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(11) | EP 0 280 550 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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Fabric-softening composition Weichmacherzusammensetzung für Textilien Composition adoucissante pour textiles |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] The present invention relates to a fabric softening composition, in particular a fabric softening composition containing a water-insoluble cationic fabric softening agent, a fatty acid and other nonionic surfactants.
[0002] One of the problems associated with fabric softening compositions is the physical instability of such compositions when stored. This problem is accentuated if storage occurs at various cycling temperatures including those below the freezing point, since irreversible gels can be formed.
[0003] It has been proposed (European Patent Specification No 21 476) to add a protonated di-polyethoxy monoalkyl amine, a lower alcohol and, optionally, a nonionic fabric conditioning agent to control the physical stability of a composition containing a quaternary ammonium fabric softener, the alcohol being additional to that present in the softener raw material. The disadvantage with the compositions disclosed is that the physical stability is only achieved if both the amine and alcohol are added to the composition.
[0004] It has been disclosed in FR-A 2 440 433 (UNILEVER N.V.) to combine 20-95 mole % of cationic softening materials with 5―80 mole % of fatty acid materials. Nonionic surfactant materials may optionally be added to these compositions.
[0005] We have now found that the addition of a nonionic surfactant to a composition containing a cationic fabric softening agent and a fatty acid gives a composition which is stable after one and multiple freeze thaw cycles without the necessity of adding additional alcohol.
[0006] Thus, according to the invention there is provided a liquid fabric softening composition comprising
(i) an aqueous base;
(ii) from 1 to 6% by weight of a water-insoluble cationic fabric softening agent;
(iii) at least 0.2% by weight of a Ca-C24 fatty acid; and
(iv) a nonionic surfactant,
wherein the mole ratio of the cationic fabric softening agent to the nonionic surfactant is within the range from 10:1 to 3:1, and wherein the mole ratio of the cationic fabric softening agent to the fatty acid is at least 1:1.
[0007] The water-insoluble cationic fabric softening agent can be any fabric-substantive cationic compound which has a solubility in water at pH 2.5 and 20°C of less than 10 g/1. Highly preferred materials are quaternary ammonium salts having two C12―C24 alkyl or alkenyl chains, optionally substituted or interrupted by functional groups such as -OH, -0-, -CONH-, -COO-, etc.
[0008] Well known species of substantially water-insoluble quaternary ammonium compounds have the formula
wherein Ri and R2 represent hydrocarbyl groups having from 12 to 24 carbon atoms; R3 and R4 represent hydrocarbyl groups containing from 1 to 4 carbon atoms; and X is an anion, preferably selected from halide, methyl sulfate and ethyl sulfate radicals.
[0009] Representative examples of these quaternary softeners include ditallow dimethyl ammonium chloride; ditallow dimethyl ammonium methyl sulfate; dihexadecyl dimethyl ammonium chloride; di(hydrogenated tallow alkyl) dimethyl ammonium chloride; dioctadecyl dimethyl ammonium chloride; dieicosyl dimethyl ammonium chloride; didocosyl dimethyl ammonium chloride; di(hydrogenated tallow) dimethyl ammonium methyl sulfate; dihexadecyl diethyl ammonium chloride; di(coconut alkyl) dimethyl ammonium chloride. Also suitable are dialkyl ethoxyl methyl ammonium sulphates based on soft or hard fatty acids. Ditallow dimethyl ammonium chloride, di(hydrogenated tallow alkyl) dimethyl ammonium chloride, di(coconut alkyl) dimethyl ammonium chloride and di(coconut alkyl) dimethyl ammonium methosulfate are preferred.
[0010] Another class of preferred water-insoluble cationic materials are the alkylimidazolinium salts believed to have the formula:
wherein R6 is an alkyl or hydroxyalkyl group containing from 1 to 4, preferably 1 or 2 carbon atoms, R7 is an alkyl or alkenyl group containing from 8 to 25 carbon atoms, Ra is an alkyl or alkenyl group containing from 8 to 25 carbon atoms, and R9 is hydrogen or an alkyl containing from 1 to 4 carbon atoms and A- is an anion, preferably a halide, methosulfate or ethosulfate. Preferred imidazolinium salts include 1-methyl-1-(tallowylamido-) ethyl -2-tallowyl- 4, 5-dihydro imidazolinium methosulfate and 1-methyl-1-(paimitoylamido)ethyl-2-octadecyl-4, 5- dihydro- imidazolinium chloride. Other useful imidazolinium materials are 2-heptadecyl-1-methyl-l- (2-stearylamido)- ethyl-imidazolinium chloride and 2-lauryl-1-hydroxyethyl-l-oleyl-imidazolinium chloride. Also suitable herein are the imidazolinium fabric softening components of US Patent No 4 127 489. Mixtures of various cationic fabric softening agents can also be used.
