WO2009121890A1

WO2009121890A1 - Process for the preparation of laundry soap bars with improved storage stability

Info

Publication number: WO2009121890A1
Application number: PCT/EP2009/053828
Authority: WO
Inventors: Niels Henrik Soerensen; Li Hao Dong; Geoffrey Duncalf
Original assignee: Novozymes AS
Current assignee: Novozymes AS
Priority date: 2008-04-01
Filing date: 2009-03-31
Publication date: 2009-10-08
Anticipated expiration: 2010-10-01
Also published as: BRPI0909390B1; BRPI0909390A2; CO6290787A2

Abstract

The present invention relates to a process for the preparation of laundry soap bars comprising the steps of a) Preparing a premix by mixing an enzyme, a stabilizer, a polyol and optionally a pH controlling agent; b) Mixing the premix of step a) with a soap,- c) Refining the mixture of b) to refined soap; and d) Plodding the refined soap of step c).

Description

PROCESS FOR THE PREPARATION OF LAUNDRY SOAP BARS WITH IMPROVED STORAGE STABILITY

FIELD OF THE INVENTION

The present invention relates to a process for preparing enzymatic laundry soap bars, more particularly enzymatic bars with improved enzyme stability. It also relates to a premix for use in the process and to use of the laundry soap bars.

BACKGROUND OF THE INVENTION

It is well known to add enzymes to laundry bars. When adding enzymes to laundry bars stability of the added enzymes during production and storage becomes an issue of significant importance. It is of course desirable to retain as much activity as possible. Activity of the added enzymes can be affected by e.g. the water content of the laundry bar. A high water content generally results in a lower activity during storage of the added enzyme, especially for proteases.

GB 2186883 describes laundry bars with a water content of 10-33% and containing proteases in which the proteolytic enzyme is stabilized by a mixture of a boron compound, a polyol, an organic acid or its alkali metal salt, and an alkali metal salt of an inorganic acid which is not a boron compound.

WO 98/54285 describes high-moisture protease containing laundry bars with improved protease stability. The improved stability is obtained by adding a stabilizing agent made of a borate compound in conjunction with a polyol, a carboxylate salt, a carboxylic acid, or mixtures thereof.

In WO 97/36985 enzyme stability of a cellulase is improved by providing a laundry bar comprising from about 0.5% to about 60% synthetic detergent surfactant, about 4% or less moisture in the finished bar composition, and from about 0.1 % to about 10% non-liquid, thixotropic binding agents, as well as the cellulase enzyme. The above cited prior art all relates to enzyme stability during storage and use, however, loss of enzyme activity during manufacturing the bars is also a significant problem when incorporating enzymes in laundry detergent bar compositions. This loss of enzyme stability is believed to result from denaturation of enzymes due to exposure of the enzymes to high shear action and high pH and/or high temperature. High temperatures are often necessary in order to process ingredients of laundry bars comprising synthetic surfactants and having relatively high moisture levels, resulting in bars having acceptable physical properties. In case enzymes are added in the form of granules or prills high shear action worked on the bar composition in a mill and/or plodder destroys the integrity of the enzyme granules and enzyme prills and exposes the enzymes to attack by hostile compounds e.g. anionic surfactants. WO 98/18897 describes a process for incorporating enzymes into laundry detergent bar compositions that minimizes the loss of enzyme stability during the manufacturing process of the bar. This is achieved by a process in which the enzyme prills are added after milling and cooling and then plodding the mixture.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a premix comprising a liquid en- zyme for the preparation of laundry bars. Another object of the present invention is to provide a soap bar which comprises enzymes and provides acceptable enzyme stability. A further object of the present invention is to provide a process for producing enzyme containing laundry bars with improved storage stability. A third object of the present invention is to provide laundry bars produced by the process of the present invention. It has surprisingly been found that preparing a premix comprising a liquid enzyme product, a stabilizer and a polyol instead of adding each component separately to the soap during manufacturing of laundry soap bars improves the storage stability of the enzyme in the laundry soap bar significantly.

Thus a first aspect of the present invention is to provide a premix comprising an en- zyme, a stabilizer and a polyol.

A second aspect of the present invention is a process for producing a laundry soap bar comprising the steps of: a) preparing a premix by mixing an enzyme, a stabilizer, a pH controlling agent and a polyol; b) Mixing the premix of step a) with a soap; c) Refining the mixture of b) to refined soap; and d) Plodding the refined soap of step c).

The present invention is further related to the use of the laundry soap bars of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

Laundry bar:

The term laundry bar or laundry soap bar includes soap bars, combo bars, syndet bars and detergent bars. A laundry bar is for hand washing laundry.

