DE69019236T2 - Fabric softener composition. - Google Patents

Description

Textile softener composition

The present invention relates to suitable textile softening agents for softening textiles in the rinse cycle of the textile washing process.

It has been proposed in DE 33 12 328 (Benckiser) to produce fabric softening agents comprising a combination of fabric softening materials and organic acids, in particular polycarboxylic acids. However, the agents disclosed in this document have low-effective amounts of up to about 10% by weight. These low-effective agents are of lamellar structure, with the molecules of the fabric softening material forming an onion-like configuration comprising concentric bilayers of softening material between which an aqueous phase containing the dissolved acid component is enclosed. When increasing the active ingredient content of these formulations, the onset of instability and/or gelation is observed when the active ingredient content exceeds a certain critical value of about 13% by weight of the agent. Therefore, it has been previously assumed that it is not possible to formulate stable fabric softening agents containing high levels of fabric softening material in combination with organic acids.

Surprisingly, it has now been found that by further increasing the active ingredient content of these compositions, a second class of stable, liquid, softening compositions can be produced. These agents are unexpectedly isotropic, they do not comprise any structure of active ingredients. These isotropic agents are preferred over lamellar compositions in that they are more resistant to temperature fluctuations and allow more flexible use of the ingredients.

US-A-4 060 505 discloses a stable, homogeneous, liquid composition for acidifying and softening textiles, containing 0.5 to 25% by weight of a softening By means of a fatty amide-based softening agent with a specific structural formula and 7.5 to 75% by weight of a water-soluble organic carboxylic acid with about 1 to 20 carbon atoms. In the examples, liquid agents are prepared which contain 1.3% by weight of a fatty amide-based softening agent.

US-A-3 984 335 discloses a stable, homogeneous, liquid composition for acidifying and softening fabrics which includes about 0.5 to 25% by weight of a fatty acid amide-based softening agent and about 7.5 to 75% of a water-soluble organic carboxylic acid. In the individual examples given, liquid compositions are prepared which contain 1.3 to 3% by weight of softening agent.

EP-A-0 043 622 describes a concentrated fabric softening agent comprising a water-insoluble, cationic softener and a viscosity control system. The viscosity control system includes two components, the first of which may be a C₁₀-C₂₄ fatty acid or ester thereof. The softener is present in a concentration of between 8 and 22% and the first control component in a concentration of between 0.5 and 6%. Of the examples given in this document, only one contains a fatty acid (stearic acid) in a concentration of 2%.

EP-A-0 123 999 describes aqueous, free-flowing concentrates containing a fabric softening quaternary ammonium compound and an alkali metal soap or the corresponding fatty acid (typically a C8-C20 acid). The claims of the document refer to a softener concentration of at least 30% by weight. Typical fatty acid concentrations are said to be between 1 and 10% by weight. In the examples given, fatty acid concentrations of 3% are used.

US-A-3 954 630 discloses a textile treatment composition including a cationic fabric softening agent and an organic "complexing acid". The document relates to the use of such a composition during a rinse cycle treatment, the composition after dilution containing between 0.01 and 0.1 wt.% of the fabric softening agent and between 0.01 and 0.1% by weight of the complexing acid. In its concentrated form, the agent contains 0 to 25% by weight of the softening agent.

EP-A-0 346 634 is prior art under Article 54(3) and (4) EPC only in respect of Spain. It describes a liquid laundry conditioning composition containing as a fabric softening agent a quaternary ammonium compound containing two 2-acyloxyalkyl groups. The composition also contains (typically C8 to C24) fatty acids. The softening agent is present in a concentration of between 1.5 and 27% by weight and the fatty acid in a concentration of between 0.5 and 10% by weight.

EP-A-0 387 064 is also prior art under Article 54(3) and (4) EPC in respect of all designated states to the present invention. It discloses a liquid fabric conditioning composition comprising an aqueous base, a cationic fabric softening material and an ethylene glycol distearate. The composition may also include a fatty acid material, preferably a C8-C24 acid material. In the examples given, the concentration of the softening material is in the range of 4.8 to 5.2%, while a fatty acid is present at a concentration of 0.5% by weight.

Accordingly, the present invention relates to isotropic, liquid, fabric softening agents comprising:

(i) between 30 and 50% by weight of a fabric softening material; and

(ii) between 5 and 40 wt.% of an organic acid.

