Abstract:
With the advancement of plastics,
the desire for ligh t-weigh t and safety of
plastic lighting material evolved. Glass
fiber reinforced polyester c6rrugated
sheet (FRP corrugated sheet) was developed
first; then, rigid polyvinyl chloride
corrugated sheet was developed as a
product in 1956. In the beginning, it
was processed by pressing calendered
sheet to form corrugation. This was the
so called pressed corrugated sheet.
Productivity was low and the price was
high for that process, so popularization
was difficult. The extrusion moulding
method of producing R. PVC corrugated
sheet, however, was developed
during 1957 - 1958, and R. PVC corrugated
sheet became the mainstream
material for taking in the light through
the roof. Since then, because of the low
price, it was popularized rapidly, and
the domestic annual production i.n 1972
exceeded more than 70,000 tons temporarily.
Since 1973, because of the promotion
of technology export and the
overseas expansion of industry, export
of products to Europe declined. Also, the
demand of users turned to other material
which is pervious to light. Consequently,
the annual production dropped
to approximately 50,000 tons. This
volume, however, has continued steadily
and has been settled. In the beginning
corrugated sheets were either transparent
or semitransparent, but now, besides
transparent and semitransparent R. PVC
corrugated sheet, there are all sorts of
variety such as galvanized iron net reinforced
corrugated sheet, glass fiber net
reinforced corrugated sheet, and embossed
corrugated sheet being sold in
the market. Here, therefore, transparent
and semitransparent R. PVC corrugated
sheets, which are most popular, will be
described.
