GB2032479A - Novel fabric softeners - Google Patents

Abstract

A fluid, water-dispersible composition for use as a fabric softener, comprises a water dispersible amido amine of the formula RNH[(CH2)nNR]mR wherein an average of from 20% to 80% of the R groups are acyl groups (12-22C), at least 20% of the R groups are -CH2CH2OH or -CH2CHOHCH3 or mixtures of these groups and any other R group is hydrogen, n is 2 or 3 and m is an integer of 2 to 5, or a water dispersible salt or partial salt thereof. The amido amine may be prepared by reacting diethylene triamine or a higher homologue thereof with two molar proportions of fatty acid, mono- ethoxylating and, optionally, wholly or partially neutralising with a lower organic acid and/or sulphur dioxide.

Description

SPECIFICATION Novel fabric softeners This invention relates to novel fabric softeners, compositions containing them and the use thereof for the treatment of fabrics.

It has been proposed that certain quaternised amido amines, quaternised imidazolines prepared by cyclising amido amines, quaternised mixtures of imidazolines and amido amines, and quaternised tertiary amines impart good softening and rewetability properties to fabrics when applied after washing, and especially after washing in non-soap detergents.

The more effective of the known fabric softening compounds, those that have hitherto actually been used commercially, are all relatively expensive and inconvenient to make. The majority are quaternary ammonium salts which are quaternised by means of reagents such as dimethyl sulphate or methyl chloride. These reagents are highly toxic, so that their use is hazardous and requires expensive precautions both to protect workers and to avoid contamination of the product with toxic residues.

According to R. R. Egan in J. American Oil Chemists Society January 1978 Voi. 55, p 118 to 121, the five most commonly found active softening agents in consumer products purchased in the U.S.A.

are all quaternary nitrogen compounds:-- (I) a methyl chloride quaternised tertiary amine, (II) a dimethylsuiphate quaternised tertiary amine, (III) a dimethyl sulphate quaternised polyethoxylated diamido amine, (IV) a dimethyl sulphate quaternised polypropoxylated diamido amine and (V) a dimethyl sulphate quaternised alkyl amido alkyl imidazoline.

German Patent Application No. 25201 50 (Brit Pat. 1,483,984) for example described the preparation of a quaternised mixture of a diamido diethylenetriamine and an imidazoline. The presence of the quaternised diamido diethylenetriamine is said to lower the softening effect of the mixture compared with the quaternised imidazoline alone but to improve the rewettability of the fabric after washing, which most known fabric softeners reduce. The patent implies that quaternised diamido diethylenetriamines alone are not effective fabric softeners.

We have now discovered that when unquaternised diamidoamines are partially neutralised, they provide salts which are surprisingly more effective as fabric softeners than any of the fabric softeners in common commercial use including the quaternised imidazoline softeners and the quaternised imidazoline/amido amine mixtures. They are moreover considerably more convenient to make, and potentially safer, since they do not require the use of highly toxic reagents. Surprisingly we have also found that they perform better in tests for skin irritancy than current commercially available fabric softeners.

However, unquaternised diamido amines, their salts and partial salts tend to be intractable solids at room temperature, which even on dilution with a suitable solvent e.g. 25% of a lower alkanol such as isopropanol, hexylene glycol, propylene glycol or mixtures thereof, are still too viscous for convenient handling.

We have now further discovered that certain novel unquaternised hydroxyalkyl diamido amine salts, can be obtained as mobile pastes in the presence of the aforesaid solvents, and exhibit much improved handling characteristics, while retaining the desirable softening properties which we have found to be characteristic of the unquaternised diamido amines. The novel salts also perform well in rewettability tests, which is unusual for such effective softeners. We have not found that the compounds of this invention cause significantly more yellowing of fabric than quaternary softeners.

Our invention therefore provides a novel composition which comprises a water dispersible amido amine of the average formula: RNH FCH2)fl Ni m R wherein an average of from 20% to 80% of the R groups per molecule are acyl groups having an average of from 12 to 22 and preferably 1 6 to 18 carbon atoms, at least 20% of the R groups are -CH2CH20H or -CH2CH(OH)CH3 or mixtures of these groups and any other R group is hydrogen, n is 2 or 3 and m is an integer from 2 to 5. Where R groups are acyl they can be saturated, e.g. strearoyl, monounsaturated, e.g. oleoyl, polyunsaturated or may be mixtures of these types.

