Glass Resins for Semipermanent
Mold Releases

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.


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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