EP0306493A4

EP0306493A4 - Detergent composition

Info

Publication number: EP0306493A4
Application number: EP19870903218
Authority: EP
Inventors: Robert Francis Donnelly
Original assignee: MACDOUGALL JOSEPHINE
Current assignee: MACDOUGALL JOSEPHINE
Priority date: 1986-05-14
Filing date: 1987-05-14
Publication date: 1990-11-28
Also published as: WO1987006950A1; JPH01502671A; EP0306493A1

Abstract

New substantially anhydrous detergent composition, and process for its production. The detergent of the present invention consists of a non-ionic surfactant, produced by the Kritchevsky method, and an anionic surfactant together with other detergent additives as required. The detergents of the present invention are produced by condensing a carboxyl group containing compound and 2-hydroxyethyl amine or di-(2-hydroxyethyl)-amine at elevated temperature, cooling, and reacting with known anionic surfactants at controlled temperature below about 38 DEG C. The present invention is particularly suitable for the production of anhydrous gel laundry detergents.

Description

DETERGENT COMPOSITION

FIELD OF THE INVENTION The present invention relates to the production of a novel alkanolamide non-ionic surfactant and its application in new, high activity gel or liquid laundry detergents. The products of the invention overcome ecological problems associated with traditional laundry detergents and as such represent a significant advance in detergent technology.

BACKGROUND ART

Traditional laundry detergents are low bulk density powders containing relatively small amounts of surfactant and large quantities of fillers and adjuncts, and are prepared by spray drying or fluid bed agglomertion of aqueous slurries. The high energy inputs and capital costs of the equipment required for dehydration are beyond the financial resources available in smaller, and in particular, developing countries.

Laundry powders contain "the actives", a term well understood by those skilled in the art, which are usually, anionic surfactants, and almost without exception are alkylbenzene sulphonates, with predominantly straight chain alkyl groups with a typical carbon chain distribution of 8.0% C₁₀, 34.0% C₁₁, 36.5% C₁₂, 20.5% C₁₃.

As a cost saving measure carboxylic acids have been used as an anionic component, saponification occurring in situ during the powder maπfacturing process. Non-ionic surfactants, with HLBs in the range 18-20 are also included in some formulations.

Other major ingredients of the prior art formulations include alkali metal carbonates, sulphates, polyphosphates, silicates, orthophosphates, phosphonates, zeolites, nitrilotriacetic acid (NTA), citric acid, ethylenediamine tetra acetic acid (EDTA) and its salts, and oxygen releasing compounds such as sodium perborate. Other lesser ingredients may include polymeric resins which enhance soil suspension, optical brightening agents, perfumes, hydrotropes, corrosion inhibitors and in certain cases bleaches.

Liquid laundry detergents are usually aqueous solutions or suspensions of the components of powdered laundry detergents and apart from offering convenience to the end user provide little in the way of overcoming problems associated with the use of powders as they only substitute water for a proportion of the inorganic components common to powder detergents. Detergents have contributed to the ecological problem of pollution of world waterways by a process termed eutrophication. Phosphate rich effluent exacerbated the problem and legislation has been enacted in many countries throughout the world prohibiting the use of phosphate formulated laundry detergents. One of the major replacements, nitrilotriacetic acid, also has ecological problems associated with its use.

Alkanol amides are versatile and widely used non-ionic surfactants having foam stabilization and detergency properties. They are effective in increasing the viscosity of detergent solutions and provide emolliency, corrosion inhibition, emulsification, wetting, and lime-soap dispersion. Diethanol amides are commonly used in liquid dishwashing detergents, shampoos, janitorial scrub soaps, textile processing, lubricating oils, and dry cleaning detergents.

Alkanolamides are formed by the condensation of alkanolamines and fatty acids or esters at elevated temperatures.