Preferably, the isotropic agents of the invention are clear or translucent. Emollient compositions that are clear are sometimes particularly appreciated by the consumer because they have a fresh and natural appearance. Transparent compositions can be prepared by ensuring that all the ingredients of the agent are completely dissolved in the liquid phase.

The textile softening material

Agents according to the invention contain 30 to 50% by weight of the fabric softening material. This material can be selected from cationic, non-ionic and amphoteric softening materials and mixtures thereof.

Suitable cationic fabric softening materials include water-insoluble cationic materials having a solubility in water at pH 2.5 and 20°C of less than 10 g/l. Highly preferred materials are cationic quaternary ammonium salts having two C₁₂-₁₄ hydrocarbon chains.

Well-known types of essentially water-insoluble quaternary ammonium compounds have the formula

wherein R₁ and R₂ are represented by hydrocarbon groups having from about 12 to about 24 carbon atoms, R₃ and R₄ are hydrocarbon groups containing from 1 to about 4 carbon atoms, and X is an anion, preferably selected from halide, methyl sulfate and ethyl sulfate radicals.

Representative examples of these quaternary plasticizers are ditallowdimethylammonium chloride, ditallowdimethylammonium methylsulfate, dihexadecyldimethylammonium chloride, di(hydrogenated tallow)dimethylammonium methylsulfate, dihexadecyldiethylammonium chloride, di(coconut)dimethylammonium chloride. Ditallowdimethylammonium chloride, di(hydrogenated tallow)dimethylammonium chloride and di(coconut)dimethylammonium methosulfate are preferred.

Suitable materials also include dialkylethoxylmethylammonium methosulfate based on a soft fatty acid, dialkylethoxylmethylammonium methosulfate based on a hard fatty acid and a material wherein R3 and R4 represent methyl, R1 is C13-15, R2 is CH2CH2OCOR where R is stearyl and X is methosulfate,

Materials in which R₂, R₃ and R₄ each represent methyl, R₁ represents the group

where R is hydrogenated tallow and X is methosulfate or R2 is methyl,

R₃ and R₄ each represent -CH₂-O- -R, where R represents hydrogenated tallow, R₁ represents CH₂CH₂OH and X represents methosulfate are also suitable.

Preferably, cationic plasticizers are used which have an active melting point (transition from the Lb to the L state) of less than 25°C, more preferably less than 20°C. Examples of these materials are diunhardened tallow dimethyl ammonium chloride and dicoconut dimethyl ammonium chloride.

Other preferred cationic compounds include those materials disclosed in EP-A-239 910 (P&G).

In this specification, the term hydrocarbon group refers to alkyl or alkenyl groups, optionally substituted or interrupted by functional groups such as -OH, -O-, -OONH, -OOO-, etc.

Other preferred materials are the materials of the formula

where R�5 is tallow, available from Stepan under the trademark Stepantex VRH 90 and

wherein R₈, R₉ and R₁₀ each represent alkyl or hydroxyalkyl groups having 1 to 4 carbon atoms or a benzyl group. R₆ and R₇ each represent alkyl or alkenyl chains having 11 to 23 carbon atoms and x is a water-soluble anion substantially free of the corresponding monoester.

Another class of preferred water-insoluble cationic materials are the hydrocarbylimidazolinium salts, which are believed to have the following formula:

wherein R₁₃ is a hydrocarbon radical having 1 to 4, preferably 1 to 2 carbon atoms, R₁₁ is a hydrocarbon radical having 8 to 25 carbon atoms, R₁₄ is a hydrocarbon radical having 8 to 25 carbon atoms and R₁₂ is a hydrogen atom or a hydrocarbon radical having 1 to 4 carbon atoms and A⊃min;⊃min; is an anion, preferably a halide, methosulfate or ethosulfate.

Preferred imidazolinium salts are 1-methyl-1-(tallowylamido)ethyl-2-tallowyl-4,5-dihydroimidazolinium methosulfate and 1-methyl-1-(palmitoylamido)ethyl-2-octadecyl-4,5- dihydroimidazolinium chloride. Other imidazolinium materials that can be used are 2-heptadecyl-1-methyl-1-(2-stearylamido)-ethylimidazolinium chloride and 2-lauryl-1-hydroxyethyl-1-oleylimidazolinium chloride. Also suitable herein are fabric softening imidazolinium components from US-A-4,127,489, the disclosure of which is incorporated into the description by this reference.