Introduction

The present invention relates to laundry bars which contain enzymes incorporated therein. The present invention is particularly concerned with the storage stability of laundry bars. Despite several attempts to improve the enzyme stability during production and storage of laundry bars it is still a significant problem that the enzymes lose their activity during production and when stored in laundry bars. We have surprisingly found that we can get significantly improved enzyme stability during production of laundry bars and upon storage of laundry bars if enzyme is prepared in a premix before mixing with soap.

The present invention further relates to an improved process for incorporating enzymes into laundry bars by which good enzyme stability and good mixing and thus a more homogeneous incorporation is obtained at the same time.

In the preparation of laundry bars it is known practise to use dry enzymes in the form of enzyme granules as enzyme granules provide a protective layer around the enzymes which prevents hostile compounds of attacking the enzyme, whereas liquid enzymes are completely exposed to hostile compounds in the detergent matrix when added, therefore the laundry bar industry has been reluctant to use liquid enzymes in the production of laundry bars due to the significant loss in enzyme stability. The drawback of using granules is that if they are added during mixing or plodding/milling step, a part of the granules are torn apart and thereby exposing the enzymes to hostile compounds also resulting in great loss in enzyme activity, which has resulted in adding a significant excess of enzyme granules.

To prevent the granules to be torn apart during the mixing and milling step the granules can be added after said process steps, as in WO 98/18897 resulting in uneven distribu- tion of enzymes in the laundry bars and still facing the plodding step where they still can get torn apart.

We have however surprisingly found that we by using liquid enzyme products and stabilizing these in a premix before mixing them with soap we are able of improving the enzyme stability of the laundry bars significantly compared to known products. If using liquid formulations comprising enzymes instead of granules we have surprisingly been able to obtain laundry bars with improved enzyme stability in comparison with laundry bars conventionally prepared with enzyme granules and we have furthermore been able to obtain a more homogeneous distribution of the enzymes in the laundry bars. The process of the invention allows the enzyme to be a liquid formulation and to be added before or during the mixing step as opposed to the method described in WO 98/54285.

It is contemplated that use of liquid enzyme formulations most likely reduces the mechanical stress on the enzyme product compared to when enzyme granulates is used like in the conventional enzyme laundry bars. This might in turn reduce the amount of frictional heat developed during mixing. The liquid enzyme formulation is also more quickly distributed in the soap mass resulting in a more homogeneous product and in a shorter time, thereby decreasing production time of the laundry bar. The liquid enzyme is also readily accessible for the enzyme stabilizers added. E.g. the protease is readily accessible for the Borax complex to form within the active site resulting in a reversible inactivation. Laundry bars are mainly being sold in the third world and the cost of the laundry bars is therefore a very important factor. By our process we do not need to add a significant excess of enzyme to the laundry bar which will reduce the end cost of the laundry bar.

The premix The premix of the present invention comprises an enzyme, a stabilizer, a polyol. The premix may further comprise a pH controlling compound.

In a particular embodiment of the present invention the premix comprises a protease as enzyme, boron comprising compound as stabilizer such as borate or boronic acid, the polyol being glycerol and citric acid or free fatty acids e.g. a C12 acid as pH controlling agent. The Premix is mixed thoroughly to obtain a homogeneous mixture prior to be added to the soap. Enzymes

The enzymes that can be stabilized by the process of the invention are any enzyme which exerts its effects during the hand-washing process, e.g. having a cleaning, fabric care, anti-redeposition and stain removing effect in a hand-wash application and which enzymes are added for such a purpose.

The enzyme in the context of the present invention may be any enzyme or combination of different enzymes. Accordingly, when reference is made to "an enzyme" this will in general be understood to include one enzyme or a combination of enzymes. It is to be understood that enzyme variants (produced, for example, by recombinant techniques) are included within the meaning of the term "enzyme". Examples of such enzyme variants are disclosed, e.g. in EP 251 ,446 (Genencor), WO 91 /00345 (Novo Nordisk), EP 525,610 (Solvay) and WO 94/02618 (Gist-Brocades NV).

Enzymes can be classified on the basis of the handbook Enzyme Nomenclature from NC-IUBMB, 1992), see also the ENZYME site at the internet: http://www.expasy.ch/enzyme/. ENZYME is a repository of information relative to the nomenclature of enzymes. It is primarily based on the recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (IUB-MB), Academic Press, Inc., 1992, and it describes each type of characterized enzyme for which an EC (Enzyme Commission) number has been provided (Bairoch A. The ENZYME database, 2000, Nucleic Acids Res 28:304-305). This IUB-MB Enzyme nomenclature is based on their substrate specificity and occasionally on their molecular mechanism; such a classification does not reflect the structural features of these enzymes.

