NO841373L - PROCEDURE FOR THE PREPARATION OF A SOFT SOFTING AGENT - Google Patents

Description

The invention relates to a method for the production of fabric softening preparations, in particular for the production of concentrated aqueous liquid fabric softening preparations containing water-insoluble cationic fabric softeners and fatty acids and other non-ionic materials with a low HLB value.

It is known from British Patent No. 2,039,556 to make aqueous liquid fabric softening compositions containing up to 20% of a mixture of water-insoluble cationic material and fatty acid, the fatty acid serving to improve the effectiveness of softening and thereby enabling the level of cationic material can be reduced without loss of performance. It is also known, from European Patent No. 13780-A, to make concentrated aqueous liquid fabric softening compositions from a mixture of a water-insoluble cationic material and a non-ionic material selected from hydrocarbons, fatty acids, fatty acid esters and fatty alcohols, Non-ionic material serves to improve the viscosity characteristics of the product when the level of cationic material is above 8%.

It is also known, from British Patent No. 2,039,556 and European Patent No. 13780, that preferred formulations may also include low levels of electrolyte, such as sodium chloride or calcium chloride respectively, to further regulate product viscosity.

It has been found that if such a preparation is prepared by dispersing a premix of the cationic and nonionic materials in

water to which the electrolyte has already been added followed by thorough mixing, the viscosity of the final product will often be higher than desired, especially if the total active level exceeds approx. 8%.

It is proposed, in European Patent No. 52517, that if the preparation is based on a mixture of cationic materials, some electrolyte is added, together with a premix of the cationic materials, to water with vigorous agitation, and then a remaining part of the electrolyte is added . Also in US patent no. 3,681,241 it is proposed that preparations based on a mixture of cationic materials are preferably made in such a way that they are essentially free of electrolytes, with electrolytes possibly being added to the resulting product to control its viscosity. Furthermore, British Patent No. 1,104,441 discloses that products based on a cationic plasticizer and a fatty acid ethanolamide can be made by adding water to a premix of the cationic and nonionic material and then, after cooling, adding an electrolyte such as .ex. sodium carbonate, to dilute the product.

We have surprisingly found that if the preparation is based on a mixture of a cationic fabric softener and a non-ionic material with a low HLB value, and is made by adding a premix of the cationic and the non-ionic to water, if the electrolyte is added only after the mixing step is completed, but not before, the viscosity of the final product will be lower. This makes it possible to reduce the level of electrolyte used without damaging the product's properties. It has surprisingly also been found that this subsequent addition of electrolyte can improve the product's long-term stability.

According to the invention, a method is therefore provided for the production of a concentrated aqueous liquid fabric softener preparation containing at least 8% by weight of water-insoluble cationic fabric softener, the method comprising the following steps: (i) forming a molten mixture containing the water-insoluble cationic fabric softener and a non-ionic material having an HLB value of not more than 10;

(ii) adding the molten mixture to water by

elevated temperature;

(iii) mixing the molten mixture and the water so as to form a dispersion of the molten mixture in droplet form in the water; and

(iv) adding electrolyte in the form of a source of lithium,

sodium, potassium, calcium, magnesium or aluminum ions to it, and the characteristic feature is that the electrolyte is added after, not before, the formation of said dispersion.

The water-insoluble cationic fabric softener can be any fabric substantive cationic compound having a solubility in water at pH 2.5 and 20°C of less than 10 g/l. Strongly preferred materials are quaternary ammonium salts which have two C^2~C24~alkyl]~ or alkenyl chains, optionally substituted or interrupted by functional groups such as e.g. -OH, -0-, -CONH, -C00-.

Well-known substances of essentially water-insoluble quaternary ammonium compounds have the following formula:

where R^ and represent hydrocarbyl groups with from approx. 12 to approx. 24 carbon atoms; R 1 and R 2 represent hydrocarbyl 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 include ditallow dimethylammonium chloride; tallow-dimethylammonium-methylsulphate; dihexadecyldimethylammonium chloride; di(hydrogenated tallow alkyl)dimethylammonium chloride; dioctadecyldimethylammonium chloride; dieicosyldimethylammonium chloride; didocosyldimethylammonium chloride; di(hydrogenated tallow)-dimethylammonium methyl sulfate; dihexadecyldiethylammonium chloride; di(coconut alkyl)-dimethylammonium chloride. Ditallow-dimethylammonium chloride, di-(hydrogenated tallow-alkyl)-dimethylammonium- . chloride, di(coconut alkyl)-dimethylammonium chloride and di(coconut alkyl)-dimethylammonium methosulf are preferred.