[0011] The level of the cationic fabric softening agent in the composition is preferably more than 1% by weight, most preferably from 3% to 6% by weight.
[0012] Suitable fatty acids which can be used in the present invention are Cs-C24 alkyl or alkenyl linear or branched chain monocarboxylic acids or polymers thereof. Preferably saturated fatty acids are used, in particular, hardened tallow C16―C18 fatty acids. Mixtures of various fatty acids can also be used.
[0013] The level of the fatty acid in the composition is preferably less than 8% by weight, most preferably from 0.2% to 2.5% by weight.
[0014] The mole ratio of the cationic fabric softening agent to the fatty acid is at least 1:1, and preferably is within the range 4:1 to 9:1.
[0015] Suitable nonionic surfactants which can be used include in particular the reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example aliphatic alcohols, acids, or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Specific nonionic surfactants are alkyl (C6―C22) phenols-ethylene oxide condensates, generally up to 25 EO, ie up to 25 units of ethylene oxide per molecule, the condensation products of aliphatic (Ca-C22) primary or secondary linear or branched alcohols with ethylene oxide, generally up to 40 EO, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine. Other so-called nonionic surfactants include amine oxides, alkyl polyglycosides, ethoxylated castor oils, sorbitan esters and ethoxylated derivatives thereof.
[0016] Preferably, the level of the nonionic surfactant is within the range from 0.1 to 4.5% by weight, most preferably from 0.15% to 3% by weight. The mole ratio of the cationic fabric softening agent to the nonionic surfactant is within the range from 18:1 to 3:1.
[0017] The composition can also contain one or more optional ingredients selected from non-aqueous solvents such as Ci-C4 alkanols and polyhydric alcohols (although the benefits of this invention can be obtained without the addition of these materials), pH buffering agents, such as weak acids, eg phosphoric, benzoic or citric acids (the pH of the compositions are preferably less than 6.0), rewetting agents, viscosity modifiers, such as electrolytes and Cs-Cz4 fatty acids included at levels from 20 to 6000 ppm, an- tigelling agents, perfumes, perfume carriers, fluorescers, colourants, hydrotropes, antifoaming agents, antiredeposition agents, enzymes, optical brightening agents, opacifiers, stabilisers such as guar gum and polyethylene glycol, anti-shrinking agents, anti-wrinkle agents, fabric crisping agents, anti-spotting agents, soil-release agents, germicides,fungicides, anti-oxidants, anti-corrosion agents, preservatives such as Bronopol (Registered Trade Mark), a commercially available form of 2-bromo-2-nitropropane-1, 3 diol, dyes, bleaches and bleach precursors, drape imparting agents, antistatic agents and ironing aids, such as silicones.
[0018] These optional ingredients, if added, are each present at levels up to 5% by weight of the composition.
[0019] Suitable silicones for use in the compositions according to the invention include predominantly linear polydialkyl or alkylaryl siloxanes in which the alkyl groups contain one to five carbon atoms. The siloxanes can be amido or amino substituted. When the siloxane is amine substituted the amine group may be quaternised.
[0020] The compositions may also contain, in addition to the cationic fabric softening agent, other non-cationic fabric softening agents, such as nonionic fabric softening agents. Suitable nonionic fabric softening agents include lanolin and derivatives thereof. Suitable materials are disclosed in European Patent Ap- plieations 88 520 (Unilever). Typically such materials are included at a level within the range of from 0.5% to 10% by weight of the composition.
[0021] In use, the fabric conditioning composition of the invention may be added to a large volume of water to form a liquor with which the fabrics to be treated are contacted. Generally, the total concentration of the cationic fabric softening agent, the fatty acid and the nonionic surfactant in this liquor will be between 30 ppm and 500 ppm. The weight ratio of the fabrics to liquor will preferably be less than 25:1, most preferably between 10:1 and 4:1.
