Non-aqueous detergent liquids have been proposed for a number of uses, such as fabric washing and dishwashing. They have advantages over powder products in that they are more rapidly dispersed in water. Further advantages over powder products are the possibility of automatic dosing and higher obtainable product densities resulting in lower transportation and packaging costs.
Non-aqueous detergent liquids have advantages over aqueous liquid products in that they are capable of including water-sensitive ingredients such as bleaches.
When non-aqueous liquid detergent compositions are used in industrial washing machines, they are generally stored in a cold environment (i.e. outdoors). Thus stored non-aqueous liquids will solidify upon storage if the melting point of the nonionic surfactant material used as liquid phase in these compositions, is not sufficiently low. As a consequence, these liquids are not any longer pumpable or pourable.
Another problem related to storage in a cold environment, is that at low temperatures the viscosity of the non-aqueous liquids may increase to such extent that they can no longer be easily and accurately dosed into a washing machine. Also with regard to pasty detergent compositions it is important that solidification does not occur at low temperatures.
It is known that non-aqueous liquid detergents with melting points lower than 0.degree. C. can be obtained if the nonionic surfactants incorporated in the liquid phase of these non-aqueous liquids comprise alkoxylated alcohols containing propylene oxide groups. However, this type of nonionic surfactant is less preferred due to its restricted biodegradability.
It is also known that the melting point of a non-aqueous liquid detergent can be lowered by incorporating into it a low melting solvent such as ethanol or heptane. However, a large amount of this solvent--generally about 30% weight or more, as calculated on the total weight of the liquid phase--is needed for sufficient lowering of the melting point if the liquid phase of the non-aqueous liquid detergent contains mostly ethoxylated alcohol. This large amount of solvent has an adverse effect on the detergency to be obtained with the thus formulated non-aqueous liquid. Besides, phase separation will generally occur when this large amount of solvent is present in the formulation.
It is an object of the invention to provide a substantially non-aqueous liquid composition comprising a liquid surfactant phase which composition is pourable at 5.degree. C., preferably at 0.degree. C.
It is a further object to provide a non-aqueous liquid composition which is stable upon storage and gives effective detergency.
EP-A-295 525 (Henkel) discloses a washing process, wherein a pasty detergent product is applied which product may contain one or more types of ethoxylated alcohols. It is also known from this document that the incorporation of two types of ethoxylated alcohol into the pasty detergent product has a beneficial effect on the pourability of this product. However, it is not mentioned in this patent application that with special blends of ethoxylated nonionics containing a narrow range ethoxylated alcohol a melting point lower than 5.degree. C. can be obtained.
We have surprisingly found that the above and other objects can be accomplished by applying special combinations of two types of ethoxylated alcohols as nonionic surfactants, of which types one being a narrow range ethoxylated alcohol, whereby the melting point of such combinations is lower than the melting point to be expected by linear interpolation.