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

where Rg is an alkyl or hydroxyalkyl group containing 1-4, preferably 1 or 2, carbon atoms, R^ is an alkyl or

alkenyl group containing 8-25 carbon atoms, Rg is an alkyl or alkenyl group containing 8-25 carbon atoms, and Rg is hydrogen or an alkyl group 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-(tallow-ylamido)-ethyl-2-tallow-yl-4,5-dihydro-imidazolinium methosulfate and 1-methyl-1-(palmitoylamido)-ethyl-2-octadecyl-4 ,5-dihydro-imidazolinium chloride. Other useful imidazolinium materials are 2-heptadecyl-1-methyl-1-(2-stearyl-amido)-ethyl-imidazolinium chloride and 2-lauryl-1-hydroxyethyl-1-oleyl-imidazolinium chloride. Also suitable herein are the imidazolinium fabric softening components of US Patent No. 4,127,489, which are hereby incorporated by reference.

According to the present invention, the water-insoluble cationic plasticizer is present at a total level of at least 8%.

The maximum level of cationic plasticizer is determined by practical considerations; even with the nonionic materials to control the viscosity, it is not generally possible to produce stable, pourable emulsions containing more than 26% cationic plasticizer. If particularly high concentrations are desired, it is preferred to use enimidazolinium plasticizers, and preferred preparations contain 12-26% imidazolinium plasticizers. If a di-long-chain non-cyclic mono-quaternary plasticizer is used, it is preferred not to exceed a level of 22%, and a preferred range is 10-18%.

The preparations further contain non-ionic materials which have an HLB value of no more than 10, preferably no more than 8. The HLB scale is a known measure of the hydrophilic/lipophilic balance

in any connection and can be determined from the literature. Nonionic materials that have lower HLB values are less hydrophilic than those that have higher HLB values.

Preferred non-ionic materials are selected from:

(i) Cg-C24 fatty acids; (ii) esters of C 8 -C 8 fatty acids with monohydric alcohols containing 1-3 carbon atoms; (iii) C 10 -C 80 fatty alcohols;

(iv) lanolin and derivatives thereof; and

Particularly preferred examples of such nonionic materials include lauric acid, myristic acid, palmitic acid, iso-stearic acid, stearic acid, oleic acid, linoleic acid, undecanoic acid, methyl laurate, ethyl myristate, ethyl stearate, methyl palmitate, dodecanol, tetradecanol, hexadecanol, octadecanol, lanolin, lanolin- alcohols, hydrogenated lanolin, ethylene glycol monostearate, glycerol monostearate and -mono-iso-stearate, sorbitan monostearate and -mono-iso-stearate.

The non-ionic material may be present at one level

of approx. 1.0% to approx. 6.0%, preferably between approx. 1.6% and approx. 4.0%.

The electrolyte is selected from the salts of lithium, sodium, potassium, calcium, magnesium, aluminum and mixtures thereof. Aluminum salts are most preferred. Sodium and potassium salts are least preferred. Preferably, the salts contain monovalent anions. Preferred examples include aluminum chloride, aluminum chlorohydrate, calcium chloride, calcium bromide, calcium nitrate and magnesium chloride. The preferred level of strong ionic electrolyte in the final product is at least 10 ppm and less than 3,000 ppm, preferably 50-2,000 ppm. In the case of electrolytes with a more covalent character, e.g. aluminum chlorohydrate, the preferred level is at least 50 ppm and less than 12,000 ppm. preferably 120-6,000 ppm.