The preferred compounds are those wherein n and m are each 2. Preferably the acyl groups are derived from tallow or lard.

The products of our invention optionally but preferably contain a compatible amount, up to 70%, preferably 10 to 50%, e.g. 25% by weight, of a fluid, water miscible hydroxyaliphatic solvent.

Typically, any water miscible hydroxy-, or polyhydroxy-, alkane or alkyiether having a viscosity of less than 30 centipoises at 200C may be used. Preferred examples include isopropanol, hexylene glycol, propylene glycol, ethylene glycol monomethylether and mixtures thereof.

Preferably the hydroxyalkyl amido amine is partially (e.g. from 10% to 80%, preferably 20 to 60%) neutralised with a lower carboxylic or hydroxycarboxylic acid, e.g. acetic, formic, propionic, lactic or glycollic acid. The product may additionally contain a minor proportion of salts of inorganic acids especially sulphites, which help to stabilise the product against oxidation.

The novel amido amines of our invention may be obtained by controlled alkoxylation of an amido amine prepared by amidating a polyalkylene polyamine, e.g. by heating it with the necessary amount of a glyceryl ester to provide the desired alkyl groups in the correct proportions. Alternatively, the polyamine may be heated with a fatty acid or methyl ester thereof while distilling off water or methanol respectively. Preferably the heating is carried out at temperatures above 1 000C but not sufficiently high to decompose any glycerol formed.

To avoid cyclisation and maintain the product as an amido amine the temperature should be maintained below 1 800C and preferably at 120 to 1 600C, e.g. 1 400C.

Higher temperatures, up to 3O00C, particularly with the application of a purge gas or vacuum will cause the amido amine to cyclise to the imidazoline with the loss of water.

Heating is preferably carried in an inert atmosphere to prevent colour degradations, e.g. under nitrogen for from 2 to 6, preferably 4 hours. The product may then be reacted with ethylene or propylene oxide at a temperature between 100 and 2000 C The presence of a catalyst should generally be avoided in order to prevent formation of polyoxyalkylene chains. The solvent may be added after alkoxylation to facilitate dispersion of the product in water.

The invention provides softening compositions comprising the novel amido amine, any glycerol remaining from the preparation of the diamide and the added solvent. The novel products of our invention may be used in conventional manner, e.g. as a post-rinse after washing.

The substantially monoethoxyiated products of our invention are significantly more fluid in the presence of organic solvent than corresponding non-ethoxylated diamidoamines.

EXAMPLES EXAMPLE 1 Example of a preparation of the subject of our patent To a reactor fitted with a heating/cooling jacket, stirrer and nitrogen purge 1 560 kg of deodorised tallow glyceride, mole weight 872, was added and heated to 500C.

The vessel was evacuated and flushed with nitrogen to displace most of the air.

287 kg of diethylene triamine, 98% purity, was added over 5 minutes, no exotherm was observed, and the charge was heated to 1 400C over 60 minutes. This temperature was maintained for 240 minutes whilst a slot stream of nitrogen was passed into the charge. A determination of base value and free ester value of the charge showed that the reaction to form the diamido amine was complete.

The reactor charge was then cooled to 1 200C and 1 32 kg of ethylene oxide fed in slowly cooling to maintain 1200 C. The product, substantially

where R = tallow alkyl was found to be pumpable at 60 to 650C without the addition of solvents.

To the product of the reaction above at 60-650C was added propylene, glycol and isopropyl alcohol, the solution cooled to 360C and sulphur dioxide and acetic acid added.

The product then contained Sulphur dioxide 0.75% Acetic acid 2.12% Isopropyl alcohol 24.64% Propylene glycol 14.96% Ethoxylated diamido amine 57.53% 100.00% The product is a hazy, mobile, pumpable liquid at 200C.

EXAMPLE 2 The above preparation was repeated but without the addition of solvents. The product was a waxy solid which was fluid at 40 to 450C. On dilution to 75% with isopropanol the product became pourable at 200C.