Alkanolamide condensation reactions were patented by Dr W Kritchevsky in 1937 and are disclosed in US patent 2089212. Kritchevsky amides are produced by the condensation of 2 mole diethanolamine and 1 mole fatty acid. It has been found by the present inventor that by selecting appropriate carboxylic acids for use in the Kritchevsky reaction, and then mixing this product with suitable sulphonic acids, detergents having unique characteristics may be produced. The process is particularly suitable for producing anhydrous gels or liquids, although the products are not restricted thereto. The present invention demonstrates a positive technological advance in the manufacture and formulation of novel products for use in laundering, which overcome the problems associated with current products. The invention does not require high energy cost equipment to produce and the products do not necessarily contain those well known ecological contaminants such as polyphosphates and NTA.

DISCLOSURE OF THE INVENTION The present invention provides a new process and substantially anhydrous, water dispersive product which is predominantly hydrophilic, and may have extremely high viscosities.

The products of the present invention are compositions of anionic and non-ionic surfactants suitable for use as active ingredients in many forms of detergent, wherein the non-ionic surfactant is produced by an alkanolamide condensation reaction of the Kritchevsky type, in which 2-hydroxyethylamine or di-(2-hydroxyethyl)-amine is condensed with mixed fatty acids or esters at elevated temperature and further reacted at a controlled reaction temperature of less than about 38°C with anionic surfactants constituting 5-50% by weight of the total weight of the composition.

Amidation may be optionally carried out with one or two molar proportions of optionally 2-hydroxyethlamine or di-(2-hydroxyethyl)-amine and carboxylic acids having from 8-18 carbon atoms or carboxylic esters reacted catalytically under reduced pressure. The carboxyl radical of the mixed fatty acids may be provided by aliphatic esters prepared by transesterification and subsequently condensed, or from fatty acids resulting from the hydrolysis of triglycerides, or from triglycerides.

Preferably, the source of the carboxyl radical is from triglycerides, more preferably, those contained in such products as tallow, coconut oil, palm oil, palm kernel, cottonseed oil, soybean oil, linseed oil and the like.

Most preferably, the unique characteristics of the product of the present invention may be achieved as a result of selection of carboxylic acids arranged in a configuration and relative proportions such as is shown in Table 1.

TABLE 1

ACID % STRUCTURAL FORMULA lauri c aci d 22.5 CH₃-(CH₂) _{1 0} - COOH myri sti c aci d 11 .3 CH₃-(CH₂) _{1 2} - COOH olei c acid 23.4 CH₂=CH-(CH₂) _{1 5} - COOH palmi ti c acid 18.0 CH₃-(CH₂) _{1 4} - COOH steari c acid 15.0 CH₃-(CH₂) _{1 6} - COOH capri c aci d 5.2 CH₃-(CH₂)₈ - COOH caproi c aci d 4.5 CH₃-(CH₂)₄ - COOH

The di-(2-hydroxyethyl)-amine and carboxyl group containing components may be condensed catalytically at a temperature of approximately 100-120°C until the Acid Value of the condensate is between 10 and 14. A suitable catalyst may be selected from the group consisting of para-toluene sulphonic acid, potassium hydroxide, and sodium methoxide. Sodium methoxide is the most preferred catalyst. The glycerol split from the triglycerides during the condensation reaction may be retained in the product as it contributes to the efficacy of the finished product.

Gels according to the present invention may be produced by combining the condensate with a suitable anionic surfactant at a controlled reaction temperature below about 38°C and optionally, further additives as required. In particular for hard water conditions, it is preferable to add any one or a mixture of aqueous or anhydrous sodium silicate, sodium tripolyphosphate or zeolite. Perfume, colour and optical brightener may also be added to the resulting homogeneous mixture. A proteolytic enzyme may then be added if desired.

Suitable sulphonic acids for use as the anionic surfactant in the above process include ester sulphonic acids comprised of sulphated primary, secondary or tertiary aliphatic carboxylic esters, either saturated or unsaturated or a composition of both, amino-sulphonic acids or alkyl aryl sulphonic acids. Most preferred are the alkyl aryl sulphonic acids.

