| 配方类型： |
RUBBER, PLASTICS, WAXES |
| 配方说明： |
High Heat Distortion Resin |
| 配方组成： |
"PAR" 6.0/-
"PAR" 2.7/43.3 wt%
A homogeneous liquid formulation is obtained by heating the dry mix
to approximately 60'C or by first melting the maleic and polyol and then
stirring in the "unox" 207. When cooled to room temperature this
formulation has a "sherbet-like" consistency. At 35'C it has a pot life
of a week or more. Water-thin solutions may be obtained by increasing
the maleic content to 1.2 mol or by maintaining a temperature of 50'C.
At 50'C this formulation has a pot life of three days.
Where a two-component formulation is desirable, the maleic anhydride and
trimethylolpropane may be prereacted at low temperature to give "PAR"
6.0 or "PAR" 2.7. The suffix number denotes the molar ratio of anhydride
to polyol. Two typical formulations are as follows
0.8 Mol Maleic Anhydride/30.0
0.13 Mol Trimethylolpropane/6.7
1.0 Mol "Unox" Epoxide 207/63.3
"Unox" Epoxide 207/63.0 wt%
"PAR" 6.0/37.0 wt%
"PAR" 2.7/-
"Un |
| 配制方法： |
Formulations based on "PAR" 2.7 have the added advantage of being virtually free of maleic anhydride, which could otherwise prove to be obnoxious without proper ventilation.
B-Stage: Any of the above formulations may be B-staged by reacting from 40 to 60% of the available carboxyl groups. When held at room temperature the reactivity is nil after about 60% of the carboxyls have reacted. After six months on the shelf, B-stage "Unox" 207 formulas are easily fused under mild pressure and temperatures of 160'C and will form up to 80% solutions in acetone-toluene mixtures.
To impregnate Glass Fibers the B-stage is prepared as follows: 1. Place 70 parts of epoxide formulation and 30 parts of toluene in a reaction kettle equipped with an agitator and reflux condenser.
2. Heat and hold at reflux temperature for toluene till about 50% of the original carboxyl groups have reacted (3 to 4 hours).
3. Cool to 50'C and add 15 parts acetone.
4. After further cooling to near room temperature discharge |
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