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The Techneglas, Inc. Glass Resins are a family of methylpolysiloxane
polymers, which have a long history of being used in semipermanent
mold releases.
The Glass Resins that are most commonly used in semipermanent
mold releases are:
GR-650
Flake: a hard resin flake that is readily soluble
in a variety of organic solvents.
GR-651 Liquid: a 35% solids solution of
resin in ethanol-butanol that also contains a catalyst of
Tetramethylammoniumhydroxide blocked with Formic acid
GR-655 Liquid: a 25% solids solution of
resin in ethanol
These three materials are manufactured to
produce a variety of molecular weight for the customer. The
GR-650 Flake has the highest M.W., followed by the GR-655
Liquid and then the GR-651 Liquid. Glass Resins cure by condensation,
so degree of cure depends on time and temperature.
Formulation
The
GR-650 Flake is the most versatile product as it is a solid
resin and can be cut in a variety of polar solvents, depending
on the flash point desired. Solvents range from ethanol to
DPMA. After the flake is dissolved in polar solvent it can
be reduced with some non-polar solvent such as an Isopar.
The tolerance for a non-polar reduction is worked out on a
case by case basis based on the solvents and resin solids
used.
The semipermanent
mold releases based on Glass Resins are generally sold at
1 to 3% resin solids and may incorporate a small percentage
of a high viscosity silicone oil for "fast break".
The GR-650
Flake can be made available in solution in a variety of solvents.
All Glass
Resins are available with a Certificate of Analysis showing
test results versus those specified by the customer.
The GR-650
Flake is sold in 25 pound bags. The GR-651 Liquid are sold
in 5 gallon pails and 55 gallon drums.
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