Method for deodorizing liquid lanolin

Liquid lanolin is deodorized by mixing it with a solvent selected from methanol, ethanol, mixtures of methanol and ethanol, or aqueous solutions of methanol and/or ethanol, and then separating and removing the solvent phase. A subsequent water-washing treatment provides a further improved deodorizing effect.

BACKGROUND OF THE INVENTION 
1. FIELD OF THE INVENTION 
This invention relates to a method for deodorizing liquid lanolin. More 
particularly, the present invention provides a method for removing 
unpleasant animal odor-causing substances for liquid lanolin, which liquid 
lanolin is obtained by purifying and dehydrating wool fat. The invention 
provides liquid lanolin of high quality having a high commercial value. 
2. DESCRIPTION OF THE PRIOR ART 
Lanolin is obtained by purifying and dehydrating wool fat that is present 
as a deposit on wool fibers. Lanolin is a wax that melts at a temperature 
approximating the body temperature of humans and it exhibits excellent 
skin-permeating and emollient effects. Accordingly, it is widely used as 
an ingredient of skin creams, skin lotions, hair creams and various other 
cosmetic and perfume products, and as an ointment base. Liquid lanolin is 
prepared from lanolin by (1) fractional crystallization from a solvent, 
(2) removal of high-melting-point waxes by addition of urea and (3) vacuum 
distillation. Liquid lanolin prepared by removing high-melting-point waxes 
from lanolin has excellent skin-permeating and emollient effects, like 
those of lanolin. As commercially available liquid lanolin products, there 
can be mentioned "Viscolan" (manufactured by American Cholesterol Col.) 
"Fluilan" (manufactured by Chroda Co.) and "Belbelan" (manufactured by 
Nippon Lanolin Kogyo Co.). The cloud points and solidfying points of 
typical commercially available lanolin and liquid lanolin are as follows: 
______________________________________ 
Lanolin Liquid Lanolin 
______________________________________ 
Cloud Point (.degree. C) 
42-46 17-18 
Solidifying Point (.degree. C) 
36-40 3-4 
______________________________________ 
Since liquid lanolin is used especially for toiletries, cosmetics, and the 
like, it is desired to remove unpleasant smells from liquid lanolin. 
As methods for deodorizing liquid lanolin, there are known a method for 
purifying liquid lanolin by adsorption using calcium sulfate, a method in 
which liquid lanolin in the form of a thin film and under a reduced 
pressure of several mm Hg is contacted with water vapor flowing 
countercurrent thereto, a molecular distillation method, and the like. 
However, each of these known methods is disadvantageous because large-size 
equipment is required for practicing the method, the cost is high and the 
deodorizing effect is insufficient. 
SUMMARY OF THE INVENTION 
We discovered that an excellent deodorizing effect is obtained when a polar 
solvent selected from the group consisting of methanol, ethanol, and 
mixtures thereof, is mixed and agitated with liquid lanolin under specific 
conditions. The odor-causing components are effectively dissolved and 
transferred into the polar solvent phase. A deodorized liquid lanolin of 
high quality can be obtained by separating the polar solvent phase from 
the liquid lanolin phase. Based on this discovery, we have now completed 
the present invention. 
More specifically, in accordance with the present invention, there is 
provided a method for deodorizing liquid lanolin characterized by using as 
a solvent methanol, ethanol, or mixtures thereof, or an aqueous solution 
containing at least 50% by weight of methanol, ethanol or mixtures 
thereof, mixing and agitating liquid lanolin and the solvent at a 
solvent/liquid lanolin weight ratio of from 0.5/1.0 to 4.0/1.0 and at an 
elevated temperature of from 40.degree. to 80.degree. C, then separating 
and removing the solvent phase and, if necessary, adding a suitable amount 
of water to the remaining liquid lanolin, mixing and agitating them at an 
elevated temperature of from 40.degree. to 100.degree. C, and then 
separating and removing the aqueous phase. 