Many other anionic surfactants can be employed in the performance of the present invention. These include compounds which are the end product of sulphonation or sulphation of hexadecyl benzene or dodecyl dimethyl benzene, sulphated fatty alcohols, such as cetyl olyl alcohol sulphosuccinates, fatty esters, fatty alkyl sulphosuccinates, fatty alkyl ether sulphosuccinates, acyl sarcosinates, acyl taurides, isethionates, sulphonated triglycerides, or the saponified fatty acids or triglycerides termed soaps. Anionic phosphate esters may also be employed. Certain so called, high molecular weight petroleum sulphonates may also prove useful adjuncts in the anionic component.

Other known non-ionic surfactants may also be added to the composition of the present invention if desired. Such non-ionic surfactants include ethoxylated amines, ethoxylated alkyloamides, ethoxylated phosphate esters, esters, propoxylated analogues of the above compounds, propoxylated or eythoxylated polyglycol carboxylic esters or polyethylene glycol carboxylic esters.

Most preferably, polyethylene glycol carboxylic esters are added to constitute 15-20% by weight of the total non-ionic surfactant composition, and thus produce a highly stable anhydrous liquid.

Suitable sodium silicates include those selected from the group consisting of Na₂O:SiO₂ ratios ranging from about 1:2 to about 1:3.5.

The most preferred aqueous sodium silicate has a Na₂O:SiO₂ ratio of 9.0:29.0 with a viscosity at 20°C of 225 centipoise. BEST MODES OF PERFORMING THE INVENTION EXAMPLE 1

The production of detergent gels according to the present invention will now be described by way of examples. It should be understood that the present invention is by no means limited to the disclosure of the examples as further embodiments falling within the scope of the present invention would be apparent to one skilled in the art. Preparation of non-ionic surfactants

1.1. The components of Table 2 are catalytically condensed at a temperature of 100-120°C until the Acid Value of the condensate is between 10 and 14.

TABLE 2 Laurie acid 13.0%

Myristic acid 6.5% Oleic acid 13.5%

Palmitic acid 10.4%

Stearic acid 8.6%

Capric acid 3.0%

Caproic acid 2.6% Di-(2-hydroxyethyl)-amine 42.0%

Catalyst 0.75%

All percentages are by weight. Other non-ionics which may be used in the performance of the present invention include: 1.2. A condensate formed by the condensation of 2 moles of di-(2-hydroxyethyl)-amine with one mole of a carboxylic acid having a chain of 12 carbon atoms.

1.3. Condensates prepared by the reaction of 2 moles of di-(2-hydroxyethyl)-amine and 1 mole of a carboxylic acid having a chain of 16 carbon atoms.

1.4. Condensates prepared by the reaction of 2 moles of di-(2-hydroxyethyl)-amine and 1 mole of a carboxylic acid having a chain of from 8-12 carbon atoms.

1.5. A non-ionic formed by condensation with 2 moles of di-(2-hydroxyethyl)-amine and 1 mole of a mixture of carboxylic acids, one of which has a chain of from 8-12 carbon atoms and one of which has a chain of from 14-18 carbon atoms. 1.6. Condensates prepared by the reaction of 2 moles of di-(2-hydroxyethyl)-amine and 1 mole of a mixture of carboxylic acids about half of which have a chain of predominantly 16 carbon atoms.

1.7. Condensates prepared by the reaction of 2 moles of di-(2-hydroxyethyl)-amine and 1 mole of a mixture of carboxylic acids having a-chain of between 10 and 18 carbon atoms. Preferably, about half the carboxylic acids have chains of about 12 carbon atoms, and the other half have chains of about 18 carbon atoms.

1.8. Condensates prepared by the reaction of 1 or 2 moles of di-(2-hydroxyethyl)-amine and 1 mole of any carboxylic acids having chains of from 10-18 carbon atoms.

1.9. Condensates prepared by the reaction of equimolar proportions of dihydroxy alkyl amines and aliphatic carboxylic esters of polyhydric alcohols. Such esters may be composed of mixtures of carboxylic acids having chains of from 10-18 carbon atoms.