[0022] The compositions of the invention may be prepared by a variety of methods. One suitable method is to form a molten mixture of the cationic fabric softening agent and the fatty acid, add this molten mixture to water with stirring to form a dispersion and thereafter add the nonionic surfactant and any optional ingredients. Another suitable method is to add the nonionic surfactant to the molten mixture before the dispersion is formed.
[0023] The invention will now be illustrated by the following non-limiting examples. In the examples all weights are expressed as weight % of the active material.
EXAMPLE 1
[0025] The cationic fabric softening agent and the fatty acid were premixed and heated together until clear (60-75°C). The molten mixture thus formed was added over a period of at least one minute, via a dip pipe, to water at 45-60°C, with constant stirring to form a dispersion. Other minor ingredients including perfume were added with constant stirring whilst the temperature of the dispersion was greater than 35°C. The nonionic surfactant was most preferably added after the mixture had cooled to 35°C or below.
[0026] In this Example, the amounts of component materials used were such that the final product had the following composition expressed as weight %.
Arquad 2HT 3.6%
Pristerene 4916 0.6%
Nonidet LE 6T 0.25%
Perfume 0.13%
Approx. mole ratio of cationic: nonionic 11.1
[0027] For comparison purposes Example 1 was repeated except that the Nonidet LE 6T was excluded from the composition (Example 1 A).
[0029] A freeze thaw cycle in this context involves storing 100 g of product in a screw-capped polyethylene bottle for 16 hours at a temperature of -12°C or less. Such low temperatures are essential to ensure that the products are completely frozen. The product is then allowed to thaw at ambient temperatures for 8 hours.
[0030] After 1 freeze thaw cycle Example 1 gave a composition which was slightly thicker than normal. After 3 and 6 freeze thaw cycles Example 1 gave a composition which had normal rinse conditioner rheology, ie. was mobile and could be poured in a continuous stream. Example 1A after 1, 3 and 6 freeze thaw cycles gave a composition which was just mobile but which did not pour in a continuous stream.
[0031] The results show that the addition of a small amount of a nonionic surfactant to a composition containing a cationic fabric softening agent and a fatty acid gives a product with improved appearance and flow characteristics which are maintained even after 6 freeze thaw cycles.
EXAMPLE 2
[0032] This Example demonstrates the effect of replacing Nonidet LE 6T by other nonionic surfactants. Compositions with the following formulations expressed as weight % were prepared by the method previously described.
Arquad 2HT 3.6%
Pristerene 4916 0.6%
Nonionic 0,4%
Perfume 0.13%
[0033] For comparison purposes a composition containing no nonionic (Example 2L) was prepared and tested. In Example 2A a level of APG 300 of 0.2% rather than 0.4% was used. Each composition was subjected to the following cap dispenser test after 1 and 3 freeze thaw cycles.
[0034] Products were allowed to recover from freezing and a known amount (usually 20 grams) was weighed into an internally screw threaded cap with a total capacity of approximately 25 cm3 and of known weight. The cap was then inverted over a waste container for 10 seconds and re-weighed. The results obtained are expressed as a percentage of the amount of product weighed into the cap. Prior to freezing, the samples were found to leave up to approximately 10% residue in the cap.
The results were as follows.
[0036] The results obtained show that the beneficial effect of adding a small amount of nonionic surfactant to a composition containing a cationic fabric softening agent and a fatty acid is retained if the Nonidet LE 6T is replaced by one of a variety of other nonionic surfactants. For some nonionic surfactants the optimum effect is achieved after several freeze thaw cycles.
[0037] Similar beneficial results can also be obtained if the Nonidet LE6T is replaced by Tween 20, Alfol 1214-7, Alfol 1214-11, Alfol 1214-13, Brij 30, Brij 35, Lutensol A07, Lutensol A08, and Synperonic All.
EXAMPLE 3
[0038] This example demonstrates the effect of increasing levels of nonionic surfactant on the freeze-thaw stability of a 4.2% active with a ratio of Arquad 2HT: Pristerene 4916 of 6:1 by weight and a perfume level of 0.13%. The compositions were prepared by the method previously described. The levels of nonionic are expressed in terms of wt% of the final formulation. The products were assessed after one freeze thaw cycle via the cap dispenser test described above.
[0039] The results show that high levels of nonionic surfactant, (low mole ratios of cationic to nonionic) promote instability to freeze thaw cycling.