The addition of a small quantity of SO2 to the di tallow amido amine ethoxylate, which also partially neutralises the amine, allows the use of less acetic acid and overcomes the acetic acid odour which might otherwise be apparent in the concentrate or the diluted fabric softener. The addition of SO2 also yields a lighter colour product which is less prone to colour deterioration on storage.

EXAMPLE 3 Domestic fabric softener formulations consist of concentrated fabric softener solutions as prepared in examples 1 and 2 dispersed into water to yield translucent liquids containing normally 2% to 8% "active" softener. By "active" we mean the non solvent component in a fabric softener concentrate.

The ease with which these dispersions can be made is of considerable practical importance to the formulator as is the appearance and storage stability of the formulated dispersions.

Taking the classifications of prior art materials given by Egen, referred to above, all at 75% active in isopropanol.

Temperature Water temperature for handling for dispersion melts 40 to 50"C 55 to 600C transport at 600C II, Ill mobile at 200C 40 IV mobile at 200C 20"C V mobile at 200C 300C Example 2 mobile at 200C 300C Example 1 mobile at 200C 30"C Example 2 but not ethoxylated Mobile at 40 C 70 C Example 2 but 2 moles EO** mobile at 200 200C Example 2 but 8 moles EO** mobile at 200C 200C Example 2 but methosulphated* mobile at 200C 20"C *prepared by reacting monoethoxylated di amido amine as described in Example 1 with di methyl sulphate in isopropanol solvent.

**prepared by adding a basic catalyst (KOH) to the mono ethoxylated di amido amine prepared as described in example 1 and continuing the addition of ethylene oxide until the calculated weight was absorbed.

EXAMPLE 4 As stated in Example 3 the appearance and stability of the aqueous dispersion of the concentrates is important for consumer acceptability. Products which yield stable dispersions with viscosities in the range 100 to 500 centipoise as measured by a "Brookfield" viscometer, model LVT, find ready consumer acceptability. Products which give dispersions which change viscosity on storage are obviously undesirable.

In general compound type I gives very high viscosity 6% active dispersions which must be reduced by additives and special preparative techniques. (As described in J. Amer. Oil Chem. Soc. Vol 56, p 542, April, 1979).

In general methosulphates, types 11, Ill, IV and V give dispersions at 6% "active" with viscosities in the range 10 to 30 cp and are often formulated with other additives to increase their viscosity.

6% active, prepared as in Example 2 dispersed water - 300 cp 6% active, prepared as in Example 2 but 2 moles E.O. - 1 70 cp 6% active, prepared as in Example 2 but 8 moleg E.O. 30 cp Water hardness 300 ppm.

Dispersions prepared from products of examples 1 and 2 are stable to extended storage.

Fabric Softening Evaluation The product of example 2 was evaluated against compounds of type I and Ill where n = 1 in a panel evaluation test as follows.

6% active dispersions of each material were prepared using soft water (20 ppm). These solutions were then further diluted with water. Napkins woven from 60% cotton and 40% polyester were washed in an automatic washing machine using a conventional low foam automatic washing powder. These napkins were then soaked for 10 minutes at 20 to 250C in the dilute dispersion of softener.

The weight of active material used was in the range 0.1 to 0.3% of the napkin weight.

The napkins were then wrung out by hand and dried on a clothes line under the same conditions.

Each napkin was cut into 4 portions and each portion given to 5 people to rank in order of softness to the touch. The softest scoring 1 , the second 2 and so on. The results were: 0.3% Active Application Example 2 Type I Type II n = 1 No. of 1 sts 11 8 1 2nds 6 6 8 3rds 3 6 11 Weighted total 32 38 50 The significance of these results were assessed using the method devised by Kromer-Journal of Food Technology 1963-17/12/124.

The example 2 product is at least as good as the best commercial type as found by Egen and significantly better than type Ill, n = 1.

A similar result was obtained at a 0.1% level of application.

Example 2 type I type III n = 1 No. of lusts 12 7 1 No. of 2nods 4 9 7 No. of 3rds 4 4 12 Weighted total 32 37 51 In a further panel test example 2 was compared to similar products, but with more moles of ethylene oxide added and with a dihydroxy compound, employed as a partial acetate salt.