Representative commercial materials of the foregoing classes are the quaternary ammonium compounds Arquad 2HT (from AKZO), Noramium M2SH (from CEKA) Aliquat-2HT (trademark of General Mills Inc.), Stepantex Q185 (from Stepan), Stepantex VP85 (from Stepan), Stepantex VRH90 (from Stepan), Synprolam FS (from ICI) and the imidazolinium compounds Varisoft 475 (trademark of Sherex Company, Columbus Ohio) and Rewoquat W7500 (trademark of REWO).

The fabric softening materials may also contain one or more amines instead of or in addition to the above-mentioned softening agents.

The term "amine" as used here may refer

(i) Amines of the formula

wherein R₁₅, R₁₆ and R₁₇ are as defined below:

(ii) Amines of the formula

wherein R₁₈, R₁₉, R₂₀ and R₂₁, m and n are as defined below.

(iii) Imidazolines of the formula

wherein R₁₁, R₁₂ and R₁₄ are as defined above.

(iv) condensation products formed from the reaction of fatty acids with a polyamine selected from the group consisting of hydroxyalkylalkylenediamines and dialkylenetriamines and mixtures thereof. Suitable materials are disclosed in EP-A-199 382 (Procter and Gamble), the disclosure of which is incorporated into the description by this reference.

When the amine is of formula I above, R₁₅ is a C₆ to C₂₄ hydrocarbon radical, R₁₆ is a C₁₅ to C₂₄ hydrocarbon radical, and R₁₇ is a C₁₅ to C₁₀ hydrocarbon radical. Suitable amines are those materials from which the quaternary ammonium compounds disclosed above are derived, in which R₁₅ is R₁, R₁₆ is R₂, and R₁₇ is R₃. Preferably, the amine is designed such that both R₁₅ and R₁₆ are C6-C20 alkyl, with C16-C18 alkyl being most preferred, and when R17 is C1-3 alkyl, or R15 is an alkyl or alkenyl group having at least 22 carbon atoms, and R16 and R12 are C1-3 alkyl. Preferably, these amines are protonated with hydrochloric acid, orthophosphoric acid (OPA), C1-5 carboxylic acids or any other similar acids for use in fabric conditioning compositions according to the invention.

When the amine has the above formula II, R₁₈ is a C₆ to C₂₄ hydrocarbon group, R₁₉ is an alkoxylated group of the formula -(CH₂CH₂O) yH where y is within the range of 0 to 6, R₂₀ is an alkoxylated group of the formula -(CH₂CH₂O)zH where z is within the range of 0 to 6 and m is an integer within of the range of 0 to 6 and preferably is 13. When m is 0, it is preferred that R₁₈ is C₁₆ to C₂₂ alkyl and that the sum of z and y is within the range of 1 to 6, preferably 1 to 3. When m is 1, it is preferred that R₁₈ is C₁₆ to C₂₂ alkyl and that the sum of y and z is within the range of 3 to 10.

Representative commercially available materials of this class are Ethomeen (from Armour) and Ethoduomeen (from Armour).

Preferably, the amines of type (ii) or (iii) are also protonated for use in the fabric conditioning compositions of the invention.

When the amine is of type (iv) given above, a particularly preferred material is

where R₂₂ and R₂₃ are divalent alkenyl chains having 1 to 3 carbon atoms and R₂₄ is an acyclic aliphatic hydrocarbon chain having 15 to 21 carbon atoms. A commercially available material of this class is Ceranine HC39 (from Sandoz).

Alkoxylated fatty amides or amines can also be used as fabric softening materials in the compositions according to the invention. Suitable materials are disclosed, for example, in EP 159 921 (Unilever) and EP 159 919 (Unilever). The fabric softening material can also comprise, instead of or in addition to the above-mentioned softening materials, one or more fabric substantive amphoteric fabric softening materials. Suitable amphoteric materials form a particulate dispersion at a concentration of less than 1 g/l at at least one temperature between 0 and 100°C. For the purpose of the invention, a fabric substantive amphoteric material is preferably an amphoteric or zwitterionic tertiary or quaternary ammonium compound having either a single very long hydrocarbon side chain or two long hydrocarbon chains. Of these compounds, the use of amphoteric or zwitterionic ammonium compounds with two long hydrocarbon chains is particularly preferred for many reasons including cost, ease of processing, and better stability and performance.

Amphoteric or zwitterionic ammonium compounds preferably have two long hydrocarbon chains, each chain with 8-24 C atoms, preferably 10-20 C atoms, most preferably around 16 C atoms.