EXAMPLE 4
[0040] This example demonstrates the effect of low levels of Nonidet LE 6T on formulations other than those containing 4.2% active and a 6:1 weight ratio of cationic fabric softening agent to fatty acid. The compositions were prepared as described above and the percentage ingredient refers to their weight % in the final product.
[0042] In both cases the addition of the nonionic surfactant was found to improve the appearance and flow characteristics of the product.
EXAMPLE 5
[0043] Compositions with the following formulations were prepared as described above. Once again the amount of each ingredient refers to weight % in the final product composition.
[0044] The compositions were assessed visually after recovery from 1 freeze thaw cycle. In each case the addition of a nonionic surfactant improved the appearance and flow characteristics of the composition. This Example demonstrates that the beneficial effect of adding nonionic surfactant is not restricted to compositions containing Arquad 2HT and Pristerene 4916.
NOTES
[0045] Alfol 1214-7:
C12―C14 straight chain alcohol (with an even number of carbon atoms), ethoxylated with an average of 7 ethylene oxide groups per molecule.
[0046] Alfol 1214-11:
As Alfol 1214-7, but with an average of 11 ethylene oxide groups per molecule.
[0047] Alfol 1214-13:
As Alfol 1214-7, but with an average of 13 ethylene oxide groups per molecule.
[0048] APG 300:
Alkyl Polyglycoside based on a C9―C11 alcohol and having an average of 1.6 glycosidic rings per mole of alcohol (supplied as a 51% active solution).
[0049] Arquad 2HT:
Commercially available form of dihardened tallow dimethyl ammonium chloride (DMDHTAC)(supplied as a 75% active paste).
[0050] Brij 30:
C12―C14 straight chain alcohol (with an even number of carbon atoms and of natural origin) ethoxylated with an average of 4 ethylene oxide groups per molecule.
[0053] Dobanol 91-6:
C9―C11 branched chain primary alcohol, ethoxylated with an average of 6 ethylene oxide groups per molecule.
[0054] Dobanol 45-18:
C14―C15 branched chain alcohol, ethoxylated with an average of 18 ethylene oxide groups per molecule.
[0056] Genapol 0-050:
Oleyl alcohol ethoxylated with an average of 50 ethylene oxide groups per molecule.
[0057] Genapol 0-200:
Oleyl alcohol ethoxylated with an average of 200 ethylene oxide groups per molecule.
[0058] Lutensol OA7:
G3-C15 branched chain alcohol ethoxylated with an average of 7 ethylene oxide groups per molecule.
[0060] Nonidet LE 6T:
Similar material to Dobanol 91-6 except that it is topped to remove volatile materials.
[0066] Synperonic All:
C13―C15 branched chain alcohol ethoxylated with an average of 11 ethylene oxide groups per molecule.
[0067] Tergitol 15-S-7:
Cii-Ci5 secondary alcohol ethoxylated with an average of 7 ethylene oxide groups per molecule.
i) an aqueous base;
ii) from 1 to 6% by weight of a water-insoluble cationic fabric softening agent;
iii) at least 0.2% by weight of a Cs-C24 fatty acid;
and
iv) a nonionic surfactant
wherein the mole ratio of the cationic fabric softening agent to the nonionic surfactant is within the range from 18:1 to 3:1, and wherein the mole ratio of the cationic fabric softening agent to the fatty acid is at least 1:1
i) alkylene oxide adducts of aliphatic alcohols, and alkyl phenols;
ii) amine oxides;
iii) alkyl polyglycosides;
iv) ethoxylated castor oil;
v) sorbitan esters, and ethoxylated derivatives thereof; and
vi) mixtures of the foregoing materials.
i) dimethyl coco amine oxide;
ii) nonyl phenol ethoxylated with an average of 20 ethylene oxide groups per molecule;
iii) polyoxyethylene sorbitan monolaurate ethoxylated with an average of 20 ethylene oxide groups per molecule;
iv) a mixture of polyethylene sorbitan monolaurate ethoxylated with an average of 20 ethylene oxide groups per molecule and sorbitan monolaurate in a 50/50 weight ratio.
v) a branched chain primary alcohol having 9 to 11 carbon atoms and ethoxylated with an average of 6 ethylene oxide groups per molecule;
vi) a straight chain primary alcohol having 12 to 14 carbon atoms and ethoxylated with an average of 4, 7, 11, 13 or 23 ethylene oxide groups per molecule; and
vii) a branched chain primary alcohol having 13 to 15 carbon atoms and ethoxylated with an average of 7, 8 or 11 ethylene oxide groups per molecule.
