Designing with Plastics

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May 2008 | Focus: Polycarbonate

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Laminated polycarbonate sheet provides high level security


MAKROLON® HYGARD® polycarbonate glazing used by Bullet Guard Corporation.

MAKROLON® HYGARD® polycarbonate glazing used by Bullet Guard Corporation.

Ensuring optimum clarity performance, laminated polycarbonate sheet offers protection from ballistic and physical attack in bullet-resisting and containment glazing applications.

A new generation of laminates, featuring a hard-coat technology, assures exceptional resistance to physical attack, abrasion and UV degradation. With its unique multilayer construction, the polycarbonate laminates can withstand both physical attack and gunfire from high- powered hand guns. Multiple levels of protection are provided, ranging from certified containment glazing to UL 752 Level 3 bullet-resistant material. The laminates will not “spider web” or spall. This allows for complete vision, which can be critical for appropriate response in the event of an attack.

Bullet Guard Corporation specializes in bullet-resistant armoring for a wide variety of industries including government, military, banking, healthcare, retail, fast food, police and fire departments and post offices.

According to Bullet Guard President Karlin Lynch, “Initially, adding bullet-resistant glazing and armoring may seem simple, and there are those who have tried to make it appear no different from other building materials. However, in actuality, the bullet-resistant field is very complex. It is extremely important to specify the right materials and apply them in the proper manner to achieve the desired level of protection, without alienating customers.”

Bullet Guard uses laminated polycarbonate sheet available in six levels of protection, ranging from containment rated sheet to UL 752 Level 3 bullet-resistant material. UL 752 Level 3 materials are capable of withstanding multiple rounds from high-powered handguns.

According to Lynch, “We like laminated polycarbonate sheet because it is lightweight and easy to fabricate for both re­model and new applications, and the proprietary hard-coated surfaces offer resistance to abrasion, UV degradation, delamination and discoloration.”

Many employers are fearful of customer rejection of bullet-resisting barriers. But customers are increasingly asking for this protection because they know they are safer in a store with visible security.

Polycarbonate laminates are ideal for security, forced entry and bullet-resistant applications. Offering top industry containment, ballistics and UL ratings, they are the ultimate choice for your security and containment glazing applications.

View the complete article online.

This article was written by Sheffield Plastics Inc., A Bayer MaterialScience Company.

In This Issue:
Laminated polycarbonate
sheet provides high
level security

Bullet-resistant and containment applications find a solution with polycarbonate.

Joining and painting polycarbonate sheet
Fabrication tips and techniques for polycarbonate.

A strong alternative:
polycarbonate glazing materials

Polycarbonate offers many advantages to glass.

Insulation value of
polycarbonate sheets

From greenhouses to garden centers, polycarbonate is the product of choice.

About polycarbonate
Properties and features of this versatile material.

Test your knowledge
What do you know about polycarbonate?

Online plastic resources
IAPD offers many online search resources at and, including distributor, processor, trade name and fabrication capability searches.

Find an IAPD Plastics Distributor or Processor

Search for Suppliers by Trade Name or Material and Shape

Search for Plastics Fabrication Capabilities

Search Other Plastics Articles Published by IAPD

View Past Issues of Designing with Plastics


About IAPD
The International Association of Plastics Distribution, founded in 1956, is an international trade association comprised of companies engaged in the distribution and manufacture of plastics materials.

Members include plastics distributors, processors, manufacturers, resin manufacturers, manufacturers’ representatives and associated products and services, all of whom are dedicated to the distribution channel.

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Joining and painting polycarbonate sheet


While a one-piece thermoformed part provides the best performance, size limitations and other factors often call for fabricating a polycarbonate part from several components. Typical joining techniques include: solvent cementing, adhesive bonding and mechanical fastening. Your choice of method depends on strength requirements and whether the components must be disassembled periodically for repair or replacement. Avoid cemented joints if high impact resistance is necessary. Also included here are tips for decorating the polycarbonate sheet with paints and inks.

Solvent cementing
Cementing joints with a solvent represents the simplest method of joining polycarbonate sheet to itself. You can use a pure solvent, polymerizable monomer/solvent or a thickened solvent. Close fitting and mating surfaces are required for solvent joints.

Butt Butt T
Plain Lap Tapered Lap

Figure 1. For strong joints, use a fine hypodermic syringe to apply solvent cements along the edge of a joint, allowing capillary attraction to penetrate the joint.

A good solvent joint should have a tensile strength of 2,500 psi. For strong joints, use a fine hypodermic syringe to apply solvent cements along the edge of a joint, allowing capillary attraction to penetrate the joint (Figure 1). The alternative, soaking the mating edges in solvent and then pressing them together, creates a weaker joint. For parts requiring service at elevated temperatures, force dry them in an oven. For a clear joint, apply pressure using a press while the solvent dries. The most common pure solvent is methylene chloride (MDC). MDC quickly dries and reaches handling strength.

