All About Italian Cellulose Acetate
by Priya Modi

After the eye exam, your optometrist shows you the wall where they display glasses in the office. Without a doubt, you are overwhelmed by the countless number of frames. The frames glisten as they are shined with a golden, warm light. There are so many colors, styles, designer brands to choose from—where do you start? Of course, you want the glasses to flatter your face, but how are you going to distinguish superior quality from the rest? Knowing which materials are used to make frames is the subtle detail that which will help you determine quality. That’s right—it could be metal, plastic, or Italian cellulose acetate. This will require some homework which is why we are here to help. For now, let’s take a deeper look into the Italian cellulose acetate material for eyewear frames.

What is Cellulose Acetate?
Do you remember chemistry class? Cellulose acetate is a synthetic compound derived from the acetylation of the plant substance called cellulose. Cellulose acetate is spun into textile fibers known as acetate rayon, acetate, or triacetate. You can think of it as your pair of frames being made from plants—isn’t that neat?

A Little History on Cellulose Acetate
Did you know that cellulose acetate was founded way before you were born? The credit goes to Paul Schutzenberger who was a French chemist particularly interested in industrial chemistry. Paul discovered that cellulose can react with acetic anhydride to form cellulose acetate in 1865. Apart from glasses, cellulose acetate has made its mark on other industries such as film, computer technology, and textile. It was used originally as a film base in photography as a component in some coatings. Cellulose acetate replaced nitrate film in the 1950s since it was less flammable and cost effective to produce. In 1952, IBM introduced cellulose acetate magnetic to use on their IBM 726 tape drive in the IBM 701 computer. This was much lighter and easier to handle than metal tape. We are pretty sure the blocks you played with as a child was most likely from the Lego brand. But did you know that they were made from cellulose acetate from 1949-1963?

In fact, you may have cellulose acetate in your closet. Acetate fiber is highly valued since it is low in cost and has excellent draping qualities. Acetate is used in fabrics such as satins, brocades, and taffetas to accentuate luster, body, drape, and beauty. This fabric feels soft and smooth to the touch and when worn it is very breathable. If it’s not in your closet it may be at your favorite wedding boutique since it’s found in bridal gowns and other party attire. Just remember that when you’re trying on those beautiful gowns. Cellulose acetate was first commercially used as a plastic then became widely used in the automotive industry because of its strength, toughness, wear resistance, transparency, and ease of moldability. Its high resistances to impact made it a desirable material for protective goggles, tool handles, oil gauges, and other things similar in nature.

Eyeglass Frames and Cellulose Acetate
Cellulose acetate in eyewear is handmade. Materials are cut into rectangular pieces about the height and width of the frame front. Materials are cut into rectangular pieces about the height and width of the frame front. Traditionally, prior to the modern technology, each cut of plastic required moving the frame from one machine to another. Over the past decade, modern factories have invested highly to automate the milling steps. Thanks to advancements in technology, "CNC" machines feature multiple cutting blades that are directed to make specific cuts and bevels, including the eye-wire groove, before producing it and grabbing a new piece of material. Multiple layer cellulose acetate provides boundless opportunities to cut and reveal various layers and colors. Tumbling for days followed by polishing agents and materials brings out the material's shine. It is the finished off by hand polishing. Lastly, temples are shaped and then "shot" with a wire core. Temple ornaments or plaques are attached in a variety of ways, including imbedding them into the plastic.

So what makes cellulose acetate frames different from other plastic frames? Other plastic frames are made by using petroleum. The petroleum is in a liquefied form so that way it can be injected into an aluminum-based or stainless mold. Then there is a spray application used to apply color and they are tumbled for shine. Injection mold frames are generally less expensive but considered to be lower quality. Cellulose acetate frames are known for durability and flexibility which makes them more expensive that injection mold frames. Be careful though—cellulose acetate frames can be distorted when exposed to intense heat.

Manufacturing Methods for Cellulose Acetate Frames Involve:

  • The technique involves forming layers of plastic into a large block of acetate
  • Different parts of the eyeglass frame are then cut from this large block of cellulose acetate sheet
  • After this careful slicing, individual parts are then hand polished and assembled into a whole frame
  • The machine used to slice these large blocks of acetate or zyl, is called a pantographing machine
  • Block acetate sheet sizes range between 3 feet (0.91 m) in length, and are typically 0.33 in (0.84 cm) thick

Benefits of Cellulose Acetate Frames
Why is cellulose acetate so valuable especially when making frames for glasses? It is known for being strong, lightweight and flexible. In the 1940s there were other problems associated with plastics, but thanks to acetate, wearers experienced more comfort from them. What else is special about cellulose acetate? It is non-petroleum based which means it is harmless to the environment. Petroleum-based products are harmful to the environment and inexpensive. Cellulose acetate is made from a renewable resource, lightweight, and strong. It also has the widest range for transparency, rich colors, and finishes. At the same, it is hypoallergenic which is why it is considered the highest quality plastic material for eyeglasses.

Disadvantages of Cellulose Acetate Frames: It is more expensive than injection molded frames and acetate frames can be distorted in very extreme heat.

Injection Molded Frames
As the name suggests, this is yet another method of making frames. The process begins with materials which are usually propionate, TR-90 (or its derivative). The materials come in sacks of pellets. There is a machine that melts the pellets and places them into a mold of the specific shape. Once it is cooled, the frame portion is tumbled smooth. Then coloring can be performed in that mold. Make sense so far? So, for example, if you want a pair of black frames, the lab would use black pellets. If you want a different color, it is usually spray-painted with paints that can be absorbed by these materials. If you want a pattern on your frames, it is done by holding a mask up to the plastic and then spraying it with color. Do you like the tortoise look? This is done by coloring the entire frame dark brown, then holding up a mask that has a series of holes and then spraying that mask with a dark brown. Once the mask is pulled away, you will have tortoise pattern.

Manufacturing Methods for Injection Molded Frames Involve:

  • The technique involves liquefying plastic into mold
  • This mold then cools and solidifies into the frame
  • The machine used in this process are similarly called injection molding machines
  • Colors are added on some of these frames through spray painting, and are further coated
  • Injection molded frames is made in massive quantities since they are economical, meaning they are produced off machine-driven assembly lines

Benefits of Injection Molded Frames:

  • Injection molded frames are more flexible, and can be bent without much damage
  • The method involves less waste, since molding only uses necessary materials, while block acetate discards unused parts around the cut
  • Less waste allows injection molded frames to be less costly than acetate frames

Disadvantages of Injection Molded Frames:

  • Injection molded frames look cheap and less of an organic feel
  • These materials can hold hidden defects from the injection process
  • Cheaper parts used to keep costs down can break easier

Now that you are familiar with the quality of frames based on materials, do you have an idea which frames you would go with? Injection molded plastic, metal, or acetate? Despite the cost, cellulose acetate frames offers durability and quality. It is plant-based which is as natural as it gets. Anything not natural may cause allergies and discomfort over time. One way to start is to think of it as an investment—you’re most likely to keep this pair of frames for a few years given that wear and tear naturally occurs over that period of time. You know you deserve the very best so go ahead and treat yourself to it. At the same time, you have the best judgment to determine what’s best for your face shape, hair color, eye color and skin tone. At Classic Specs, we offer frames made from premium cellulose acetate from a family-owned factory in Northern Italy. By knowing this detail, you will never look at our collection the same way again.