The amidation of examples 1.2 to 1.9 are preferably carried out at

115°-120ºC in the presence of a catalyst, selected from the group specified hereinbefore, at a pressure of 100-125 millimetres of mercury absolute.

The alcohol distills off in the stoichiometric quantity, indicating completion of the reaction. The weight ratio of dihydroxyalkyl amine to aliphatic ester is 17.5:32.0, or, expressed in molar proportions, is either

1:1.1 or 2:2.1.

Other known non-ionic surfactants suitable for use in conjunction with the above non-ionic surfactants include polyethylene glycol carboxylic esters. The following three components of the present example are produced by methods well known to those skilled in the art:

1.10 A product formed by the catalytic reaction of polyethylene glycol 400 (i.e. MW 400) and carboxylic acids having 8-12 carbon atoms as half the total fatty acids and other half having from 14-18 carbon atoms. The reaction is carried to completion.

1.11 The ester formed by the reaction of polyethylene glycol 600 and a carboxylic acid having predominantly 12 carbon atoms, both are reacted in 1:1 molar proportions with a suitable catalyst.

1.12 The esters formed by the reaction of polyethylene glycols of molecular weights from 400-2000 with carboxylic acids having from 8-18 carbon atoms, suitably catalysed, are suitable for use as adjuncts with the alkanol amides in Examples 1.1 to 1.9.

The utilization of the esters so described is limited by economic factors, viz the relatively high cost of the polyethylene glycols. Preparation of detergent

The above-mentioned non-ionics are cooled and mixed with alkyl benzene sulphonic acid in the weight ratio of about 78:22. The reaction is controlled to ensure the temperature does not rise above about 38°C. The gel produced by this process may contain as little as 0.25% total water, depending upon the water contamination of the sulphonic acid. This water may be removed by known methods to produce 100% surface active material in which the surfactant system itself is the continuous phase. The resultant gel, either with or without the water removed, is surface active and requires no fillers or diluents as employed in powder and liquid detergents.

To transfer the gel produced by the anionic/non-ionic mixture to an efficacious laundry detergent requires the addition of one or more of the following additives: optical brightening agents enzymes, anti redeposition compounds, bleaches, perfumes etc. In areas of unfavourable water quality further ingredients such as chelating agents and water softeners may also be incorporated. However due to the unique nature of the blend of fatty acids in the non-ionic components chosen it is not necessary to include such components as fabric softeners and other additives to remove the harsh "feel" caused by laundering. The inclusion of large chain, i.e. C16 and C18, fatty acids in the non-ionic component produces aklanolamides which are substantive and leaves the fabric with a "soft" feel. The preferred alkylbenzene sulphonic acid is the biodegradable dodecylbenzene sulphonic acid, known under the generic name Bioacid.

EXAMPLE 2 Detergent Gel I

The condensate of Example 1.1 is transferred to a suitable blender such as a Nautamixer. Alkyl aryl sulphonic add is added to the blender, with stirring in operation and the reaction temperature is maintained below 38°C. Agitation is continued until homogeneity is achieved. Perfume, anti redeposition compound, colour and optical brighteners are added and thoroughly blended. Finally, proteolytic enzyme is added and thoroughly blended into the gel. The formula for the detergent gel of the above process is given in Table 3. TABLE 3

COMPONENT w/w

Components of Table 2 68.92

2-Hydroxyethyl amine 0-5.0 di(2-hydroxyethyl)amine 0-2.5 tri(2-hydroxyethyl)amine 0-1.7

Alkyl aryl sulphonic acid 25.0

Optical brightener 0.03

Colour 0.10

Perfume q.s.

Proteolytic Enzyme 0.8

The total amine used depends on which amine is used or the proportions if more than one. For instance if only 2-hydroxyethylamine is used then 5 parts (w/w) are added. However, if di- and tri(2-hydroxyethyl)-amines are also used then the amounts added are in proportion to their combining weights.