The first step in the method according to the invention is to form a molten mixture of cationic and non-ionic components. The temperature of this mixture is suitably below 100°C. When this molten mixture is added to water at an elevated temperature, e.g. above 40°C, preferably above 60°C, and mixed thoroughly, a dispersion of the active materials is created in droplet form. The water preferably contains practically no electrolyte at this stage. Some electrolyte can be tolerated, however, provided that the weight ratio between electrolyte in the final product and that originally present is at least 3:1, and provided that the water does not initially contain more than 300 ppm of electrolyte. It is preferred that the level of cationic material in this dispersion is from 8 to 40% by weight, and the level of the non-ionic material is preferably 1-9% by weight. Although this dispersion can be cooled to ambient temperature at this stage, it is preferred not to cool the dispersion until after addition of the electrolyte. The electrolyte must be added after the dispersion of the active material in droplet form has been created. At this stage, provided that at least 8% cationic fabric softener has been added, further amounts of the molten mixture can be added. The electrolyte is preferably added in the form of a concentrated solution, e.g. about. 1-10% by weight.

Thus, in a preferred embodiment of the invention, the electrolyte is added in the form of a concentrated solution, after the formation of the dispersion, but before the dispersion is cooled below 40°C. This is of particular benefit if the cationic plasticizer contains cured (ie, substantially saturated) alkyl groups.

If the cationic raw material used to make the product already contains electrolyte, we have found it advantageous that at least part of the added electrolyte contains the same cation. If thus e.g. the cationic raw material contains sodium ions, preferably the added electrolyte also contains some sodium ions, advantageously together with an electrolyte containing more strongly charged ions, e.g. calcium ions.

The preparations may also contain one or more possible

ingredients selected from non-aqueous solvents such as C 1 -C 2 alkanols and polyhydric alcohols, pH buffering agents such as weak acids, e.g. phosphoric, benzoic or citric acid (the pH value of the preparations is preferably below 6.0), anti-gelling agents, perfume, perfume carriers, fluorescent agents, coloring agents,

hydrotropes, antifoam agents, antigen deposition agents, enzymes, optical brighteners, opacifying agents, stabilizers, e.g. guar gum and polyethylene glycol, anti-shrink agents, anti-crease agents, fabric softeners, stain agents, soil release agents, germicides, fungicides, antioxidants, anti-corrosion agents, preservatives, dyes, bleaches and bleach precursors, agents that that the laundry falls, as well as antistatic agents.

These optional ingredients can be added to the active melt, to the water before the dispersion is formed or after the electrolyte is added, as appropriate.

It is particularly advantageous if the water to which the molten cationic/nonionic mixture is added already contains a dispersing aid. This dispersing aid should be a water-soluble non-anionic surfactant having an HLB value above 10, ideally above 12. In this context, the term "water-soluble" means having a solubility of more than 1.0 g/l in water at pH 2.5 and at 20°C. Preferred examples include water-soluble quaternary ammonium salts (e.g.

"Arquad" 16, "Arquad"2C), ethoxylated quaternary ammonium salts (e.g. "Ethoquad" 0/12), quaternary diamine and ethoxylated diamine salts (e.g. "Duoquad" T), ethoxylated amines and diamines (e.g. "Ethoduomeen" T/25, "Ethomeen" T/15) and their acid salts, ethoxylated fatty acid esters of polyhydric alcohols (e.g. sorbitan monolaurate-20 EO), ethoxylated fatty alcohols (e.g. "Brij" 58 - cetyl alcohol-20 EO) and ethoxylated fatty acids (e.g. "Myrj" 49 - stearic acid-20 EO).

A useful test as to whether a particular material will be

a suitable dispersing aid is one which results in a lower product viscosity after addition of the electrolyte.

The dispersing aid may be present at a level of at least 0.1%, preferably at least 0.2%, by weight based on the final product. Generally it will not be necessary to use more than 2.5%, preferably not more than 1.0%, of dispersing aid.

It is preferred that the weight ratio between the cationic fabric softener material and the non-ionic material with a low HLB value is in excess of approx. 2.0:1, e.g. in excess of approx. 3.0:1, preferably within the range of 5:1 to 20:1. A preferred preparation contains approx. 8% to approx. 22% of the cationic material, approx. 1.0% to approx. 6% of the non-ionic material and from approx. 0.01% to approx. 0.2% of the electrolyte.

In the following, the invention shall be illustrated by means of

the non-limiting examples, where parts and percentages indicate weight, based on the weight of the final product. When materials are designated by their trade names, the percentages indicated are percentages of the active materials.

