Download Unsaturated PE Tech

The Use Of REAXIS® Catalysts
In The Production Of An Unsaturated Polyester Resin
A conversion of maleic anhydride as well as of phthalic anhydride with 1.2-propylene
glycol was tested for a model formulation.
Formulation
Raw Material
Maleic anhydride
Weight (g)
mol
49.0
0.5
Phthalic anhydride
148.12
1.0
1.2-propylene glycol
148.4
1.95
Catalyst
0.1%
Remarks
30 mol-% OH
surplus
As a % of
formulation
Procedure
The new materials are filled into a 500 ml four-necked flask equipped with distillation
bridge, nitrogen inlet, thermometer and a temperature control unit. Under a constant flow
of nitrogen, the mixture is heated and stirred. At 80 – 85 °C the catalyst is added.
The reaction temperature is continuously increased up to 240 °C, ensuring continuous
distillation of reaction water. The reaction is stopped after 5 hours.
Results
The REAXIS® products esterify the secondary hydroxyl groups which are difficult to
esterify. Thus per the given conditions, an acid value of < 20 is reached after 5 hours.
The use of p-toluenesulfonic acid made the conversion more difficult and the final
products darker.
Catalyst
Reaction
temperature
°C
Final acid value
mg
KOH/l g
Iodine color
number
180 – 238
187.1
4
180 – 235
13.2
2
0.1 % REAXIS C248
180 – 240
14.2
2
0.1 % REAXIS® C256
180 – 240
15.3
2
0.1 % p-toluenesulfonic
acid
187 – 235
113.1
7
0.2 % REAXIS® C129
®
09/99