EXAMPLE 3 Detergent Gel II The process of Example 2 is followed until homogeneity of the condensate and sulphonic acid is achieved. Aqueous sodium silicate is then added with continued agitation until homgeneity is again achieved. The process of Example 2 is then continued.

The formula for the detergent gel produced by the above process is given below in Table 4.

TABLE 4

COMPONENT Parts by Weight

Components of Table 2 78

Alkyl aryl sulphonic acid 12

Aqueous sodium silicate 10

Optical brightener 0.03

Colour 0.1

Perfume q.s.

Proteolytic Enzyme 0.8 EXAMPLE 4 Liquid Detergent

The product of Example 2 may be produced in liquid form by increasing the ratio of amine to sulphonic acid in the non-ionic component. The ratio in Example 2 is 1:5. An increase in the ratio will result in a liquid concentrate which may be adapted for use as a detergent concentrate or a laundry prewash soaker, a nappy (diaper) soaker laundering aid to which may be added oxygen or halogen releasing compounds, or a concentrated wool wash detergent. Stain removers such as aliphatic and aromatic hydrocarbons, glycol ethers, alcohols, cyclohexanol, or methyl cyclohexanol may be incorporated in the formulae to enhance stain removal.

EXAMPLE 5 Liquid Detergent

2 moles of di-(2-hydroxyethyl)-amine and 1 mole of a mixture of carboxylic acids containing chains of from about 8-18 carbon atoms, are catalytically condensed at a temperature of 100-110°C until the Acid Value of the condensate is between 10 and 14. Separately, equimolar proportions of dihydroxy alkyl amines and aliphatic carboxylic esters of polyhydric alcohols, said esters being composed of mixtures of C10-C18 carboxylic acids, are catalytically condensed at a temperture of 115°C-120ºC at a pressure of 100-125 millimetres of mercury absolute. The two condensates are cooled and combined in the ratio of about 85:15 by weight.

Alkyl benzene sulphonate is added with stirring to make up 25% by weight of the composition, and the reaction temperature is maintained below about 38ºC. Stirring is continued until homogeneity is achieved. In alternatives of this formulation, perfume, colour, optical brightness and zeolite are added and thoroughly blended. Proteolytic enzyme is then added and blended.

The following Example serves to demonstrate the efficacy of the laundry detergents produced according to the process of the present invention.

The efficacy of a laundry detergent is determined by its ability to remove a variety of soils, prevent redeposition and present the fabric, after laundering, in an acceptable state of cleanliness. This performance criteria is generally considered fulfilled in the well known powder and liquid technology by inclusion of phosphates, silicates and alkali metal carbonates. Protein bonded soils do not always respond to the traditional methods imposed by high alkaline washing techniques. The detergents of the present invention have surfactant as the continuous phase, and as is to be expected, it is ideally suited for the emulsification of hydrophobic soils such as sebum and triglycerol. The inclusion of highly active enzymes provides additional means for the removal of tenacious protein bonds. The pH range of the finished novel system determines the selection of the enzyme suitable for pH ranges from 7.0-10.0 and, as the surfactant system is stable over a pH range from 7.0-10.0, an enzyme may be selected to suit particular washing conditions. The anhydrous character of the invention, and the low degree of electrolytes necessary for ideal results, provide the best conditions for enzyme stability.

EXAMPLE 6 Proteolytic enzymes prepared from the Bacillus subtil is type microorganism were tested in the formulated laundry detergent using the novel surfactant system, and as the following test results demonstrate, produced superior protein stain removal characteristics.

The detergent system of Example 2 was tested with three different proteolytic enzymes; Alcanase, Esperase and Savinase. Table 5 demonstrates the results of experiments conducted using the three proteases under three different wash conditions. The values given are the difference between reflection measurements before and after washing.

