What is CR39 sunglasses lenses?
CR39 sunglasses lenses are currently one of the most widely used lenses, widely used in various types of frames, especially mid-to-high-end acetate sunglasses and metal sunglasses. This article allows us to learn more about CR39 lenses.
CR39 sunglasses lenses for acetate sunglasses
The CR39 resin lens material is a thermosetting resin. The mold is opened first, and then it is manufactured by compression casting. At present, most of the resin lenses for correcting vision and sunglasses are made of CR39 resin material, which was developed by the Columbia Research Institute of PPG Company in 1942, so it is called "Columbia resin". CR39 lens is one of the most used lenses.
Features of CR39 sunglasses. Among the most commonly used lenses of CR39, nylon, and PC, CR39 has the characteristics of good light transmittance, high hardness, not fragile, moderate weight, and rich colors. It is one of the lens types that many consumers love and is widely used. Now popular acetate sunglasses, metal sunglasses and so on.
The craftsmanship of CR39 sunglasses. First open the casting mold (such as different specifications, cambers, thickness, etc.), and then cast CR39 resin material to form a CR39 white lenses (many samples of eyewear use CR39 white lenses).
CR39 white lenses
CR39 sunglasses lens process 1: CR39 sunglasses lens dyeing process. After the white lenses comes out, through the dyeing process, the CR39 white lenses is dyed into various monochrome lenses (such as single gray, single green, single tea, single yellow, single red, etc.), fader (such as gradient gray, gradient green, gradient tea etc.). In addition to the colors of the lens factory itself, color copying can also be carried out according to customer requirements.
CR39 sunglasses lens process 2: Coating process of CR39 sunglasses lens. Common coating colors include gold lenses, silver lenses, blue lenses, green lenses, pink lenses, orange lenses, etc. Generally, a vacuum coating machine is used to attach different pigments to the surface of the lens layer by layer, and finally become the desired colour. Coated sunglasses lenses are also one of the most popular sunglasses lenses. The back blue (or other colors) is also after the coating process, that is, a layer of lenses is coated on the back of the lens. It can effectively absorb some light reflections from the back. Another function is to wear back blue (or other) sunglasses. Not let others see your own eyes.
The craft of CR39 sunglasses lens 3: Add UV400. Mainly by adding UV toner to the material, UV400 is a yellowish material, so the CR39 lenses with UV400 added is light yellow, and the CR39 white lenses is superior. Now almost all mid-to-high-end sunglasses must be equipped with UV400, which can filter out most of the ultraviolet rays that are harmful to the eyes. (Like UV400, light transmittance, etc., the general lens factory can provide test reports).
CR39 sunglasses lens process 4: CR39 strengthening process. CR39 itself is not very hard (but better than nylon and PC, etc.), so many middle and high-end CR39 sunglasses will be strengthened, that is, the dyed CR39 lens is passed through the strengthening solution and then dried. Recognition method: The side of the unenhanced CR39 lenses is matte, while the enhanced one looks light.
Process 5 of CR39 sunglasses lens: Water-proof and oil-proof process. After the strengthening process, a waterproof or oil-proof lenses can be added according to customer requirements. Waterproof membrane identification method: Sprinkle some water on the lens, stand the lens up, the water will immediately harvest into drops and drip easily. The ones that are not waterproof are not easy to harvest and drip. Oil-proof lenses identification method: Use an oil-based pen to draw on the surface of the lens, the vertical color will shrink into a drop shape, and it will be removed by gently rubbing it with a cloth. It is not oil-proof, that is, it does not shrink into drops and is difficult to wipe off. According to requirements, only waterproof or oil-proof effect can be added, or both effects can be added, namely oil-proof and waterproof. According to requirements, it can also be used for general waterproof and oil-proof effects, or super-water-proof and super-oil-proof effects (that is, the oil-proof and waterproof effect is particularly good).
The CR39 Sunglasses lens with water-proof
How to identify CR39 lenses. This is mainly for nylon and PC lenses. 1) Knife bracket method: Use a utility knife to wrap it on the side. The powdered one is CR39. Nylon and PC are filamentous. 2) Shape recognition method: CR39 lenses generally do not have a handle, and nylon and PC lenses have a handle. 3) Voice recognition method: Use your fingers to flick the surface of the lens, CR39 sounds solid and heavy, nylon is relatively brittle, and PC lenses is the most brittle.
Application of CR39 sunglasses lens. 1) Most myopia lenses now use CR39 resin lenses; 2) CR39 sunglasses lenses are also one of the most widely used lenses at the moment. They are widely used in acetate glasses, metal glasses, titanium glasses and buffalo horn frames etc. (but irregular glasses rings Not suitable, for example, the corners are more obvious; and fish-line glasses, three arrows are not suitable).