfactant from step (ii) through an extruder/plodder having a perforated plate at the discharge end, whereby dry noodles of soap/surfactant are obtained. 11. A process as claimed in claim 10 wherein an anti-talc agent is added to the dried soap/surfactant being fed into the extruder/plodder. 12. A process as claimed in anyone of claims 10 or 11 wherein the extruder/plodder used includes a cooling means, preferably a cooling jacket, which provides sufficient cooling to ensure the noodles leaving the extruder/plodder are at a temperature of no more than 35°C. 13. A process as claimed in anyone of claims 10 to 12 wherein a liquid with an inlet temperature of no more than 15°C is circulated through the cooling means. 14. A process as claimed in anyone of claims 10 to 13 wherein the liquid inlet temperature is in the range from 5 to 15°C preferably 8 to 12C. 15 15. A process as claimed in anyone of claims 10 to 14 comprising admixing the noodles with one or more other solid ingredients to produce a powder detergent composition. 16. A process as claimed in any preceding claim wherein the atomizer used is maintained under a vacuum of 45 to 55 mm Hg. 17. A process as claimed in any preceding claim wherein the atomizer used has a nozzle of diameter in the range of from 4" to 15 mm preferably 8 to 15„,and more preferably 10 to 12 mm. 18. A process as claimed in any preceding claim wherein the preheated paste is pumped to the atomizer at a rate 1 to MT/hr by a positive displacement pump. 19. A process as claimed in any preceding claim wherein the back pressure on the preheated paste at the inlet to the atomizer is in the range from 3 to 6 kg/cm2 preferably 4 to 4.5 kg/cm2. Dated this 7th day of December 2000 6

Documents:

926-bom-1999-cancelled pages(07-12-2000).pdf

926-bom-1999-claims(granted)-(07-12-2000).pdf

926-BOM-1999-CORRESPONDENCE(8-2-2012).pdf

926-bom-1999-correspondence(ipo)-(15-10-2007).pdf

926-bom-1999-correspondence1(07-12-2000).pdf

926-bom-1999-correspondence2(19-12-2006).pdf

926-bom-1999-form 1(16-12-1999).pdf

926-bom-1999-form 2(granted)-(07-12-2000).pdf

926-bom-1999-form 3(07-12-2000).pdf

926-bom-1999-form 3(26-06-2003).pdf

926-bom-1999-form 4(12-07-2004).pdf

926-bom-1999-form 5(07-12-2000).pdf

926-bom-1999-form 5(26-06-2003).pdf

926-bom-1999-form-pct-isa-210(26-06-2003).pdf

926-bom-1999-petition under rule 124(23-07-2001).pdf

926-bom-1999-power of attorney(30-06-2003).pdf