Everything You Need To Know About Polycarbonate (PC)
What is Polycarbonate sheet, and What is it Used For?
Polycarbonate possesses excellent impact strength, high heat resistance and good dimensional stability. It was one of the first thermoplastics to offer these properties. Although it is stable to water, mineral and organic acids, it is partially soluble in aromatic hydrocarbons, soluble in the chlorinated ones, and decomposes in strongly alkaline substances. It has good electrical properties.
The strength and dimensional stability of polycarbonates are further enhanced with fibrous glass reinforcement.
Reinforcement with 40% glass reduces the thermal expansion to 1.0 in/in/degrees F x 10E-5 (1.8 cm/cm/degrees C x 10E-5), which is below that of most thermoplastics and some metals. The tensile modulus is increased fivefold. Flexural, tensile and compressive strengths are doubled. Mold shrinkage is reduced, making it possible to produce very precise parts.
You’ve probably used a product with polycarbonate in it today, even if you don’t realize it. After all, polycarbonate is just about everywhere; it’s used in eyeglasses, medical devices, auto parts, lighting fixtures, DVDs and Blu-Rays, to name a few. As a naturally transparent amorphous thermoplastic, polycarbonate’s usefulness is in its ability to internally transmit light almost as effectively as glass and to withstand impacts far greater than many other commonly used plastics. Furthermore, the pliability of the material allows it to be created at room temperature without cracking or breaking and to be reformed even without the application of heat. That’s the “amorphous” element. The “thermoplastic” part refers to the nature of polycarbonate and other similar plastics to become liquid at their melting point, which allows, among other things, for easy injection molding and recycling.
Polycarbonate (PC) plastics are a naturally transparent amorphous thermoplastic. Although they are made commercially available in a variety of colors (perhaps translucent and perhaps not), the raw material allows for the internal transmission of light nearly in the same capacity as glass. Polycarbonate polymers are used to produce a variety of materials and are particularly useful when impact resistance and/or transparency are a product requirement (e.g. in bullet-proof glass). PC is commonly used for plastic lenses in eyewear, in medical devices, automotive components, protective gear, greenhouses, Digital Disks (CDs, DVDs, and Blu-ray), and exterior lighting fixtures. Polycarbonate also has very good heat resistance and can be combined with flame retardant materials without significant material degradation. Polycarbonate plastics are engineering plastics in that they are typically used for more capable, robust materials such as in impact resistant “glass-like” surfaces.
Another feature of polycarbonate is that it is very pliable. It can typically be formed at room temperature without cracking or breaking, similar to aluminum sheet metal. Although deformation may be simpler with the application of heat, even small angle bends are possible without it. This characteristic makes polycarbonate sheet stock particularly useful in prototyping applications where sheet metal lacks viability (e.g. when transparency is required or when a non-conductive material with good electrical insulation properties is required).
What are the Characteristics of Polycarbonate?
Now that we know what it is used for, let’s examine some of the key properties of Polycarbonate. PC is classified as a “thermoplastic” (as opposed to “thermoset”), and the name has to do with the way the plastic responds to heat. Thermoplastic materials become liquid at their melting point (155 degrees Celsius in the case of Polycarbonat). A major useful attribute about thermoplastics is that they can be heated to their melting point, cooled, and reheated again without significant degradation. Instead of burning, thermoplastics like Polycarbonate liquefy, which allows them to be easily injection molded and then subsequently recycled.
By contrast, thermoset plastics can only be heated once (typically during the injection molding process). The first heating causes thermoset materials to set (similar to a 2-part epoxy) resulting in a chemical change that cannot be reversed. If you tried to heat a thermoset plastic to a high temperature a second time it would simply burn. This characteristic makes thermoset materials poor candidates for recycling
Polycarbonate is also an amorphous material, meaning that it does not exhibit the ordered characteristics of crystalline solids. Typically amorphous plastics demonstrate a tendency to gradually soften (i.e. they have a wider range between their glass transition temperature and their melting point) rather than to exhibit a sharp transition from solid to liquid as is the case in crystalline polymers.Lastly, Polycarbonate is a copolymer in that it is composed of several different monomer types in combination with one another.
