Plastic was the most revolutionary material in the 20th century, and soon became the major material in the eyewear industry. The plastic frame is gaining popularity due to its wide variety of colors, textures, and styles. The easy molding of plastic makes it possible to produce any kind of complicated style of the plastic glasses frame. There are many kinds of plastic materials that can be used to make plastic frames. Cellulose acetate of lightweight and adjustability The most common and inexpensive plastic frame is made of Zyl, also called zylonite or cellulose acetate. The plastic glasses frame made of Zyl is pretty lightweight and can be easily adjusted. Currently, a very popular style of plastic glasses frame is the laminated Zyl frame mixed with a couple of layers of colors. First occurring in 1865, this material has also wide application in other fields. In photography, Zyl is utilized as a film base. And in some adhesives, it is a basic component. In addition, some cigarette filters and playing cards also make use of this material as a synthetic fiber. Nylon-based cellulose propionate The second material is cellulose propionate. The plastic frame in this nylon-based material is lightweight and easily molded for any style. Compared with cellulose acetate, cellulose propionate has lower plasticizer migration and is stiffer. It also has better low-temperature impact properties. But special attention needs to be paid to the heating when adjusting this plastic frame. Overheating this type of plastic frame may cause shrinkage and even damage. This is because cellulose propionate has lower weathering resistance. Kevlar for sports glasses Kevlar is another material researched and developed by DuPont in 1965. This is a para-aramid synthetic fiber. Once used in the military bulletproof vest, Kevlar is impact-resistant and very strong. Plastic frames made of Kevlar are mainly used in sports glasses. In the beginning, this material was used as a replacement for steel in racing tires. But now, it has been a popular material for bicycle tires, racing sails, and body armor. Plastic glasses frames made of nylon started in the 1940s. Nylon was developed because the early plastic glasses frame was crispy and easily breakable. A nylon plastic frame is high in strength and light in weight and is resistant to extreme high and cold temperatures, therefore is also good for sports eyewear. Nowadays, most eyewear manufacturers take a variation called blended nylon, which helps produce strong and lightweight frames. They have valuable resistance to both cold and hot and are flexible and stiff. Style with extreme strength Style is a special plastic material, which is lighter and stronger than Zyl. A plastic frame made of style is similar to a memory metal frame which can be restored to the molded shape. Adjustments to this type of plastic frame are difficult and much care should be taken to overheat which may ruin the frame. |