CR-39® monomer is the dominant material for eyeglass lenses. Homalite casts CR-39® monomer into sheet form known by the trade name H-911. Homalite H-911 is a clear, hard, almost colorless, thermally set plastic, possessing surfaces comparable in smoothness, luster and chemical resistance to polished plate glass.


Chemical and solvent resistance:

H-911 is resistant to the effects of virtually all solvents including acetone, benzene and gasoline, and to most chemicals other than highly oxidizing acids.

Resistance to abrasion:

Abrasion resistance, as measured by a modified Taber method, may be 30 to 40 times that of acrylic plastics. H-911 approximates the abrasion resistance of glass as measured by the falling emery abrasion test. In certain industrial applications it out-performs both glass and other plastics. Resistance to scratching by high-speed particles is especially good.

Impact resistance:

At normal temperatures H-911 has approximately the same impact resistance as cast acrylic. Impact strength at very low temperatures is unusually good.

Resistance to pitting:

H-911 is more resistant than glass to pitting by small hot flying particles, and is many times more resistant to welding sparks.

Stability of optical properties:

H-911 material maintains optical properties through a variety of difficult environments and conditions of use. Age, stress or contact with solvents will not cause them to check or craze. Photoelasticity is excellent; strain does not produce any loss of optical properties.


In light transmission , H-911 is approximately equal to optical glass. Its index of refraction is only slightly lower than that of crown glass.

Heat Resistance:

Because H-911 is a thermosetting plastic it has good properties of heat resistance and dimensional stability. In tests it has shown distortion of only 30 to 65 mils at 130°, a temperature at which acrylics are melted. It has a burning rate of only one-fourth that of cast acrylic materials.

Resistance to gamma irradiation:

The transmission loss of H-911 is only 5% after 100 million roentgens exposure compared to 45% transmittance loss for acrylics subjected to the same exposure. Many glasses discolor even more rapidly than acrylics when subject to radiation. H-911 withstands about 50 times as much radiation as acrylic materials before its physical properties are reduced by 50%.

Complete Specifications for Homalite H-911 made from CR-39 monomer.

Applications for H-911:

The following is a partial list of applications using Homalite H-911. H-911 is used in a variety of applications which would benefit from its unique properties. Designers and specifiers should regard this list only as an indication of the kinds of applications in which H-911 plastic has been found to be advantageous.

Electronic Display windows
Available with a gloss finish or a low-reflectance finish.

  • Medical equipment
  • Ruggedized PCs for applications such as police vehicles, marine use and outdoor heavy equipment.
  • Process Control equipment.


  • Crane enclosures
  • Glazing subject to hydrofluoric acid attack


  • Dial and gauge covers

Nuclear Labs

  • Window panels
  • Glove box panels
  • Viewing windows


Homalite H-911 is available in sheet stock or as finished parts cut to size. Most finished parts are laser-machined. Thicknesses range from .031" to .5". Thicker material (up to 1") is available for glazing applications. Homalite will furnish thicknesses over .5" cut to size only. This material is fabricated using a lamination method and has excellent optical properties but cannot be machined.

Samples and quotes are available on request.




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