Another classification of certain glycoside hydrolase enzymes, such as endogluca- nase, xylanase, galactanase, mannanase, dextranase and alpha-galactosidase, in families based on amino acid sequence similarities has been proposed a few years ago. They current- Iy fall into 90 different families: See the CAZy(ModO) internet site (Coutinho, P.M. & Henris- sat, B. (1999) Carbohydrate-Active Enzymes server at URL: http://afmb.cnrs-mrs.fr/~cazy/CAZY/index.html (corresponding papers: Coutinho, P.M. & Henrissat, B. (1999) Carbohydrate-active enzymes: an integrated database approach. In "Recent Advances in Carbohydrate Bioengineering", HJ. Gilbert, G. Davies, B. Henrissat and B. Svensson eds., The Royal Society of Chemistry, Cambridge, pp. 3-12; Coutinho, P.M. & Henrissat, B. (1999) The modular structure of cellulases and other carbohydrate-active enzymes: an integrated database approach. In "Genetics, Biochemistry and Ecology of Cellulose Degradation"., K. Ohmiya, K. Hayashi, K. Sakka, Y. Kobayashi, S. Karita and T. Kimura eds., Uni Publishers Co., Tokyo, pp. 15-23).

The types of enzymes which may be incorporated in laundry bars of the invention include oxidoreductases (EC 1.-.-.-), transferases (EC 2.-.-.-), hydrolases (EC 3.-.-.-), lyases (EC 4.-.-.-), isomerases (EC 5.-.-.-) and ligases (EC 6.-.-.-).

Particularly suitable enzymes include lyases or hydrolases (EC 3.-.-.-), particularly proteases, amylases, lipases, pectate lyases, carbohydrases and/or cellulases.

Preferred oxidoreductases in the context of the invention are peroxidases (EC 1.11.1 ), laccases (EC 1.10.3.2) and glucose oxidases (EC 1.1.3.4)]. An Example of a commercially available oxidoreductase (EC 1.-.-.-) is Gluzyme™ (enzyme available from Novo- zymes A/S). Further oxidoreductases are available from other suppliers. Preferred transfe- rases are transferases in any of the following sub-classes: a) Transferases transferring one-carbon groups (EC 2.1 ); b) transferases transferring aldehyde or ketone residues (EC 2.2); acyltransfe- rases (EC 2.3); c) glycosyltransferases (EC 2.4); d) transferases transferring alkyl or aryl groups, other that methyl groups (EC

2.5); and e) transferases transferring nitrogeneous groups (EC 2.6).

A most preferred type of transferase in the context of the invention is a transglutaminase (protein-glutamine gamma-glutamyltransferase; EC 2.3.2.13). Further examples of suitable transglutaminases are described in WO 96/06931 (No- vo Nordisk A/S).

Preferred hydrolases in the context of the invention are: carboxylic ester hydrolases (EC 3.1.1.-) such as lipases (EC 3.1.1.3); phytases (EC 3.1.3.-), e.g. 3-phytases (EC 3.1.3.8) and 6-phytases (EC 3.1.3.26); glycosidases (EC 3.2, which fall within a group denoted herein as "carbohydrases"), such as alpha-amylases (EC 3.2.1.1 ); peptidases (EC 3.4, also known as proteases); and other carbonyl hydrolases. Examples of commercially available phytases include Bio-Feed™ Phytase (Novozymes), Ronozyme™ P (DSM Nutritional Products), Natu- phos™ (BASF), Finase™ (AB Enzymes), and the Phyzyme™ product series (Danisco). Other preferred phytases include those described in WO 98/28408, WO 00/43503, and WO 03/066847.

In the present context, the term "carbohydrase" is used to denote not only enzymes capable of breaking down carbohydrate chains (e.g. starches or cellulose) of especially five- and six-membered ring structures (i.e. glycosidases, EC 3.2), but also enzymes capable of isomerizing carbohydrates, e.g. six-membered ring structures such as D-glucose to five- membered ring structures such as D-fructose.

Carbohydrases of relevance include the following (EC numbers in parentheses): alpha-amylases (EC 3.2.1.1 ), beta-amylases (EC 3.2.1.2), glucan 1 ,4-alpha- glucosidases (EC 3.2.1.3), endo-1 ,4-beta-glucanase (cellulases, EC 3.2.1.4), endo-1 ,3(4)- beta-glucanases (EC 3.2.1.6), endo-1 ,4-beta-xylanases (EC 3.2.1 .8), dextranases (EC 3.2.1.1 1 ), chitinases (EC 3.2.1.14), polygalacturonases (EC 3.2.1.15), lysozymes (EC 3.2.1.17), beta-glucosidases (EC 3.2.1.21 ), alpha-galactosidases (EC 3.2.1.22), beta- galactosidases (EC 3.2.1.23), amylo-1 ,6-glucosidases (EC 3.2.1.33), xylan 1 ,4-beta- xylosidases (EC 3.2.1.37), glucan endo-1 ,3-beta-D-glucosidases (EC 3.2.1.39), alpha-dextrin endo-1 ,6-alpha-glucosidases (EC 3.2.1.41 ), sucrose alpha-glucosidases (EC 3.2.1.48), glucan endo-1 ,3-alpha-glucosidases (EC 3.2.1.59), glucan 1 ,4-beta-glucosidases (EC 3.2.1.74), glucan endo-1 ,6-beta-glucosidases (EC 3.2.1.75), galactanases (EC 3.2.1.89), arabinan endo-1 ,5-alpha-L-arabinosidases (EC 3.2.1.99), lactases (EC 3.2.1.108), chitosanases (EC 3.2.1.132), endo-mannanase (EC 3.2.1.78) and xylose isomerases (EC 5.3.1.5). In a particular embodiment of the present invention the enzyme is a protease. In a particular embodiment the enzyme is a bacterial protease.

