1. Field of the Invention
The present invention relates to a softener, more particularly to a concentrated softener for clothes which can impart excellent softness and antistatic properties to various fibers and which causes little change in handleability with the lapse of time even when stored in a state exposed to the air.
2. Description of Related Art.
Clothes are liable to be stiffened by the washing-off of a fiber treatments or the deterioration of the fibers themselves during the repetition of wearing and washing to result in uncomfortable handling. Therefore, a softener which can impart softness and antistatic properties to fibers has recently been used frequently in many families.
Most of the current commerically available household softeners comprise a cationic surfactant having 1 to 2 long-chain alkyl groups, and in particular, di(hardened tallow alkyl)dimethylammonium salt as a main cationic surfactant component.
A softener base material comprising such a quaternary ammonium salt as a main component is difficultly soluble in water, so that the above softeners are generally prepared in the form of a 3 to 5% by weight aqueous dispersion or emulsion. As clothes to be treated with a softener have increased, a concentrated softener, for clothes which is constituted of a high-concentration aqueous dispersion, has been strongly desired in order to reduce distribution and/or packaging costs or to reduce the storage space in a shop, home or the like.
However, the above aqueous dispersion type softener is so viscous when its concentration is 5% by weight or above it causes various problems in handling.
Known processes for the preparation of such a higly-concentratted softener include:
1) a process which comprises adding a water-soluble cationic surfactant, PA1 2) a process which comprises adding an adduct of a higher alcohol or an alkylphenol with ethylene oxide, PA1 3) a process which comprises adding urea or ethylene glycol, and PA1 4) a process which comprises adding a water-soluble salt. PA1 (a) 7 to 30% by weight of at least one neutralization product of one of the following amine compounds with an inorganic acid or an organic acid having not more than 6 carbon atoms: PA1 (b) at least one polyether which is a polyoxyalkylene adduct of a compound having at least 3 active hydrogen atoms, with an alkylene oxide component comprising ethylene oxide as an essential component wherein the sum total of polyoxyethylene chain segments produced is at least 50% by weight of the weight of said polyether and wherein the average molecular weight is 5,000 to 2,000,000, and derivatives thereof. PA1 (A-9) amides each prepared by the condensation of R.sup.2 COOH with an N-(long-chain alkyl or alkenyl)-polyalkylenepolyamine having 4 to 5 nitrogen atoms at a molar ratio of between 1:1 and 2:1 through dehydration, PA1 (A-10) ion pairs each constituted of R.sup.1 NH(C.sub.n H.sub.2n NH).sub.l H and R.sup.2 COOH at a molar ratio of 1:1 PA1 wherein
When a softener has an increased viscosity, it gels and gets filmy on the surface, it can result in difficult pouring from a container, will clog at the outlet of a container, can be difficulty measured and will get difficulty dispersible.
In the prior arts it is known to add the compounds of processes (1) to (4) discussed, supra, to a softener base.
In the cases of (1) to (3), a sufficient concentration cannot be obtained. The viscosity of the resultant softner increases on storing and can provide no softening effect. As for (4), the viscosity initially decreases. After that, it is difficulty prevented from increasing. A large amount of a salt added thereto will cause phase separation of the dispersion.
Recently, a concentrated softener which comprises a quaternary ammonium salt and a specific polyether compound and which exhibits little change in the viscosity over time has been proposed (see Japanese Patent Laid-Open Nos. 26788/1989 and 19573/1990). However, when this softener is allowed to stand in a state in contact with, its handleability is remarkably deteriorated over timw owing to a dissolved state generated by the evaporation of water. Further, when it is stored in an uncapped bottle, it is thickened, gelled or filmed. Thus, no satisfactory concentrated softener for clothes has been found as of yet.
Under these circumstances, the present inventors have eagerly studied this matter to solve the above problem, thus accomplishing the present invention which relates to a concentrated softener for clothes.