i) eine wässrige Grundlage,
ii) von 1 bis 6 Gewichts-% eines wasserunlöslichen kationischen Weichmachermittels für Textilien, iii) mindestens 0,2 Gewichts-% einer C8-C24 Fettsäure, und
iv) ein nichtionisches Tensid,
worin das Molverhältnis des kationischen Weichmachermittels für Textilien zum nichtionischen Tensid Innerhalb des Bereiches von 18:1 bis 3:1 ist, und worin das Molverhältnis des katlonischen Weichmachermittels für Textilien zur Fettsäure mindestens 1:1 ist.
i) Alkylenoxid-Addukten von aliphatischen Alkoholen, und Alkylphenolen
ii) Aminoxiden
iii) Alkyl-Polyglykosiden
iv) ethoxyliertem Rizinusöl
v) Sorbitanestern, und ethoxylierten Derivaten davon; und
vi) Mischungen der vorstehenden Materialien.
i) Dimethyl-Kokos-Aminoxid,
ii) Nonylphenol ethoxyliert mit durchschnittlich 20 Ethylenoxidgruppen je Molekül,
iii) Polyoxyethylen-Sorbitan-Monolaurat ethoxyliert mit durchschnittlich 20 Ethylenoxidgruppen je Molekül,
iv) einer Mischung von Polyethylen-Sorbitan-Monolaurat ethoxyliert mit durchschnittlich 20 Ethylenoxidgruppen je Molekül und Sorbitan-Monolaurat in einem Gewichtsverhältnis von 50:50,
v) einem verzweigtkettigen primären Alkohol mit 9 bis 11 Kohlenstoffatomen und ethoxyliert mit durchschnittlich 6 Ethylenoxidgruppen je Molekül,
vi) einem geradkettigen primären Alkohol mit 12 bis 14 Kohlenstoffatomen und ethoxyliert mit durchschnittlich 4, 7, 11, 13 oder 23 Ethylenoxidgruppen je Molekül, und
vii) einem verzweigtkettigen primären Alkohol mit 13 bis 15 Kohlenstoffatomen und ethoxyliert mit durchschnittlich 7, 8 oder 11 Ethylenoxidgruppen je Molekül.
i) une base aqueuse;
ii) de 1 à 6% en poids d'un agent d'adoucissement cationique non hydrosoluble de textiles;
iii) au moins 0,2% en poids d'un acide gras en Ce-24; et
iv) un surfactif non ionique, dans laquelle le rapport molaire de l'agent cationique d' adoucissement de textiles au surfactif non ionique est compris entre 18:1 et 3:1, et dans laquelle le rapport molaire de l'agent cationique d'adoucissement de textiles à l'acide gras est d'au moins 1:1.
i) les produits d'addition d'oxyde d'alkylène avec des alcools aliphatiques et des alkylphénols;
ii) les oxydes d'amines;
iii) les alkylpolyglycosides;
iv) l'huile de ricin éthoxylée ;
v) les esters de sorbitanne et leurs dérivés ethoxylés; et
vi) des mélanges des matières.citées.
i) l'oxyde de diméthyl-coco-amine;
ii) le nonylphénol éthoxylé avec, en moyenne, 20 motifs d'oxyde d'éthylène par molécule;
iii) le monolaurate de polyoxyéthylène-sorbitanne éthoxylé avec, en moyenne, 20 motifs d'oxyde d'éthylène par molécule;
iv) un mélange de monolaurate de polyéthylènesorbitanne éthoxylé avec, en moyenne, 20 motifs d'oxyde d'éthylène par molécule et de monolaurate de sorbitanne dans un rapport pondéral 50:50;
v) un alcool primaire à chaîne ramifiée contenant de 9 à 11 atomes de carbone et éthoxylé avec, en moyenne, 6 motifs d'oxyde d'éthylène par molecule;
vi) un alcool primaire à chaîne droite de 12 à 14 atomes de carbone éthoxylé avec en moyenne 4, 7, 11, 13 ou 23 motifs d'oxyde d'éthylène par molécule; et
vii) un alcool primaire a chaîne ramifiée de 13 à 15 atomes de carbone éthoxylé avec en moyenne 7, 8 ou 11 motifs d'oxyde d'éthylène par molécule.