Example 1

A homogeneous molten premix containing 10.9% di(soft tallow)-dimethylammonium chloride ("Arquad" 2T) and 2.6% hardened tallow fatty acid ("Pristerene" 4916) was prepared. At a temperature of 60°C, this premix was added to demineralized water at the same temperature. After thorough mixing with a high-speed constant torsion stirrer, the resulting dispersion was allowed to cool to 25°C, and then 0.1% calcium chloride (as a 10% solution) and 1% perfume were added.

The viscosity of the product measured at 110 sec ^ was 30 cP.

The experiment was repeated with the only difference being that the calcium chloride was pre-dissolved in the water. In this case the viscosity of the product was 438 cP.

This example shows the advantage of post-addition of the electrolyte.

Example 2

Example 1 was repeated using a molten premix of 17% di(soft tallow)-imidazolinium methosulfate ("Varisoft" 475) and 3% "Pristerene" 4916. In this example, different levels of different electrolytes were added. The viscosity of the product was measured immediately after manufacture and then again after 12 weeks of storage at room temperature. The results are reproduced in the following table.

This example illustrates the advantage of using calcium, magnesium or aluminum salt as electrolyte over sodium salts.

Example 3

Similar beneficial results can be obtained by similarly preparing preparations with the following compositions:

Similar results are obtained if the calcium chloride is replaced by the same amount of aluminum chloride or sodium chloride, added at 60°C and/or if the amounts of "Arquad" 2HT and "Pristerene" 4916 are changed to 10.9% and 2.6% respectively. A lower initial viscosity is obtained with these products than if identical mixtures are prepared by adding the electrolyte after cooling.

This preparation is particularly beneficial if the sodium chloride is added at 60°C, and even more beneficial if the sodium chloride is replaced by calcium chloride, magnesium chloride or aluminum chloride.

Example 4

Equally good results can be achieved by making preparations with the following compositions in the same way:

In this example "Arquad" 2HT can be replaced with "Varisoft" 445.

Example 5

Equally good results can be achieved by making preparations with the following compositions in the same way:

In this example, the calcium chloride can be added after or (more preferably) before cooling the dispersion. Calcium chloride can be replaced with magnesium or aluminum chloride. "Arquad" 2HT can be replaced with "Varisoft" 445. The octadecanol can be replaced with glycerol monostearate, glycerol mono-iso-stearate, sorbitan monostearate or sorbitan mono-iso-stearate. Any two or more of these modifications may be combined.

Example 6

The following mixture was prepared by the procedure indicated below:

The molten mix of "Arquad" 2HT and lanolin was formed at 60°C. This molten mix was added to demineralized water at 60°C, which already contained the phosphoric acid (added as a pH buffer). After thorough mixing to form a dispersion of the active materials in droplet form, the calcium chloride was added in the form of a 10% solution. The mixture was then cooled to ambient temperature and perfume and dye added.

Example 7

The following compositions show the range of active levels possible within the scope of the invention. In each case, the active materials were premixed at 60°C, added to water at the same temperature and sheared to form a dispersion in droplet form. Then the calcium chloride was added in the form of a 10% solution. After further mixing, the perfume and dye were added and then the mixture was cooled to ambient temperature.

Example 8

The advantage of including a dispersing aid in the water to which the active premix is added is illustrated as follows: An active premix was prepared by mixing 10.5 parts "Arquad" 2HT with 2.5 parts "Pristerene" 4916 and heating this to 70 °C. This premix was then added to distilled water at 70°C containing the dispersing aid. After stirring to form a dispersion in droplet form, calcium chloride was added to the hot mixture using a 10% solution. The composition of the final product was:

After cooling to room temperature, the viscosity of each product was measured at 110 sec at 25°C. Various materials were used as dispersing aids. The results were as follows:

In a further set of experiments where an apparatus of slightly different dimensions was used, but where otherwise a similar technique was used, the results were as follows:

These results show that the viscosity of the product is lowered when the dispersing agent has an HLB value of more than 10 (Ex. 8H is an example of this), but not when the dispersing agent is less than 10 (Ex. 8E). It is also apparent that the benefit is most notable when the dispersing aid has an HLB value above 12.0 (Examples 8A to 8C, 8F and 8G).