Why is Polycarbonate used so often?
Polycarbonate is an incredibly useful plastic for applications requiring transparency and high impact resistance. It is a lighter alternative to glass and a natural UV filter, so it is often used in eyewear. For used Polycarbonate in a number of applications across a range of industries. A few examples include the following:
- · clear windows on prototype models
- · color tinted translucent prototypes
- · clear tubes for sports equipment prototypes
- · diffusers and light pipes for LEDs
- · clear molds for urethane and silicone casting
- · 3D printed models for high heat applications when ABS is not an option
- · machinery guards
- · Molds for urethane and silicone casting
- · 3D printed models for high heat applications
- · Machinery guards
- · LED light pipes and diffusers
- · Vehicle headlights
- · Small vehicle windshields
- · Bullet-resistant “glass”
- · Phone and computer cases
- · Fountain pens
- · Luggage
We have seen tinted Polycarbonate used for the purposes of reducing glare (for example to cover lighted signs on the highway). Companies that manufacture this type of product often put tinted Polycarbonate on the front of their signs to both protect the LEDs and to reduce glare.
What Are The Different Types of Polycarbonate?
According to AZO Materials, polycarbonate was concurrently developed in the middle 20th century by GE in the United States and Bayer in Germany. In the modern era it is manufactured by a large number of firms, each typically with their own production process and unique formula. Trade names include well known variants (or “resins”) like Lexan® by SABIC, or Makrolon® by Bayer MaterialScience. You can view a full list of material manufacturers here.
There are various industry grades of polycarbonate available. Most are called by the generic name (polycarbonate) and are typically differentiated by the amount of glass fiber reinforcing they contain and the variance in melt flow between them. Some polycarbonates have additives such as “ultraviolet stabilizers” that protect the material from long-term exposure to the Sun. Injection moldable polycarbonate might include other additives such as mold release agents that lubricate the material during processing. Finished polycarbonate is typically sold in cylinders, rods or sheets.
The best types of polycarbonate sheets to use in your next project or build are
- · Clear GP Sheet
- · Bulletproof Polycarbonate
- · Clear SL Sheet
- · Clear SL2 Sheet (Double sided)
- · Colored Polycarbonate
- · Mirror Sheet
- · Colored Polycarbonate
- · Tinted Polycarbonate
- · Abrasion-Resistant
- · Anti-Static Polycarbonate
Types of Polycarbonate
Though polycarbonate sheeting was initially and concurrently developed in the mid-20th century by GE and Bayer, the current plastics marketplace features a variety of developers who each possess a unique polycarbonate formula and production process. Here are a few details on some of the modern variations and their common uses.
MAKROLON Clear GP Sheet
Designed for glazing and industrial uses, the Clear GP stands alone as the best polycarbonate on the market for protection against vandalism and intentional breakage. This high-impact sheet boasts an impact strength 250 times that of glass and 30 times that of acrylic sheeting, meaning that whatever it’s protecting is going to stay protected. Backed by a five-year warranty against breakage, Clear GP polycarbonate stands head and shoulders above any product in its class.
MAKROLON Clear SL Sheet
Natural light can eventually erode even the sturdiest materials, but that erosion can be slowed dramatically through the protection offered by the enhanced UV resistance of the Clear SL. This material is designed to weather brutal environments and provide unmatched extension of service life and color-shifting resistance. The MAKROLON Clear SL2 provides the same protection on both sides of the sheet for all-around UV resistance.
Polycarbonate Mirror Sheet
This versatile product offers the mirroring of glass with superior impact strength, heat resistance, and both dimensional and UV stability. Ideal for the security and automotive industries, this polycarbonate is the basis for what is commonly referred to as a two-way mirror. It can also be used to create traditional mirrors in high-stress environments, such as in vehicles, retail displays, and institutional bathrooms.