Examples of commercially available proteases (peptidases) include Kannase™ , Everlase™, Esperase™, Alcalase™, Alcalase Ultra™, Neutrase™, Durazym™, Savinase™, Savinase Ultra™, Ovozyme™, Pyrase™, Pancreatic Trypsin NOVO (PTN), Bio-Feed™ Pro and Clear-Lens™ Pro (all available from Novozymes A/S, Bagsvaerd, Denmark). Other preferred proteases include those described in WO 01/58275 and WO 01/58276.

Other commercially available proteases include Ronozyme™ Pro, Maxatase™, Max- acal™, Maxapem™, Opticlean™, Propease™, Purafect™, and Purafect Ox™ (available from Genencor International Inc., Gist-Brocades, BASF, or DSM Nutritional Products). Examples of commercially available lipases include Lipex™, Lipoprime™, Lipopan™,

Lipolase™, Lipolase™ Ultra, Lipozyme™, Palatase™, Resinase™, Novozym™ 435 and Leci- tase™ (all available from Novozymes A/S).

Other commercially available lipases include Lumafast™ (Pseudomonas mendocina lipase from Genencor International Inc.); Lipomax™ (Ps. pseudoalcaligenes lipase from Gist- Brocades/Genencor Int. Inc.; and Bacillus sp. lipase from Solvay enzymes. Further lipases are available from other suppliers.

Examples of commercially available carbohydrases include Alpha-Gal™, Bio-Feed™ Alpha, Bio-Feed™ Beta, Bio-Feed™ Plus, Bio-Feed™ Wheat, Bio-Feed™ , Z Novozyme™ 188, Carezyme™, Celluclean™, Celluclast™, Cellusoft™, Celluzyme™ Ceremyl™, Citro- zym™, Denimax™, Dezyme™, Dextrozyme™, Duramyl™, Energex™, Finizym™, Funga- myl™, Gamanase™, Glucanex™, Lactozym™, Liquezyme™, Maltogenase™, Natalase™, Pentopan™, Pectinex™, Promozyme™, Pulpzyme™, Novamyl™, Termamyl™, AMG™ (Amy- loglucosidase Novo), Maltogenase™, Sweetzyme™ and Aquazym™ (all available from Novo- zymes A/S). Further carbohydrases are available from other suppliers, such as the Roxazy- me™ and Ronozyme™ product series (DSM Nutritional Products), the Avizyme™, Porzyme™ and Grindazyme™ product series (Danisco, Finnfeeds), and Natugrain™ (BASF) , Purastar™ and Purastar™ OxAm (Genencor).

Other commercially available enzymes include Mannaway™, Pectaway™, Stainzy- me™ and Renozyme™.

In a particular embodiment of the present invention the enzyme is a protease. Protease: Any protease suitable for use in a laundry bar can be used. Suitable proteases include those of animal, vegetable or microbial origin. Microbial origin is preferred. Chemically or genetically modified mutants are included. It may be a serine protease, prefer- ably an alkaline microbial protease or a trypsin-like protease. Examples of alkaline proteases are subtilisins, especially those derived from Bacillus, e.g. subtilisin Novo, subtilisin Carlsberg, subtilisin 309, subtilisin 147 and subtilisin 168 (described in WO 89/06279).

In a particular embodiment of the present invention the enzymes added to the laundry bar are a mixture of proteases and one or more enzymes selected from the group consist- ing of cellulases, lipases, amylases, pectate lyases and carbohydrases.

The enzyme can either be incorporated in a granule or in a liquid formulation. In a particular embodiment the present invention the enzyme is added to the process of the invention as a granule. In a more particular embodiment of the present invention the enzyme is added to the process as a liquid formulation. Stabilizer

The stabilizer of the present invention is a stabilizer which is capable of stabilizing the enzyme during storage. In a particular embodiment the stabilizer is a protease inhibitor.