R = tallow.

I 0.2% Application Example type lil 2 moles 8 moles di- Water 2 n=1 E.O. E.O. hydroxy only No. lists 7 6 0 1 6 0 No. 2nds 4 4 2 4 4 2 No. 3rds 5 3 4 4 2 2 No. 4ths 4 6 4 3 3 0 No. Sths 0 0 5 4 3 8 No. 6ths 0 1 5 4 2 8 Weighed total 46 53 87 77 59 98 Using the Kromer method to evaluate these results.

For a panel of 20 and six samples, significance range is 52 to 88. Hence Example 2 is better and Water worse than all the others. Omitting results for Example 2 and water only from the scores above gives type lil 2 moles 8 moles di n = 1 E.O. E.O. hydroxy Weighted total 38 62 57 43 For a set of 4 samples and a panel of 20 the significance range is 37 to 58, i.e. there is no significant difference between these 4 samples.

Rewettability Test It is a well known fact that excessive or continual use of certain fabric conditioning materials can produce a waterproofing effect on fabrics. This effect is undesirable, particularly on fabrics designed for their moisture absorbency e.g. towels and baby diapers.

Napkins treated by the same technique as that used to prepare the samples for the softening evaluation above were cut into strips and the test strips suspended in an aqueous solution of a dye, Kiton green (0.5 gm/litre, temperature = 200C).

The rate at which the dye front travelled above the solution was measured.

Napkins treated with 0.2% weight of softener active were evaluated with the following results:

Immersion Time (mm) Height of dye front above solution Example type lil 2 moles 8 moles di- type Water Minutes 2 n=-1 E.O. E.O. hydroxy I only 1 20 20 20 30 20 20 35 5 40 40 50 45 40 35 55 10 55 55 60 65 65 45 70 15 65 70 80 80 75 55 90 30 80 80 95 90 85 65 110 The product of Example 2 shows better rewettability properties than type I which has a similar softening ability.

Claims (14)

1. A fluid, water-dispersible composition for use as a fabric softener, which comprises a water dispersible amido amine of the average formula:- FNH [CH2)nNRi ,R wherein an average of from 20% to 80% of the R groups per molecule are acyl groups having an average of from 12 to 22 carbon atoms, at least 20% of the R groups are -CH2CH20H or -CH2CH0HCH3 or mixtures of these groups and any other R group is hydrogen, n is 2 or 3 and m is an integer from 2 to 5; or a water dispersible salt or partial salt thereof.

2. A composition according to Claim 1 wherein from 50 to 70% of the R groups are acyl groups and from 30 to 40% of the R groups are hydroxyethyl.

3. A composition according to either of Claims 1 and 2 wherein the acyl is derived from tallow or lard.

4. A composition according to any foregoing claim wherein the amido amine is present as is present as its salt or partial salts with caryboxylic or hydroxy carboxylic acid having from 1 to 3 carbon atoms.

5. A composition according to Claim 4 wherein the amido amine is from 10 to 80% neutralised with lactic or acetic acid.

6. A composition according to any foregoing Claim comprising up to 70% by weight of a fluid, water-miscible hydroxy aliphatic solvent.

7. A composition according to Claim 6 containing 10 to 50% by weight of the composition of the hydroxy aliphatic solvent.

8. A composition according to either of claims 6 and 7 wherein the hydroxy aliphatic solvent has a viscosity of less than 20 centipoises.

9. A composition according to any of Claims 6 to 8 wherein the hydroxy aliphatic solvent is a hydroxy- or polyhydroxyalkane or alkyl ether.

1 0. A composition according to Claim 9 wherein the hydroxy aliphatic solvent has less than four carbon atoms.

11. A composition according to any foregoing claim wherein n and m are each 2.

12. Ditallowyl mono(hydroxyethyl) diethylene triamine or a water dispersible salt thereof.

1 3. A composition according to any foregoing claim substantially as described herein with reference to any one of the examples.

14. A method of softening fabric which comprises applying thereto an aqueous solution or dispersion of composition according to any foregoing claim.