Colorless transparency, stability against aging, thermoplasticity, and chemical resistance to many reagents are the general characteristics of the acrylate resins. In consistency they range from soft, sticky, semiliquids to hard, tough, thermoplastic solids. Since these widely varying properties are obtained by control of manufacturing conditions, rather than by the use of plasticizers, the resins retain their initial properties indefinitely. Aging and weathering have no effect as they are stable under exposure to heat, light, and oxidizing agents. The methacrylates are harder and tougher but less elastic than the acrylates. Properties and uses. The acrylate resins are marketed in a number of forms, such as solutions in organic solvents, dispersions in water, solid cast sheets, rods and tubes, and molding powders. All of these are distinguishable from many other resins by their colorless transparency, adhesive qualities, great elasticity, and chemical resistance. The brilliant water-white color makes it possible to secure masses having a high degree of light transmission and great optical clarity. The earliest commercial use of the acrylate resins was in laminated safety glass marketed as Plexigum in the United States and as Luglas and Sigla in Europe. The extensibility and elasticity of the resin film gives the laminated glass a flexible or yielding type of break when subjected to a hard impact. Having excellent adhesion to glass there is no need of an auxiliary cement to bond the resin to the glass, nor is it necessary to seal the edges since the resin has good resistance to moisture. The acrylate resin used for this purpose is in the form of a viscous solution in an organic solvent. A film is applied to each sheet of glass, the solvent removed by drying, and the sheets are pressed together. The harder acrylic resins are used in the form of solid thermoplastics. Methyl methacrylate is of special interest. As the monomer is a mobile liquid it can be cast-polymerized to a solid of any desired shape in predesigned molds or produced in finely divided form for use as molding powder. The cast resin is marketed in this country as Crystalite, Plexiglas and Lucite, and in England as Diakon. The solid acrylate resins are clearer than cast phenolic resins, not as brittle as the polystyrene resins, and not as tough as cellulose acetate or nitrocellulose plastics. Their transparency and resistance to aging and weather permit their use in applications not previously considered for synthetic resins. Sheets of this resin may be formed or molded into many useful shapes. The aircraft industry has found them suitable for windshields and cockpit enclosures to effect streamlining and thus greatly reduce wind resistance.