Suitable stabilizers include boronic acid or a derivative thereof. In a particular embodiment the stabilizer is boronic acid or borate. There are many examples of suitable borate compounds useful herein. Water soluble borate compounds such as boric acid are preferred, although other compounds such as borax, boric oxide, hydroborates and other alkali metal borates such as sodium ortho-, meta- and pyroborates and sodium pentaborate are suitable. Substituted boric acid such as phenylboronic acid, butane-boronic acid and p-bromo phenyl- boronic acid can also be used herein. Mixtures of the above borate compounds are also suit- able for use herein.

A suitable enzyme stabilizing agent may be a phenyl boronic acid derivatives substituted in the para-position with carbonyl group adjacent to the phenyl boronic acid.

The phenyl boronic acid derivative enzyme stabilizer has the following formula:

wherein R is selected from the group consisting of hydrogen, hydroxy, C-i-Cβ alkyl, substituted d-C₆ alkyl, CrC₆ alkenyl and substituted d-C₆ alkenyl.

In a particular embodiment of the present invention the premix comprises an enzyme and a phenyl boronic acid derivative enzyme stabilizer of the formula disclosed above, wherein R is a C-i-Cβ alkyl, in particular wherein R is CH₃, CH₃CH₂ or CH₃CH₂CH₂, or wherein R is hydrogen.

In a particular embodiment of the present invention the phenyl boronic acid derivative enzyme stabilizer is 4-formyl-phenyl-boronic acid (4-FPBA).

In a particular embodiment of the present invention the laundry bar only comprises a phenyl boronic acid derivative as enzyme stabilizing agent. In an even more particular em- bodiment of the present invention the laundry bar only comprises a 4-FPBA as enzyme stabilizing agent.

The stabilizer may be present in amounts of between 0.01 % to 30% by weight of the total bar composition. In a more particular embodiment the stabiliser is present in amounts of between 0.05% and 20% by weight of the total bar composition. The laundry bar may contain 0.1 % to 10% w/w of stabilizer of the final bar composition. In a particular embodiment the laundry bar comprises 0.5% to 5% w/w of stabilizer. In a more particular embodiment the laundry bar comprises 0.5% to 4% w/w of the stabilizer. In a particular embodiment the laundry bar comprises at least 0.001 % w/w of the stabilizer. In a particular embodiment the laundry bar comprises around 4% w/w of the final bar composition. Polvol

Polyols useful in the present invention are characterized by solubility in water, carbon backbones of length between C2 and C6 and multiple hydroxyl groups, preferably containing between 2 and 6 hydroxyl groups per molecule.

Polyols useful herein include, but are not limited to 1 ,2-butane diol, 3-chloro-1 ,2- propane diol, ethylene diol, 1 ,2-hexane diol, glycerol, mannose, propylene glycol, sorbitol, sucrose and mixtures thereof. The polyol level will usually be between 0.5% and 10%, and preferably between 1 % and 5%, and more preferably between 1 .5% and 3% by weight of the final bar composition. pH controlling compound

It has been found that it may be necessary to lower the pH to improve stability of the enzyme. The pH controlling agent may be any suitable compound which is able of controlling the pH. In a particular embodiment the pH controlling agent is an acid.

In a particular embodiment the pH controlling compound may be selected from the group consisting of a fatty acid, Acetic acid, Aconitic acid, Adipic acid, Arachidic acid, Arachi- donic acid, Aspartic acid, Behenic acid, Butyric acid, Capric acid, Capronic acid, Cerotic acid, Citric acid, Formic acid, Fumaric acid, Glutamic acid, Glutaric acid, Glyceric acid, Glyceric ac- id-3-phosphate, Glyoxylic acid, lsocitric acid, α-Ketoglutaric acid, Lactic acid, Laurie aicd, Li- noleic acid, Linolenic acid, Maleic acid, Malic acid, Malonic acid, Myristic acid, Oleic acid, Oxalic acid, Oxaloacetic acid, Palmitic acid, Palmitoleic acid, Phosphatidic acid, Phosphoe- nolpyruvic acid, Pimelic acid, Propionic acid, Pyruvic acid, Stearic acid, Succinic acid, Tartraic acid and Valeric acid. The pH controlling agent will usually be present at a level between 0.05% and about

8%, preferably between 0.1 % and 6%. And more preferably between 0.2% and about 4% by weight of the final bar composition. The amount of pH controlling agent is in a particular embodiment 0.001 % to 5% w/w of the soap bar. In a more particular embodiment the amount of the pH controlling agent is 0.01 % to 2% w/w of the soap bar. In a most particular embodiment the amount of the pH controlling agent is 0.05% to 1 % w/w of the soap bar. In a particular embodiment the amount of pH controlling agent is around 0.2% w/w of the final bar composition. Moisture content

Moisture enhances the mixing of the premix ingredients. Moisture further provides the laundry bar with acceptable feel and other physical characteristics. Moisture e.g. water can be added to the premix by being included with an ingredient and/or as free water added to the premix.