TABLE 5

A B C

Presoak 18 h

40ºC, 12min 25ºC, 30min +25ºC, 30min

0.50% Alcalase 2.5 L 10.1 15.8 41.4

1.00% 20.3 23.9 58.8

1.50% 30.9 30.7

0.50% Esperase 8.0 L 8.8 11.6 25.3

1.00% 13.6 15.7 35.9

1.50% 14.9 16.4

0.50% Savinase 8.0 L 13.8 13.5 32.9

1.00% 22.8 22.0 47.1 1.50% 25.3 28.9

The detergent of Example 2 containing the proteases hereinbefore mentioned was then tested for storage stability, with the initial activity set to 100%. Table 6 gives the residual activity after different storage periods at 37°C.

TABLE 6

Alcalase Esperase Savinase

2.5 L 8.0 L 8.0 L

Week 0 100% 100% 100%

- 1 94% 84% 92%

- 2 88% 71% 82%

- 3 85% 62% 75%

- 4 80% 49% 64%

Claims

1. A detergent composition of anionic and non-ionic surfactants, wherein at least one non-ionic surfactant is produced by an alkanol amide condensation reaction of the Kritchevsky type (as hereinbefore defined), in which 2-hydroxyethylamine or di-(2-hydroxyethyl)-amine is condensed with mixed fatty acids or esters at elevated temperature and further reacted at a controlled reaction temperature of less than about 38°C, with at least one anionic surfactant constituting 5-50% by weight of the total weight of the composition.

2. A composition according to Claim 1 wherein the carboxyl radical of the mixed fatty acids or esters is provided by aliphatic esters prepared by transesterification and subsequent condensation, or from fatty acids resulting front the hydrolysis of triglycerides, or from tryglyercides.

3. A composition according to Claim 2 wherein the carboxyl radical of the mixed fatty acids Is derived from triglycerides.

4. A composition according to Claim 3 wherein the carboxyl radical of the mixed fatty acids is provided by triglyercides contained in tallow, coconut oil, palm oil, cotton seed oil, soya bean oil or linseed oil.

5. A composition according to any one of Claims 1-4, wherein the non-ionic surfactant component further contains up to 20% by weight of one or more non-ionic surfactants selected from the group comprising ethoxylated amines, ethoxylated alkyloamides, ethoxylated phosphate esters, propoxylated analogues of one or more of the aforesaid surfactants, propoxylated or ethoxylated polyglycol carboxylic esters or polyethylene glycol carboxylic esters.

6. A composition according to Claim 5 wherein the further non-ionic surfactant component comprises about 15-20% by weight of polyethylene glycol carboxylic esters.

7. A composition according to any one of Claims 1-6, said composition further comprising one or more additives selected from the group consisting of optical brightening agents, water softening agents, bleaches, perfumes, anti redeposition agents, colours and enzymes.

8. A process for preparing detergent compositions according to Claim 1 comprising:

(i) condensing 2-hydroxyethylamine or di-(2-hydroxyethyl)-amine and a carboxyl group containing compound at a temperature of about 100-120°C in the presence of catalyst, until the Acid Value of the condensate is between 10 and 14; (ii) cooling the resultant condensate; and (iii) adding an anionic surfactant at a controlled reaction temperature below about 38°C with mixing until the anionic surfactant component constitutes 5-50% of the total reaction mixture by weight.

9. A process according to Claim 8, wherein the catalyst is selected from the group consisting of para-toluene sulphonic acid, potassium hydroxide and sodium methoxide.

10. A process according to Claim 9 wherein the catalyst is sodium methoxide.

11. A process according to any one of Claims 8-10 wherein the anionic surfactant is a sulphonic acid.

12. A process according to Claim 11 wherein the anionic surfactant is an alkyl aryl sulphonic acid.

13. A process according to any one of Claims 8-12 wherein step (iii) is followed by blending into the composition, one or more components selected from the group consisting of water softening agents, optical brightening agents, bleaches, perfumes, colours and enzymes.

14. A process according to any one of Claims 8-13 wherein up to 20% by weight of polyethylene glycol carboxylic esters are added to the composition after step (i).

15. A process according to Claim 14 wherein the polyethylene glycol carboxylic esters are present between 15% and 20% by weight of the total non-ionic surfactant component.

16. A detergent composition produced by the process defined by any one of Claims 8-15.