The deodorizing method of the present invention utilizes, in principle, the 
difference of the affinity of the odor-causing components between the 
solvent and liquid lanolin. However, the final and collective deodorizing 
effect cannot be predicted only by such difference of affinity, but rather 
it is greatly influenced by such factors as the ease of separation of the 
odor component-solvent phase from the liquid lanolin and the means and 
conditions for effecting such separation. The present invention has been 
completed after taking into consideration all of these factors 
comprehensively. 
As the solvent that can be used in the present invention, there can be 
mentioned methanol, ethanol, mixtures thereof and aqueous solutions 
thereof having a concentration of at least 50% by weight. Alcohols having 
3 or more carbon atoms, such as isopropyl alcohol and n-butyl alcohol, 
have a high solubility to liquid lanolin and they dissolve liquid lanolin 
homogeneously. Therefore, separation of odor components is impossible. 
Thus, alcohols having 3 or more carbon atoms cannot be used in the present 
invention. Further, since various other organic solvents such as n-hexane, 
chloroform, diethyl ketone, dimethyl ketone, diethyl ether and the like 
also dissolve liquid lanolin homogeneously, they cannot be used in the 
present invention. In view of the deodorizing effect, methanol is the most 
preferred solvent for the purposes of this invention. Since a small amount 
of ethanol remains dissolved in the liquid lanolin after treatment, the 
deodorizing effect achieved by the use of ethanol is a little inferior to 
the effect attained by the use of methanol. The use of an aqueous solution 
of such alcohol is preferred, because the amount of the alcohol that 
remains in the treated liquid lanolin is reduced. The weight ratio of the 
solvent to liquid lanolin (herein referred to as "solvent ratio"), is from 
0.5 to 4.0, preferably from 1.0 to 2.0. At a solvent ratio lower than 0.5, 
a sufficient deodorizing effect cannot be attained, while at a solvent 
ratio higher than 4.0 the amount of the solvent that dissolves and remains 
in the liquid lanolin increases and the deodorizing effect is reduced. 
Further, in the latter case, economic disadvantages occur as regards the 
recovery of the solvent and the like. 
In the present invention, liquid lanolin and the solvent are heated at 
40.degree. to 80.degree. C and they are mixed with agitation. Then, the 
solvent phase is separated from the liquid lanolin phase and is removed 
therefrom. The mixing under agitation is generally conducted for 10 to 60 
minutes. The change of the viscosity of a mixture of liquid lanolin and 
the solvent in response to temperature is hyperbolic. The viscosity is 
drastically increased when the temperature is lower than the critical 
level of about 40.degree. C. For example, the viscosity of liquid lanolin 
at 25.degree. C is about 2,000 to about 2,500 cp, but it is about 250 cp 
at 50.degree. C. Therefore, at temperatures lower than 40.degree. C, phase 
separation of liquid lanolin and the solvent is very difficult, and the 
amount of the solvent left in the liquid lanolin increases and the 
deodorizing effect is drastically lowered. For example, when the 
deodorizing treatment is conducted at 50.degree. C, using methanol as the 
solvent, and the resulting mixture is allowed to stand still at 25.degree. 
C, 8 to 10 hours are required for completion of the phase separation and, 
indeed, complete separation cannot be attained. However, if the mixture is 
maintained at 50.degree. C after the deodorizing treatment, it separates 
completely into two phases within 2 to 3 hours. Various conventional 
procedures can be adopted for effecting separation and removal of the 
solvent, but in general, settling separation and centrifugal separation 
methods are employed. The deodorizing effect can be further improved by 
repeating the above procedures two or more times, and in this case, the 
solvent ratio in each individual stage can be less than 0.5, although the 
overall solvent ratio for the sum of the stages should be at least 0.5. 
