Composite material reinforcement materials. Another important factor is the gross quantity of material to be produced. Large quantities can be used to justify high capital expenditures for rapid and automated manufacturing technology. Small production quantities are accommodated with lower capital expenditures but higher labour and tooling costs at a correspondingly slower rate. Many commercially produced composites use a polymer matrix material often called a resin solution. There are many different polymers available depending upon the starting raw ingredients. There are several broad categories, each with numerous variations. The most common are known as polyester, vinyl ester, epoxy, phenolic, polyimide, polyamide, polypropylene, PEEK,
Unusual types of gramophone records all 7-inch until 1901, when 10-inch records were introduced. 12-inch records joined them in 1903. By 1910, other sizes were retired and nearly all discs were either 10-inch or 12-inch, although both sizes were normally a bit smaller than their official diameter. In Europe, early 10-inch and 12-inch shellac records were produced in the first three decades of the twentieth century. 7-inch children's records were sold before World War II but nearly all were made of fragile shellac, not an ideal material for use by children. In the late 1940s, small plastic records, including some small picture discs, replaced them.