The dispersing aids that were used in this example are commercial materials that have approximately the following content: "Ethoduomeen" T/25: Ethoxylated N-tallow-yl-1,3-propane-diamine with 15 ethoxylene oxide groups per molecule.

"Myrj" 49: Ethoxylated stearic acid with 20 ethylene oxide groups per molecule.

"Brij" 76: Ethoxylated stearyl alcohol with 10 ethylene oxide groups per molecule.

"Span" 20: Sorbitan monolaurate.

"Arquad" 16: Cetyltrimethylammonium chloride.

"Ethoquad" 0/12: Oleylmethyl-bis-(2-hydroxyethyl)-ammonium chloride.

"Duomac" T: N-tallow-yl-1,3-propanediamine diacetate.

Example 9

Using the method described in Example 1, a product was formed containing 10.9% "Arquad" 2T, 2.6% "Pristerene" 4916, 0.05% calcium chloride and 0.75% post-dose perfume. The calcium chloride was added either before adding the molten active material to the water (pre-dosed), after formation of the dispersion (post-dosed) or partly pre-dosed and partly post-dosed. In each case the viscosity of the product was measured. The results were:

These results show the particular benefit of adding all the electrolyte after the dispersion is formed.

In all of the above examples, the initial level of electrolyte in the production water was less than 10 ppm.

Example 10

82.5 parts of water containing 50 ppm Ca/MgCO^ water hardness and small amounts of dye were heated to 66°C in a vessel containing 3 inclined paddles of 0.88 x vessel diameter.

17.5 parts of a premix of "Arquad" 2HT (75% active) and "Pristerene" 4916 at 65°C was added to the stirred hot water over 10 minutes via a jet manifold between the top two agitators. This mixture was stirred for 20 minutes, at which time 0.25 part of a 10% CaCl 2 solution was added. After stirring for an additional 10 minutes, the mixture was cooled to 35°C. 0.72 part perfume was added and stirring continued for another 5 minutes. The product was finally cooled to 30°C and stored.

The final product had the following composition:

Claims (9)

1. Process for the preparation of a concentrated aqueous liquid fabric softener preparation containing at least 8% by weight of water-insoluble cationic fabric softener, comprising the following steps: (i) forming a molten mixture containing the water-insoluble cationic fabric softener and a non-ionic material having an HLB value of no more than 10; (ii) adding the molten mixture to water at an elevated temperature; (iii) mixing the molten mixture and the water so as to form a dispersion of the molten mixture in droplet form in the water; and (iv) adding electrolyte in the form of a source of lithium, sodium, potassium, calcium, magnesium or aluminum ions to it, characterized in that the electrolyte is added after, but not before, said dispersion is formed. 2. Method as stated in claim 1, characterized in that the preparation is cooled to ambient temperature after addition of the electrolyte. 3. Method as stated in claim 1, characterized in that the electrolyte is selected from a source of calcium, magnesium or aluminum ions. 4. Method as stated in claim 1, characterized in that the water-insoluble cationic fabric softener is selected from among water-insoluble quaternary ammonium salts and imidazolinium salts. 5. Method as stated in claim 1, characterized by the non-ionic material being chosen from among (i) Cg-C24 fatty acids; (ii) esters of C3~C24~ fatty acids with monohydric alcohols containing 1-3 carbon atoms; (iii) C 10 -Cl 2 fatty alcohols; (iv) lanolin and derivatives thereof; and (v) fatty acid esters of C^-Cg polyhydric alcohols. 6. Method as stated in claim 1, characterized in that a weight ratio between cationic fabric softener and non-ionic material in the preparation of from 5:1 to 20:1 is used. 7. Method as stated in claim 1, characterized in that the water to which the molten mixture is added in step (ii) already contains a dispersing aid. 8. Method as stated in claim 7, characterized in that the dispersing aid is selected from among water-soluble cationic and water-soluble non-ionic surfactants which have an HLB value of more than 10. 9. Method as stated in claim 1, characterized in that after addition of the electrolyte, the preparation contains from 8 to 22% of the water-insoluble cationic fabric softening material, from 0.5 to 4% of the non-ionic material and from 0.01 to 0.2% of the electrolyte.