Deodorized liquid lanolin can be obtained according to the foregoing 
method. When the thus-deodorized liquid lanolin is subjected to a water 
washing treatment in the following manner in order to remove the odor 
component-containing solvent left in the liquid lanolin, liquid lanolin of 
much higher quality can be obtained. More specifically, the separated 
liquid lanolin is mixed with a suitable amount of water and the mixture is 
agitated at an elevated temperature of 40.degree. to 100.degree. C. Then, 
at the same elevated temperature, the aqueous phase is separated from the 
liquid lanolin phase and it is removed therefrom. The amount of water used 
for washing is not particularly critical, but it is generally 1.0 to 10 
times the amount of the liquid lanolin on a weight basis. It is necessary 
that the system should be heated at 40.degree. to 100.degree. C during the 
water washing and separating steps. If the temperature is lower than 
40.degree. C, the separation effect is drastically lowered as in the case 
of the above-mentioned solvent treatment. 
The thus-treated liquid lanolin is deodorized sufficiently and it is 
substantially odorless, and no quality degradation is observed. As is seen 
from the foregoing description, liquid lanolin can be deodorized 
relatively simply at a low cost according to the method of the present 
invention, and a more valuable product for toiletries, cosmetics and the 
like can easily be obtained.

The present invention will now be further described in detail by reference 
to the following illustrative Examples. 
EXAMPLE 1 
Various solvents, as indicated in Table 1, were mixed and agitated with 
liquid lanolin sufficiently under the conditions set forth in Table 1, and 
then the mixture was allowed to stand still. The liquid lanolin phase was 
separated from the solvent phase and was recovered to obtain deodorized 
liquid lanolin. 
Table 1 
__________________________________________________________________________ 
Deodorizing Conditions 
Agita- 
Time Required 
tion 
for Separation 
Run Solvent Ratio 
Tempera- 
Time 
by Standing 
No. 
Solvent (liquid lanolin:solvent) 
ture (.degree. C) 
(min.) 
Still 
__________________________________________________________________________ 
1 water 1 : 0.5 25 30 not separated* 
2 methanol 1 : 0.5 25 30 about 10 hours 
3 ethanol 1 : 0.5 25 30 about 10 hours 
4 isopropanol 1 : 0.5 25 30 not separated 
5 acetone 1 : 0.5 25 30 not separated 
6 diethyl ether 
1 : 0.5 25 30 not separated 
7 n-hexane 1 : 0.5 25 30 not separated 
8 methanol 1 : 0.5 50 30 about 2 hours 
9 ethanol 1 : 0.5 50 15 about 1 hour** 
10 methanol 1 : 1 80 15 about 2 hours 
11 methanol 1 : 2 80 15 about 2 hours 
12 aqueous solution of 
1 : 1 80 15 about 2 hours 
methanol (50%) 
13 aqueous solution of 
1 : 1 80 15 about 2 hours 
ethanol (50%) 
14 methanol (twice treated) 
1 : 0.5 50 15 about 2 hours 
15 ethanol (twice treated) 
1 : 0.5 50 15 about 2 hours 
__________________________________________________________________________ 
Notes: 
*a highly viscous emulsion was formed and separation was impossible 
**the temperature was 30.degree. C 
The smell of each of the thus-treated liquid lanolins was evaluated and the 
results shown in Table 2 were obtained. For comparison, the smell of 
liquid lanolin deodorized according to the conventional deodorizing method 
using steam in vacuo was also treated, and the results for this treatment 
are also shown in Table 2. 
The conventional deodorizing method using water vapor in vacuo were 
conducted in the following manner: 
Liquid lanolin was flowed down at a rate of about 150 Kg/hr.m.sup.2 in the 
form of a thin film along the inner wall of a cylindrical vessel 
maintained under a pressure of 5.0 mm Hg. Simultaneously, the system was 
heated at about 110.degree. C and steam was blown in from the lower 
portion of the vessel at a rate of about 20 Kg/hr.m.sup.2 and contacted 
with the liquid lanolin to effect deodorization. 
