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High performance foams have special markets in niche applications

High performance foams have special markets in niche applications

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High performance foams have special markets in niche applications
High performance foams have special markets in niche applications  
 

The demand for high-performance plastic foams is expanding all across a broad spectrum of market sectors, including transportation, electronics, healthcare, industrial equipment, consumer appliances, building and construction, footwear and sporting goods. The main reason for the expanding usage is that these materials offer the light weight and cushioning properties of conventional foams, plus various combinations of special features, such as exceptional strength, heat and flame resistance, sound damping, chemical inertness and biocompatibility.

Polymers used in high-performance foams include polyurethanes, polyolefins, silicones, fluoropolymers, styrenics and engineering resins. Some of these materials possess intrinsically superior mechanical, thermal or chemical properties; others are made that way by chemical modifications in their polymer chains, cross linking treatments, or the use of special additives. Foaming of high-performance materials is done with standard methods such as chemical blowing agents and physical blowing agents (hydrocarbons or fluorocarbons are typical ones).
High-performance foams compete with non-foamed thermoplastics, metals, and natural and synthetic rubber. The foams are used in such parts as gaskets, seals, heat shields, shock and vibration cushions, prosthetic devices, and EMI/RFI shields for electronic equipment.

Polyurethanes make up the largest segment of high-performance foams. When suitably formulated and processed, these materials provide the following advantages:

  • High resistance to compression set, which makes them useful for gaskets, seals and cushions.
  • Efficient energy absorption, thus providing high resiliency, good vibration damping and impact attenuation.
  • Low outgassing, that eliminates fogging in auto interiors.
  • A broad service temperature range. One supplier features products that can be used between -40°C and 90°C.
  • Inherent flame retardance in many cases.
  • High chemical and environmental resistance, which minimizes damage from ozone and UV light.

In the automotive sector, high-performance polyurethane foams are used in air conditioner vent gaskets, spare tire mounts, tail-light gaskets, cup holders, engine vibration mounts, dashboard impact pads, gas tank isolator pads, and instrument cluster gaskets.
In communications, pads made of urethane foams protect the fragile LCD assemblies of cell phones. In desktop and laptop computers, these foams are used in thermal insulation, EMI/RFI shielding and battery shock absorbers.
Noise absorption is another outlet for the urethane materials. In this application they are used in headliners and panels for automobiles, ventilation ducts of commercial aircraft, off-road vehicles, appliances, air compressors and snowmobiles.
The healthcare industry employs high-performance urethane foams for custom orthopedic equipment and prosthetic padding.
Lower end polyurethanes have long been used as cushioning in furniture, but in a new trend, specialized polyurethane foams, that combine the properties of both cushions and the underlying metal springs, are being introduced. As a result, these foams eliminate the need for the metal springs and the labor-intensive process of installing them.

The major high-performance of Polyolefin is: crosslinked polyethylene elastomers and plastomers. (Plastomers have a specific gravity of 0.89 and above; elastomers have a specific gravity below 0.89.) Foamed PP has some specialized uses, particularly in low-density packaging. Polyolefin foams, which possess exceptional tensile and elongation properties, look and feel like rubber but process like other polyethylene resins. They can easily be thermoformed or laminated to other materials.
In the automotive sector, foamed polyolefins are gaining ground due to their weight saving properties and easy recyclability. Uses of the foams in this industry include door panels, sound-absorbing hood liners and instrument panel laminates.
In footwear, the ruggedness and impact-absorption features of foamed polyolefins are making them useful as shoe insoles and ski boot linings.
Construction applications of the foamed polyolefins include thermal insulators, sealants against moisture and dust, impact and vibration attenuators, and underlays for parquet floors.
In consumer goods such as luggage, toys, helmets and sporting gear, foamed polyolefins function as shock absorbers, thermal insulation, and pressure distributors.

Silicone foams are known for their resistance to temperature extremes, UV light, ozone and extreme mechanical stress. They are also flame retardant and highly resistant to compression set and creep. The properties of silicone foams make them particularly useful inside commercial aircraft, where they are used as thermal and noise insulators, cargo fire barriers, carpet underlay, and HVAC (heating, ventilation and air conditioning) gaskets and seals.
In electronics, silicone foams find applications in EMP/RFI shielding, vibration and thermal insulation.
Mass transit is another market for silicone foams. Among their uses in that sector are gasketing, sealing, sound dampening and cushioning.
Because silicone foams maintain their dimensional stability when exposed to sterilizing agents such as dry heat, steam, electron beam and gamma radiation, they are often used in medical components. These include body contact surfaces for sonogram equipment and surfaces for rubber articles intended for repeated use.

PVDF is the most common high-performance fluoropolymer. It is inherently flame retardant and can be made in a closed-cell structure that gives it very low thermal conductivity. Foamed PVDF also features low gas and moisture permeability, plus resistance to UV, most chemicals and ionizing radiation.
Manufacturers of foamed fluoropolymers are targeting applications in aircraft insulation, particularly for ducts and air conditioning. In industry, the foams are suited for applications in seals for chemically harsh environments, and in the floats of chemical tanks. PVDF can be made in very high purity, so that it is less likely to contaminate industrial chemical formulations than other foams. Its flame retardance is also an asset in manufacturing situations where fire hazards are present.

EPS foam has long had a role in low-cost packaging, but it is also widely used in the construction industry. In this area it finds applications in structural insulation panels, roofing systems, floors, walls and ceilings, geofoams (ground-fill materials), cold storage systems, and below-grade foundations. Producers of EPS for construction emphasize its energy efficiency, stability, versatility and ease of installation. They also point out that the foams are not manufactured with blowing agents that contribute to global warming.

Engineering resins (ETP) are on the higher end of the performance spectrum. Foaming these materials preserves most of their useful features, while introducing the advantage of lightweight.
A foamed material such as expanded PC, for example, has the typical polycarbonate properties of high impact resistance, high-temperature and flame resistance, low water absorption and good electrical properties. But EPC sheets are only about half the weight of comparable size solid polycarbonate sheets. Among the uses of EPC sheets are roof insulation for automobiles, housings for office machines, traveling cases for sports equipment, sterilizable trays for medical laboratories, and backlit highway signs.

High-performance foams are benefiting from several trends. First, manufacturers are building lighter weight transportation vehicles for greater fuel economy. They are also producing lighter cell phones, computers and other electronic devices, which appeal to consumers. But manufacturers are unwilling to sacrifice quality or durability for weight savings, which is creating opportunities for structural and insulating components that are both low in density and rugged. In addition, many industrial processes are operating at higher and higher temperatures, where energy efficiency is greatest. Consequently, there is a growing demand for insulation, gaskets, seals and jacketing that can stand up to these rigorous conditions. Industry sources say these trends have not yet run their course, forecasting continued vibrant growth for high-performance foams, at least for the next few years

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SML Lenzing Cast Film Line

SML Lenzing Cast Film Line