Polymerizable monomer cements, such as Weld-On® 55 and 58 (Industrial Polychemical Science Corporation [IPS], Compton, CA, USA) and PS-18 and PS-30 (Caseway Industrial Products, Fort Myers, FL, USA), give a better-looking joint than solvent cement since voids can be eliminated. These joints are less brittle and they blush less than a solvent cemented joint.

Thickened cements, with 10 to 15 percent of the parent material dissolved in a solvent, are helpful when two mating joint parts do not fit well together. The polymer fills some voids. The strength is not as high as a solvent joint. Thickened cements cannot enter the joint by capillary attraction like MDC; they require open access to the joint.

View the complete article online. The complete article includes other joining and painting techniques for polycarbonates.

This article was written by Elizabeth Grimes, Altuglas International of Arkema Inc.

A strong alternative: polycarbonate glazing materials


Polycarbonate is a tough, transparent thermoplastic material that is characterized by high impact strength. Since its inception, it has been used where safety concerns are at the forefront — space shuttle windows, astronaut visors and industrial eye protection.

Today, polycarbonate has found a large audience as an architectural sheet product, replacing traditional glazing in skylights, sidelights, greenhouses, transportation shelters, walkway covers and many other applications requiring strength and transparency.

We have seen the worldwide market for multiwall sheets more than double in the last 10 years. Several key factors are responsible for this kind of rapid growth in the polycarbonate marketplace.

An example of CO-EX’s Macrolux material spanning from roof ridge to eave.
An example of CO-EX’s Macrolux material spanning from roof ridge to eave.

Polycarbonate to the rescue
Because polycarbonate is virtually indestructible, lightweight and non-fragmenting, it is virtually the perfect safety glazing. The same qualities that make it perfect for use in space, make it ideal for use here on earth.

Single wall polycarbonate provides an inexpensive yet attractive method to add natural sunlight to a structure’s interior spaces. Multiwall polycarbonate creates greater strength and introduces the greater R-values with its small air pockets built right into the product. It is well suited for greenhouse use with its light diffusing and insulating properties but works equally well in factory, corporate and home environments.

Strong protection
A distinct advantage over glass, all polycarbonate resists hailstone damage and is able to withstand extreme abuse. Its impact strength is 250 times greater than glass and 10 times greater than acrylic sheet. This shock resistance makes it an excellent choice in vandal prone areas, and it resists the “smash and grab” theft that glass is prone to allow. Vandals with rocks cannot shatter factory windows if they are glazed with polycarbonate.

Polycarbonate also provides a protective safety net for a myriad of other applications. In gymnasiums, time clocks, lighting and emergency exits can be effectively shielded from basketballs behind polycarbonate sheeting. Priceless, historic stained glass can be protected from hail, vandals or the effects of weather with an application of a protective polycarbonate sheet on the exterior of the building, without detracting from the beauty of the glass.

Where weather factors like hail and wind borne debris are prevalent, polycarbonate panel can be used as a replacement to traditional glass. It can effectively and inexpensively glaze industrial buildings and be a strong choice for skylight and clerestory lighting.

To give you an idea of its strength, we’ve tested our 8 mm panel and know it will withstand the impact of 16 lbs. dropped 25 feet with no breakage. What’s more, it can maintain its strength over a wide temperature range, from -40°F (-40°C) to 250°F (121.1°C).

Weighing just 1/8th the weight of glass, polycarbonate panels are self-supporting and do not require the extensive structural support that a heavier glass wall or skylight needs. That’s why polycarbonate has found a strong niche in the horticultural greenhouse market and in large pool enclosures. The lightness of the polycarbonate also makes it ideal for smaller projects like home greenhouses, patio cov­ers and carports.

Energy saving
Just as insulated glass has air pockets to reduce heat transfer, polycarbonate sheets can be manufactured with a variety of walls and air space configurations. These walls and air pockets lend greatly enhanced thermal insulating values and also add extra strength to the panels. The thermal resistance or R value can be as much as 60 percent better than traditional glazing. (R value is a commercial unit used to measure the effectiveness of thermal insulation. A larger number represents a higher insulation value and therefore greater heating and cooling efficiency.) The multi-layered construction of an 8 mm four-wall polycarbonate sheet offers a 30 percent increase in the U value and R factor over the traditional 8 mm twin wall sheet. Polycarbonate panels can go to five walls thick and more for real thermal enhancement!

Single wall corrugated polycarbonate sheets are engineered to capture the early morning and late afternoon angled light for increased solar gain during colder early spring and late fall or winter months. This saves energy costs in greenhouses and pool enclosures.

View the complete article online.

This article was written by Janice Pravorne, CO-EX Corporation.