Suitable amphoteric textile substantive materials for use in a textile treatment composition according to the invention are, for example: ampholytes, hydrocarbyl betaines, hydrocarbyl amide betaines, glycinates, propionates and tertiary amine oxides. These materials are described in our pending patent application EP-0 332 270.

Particularly preferred amphoteric plasticizing materials are tertiary amine oxides of the following formula

wherein:

a) R₂₅ and R₂₆ are hydrocarbon chains, R₂₇ is a hydrocarbon group containing 1 to 4 carbon atoms or a group -(CH₂CH₂O)nH, R₃₁ is R₂₇ and r is 0 or 1 and n is an integer from 1 to 6;

or

b) R₂₅ is a C₁₆-₅�0 hydrocarbon chain, R₂₆, R₂₇ are hydrocarbon groups containing 1 to 4 carbon atoms or a group -(CH₂CH₂O)nH, R₃₁ is R₂₇ and r is 0 or 1 and n is an integer from 1 to 6.

Preferably, the amphoteric textile substantive materials are water-soluble and have a solubility in water at pH 2-5 at 20ºC of less than 10 g/l.

The HLB value of the amphoteric textile substantive material is preferably less than 10.0.

Examples of amphoteric materials of the above groups and their preparation processes are given in our pending European patent application EP-0 326 213.

The compositions may also contain, instead of or in addition to the fabric softening agents mentioned above, non-cationic fabric softening agents such as non-ionic fabric softening agents. Suitable non-ionic fabric softening agents include glycerol esters such as glycerol monostearate, fatty alcohols such as stearyl alcohol, alkoxylated fatty alcohols, C9-C24 fatty acids such as Dobanol 91-6 (Shell) and lanolin and derivatives thereof. Suitable materials are disclosed in European Patent Application 88 520 (Unilever PLO/NV Oase 01325), 122 141 (Unilever PLO/Nv Oase 01363) and 79 746 (Procter and Gamble), the disclosures of which are incorporated by reference.

Preferred compositions according to the invention contain at least some cationic fabric softening materials. Preferably at least 50% of the fabric softening material is a cationic fabric softening material.

The total amount of fabric softening material comprises between 30 and 50% by weight, preferably between 35 and 50% by weight, typically between 40 and 50% by weight of the agent.

The agents according to the invention preferably contain substantially no anionic material, in particular no anionic surfactant. If such materials are present, the weight ratio of the cationic fabric softening agent to the anionic material should preferably be greater than 5:1.

The organic acid material

The organic acid material for use in the inventive agents can be selected from the group of mono-, di-, tri- or polycarboxylic acids, preferably with a total number of carbon atoms of 8 or less, preferably 4 or less.

Examples of suitable organic acid materials are succinic acid, malic acid, tartaric acid, citric acid, glutaric acid, acetic acid, propionic acid and lactic acid or mixtures thereof. To provide stable products over a wide concentration range, the use of lactic acid and acetic acid is preferred. To provide products with a particularly interesting appearance and good color stability, it is preferred to use citric acid.

The proportion of acid material in the composition (calculated on an anhydrous basis) of the acid material comprises between 5 and 40%, preferably between 10 and 40%, typically between 15 and 35% by weight of the composition.

Components present, if any

The agent may also contain one or more optional ingredients selected from non-aqueous solvents such as C₁-C₄ alkanoics and polyhydric alcohols, pH buffering agents, rewetting agents, viscosity modifiers such as electrolytes, antigelling agents, perfumes, perfume carriers, fluorescence agents, colorants, hydrotropes, antifoaming agents, hydrocarbons, antiredeposition agents, enzymes, optical brightening agents, opacifiers, washing stabilizers such as guar gums and polyethylene glycol, emulsifiers, antishrink agents, lanolin or lanolin-like substances, anticreasing agents, laundry starch, antistain agents, soil release agents, germicides, linear or branched silicones, fungicides, antioxidants, anticorrosive agents, preservatives such as bronopol (trademark) a commercially available form of 2-bromo-2-nitropropane-1,3-diol, dyes, bleaches and bleach precursors, draping agents, antistatic agents and ironing aids.

These optional ingredients, if added, are each present in proportions of up to 5% by weight of the composition, excluding hydrocarbons and non-aqueous solvents which may be included in proportions of up to 30%. The pH of the composition is preferably below the pK of the organic acid, more preferably at least one unit below the pK, typically between 2.0 and 5.0.

Soil-releasing agents that are particularly preferred in the compositions of the invention are polymers. Suitable polymers include alkyl and hydroxyalkyl cellulose ethers such as methyl cellulose and polyvinylpyrrolidone.