The laundry bar comprises from about 5% to about 30%, preferably from about 10% to about 25% moisture by weight of the finished bar. Laundry bar ingredients

The laundry bar of the invention comprises the premix and soap. The laundry bar may further comprise complexing agents like EDTA and EDHP, perfumes and/or different type of fillers. Additional Compounds The laundry soap bar may comprise additional compounds. Said compounds are not limited to surfactants e.g. anionic synthetic surfactants, builders, polymeric soil release agents, detergent chelants, glycerol (glycerine), stabilizing agents, fillers, dyes, colorants, dye transfer inhibitors, alkoxylated polycarbonates, suds suppressers, structurants, binders, leaching agents, bleaching activators, clay soil removal agents, anti-redeposition agents, polymeric dispersing agents, brighteners, fabric softeners, perfumes and/or other compounds known in the art. Soap The soap suitable for use of the present invention includes water soluble salts of higher fatty acids. Soap can be made by direct saponification of fats and oils or by neutralisation of free fatty acids. Suitable soaps are sodium, potassium, ammonium, and alkyloammo- nium salts of higher fatty acids containing from about 8 to about 24 carbon atoms, such as from 12 to about 18 carbon atoms. In a particular embodiment the soap is selected from so- dium and potassium salts of mixtures of fatty acid derived from coconut oil and tallow, such as sodium or potassium tallow and palm oil. Furthermore nut oil may be added like coconut or palm kernel oil from 5-30% by weight of the final bar. Glycerine

During known soap manufacturing glycerine is either being removed due to commer- cial reasons or it is left in the soap. Therefore soaps can be described as either high glycerine or low glycerine soaps. Low glycerine soaps comprises from 0 to 2% glycerine, if more glycerine is needed it may be added in the manufacturing of the soap while the soap is still liquid to ensure proper uptake or to soap noodles. In a particular embodiment the laundry soap bar comprises from 1 to 6 % glycerine. In a more particular embodiment of the present invention the laundry soap bar comprises from 2% to 5% glycerine by weight of total soap bar. In a most preferred embodiment the laundry soap bar comprises about 4% glycerine. Surfactants

Synthetic anionic surfactants which are suitable for use in the present invention include the water soluble salts, preferably the alkali metal, ammonium and alkyl ammonium salts of organic sulphuric reaction products having in their molecular structure an alkyl group containing from about 10 to about 20 carbon atoms and a sulfonic acid or sulphuric acid ester group. Examples of this group of synthetic surfactants are the sodium and potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (C8-18 carbon atoms) such as those produced by reducing the glycerides of tallow or coconut oil; and the sodium and potassium alkyl benzene sulfonates in which the alkyl group contains from about 9 to about 15 carbon atoms, in straight chain or branched chain configuration. Especially valuable are the linear straight chain alkyl benzene sulfonates (LAS) in which the average number of carbon atoms in the alkyl group is from about 1 1 -13, abbreviated as C1 1 -13 LAS. The alkali metal salts, particularly the sodium salts of these surfactants are preferred. Other examples of an anionic synthetic detergent suitable for use herein are the sodium alkyl glyceryl ether sulfonates (AES), especially those ethers of higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyceride sulfonates and sulfates; and sodium or potassium salts of alkyl ethylene oxide ether sulfates containing about 1 to about 10 units ethylene oxide per molecule and wherein the alkyl group contains from about 10 to about 20 carbon atoms.

In addition, a suitable anionic synthetic detergent also includes the water soluble salts of ester of alpha- sulphonated fatty acids containing from about 6 to about 20 carbon atoms in the fatty acid group and from about 1 to about 10 carbon atoms in the ester group; water soluble salts of 2-acyloxyalkane-1 -sulfonic acids containing from about 2 to about 9 carbon atoms in the acyl group and from 9 to about 23 carbon atoms in the alkane moiety; water soluble salts of olefin and paraffin sulfonates containing from about 12 to about 20 carbon atoms; and beta-alkyloxy alkane sulfonates containing from about 1 to about 3 carbon atoms in the alkyl group and from about 8 to about 20 carbon atoms in the alkane moiety.

Preferred anionic synthetic surfactant examples are C10-18 alkyl sulfates (AS), C10- 18 linear alkyl benzene sulfonates (LAS), C10-14 alkyl glyceryl ether sulfonates (AES), and mixtures thereof.

An example of ingredients comprised in a conventional laundry bar (syndet bar) is: Linear alkyl benzene sulfonate, coco fatta alcohol sulphate, soda ash, sulphuric acid, sodium tripolyphophate, calcium carbonate, coco faaty alcohol, TiO2, cellulase, Diethylene- triamine (methylenephosphonic acid), coco monoethanolamide, fluorcent agents, substituted methylcellulose, perfume, moisture.

