 |
| METOLOSE
is a nonionic water-soluble cellulose ether which is prepared
from cellulose (pulp), a widely distributed natural material.
The cellulose is processed with caustic soda and then treated
with an etherification reagent such as methyl chloride, propylene
oxide or ethylene oxide. METOLOSE is classified into three types,
namely, SM, SH, and SE according to the
kind of etherification reagent used. |
| Chemical
Structure of METOLOSE |
 |
 |
 |
| Metolose
is available in the following four types, each type having 17
standard grades of different viscosity (polymerization degree).
|
| |
Methoxy
Groups
(%)
|
Hydroxy-
propoxy
Groups
(%) |
Degree
of
Sub-
stitution
(D.S.) |
Grade
Viscosity
(2%, 20'C)
|
Thermo-
Gelation
Tem-
perature
(2%) |
References
for the Selection of Grades (Special Properties of Each
Factor) |
| SM |
27.5~31.5 |
--กก |
1.79~1.83
|
15,25,100
400,1500 4000,8000 |
Approx.
52'C |
High
Water-retaining property
High visco-elasticity High thermostability |
| 60SH |
28~30 |
7~12 |
1.86~1.90 |
50
4000 |
Approx.
60'C |
Readily
soluble in organic
solvents Good plasticity Excellent film formation |
| 65SH |
27~29 |
4~7.5 |
1.71~1.81 |
50,400
1500,4000 |
Approx.
65'C |
High
solubility in other substances High emulsion stability |
| 90SH |
19~24 |
4~12 |
1.36~1.42 |
100,4000
15000, > 30000 |
Approx
85'C |
High
thermogelation temperature Excellent lubricating property
of aqueous solution |
|
 |
| SM |
SH |
SE |
| 60SH |
65SH |
90SH |
SEB |
SEW |
|
|
|
|
27.5 - 31.5 |
28.0-
30.0 |
27.0 - 30.0 |
19.0-
24.0 |
21.0- 26.0 |
20.0-
26.0 |
| |
Hydroxypropoxyl
content (%) |
|
-- |
7.0- 12.0 |
4.0-
7.5 |
4.0-
12.0 |
-- |
-- |
| |
Hydroxyethoxyl
content (%) |
|
-- |
-- |
-- |
-- |
4.0-
8.0 |
9.0- 15.0 |
| |
Loss
on drying (in package) (%) |
|
not
more than 5.0 |
not
more than 5.0 |
not
more than 5.0 |
not
more than 5.0 |
not
more than 5.0 |
not
more than 5.0 |
| |
Ash
content (sulfated ash) (%) |
|
not
more than 1.0 |
not
more than 1.0 |
not
more than 1.0 |
not
more than 1.0 |
not
more than 1.0 |
not
more than 1.0 |
|
|
In
accordance with the viscosity standard table below |
|
 |
| Thermal
Gelation of An Aqueous Solution |
An
aqueous solution of METOLOSE is converted into a gel by heating.
This phenomenon is called thermal gelation, and depending on
the type of METOLOSE, different gelation behavior is seen. The
gel reverts to the original aqueous solution when cooled. The
phenomenon of gelation is shown in Fig.6.
The thermal gelation behavior of an aqueous solution of METOLOSE
is influenced by its concentration and the rate of temperature
increase. |
Test
Conditions:
Measuring instrument : Torsional vibration type viscometer
Rate of temperature increase : 1'C/min.
Cooling rate : 0.5'C/min.
(For details refer to "Kobunshi Ronbunshu" Vol.38,
No.3, pp.113-137, March, 1981.) |
| The
measurement results of viscosity grade 4000 cP of different
types of METOLOSE under the same conditions are shown below.
|
| |
Thermal
gelation
temperature('C) |
| T1 |
T2 |
|
|
| SM |
-- |
55 |
| SH |
60SH |
60 |
75 |
| 65SH |
70 |
75 |
| 90SH |
70 |
85 |
| SE |
SEB |
70 - 80 |
-- |
| SEW |
80 |
-- |
|
|
Behavior of an aqueous
solution of METOLOSE
(SM-4000 2wt.%)
|