Table 2 
__________________________________________________________________________ 
Deodorizing Effect 
Run Change of Smell Average Yield 
No. before treatment 
after treatment 
Judgment 
(%) 
__________________________________________________________________________ 
1 strong animal smell 
considerable smell 
X not separated 
2 " slight smell 
.DELTA. .about. X 
96.6% 
3 " considerable smell 
X 93.8 
4 " -- -- not separated 
5 " -- -- " 
6 " -- -- " 
7 " -- -- " 
8 " little smell 
.circle. 
96.0 
9 " " .DELTA. .about. .circle. 
92.0 
10 " odorless .circleincircle. 
95.0 
11 " " .circleincircle. 
92.0 
12 " little smell 
.circle. 
96.0 
13 " slight smell 
.DELTA. 
93.0 
14 " odorless .circleincircle. 
93.0 
15 " substantially 
.circle. .about. .circleincircle. 
85.0 
odorless 
16* " slight smell 
.DELTA. 
-- 
__________________________________________________________________________ 
*conventional vacuum-steam method 
In the foregoing table, 
X means poor results 
.DELTA. means fair results 
.circle. means good results 
.circleincircle. means excellent results 
As is apparent from the foregoing results, when water is used as the 
solvent (Run No. 1), no deodorizing effect was obtained. When solvents 
other than methanol and ethanol are employed (Runs Nos. 4 to 7), since 
homogeneous solutions are formed, these solvents cannot be used for the 
method of the present invention. Even when methanol or ethanol is used as 
the solvent, if the treatment temperature is lower than 40.degree. C (Runs 
Nos. 2 and 3), a considerable time is required for phase separation and 
complete separation cannot be attained. Further, the deodorizing effect is 
insufficient. In contrast, when the deodorizing treatment is carried out 
under the conditions of the present invention (Runs Nos. 8 to 15), a good 
deodorizing effect is obtained, and the best results are obtained when the 
solvent ratio is within the range of from 1 to 2 or when the same 
procedures are repeated twice (twice heated) even if the solvent ratio is 
0.5. Example 2 
The deodorized liquid lanolins obtained in Example 1 (exclusive of those 
obtained in Runs Nos. 1 and 4 to 7) were subjected to a water washing 
treatment under conditions indicated in Table 3. After the water washing 
treatment, each of the resulting mixtures was subjected to centrifugal 
separation to separate the liquid lanolin phase from the aqueous phase. 
The aqueous phase was removed from the liquid lanolin phase to obtain 
deodorized liquid lanolin. The smell of the resulting liquid lanolin was 
judged according to the scale mentioned in Table 2. The results are shown 
in Table 3. 
Table 3 
______________________________________ 
Results of Water Washing Treatment 
Water Washing Conditions 
Temper- Judgment 
Run liquid lanolin 
ature Agitation 
before after 
No. : washing water 
(.degree. C) 
time (min) 
washing 
washing 
______________________________________ 
2 1 : 5 80 30 .DELTA. .about. X 
.DELTA. 
3 1 : 10 80 30 X .DELTA. 
8 1 : 5 80 30 .circle. 
.circleincircle. 
9 1 : 10 80 30 .DELTA. .about. .circle. 
.circle. 
10 1 : 5 80 30 .circleincircle. 
.circleincircle. 
11 1 : 5 80 30 .circleincircle. 
.circleincircle. 
12 1 : 5 80 30 .circle. 
.circle. .about. .circleincircle. 
5 
13 1 : 10 80 30 .DELTA. 
.circle. 
14 1 : 5 80 30 .circleincircle. 
.circleincircle. 
15 1 : 5 80 30 .circle. .about. .circleincircle. 
.circleincircle. 
16 1 : 10 80 30 .DELTA. 
.DELTA. 
______________________________________ 
As is apparent from the foregoing results, even when the deodorizing effect 
by the solvent treatment is relatively insufficient, if the water washing 
treatment is carried out after the solvent treatment, a product which is 
substantially odorless can be obtained.