An example of detergent ingredients comprised in a conventional laundry bar (com- bo bar) is:

LAS, soap, cellulase, protease, boric acid, borax, sodium formate, sodium citrate, sodium carbonate, glycerol, propylene glycerol, ethylene glycol, MgSO4, soda ash, STPP, talc, moisture.

Preparation of laundry bars The laundry bars of the present invention may be processed in conventional laundry bar making equipment such as but not limited to: mixers, plodders, e.g a two stage vacuum plodder, extruders, cutters, logo-stampers, cooling tunnels and wrappers. The premix is prepared before adding it to the soap.

Of the invention the process is a way of incorporating enzymes into laundry soap bars and still maintains enzyme activity.

A process of the invention is for the preparation of laundry soap bars comprising the steps of a) preparing a premix by mixing an enzyme, a stabilizer, a pH controlling agent and a polyol b) Mixing the premix of step a) with a soap; and c) Refining the mixture of b) to refined soap d) Plodding the refined soap of step c). The premix of the invention may be added to the soap at different stages of the process. In a particular embodiment of the present invention the premix is added to the soap before the refining step.

In a particular embodiment of the present invention the enzyme added is on liquid form.

The mixing of the premix, step a), may take place in a mixer e.g. in a Double Sigma Amalgator type MSA-100 mixer. The mixing step of a) takes preferably no more than 1 min., 5 min., 10 min., 15 min. 30 min., 45 min., no more than 1 hour.

After preparation of the premix it can be stored until it is to be used in the production of laundry bars, or it can be used immediately in the production of laundry bars. After preparation of the premix, it is dosed to the soap. In a particular embodiment the premix is mixed with the soap at the refining step before plodding in order to ensure proper mixing of the premix into the soap. The refining step may take place by in-line refiner or plodder with screen mounted in the head or by refining in final plodder. The plodding step is performed in a plodder e.g. a Duplex plodder. The plodder operates preferably at high vacuum, so that entrapped air/gas is removed.

The product is extruded and the extruded bar subsequently moves to the cutter where the bar is cut to the desired bar length. Optionally the pieces are stamped into their final shape in stamping presses. High-speed presses are normally used on high-volume pro- duction lines. Preferably the high-speed presses have refrigerated dies. The bar can be cooled, e.g. in a cooling tunnel, before it following normal procedure is wrapped, cased and sent to storage.

Additional compounds may be added to the to the mixture comprising the soap and the premix. These compounds include but are not limited to brightener, colorant, structurant, binder, photoactive bleach, soil release polymer, and anti-redeposition agent.

Use of laundry bars

The laundry bar of the invention is for use in hand washing laundry or for dish washing.

The present invention is further described by the following examples which should not be construed as limiting the scope of the invention.

EXAMPLES

Example 1

This example shows the normal procedure of manufacturing soap bars with enzymes; where the different ingredients are added to the soap separately. Stabilizing ingredients added separately to the soap.

Three different proteases were tested: 0.2% by weight of final laundry bar EVERLASE 16L 0.2% by weight of final laundry bar SAVINASE 16L 0.2% by weight of final laundry bar SAVINASE ULTRA 16L

These proteases were added to the soap and mixed at RT. Further 2% glycerine, and 0.2% Citric acid were added separately to the soap and mixed.

2% sodium borate was added to the mixtures comprising Everlase 16L and Savinase 16L.

The mixture was transferred to a refiner and thereafter a plodder, and finally it was stamped.

Stability results shown as % remaining enzyme activity after storage at 35°C for 2, 4, 6 and 8 weeks

If no activity loss has occurred the theoretical remaining activity (100%) due to water loss from soap during storage should have been as shown by below table.:

% THEORETICAL REMAINING ACTIVITY

2 4 6 8 WEEKS

105 108 1 10 1 12

The storage of soaps in open climate chambers will always result in evaporation of water from the bars leading to weight loss. Hence the calculation of theoretical remaining ac- tivity.

Example 2

In this example the stabilizing agents were added in a premix and thereafter the premix was mixed with the soap without refining.

The components of the premix being EVERLASE 16L 0.2%

GLYCERINE 2% BORAX 2% CITRIC ACID 0.2% The ingredients of the premix were blended in a mixer to make a slurry and then added directly to the soap. The mixture was transferred directly to the plodder thereafter the product was stamped.

These results show a surprisingly high storage stability.

Example 3

The stabilizing agents were added to the premix and then to the soap while refining into thin noodles before moving to the plodder for final soap extrusion. Thereafter it was stamped.

The components of the premix being: EsVERLASE 16L 0.2% GLYCERINE 2% BORAX 2% CITRIC ACID 0.2%

The results were again compared to the theoretical maximum obtainable activity due to water loss from soap.

The high storage stability was maintained.

Example 4

A premix was prepared comprising the stabilizing agents. The components being: EVERLASE 16L 0.2% GLYCERINE 2% BORAX 2%

EDHP 0.05% AND EDTA 0.05% CITRIC ACID 0.2% The premix was added to the soap while refining into thin noodles before added in plodder for final soap extrusion. Here complexing agents EDHP and EDTA are added for oxidation protection purposes.

