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Materials Test 4
| Question | Answer |
|---|---|
| Where did the term "zyl" come from? | Zylonite (cellulose nitrate); a material that was commonly used in the past |
| What does "zyl" most commonly refer today? | Cellulose acetate; but generally all plastic frames |
| Metal frames are all metal except for...? | The nose pads and the posterior temples (plastic earpieces) |
| What are nylon cord frames also referred to as? | String mounted frames and nylon supras |
| How is the lens held in place in a nylon cord frame? | A nylon cord that fits around the edge of the lens; and the top of the lens is fitted into the upper rim of the frame |
| What is a combination frame? | Specifically, a metal chassis with plastic top rims and temples; technically any frame using both metal and plastic |
| What is a chassis? | The eyewire and bridge section |
| What is a half eye frame used for? | made for those needing a reading correction and no distance correction; sit lower on the nose |
| What are rimless frames? | Lenses held in place by some method other than nylon cords or eyewires; often nuts, bolts, and screws are used; also plastic posts, clamps, and cement |
| What are rimless mountings also referred to as? | 3 piece mountings |
| What is a semirimless mounting? | similar to rimless except for a metal reinforcing arm which follows the upper posterior surface of the lens and joins the centerpiece of the frame to the endpiece |
| What is a numont mounting? | hold the lenses in place only at their nasal edge |
| What were the first two plastic materials used for frames, and why are they no longer used? | bakelite and galaith; were too brittle when used in cold weather |
| What was used after bakelite and galaith for plastic frames? | cellulose nitrate (zylonite) |
| Why is zylonite no longer used for plastic frames? | highly flammable; FDA banned |
| What is cellulose acetate extracted from? | cotton or wood pulp |
| After the cotton or wood material is extracted, how does it become plastic? | treated with a mix of anhydride and acetic acide using sulfuric acid as a catalyst; plasticizers and aging stabilizers are added. |
| Even with stabilizers, cellulose acetate can become _______ with age. | brittle |
| Cellulose is coated with a ___________ to seal the surface. | UV inhibitor |
| What allows frame parts to be cut from cellulose acetate? | It can be poured into sheets of plastic |
| What is propionate also known as? | cellulose aceto-propionate |
| While it has many of the same characteristics as cellulose acetate, but works better with....? | injection molding |
| Propionate has less ______________, unless coated will fade within a short period of time. | color stability |
| Propionate weighs __% less than cellulose acetate? | 25 |
| Optyl is an __________. | epoxy resin |
| Optyl is a _____________ material, which means the material will return to its original shape when reheated. | thermoelastic |
| Cellulose acetate is a _____________ material and does not return to its original shape when reheated. | thermoplastic |
| Optyl is __% lighter than cellulose acetate. | 30 |
| The thermoelastic property of optyl can make it....? | difficult to adjust |
| Nylon is highly flexible, and must be soaked in _____ overnight or it will become brittle. | water |
| Polyamide is __% lighter than cellulose acetate. | 28 |
| Polyamide is resistant to chemicals and solvents, and is also very...? | hypoallergenic |
| Grilamid is a nylon-based material, what is it's primary use? | sports eyewear |
| What makes grilamid superior to regular nylon? | Has a wider variety of color possibilities. |
| Carbon fiber creates a ____, ______frame. | thin, strong |
| Carbon fiber is __% lighter than cellulose acetate. | 40 |
| Carbon fiber is not very adjustable, there for it used primarily for...? | frame fronts; not used for temples |
| Carbon fiber is black, and therefore.... | is available in only a few select opaque colors |
| Polycarbonate is used primarily for what because of its impact resistance. | Sports or safety frames |
| While polycarbonate is impact resistant it can also be...? | difficult to adjust |
| Is it common for frames to be made from more than one type of metal? | Yes |
| What is a strong and malleable material commonly used for frames? | Nickel |
| What is one major disadvantage of nickel? | Nearly 10% of the population has an allergic reaction to nickel |
| What are some advantages of pure nickel? | resists corrosion; malleable and easily adjusted; accept color well and is very versatile |
| What is the makeup of nickel silvers? | more than 50% copper; 25% nickel; and the rest zinc |
| Nickel silvers contain how much silver? | NONE |
| What adds strength to nickel silvers? | zinc |
| What is another name for nickel silver? | German silver |
| Monel metal is an inexpensive, very popular frame material. What are some other properties of it? | White in color; resist corrosion; easy to adjust; accepts high polish |
| What is monel metal mostly made from? | Nickel; also made from copper, iron, and traces of other elements (silicium, carbon, sulfur) |
| What is a strong and extremely lightweight material that can be finished in a wide variety of colors and does not corrode? But also has no flexibility | Aluminum |
| Aluminum does not ______ or ____ and must be made to be assembled with screws or rivets. | Solder or weld |
| What is made mainly from iron and chrome and is highly resistant to corrosion? | Stainless steel |
| Stainless steel is ideal for what because of its springy and flexible nature? | temples |
| Stainless steal is what type of material, allergenic or non-allergenic? | non-allergenic |
| Titanium is extremely lightweight, it is __% lighter than other metal materials. | 48 |
| What is the metal of choice for people with skin allergies? | Titanium |
| When combined with other metals, titanium allows frames to become very....? | flexible |
| What are some disadvantages of titanium? | very hard to solder or weld; more expensive |
| Who established guidelines for frames containing titanium and who tests the frame? | Vision Council of America; an independent/accredited lab |
| To be certified 100% titanium, all major components of the frame are at least __% titanium by weight and contain no ______? | 90%; no nickel |
| Certified Beta Titanium, all major components of the frame are at least __% titanium by weight, and must contain no nickel. | 70 |
| What is a metal alloy from copper and tin? | Bronze |
| While magnesium is even lighter in weight than titanium and exceptionally durable, it is highly....? | corrosive; and therefore must be sealed |
| What materials are the most hypoallergenic? | Optyl; Polyamide; Titanium; Stainless Steel |
Created by:
griffiskr
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