Silicones may be included in the agents as ironing aids, rewetting agents or antifoaming agents. Suitable silicones for use in the compositions of the invention are predominantly linear polydialkyl or alkylarylsiloxanes in which the alkyl groups contain 1 to 5 carbon atoms. The siloxanes may be amido or amino substituted. If the siloxane is amine substituted, the amino group may be quaternized.

Fatty acid materials or other non-ionic extenders may also be included in the compositions of the invention. Suitable materials and their amounts are disclosed, for example, in EP 13 780 (P&G) and DE 29 43 606 (Unilever).

The balance of the agent is preferably water. Although anhydrous systems are also within the scope of the invention, the amount of water in the agent is preferably greater than 20% by weight, more preferably greater than 25% by weight. Generally, the water content will be less than 70%, more preferably less than 60%, most preferably less than 55%, typically between 55% and 25%.

The viscosity of the product is preferably less than 250 mPas at 106 s⊃min;¹.

When used, the agents according to the invention can be dosed in pre-diluted or concentrated form into the rinse cycle of the textile washing process. The material is preferably used in a concentration of between 0.01 and 2 g/l, in particular between 0.1 and 1 g/l.

The invention is further explained with the help of the following examples:

Example I

Fabric softening compositions containing water, tartaric acid (on a dry basis) and a cationic fabric softening material Prapagen 3445 (70% di-unhardened tallow dimethyl ammonium chloride 20% isopropyl alcohol, 10% water) were prepared by mixing with gentle agitation.

For each agent, the structure and appearance were evaluated, the results are given in Table 1 and graphically presented in Figure 1. Composition Water/Prapagen/Tartaric acid (%) Result lamellar/milky Gel isotropic/clear Phase separation isotropic/clear (some phase separation)

These examples clearly show that lamellar/milky products are formed at low active ingredient concentrations; by increasing the active ingredient content, unacceptable gelled products are obtained, but surprisingly, by further increasing the active ingredient content, isotropic/clear agents are obtained (compositions 12, 15, 18 and 19 according to the present invention).

Example II

Example I was repeated replacing tartaric acid with citric acid. The results are presented in Table 1 and Figure 2. Composition Water/Prapagen/Tartaric acid (%) Result lamellar/milky Gel isotropic/clear Phase separation isotropic/clear

Again, surprisingly, isotropic liquids can be formulated according to the invention (compositions 30, 32, 33, 34) by increasing the proportion of fabric softening materials. Particularly interesting was the clear natural yellow appearance of the product, no discoloration was observed during storage.

Example III

Example I was repeated replacing the tartaric acid with acetic acid or with lactic acid.

Using acetic acid, isotropic/clear agents could be formulated when proportions of plasticizers were 50% or greater. At lower concentrations, a similar behavior to that observed for tartaric acid was observed: lamellar systems at low concentrations and gelled systems at intermediate concentrations of the plasticizing material.

When lactic acid was used, similar results were observed as with acetic acid. This indicates that the use of acetic acid and lactic acid is preferred for stability reasons, especially with high proportions of plasticizing materials.

Example IV

By replacing tartaric acid with propionic acid, isotropic/clear agents can be formulated, even with low acid contents such as 5%. Typical formulations are: Formulation wt. % Arquard Isopropyl alcohol Propylene glycol Propionic acid Water Balance

Claims (10)

1. An isotropic liquid fabric softening agent, comprising: (i) between 30 and 50% by weight of a fabric softening material; and (ii) between 5 and 40 wt.% of an organic acid. 2. Agent according to claim 1, having a transparent appearance. 3. Agent according to one or more of the preceding claims, wherein the fabric softening material comprises a cationic fabric softening material. 4. Agent according to one or more of the preceding claims, wherein the organic acid is a carboxylic acid having a total number of carbon atoms of 8 or less. 5. The agent of claim 4, wherein the organic acid has a total number of carbon atoms of 4 or less. 6. A composition according to claim 4, wherein the organic acid comprises propionic acid. 7. A composition according to claim 4, wherein the acid comprises lactic acid or acetic acid. 8. Agent according to one or more of the preceding claims, comprising at least 10% by weight of organic acid. 9. Agent according to one or more of the preceding claims, comprising at least 20% by weight of water. 10. A method for treating textiles, comprising bringing textiles into contact with an aqueous lye comprising 0.01 to 2 g/l of an agent according to one or more of the preceding claims.