Results again compared to the theoretical maximum obtainable activity due to water loss from soap.

The complexing agent has an initial negative effect on the storage stability (titrating the activity) however the storage stability remains constant throughout the whole period.

Example 5

The premix was prepared by mixing the following ingredients: EVERLASE 16L 0.2% GLYCERINE 2% BORAX 2% CITRIC ACID 0.2%

In a two step process the premix was added to a fraction of disintegrated noodles. This mixture was added to the mixer before plodding and stamping. This in order to improve the absorption to the soap material as we would expect will happen in a production scale process where a refining is adding in the one of the plodder steps before final extrusion or where a mixing occurs before plodding (depending of the process line).

Again there was a perfect mach with the theoretical 100% stability level. Example 6

The stabilizing agents are added in the premix and then to the soap while refining into thin noodles before moving it to the plodder for final soap extrusion and stamping. The components being

EVERLASE 16L 0.2% GLYCERINE 2% BORIC ACID 2%

Example 7

The components of the premix are EVERLASE 16L 0.2% GLYCERINE 2% BORIC ACID 1.3% BORAX 0.7%

The premix was prepared by mixing where after it was added to the soap while refining into thin noodles before adding the mixture to the final soap extrusion.

This combination was giving a very good stability also.

Example 8

Four samples were prepared with different premixes, as follows. For sample #1 , a premix was prepared by mixing the following components, and the premix was added to translucent soap base. Everlase 16L: 0.2% Glycerol: 2% Borax: 2% Citric acid: 0.2%

Sample #2 was prepared as sample #1 , except that 4% of extra glycerol was added to the soap base before adding the premix.

For sample #3, premix A was prepared by mixing the following components: Savinase Ultra 16XL: 0.2% Borax: 2% Glycerol: 3% Water: 1 %

Further, for sample #3, premix B was prepared by mixing 0.4% citric acid and 1 % water. Finally, sample 3 was prepared by adding premixes A and B after dissolving partly to translucent soap base.

Sample #4 was prepared as sample #3, except that the amount of borax was 0.5%. The soap bars were stored for 4 weeks at 37°C in closed plastic bags. The washing performance on egg swatches and EMPA 1 17 was determined before and after storage. A blank without enzyme, and controls with Everlase or Savinase freshly added during washing were also tested.

The fresh enzymatic laundry bars showed significant benefits, and after 4 weeks storage at 37°C, the 4 samples still performed well. The best results were obtained with samples #3 and #4, using a premix which contains a liquid enzyme product (Savinase or Ever- lase), a stabilizer (borax) and a polyol (glycerol), and adding a pH controlling agent (citric acid) separately.

Claims

1. A process for the preparation of laundry soap bars comprising the steps of a) preparing a premix by mixing an enzyme as a liquid formulation, a stabilizer, and a polyol; b) mixing the premix of step a) with a soap; c) refining the mixture of b) to refined soap; and d) plodding the refined soap of step c).

2. The process of claim 1 , further comprising addition of a pH controlling agent in step a).

3. The process of claim 1 , further comprising mixing the soap with pH controlling agent or pH controlling agent solution before step a).

4. The process of any of claims 1-3, further comprising addition of water in step a).

5. The process of any of claims 1-4, wherein the pH controlling agent is an acid.

6. The process of any of claims 1-4, wherein the enzyme of the mixture is a protease.

7. The process of claim 6, wherein the mixture further comprises a second enzyme se- lected from the group consisting of cellulases, lipases, amylases, pectate lyases and carbohy- drases.

8. The process of any of claims 1-7, wherein the stabilizer is a borate, boronic acid or a boronic acid derivative.

9. The process of any of claims 1-8 wherein the stabilizer is a phenyl boronic acid deriva- tives substituted with a carbonyl group in the para-position, particularly 4-formyl-phenyl- boronic acid.

10. The process of any of claims 1-9 wherein the polyol is glycerine.

1 1. A laundry bar obtainable by the process of any of claims 1-10.

12. A premix to be used in the process of any of claims 1-10, comprising an enzyme, a stabi- lizer and a polyol.

13. The premix of claim 12 further comprising a pH controlling agent.

14. The premix of claim 12 or 13, wherein the stabilizer is a borate, boronic acid or a boronic acid derivative.

15. The premix of any of claims 12-14, wherein the enzyme is a protease.

16. The premix of claim 15, wherein the premix further comprises one or more enzymes selected from the group consisting of cellulases, lipases, amylases, pectate lyases and car- bohydrases.

17. The premix of any of claims 12 to 16, wherein the polyol is glycerine.

18. Use of the laundry bar of claim 11 for washing laundry by hand.