Insulation value of polycarbonate sheets


Polycarbonate sheets play an important role in today’s agricultural marketplace. From greenhouses to garden centers, polycarbonate is the product of choice. Polycarbonate is light weight, easy to install and allows abundant natural light into interior spaces. In addition, polycarbonate boasts the best fire rating among plastic products and has excellent insulation properties, all leading toward the design and construction of safe, energy-efficient agricultural buildings.

Winding Creek Nursery in Millbrook, IL, reaps the benefit of using Gallina S.U.V. Super “U” Value (8 mm four layer) poly carbonate sheet for energy-efficient greenhouses.
Winding Creek Nursery in Millbrook, IL, reaps the benefit of using Gallina S.U.V. Super “U” Value (8 mm four layer) poly carbonate sheet for energy-efficient greenhouses.

There are two alternatives available for covering greenhouses: a soft cover utilizing polyethylene or a hard cover utilizing polycarbonate. Because most greenhouses not only shelter flora and fauna but also state-of-the-art equipment, a hard, polycarbonate cover is most often selected.

Once the decision to utilize a hard cover has been made, then you must again choose between corrugated polycarbonate and twin-wall polycarbonate. Because of better thermal efficiencies and greater diffusion of natural sunlight, twin-wall polycarbonate is likely the product of choice.

Building owners should always keep in mind that utility costs are directly related to the energy efficiencies of any building. For greenhouses, the energy cost is equal to the energy lost. As we keep heating, we lose energy through the covering.

Four wall, 8 mm (5/16'') thick polycarbonate sheets offer the perfect solution for today’s energy and budget conscious market. With an R value of 2.08, about 15 percent more efficient than comparable two wall sheets, the material will actually pay for itself in less than three years by reducing the heating cost. “Pay more to pay less!”

View the complete article online.

This article was written by Amit Israeli, Gallina USA LLC.

About polycarbonate

Polycarbonates are high-molecular weight, amorphous engineering thermoplastics that have exceptionally high-impact strength over a wide temperature range.

Resins are available in general-purpose molding and extrusion grades and in several special grades that provide specific properties or processing characteristics. These include flame-retardant formulations, grades that meet FDA regulations for parts used in food-contact and medical applications, blow-molding grades, glass-reinforced grades for applications requiring maximum strength and stiffness, and structural-foam grades. Polycarbonate is also available in extruded sheet. The natural resin is water-clear and transparent.

Polycarbonates are characterized by an excellent combination of toughness, transparency, heat and flame resistance and dimensional stability. In unnotched Izod impact tests and falling-dart tests, the unreinforced material resists breakage at very low temperatures — -65°F (-54°C) and in thick sections. Humidity changes have little effect on dimensions or properties of molded polycarbonate parts. Even boiling water exposure does not change dimensions more than 0.001 in/in (0.001 m/m) after parts are returned to room temperature. Creep resistance is excellent throughout a broad temperature range and is improved by a factor of two to three in glass-reinforced compounds.

The insulating and other electrical characteristics of polycarbonate are excellent and almost unchanged by temperature and humidity conditions. One exception is arc resistance, which is lower than that of many other plastics.

Polycarbonates are generally unaffected by greases, oils and acids. Nevertheless, compatibility with specific substances in a service environment should be checked with the supplier. Water at room temperature has no effect, but continuous exposure in hot water — 149°F (65°C) causes gradual embrittlement. While the resins are soluble in chlorinated hydrocarbons, they are attacked by most aromatic solvents, esters and ketones which cause crazing and cracking in stressed parts. Grades with improved chemical resistance are available and special coating systems can be applied to provide additional chemical protection.

For more information on polycarbonate and other plastic materials, IAPD’s Introduction to Plastics is an invaluable training manual. Details about it and other IAPD educational resources are available online at

Test your knowledge

What do you know about polycarbonate? Answers are at

1. One disadvantage polycarbonate has versus acrylic is the percentage of optical transmittance. What is the percentage of optical transmittance for polycarbonate per ASTM D 1003?

  1. 80 to 84 percent
  2. 85 to 89 percent
  3. 90 to 94 percent
  4. 95 to 99 percent

2. Polycarbonate is how many times stronger than glass?

  1. 50
  2. 100
  3. 250
  4. 320

Online plastic resources

Your IAPD Distributor is your choice in finding the right material for your application. Go to to find a distributor in your area. You can search by company name, location or product category.

The IAPD Magazine web site at allows you to search by material, trade name and fabrication process. You can also search for fabrication capabilities.

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© 2008

International Association of Plastics Distribution
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Phone: +913.345.1005 | Fax: +913.345.1006

Designing with Plastics is published by the International Association of Plastics Distribution. While every effort has been made to ensure accuracy, IAPD encourages you to verify information with a plastics distributor to ensure you select the correct plastic products to meet your needs.