The flexibility of polycarbonate allows for each of these products to be created in a variety of sizes, shapes, colors and transparencies. All of them provide unmatched strength, functionality and cost-effectiveness.
How is Polycarbonate made?
Polycarbonate, like other plastics, starts with the distillation of hydrocarbon fuels into lighter groups called “fractions” some of which are combined with other catalysts to produce plastics (typically via polymerization or polycondensation). You can read about the process in more depth here.
Polycarbonate for Prototype Development on CNC Machines and 3D Printers
PC is available in sheet stock and round stock, making it a good candidate for subtractive machining processes on a mill or lathe. Colors are usually limited to clear, white, and black. Parts that are machined from clear stock usually require some post processing to remove tool marks and to restore the transparent nature of the material.
Because Polycarbonate is a thermoplastic material, certain 3D printers are able to print with Polycarbonate using the FDM process. The material is purchased in filament form and the 3D printer heats and deposits the filament into the desired 3D shape. Polycarbonate for 3D printing is usually limited to a white color. PC/ABS blends are also available for 3D printing on an FDM machine.
Is Polycarbonate Toxic?
There is a potential that certain types of polycarbonate could be hazardous in food contact situations due to the release of Bisphenol A (BPA) during hydrolysis (degradation due to material contact with water)1. The most commonly made types of polycarbonate are created by the combination of BPA and COCl2, however, there are BPA free polycarbonates that have become particularly marketable for applications involving perishable food or water.
There have been roughly 100 studies conducted on BPA and the results are somewhat controversial in that a correlation between funding source and risk assessment has been shown to exist. Most studies with government funding showed BPA to be a hazardous risk to health while many with industry funding showed lower to no medical risks. Regardless of the contradictory studies on the negative effects of BPA, certain types of Polycarbonate have been associated with its release. This has led to the advent of “BPA-Free” polycarbonate products (commonly shown on consumer products such as canning jars).
What are the Disadvantages of Polycarbonate?
Although Polycarbonate is known for its high impact resistance, it is very susceptible to scratching. For this reason, clear surfaces such as a polycarbonate lenses in a pair of glasses will typically be coated with a scratch-resistant layer for protection.
Roofing canopy Technical Specification:
Providing and Fixing of MultiCell Polycarbonate Panel System of approved color in 10 mm Thick (minimum) 6 WALL -5 CELL having uniform in color, Vertical Standing Seam manufactured at both sides of the panel. Snap-on connector to interlock the panels shall have a grip-lock double tooth locking mechanism Panel shall in fixed with M.S. Structure with Aluminum Extruded Single Piece Cleats in which 3 Self Drilling SDST Screw will be applied to handle best Up Lifting Pressure. Panel shall be co-extruded UV protected. The full system shall be fitted on MS purlins perpendicular to direction of sheeting with purlin spacing as specified by Manufacturer. 7000N Tested as per ISO 6892:1998 and IS 1608:2005, as per design requirement. Panels must satisfy Dart drop impact test as per IS 14443-97 shall show no sign of breakage on Polycarbonate sheet which have been exposed to UV for a min of 500 Hours as per ASTM G155. Panel shall not have Yellowness Index as per ASTM D1925 of 15 units when tested on samples exposed to UV for 500 Hours as per ASTM G 155. U Value shall not be more than 1.9 W/m2K as per EN ISO 10077-2 :2018. Polycarbonate Panel Ends shall be closed with Aluminum U profile /F Profile as and when required. The rate includes cost of all the operations, labour and all materials involved such as bolts nuts and screws etc. and labour for cutting bending to required profile. Work complete for at all floor, all level, all depth, all Height, all lead and lift etc. work complete as per the Detailed specification, shop drawing , approved sample, instruction of Architect/EIC. Sample mock shall be approved from Architect/EIC. Roof plan area shall be measured for payment.
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