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
  Methoxyl content (%)
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
  Viscosity (cP)
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.%)