Written:  October 18,1971
     The story of Rostone is a story of research . . . research that had its
     beginning in 1925 and has continued every year with significant milestones
     in 1927, 1937 and 1957.
Announcement was made at Lafayette, Indiana in 1927 of physical and chemical processes by which natural materials of the earth could be reconstituted into true, homogenous stone.  After first introducing this new material, "ROSTONE", in the building field in the early 1930's, applications were developed for its use in electrical insulation moldings.  These moldings, characterized by the inherent heat resistance and dimensional stability of the synthetic stone reaction, were given the name, "ROSITE".  In 1937 Rosite entered the field as a new kind of arc-proof, non-carbonizing material which could be molded accurately to complex shapes.
Beginning with completely inorganic compositions, basically inert and inflammable, other specialized organic and inorganic bonded materials have been added to the Rosite line.  Certain of these materials provide actual "arc-quenching" and improved interruptive capacity.  Through this capability and the minimizing of required clearances for protection against tracking, physical reduction in size for a number of electrical devices has been accomplished.
For more than twenty years, Rostone Corporation has continued in the development of Rosite and has specialized in the manufacture of custom moldings of the material for high temperature applications and for those requiring freedom from tracking when exposed to high intensity arcs or arc promoting conditions.
Rosite inorganics with improved mechanical strength and superior dimensional accuracy as compared with fired materials -- and with inherent high temperature resistance, dimensional stability, and inertness -- have been especially successful in resistors, thermostats, and for other applications at high temperature.  Ability to be molded with metal inserts also increased Rosite's suitability for such applications.
           In 1957 a significant addition to the Rosite line came into being with the development of hot-molded, non-tracking, arc-quenching materials.  These materials make it possible to offer increased mechanical and dielectric strength, over cold-molding, and can lead to refinement in section with consequent size reduction.  Moldability of these materials is excellent, which results in economy and efficiency in production.
Although hot-molded materials were originally developed for electrical applications, the material research and development at Rostone has continued at a rapid pace since 1957.  There are now new Rosite compositions available which exhibit such properties as wear resistance, corrosion resistance and low shrinkage.  Each of these has lead to applications in markets heretofore untouched by plastics.
Through our years of experience as custom molders, the Rostone Corporation has developed an Engineering Staff trained to (1) formulate special compositions for molding and (2) assist in the development of mechanical designs to achieve moldings with optimum characteristics.
            To keep pace with the demand for plastics, the Rostone Corporation maintains two modern well-equipped plants located in the Midwest, a plant in Canada, and an active affiliate in England.
Author Unknown 1971


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