Curv® is an ideal material for luggage and transportation cases. It can be used for the entire shell or for light weight reinforcement. Some well proven examples are suitcases, briefcases, tool cases and backpacks.
The high impact strength of Curv® is one of the critical features for this end use. The impact strength is achieved by our unique compaction process, using fabrics made of highly oriented polypropylene tapes. The performance of Curv® surpasses most other materials used in the luggage industry.
Samsonite manufactures suitcases from Curv® and rigorously tests these suitcases, including a drop test from a height of several meters. Samsonite has run over the suitcase with a truck and attaches the still intact piece of luggage to the wall with chewing gum. The case regains its shape without cracking or splitting. No other suitcase material provides the same combination of strength and light weight.
The woven structure imbedded in the Curv® sheet enables high energy absorption and prevents splintering or brittle failure of the material. The impact strength of Curv® is about 3,400 J/m at room temperature and the material increases in strength and remains ductile at sub-zero temperatures. This strength, paired with the high rigidity of Curv® (four times higher than standard polypropylene), makes wall thicknesses of less than 1 mm feasible without additional stiffeners. The result is a piece of luggage that is robust and durable, yet flexible, in all climatic conditions. Curv® is also valued in other cases, for transporting guns or bicycles.
The unique look of Curv® is also attractive in the consumer sector. The carbon fiber-like design can be customized in a variety of colors. Curv® can be supplied with an outer protective layer, or with a metallic, three-dimensional effect. Curv® is supplied as prefabricated sheet or in rolls, depending on the thickness. Thermoforming of Curv® can be done with a conventional hydraulic press, with slight modifications.
For larger luggage or transport box designs, Curv® can be supplied in a sandwich construction on a foam or honeycomb core. Choosing a polypropylene core construction creates a material that can not only be bent and welded, but is also recyclable. For example, Curv®-on-Core sandwich panels with a hexagonal honeycomb core are approx. 5 kg/m² lighter than birch plywood and are used to manufacture air cargo boxes. This type of transport box has proven its longevity in applications from NASA to rock bands. Other fields of application include coolers or refrigerated transport where Curv® not only provides strength at light weight but also effective insulation, demonstrating ductility and impact toughness at low temperatures.
Curv® is used in anti-ballistics in conjunction with a bullet-resistant material such as aramid. The aramid material stops the projectile, the most important task of ballistic protection. However, the kinetic energy of the projectile impact can cause blunt trauma to a person wearing the protection. A thin layer of Curv® incorporated behind the aramid layer disperses the impact energy over a wider area, reducing the blunt trauma to the wearer.
The use of such a Curv®-aramid laminate is shown to significantly reduce the back face deformation caused by a non-penetrating projectile. The deformation of the back face is reduced by 30 % when our thinnest Curv® material is used in combination with aramid. The deformation can be further reduced to more than 45 % by using Curv® of less than 600 g/m². The trauma is correspondingly lower, without sacrificing comfort or adding significant extra weight. Ballistic protection vests using a Curv®-aramid laminate are manufactured by Teijin Aramids (Twaron LFT AT / AT Flex products), jointly developed with Propex and the best combination of weight, volume and protection available in the market.
Curv® has been successfully used for soft ballistic protective equipment. The stability and high potential for energy dispersion of Curv® are ideal as a framework for an anti-ballistic pack. Other anti-ballistic applications made from Curv® are in the fields of helmets and protectors. Curv® can also be used in vehicle hard armor applications for reinforcing body parts or as anti-spalling protection in military vehicles.
Curv® is used as a component in footwear. The low-temperature impact strength has value in sports such as ice hockey or skiing. For many years Propex has worked in the skate segment with Bauer, the leading supplier of professional ice hockey equipment and skates. Bauer uses Curv® both in the outer body of the skate and for additional, internal reinforcement. These skates are attractive in design and light weight, while providing a high level of protection for the athlete. The protection can be clearly seen when the skate is hit by a puck moving at 80km/h.
Curv® is also used in hockey protective equipment for field players and goalies. Manufacturing with Curv® allows a wide array of visual and design options through sublimation printing or by tailoring Curv® to adhere to a variety of different materials such as polyurethane, polyamide or polyester. Thermoforming cycle times of less than 60 seconds can be achieved during processing.
Recently, Curv® was introduced in ski boots. By reinforcing the upper shaft area of a touring boot, Curv® enhances stability and downhill performance while providing flexibility and ease of climb. It is also a good insulator. For manufacturing, it is possible to process Curv® on common molding equipment. Curv® can also be easily sewn to other components, so no special joining technologies are needed.
In addition to footwear for winter sports, Curv® promise an attractive range of applications from soccer cleats to safety shoes.
In the automotive sector, Curv® is used in both interior and exterior components. Exterior applications include bumpers, spoilers, body panels, underbody shields, truck bodies and wheel wells. Interior applications include headliners, door panels, airbag components, cargo floor covers, knee bolsters, pillar coverings and luggage racks. In the area of passenger protection, Curv® is valued as superior to alternative materials. Curv®, as a component in a textile airbag hinge, is used by many European car manufacturers. It does not splinter or throw fragments when the air bag is triggered, even when the air bag is activated at low temperatures.
Curv® is used for local reinforcement in applications in over-injected molded components, including battery boxes, supports for door liners and dashboards. Using Curv® as an inlay increases the performance of the part without heavily investing in new materials or technologies. A pre-heated Curv® insert is placed in the mold. During the over-injection, Curv® bonds with the polymer melt without compromising the properties of the composite. The resulting parts demonstrate improved impact resistance, better crash behavior through higher energy absorption, improved wear resistance, and/or material and weight savings.
Replacing glass fiber reinforced components with parts made from Curv reduces weight by up to 20-30% due to the low specific gravity. The mechanical properties of Curv® allow down-gauging, reducing weight by another 20-30%. Various applications have achieved weight savings of up to 50%. Including Curv® in an over-injection molded part will improve part properties, or allow achievement of the same properties at lower weight. Also, the thermal expansion of Curv® is around 50% lower than standard polypropylene, which makes it easier to combine it with other materials. Compared to glass fiber reinforced materials, there is less wear on tooling and edge trim or parts from end-of-life vehicles can be easily recycled.
Sporting goods is a versatile application area, ranging from ice hockey, football, skating and cycling to kite-surfing, paddle tennis and many more. Depending on a customer’s needs, Curv® can be supplied in a variety of thicknesses, constructions and designs and with a broad array of processing options. Curv® also scores high in the consumer sector with its unique and attractive appearance. The carbon fiber-like look can be customized in a variety of colors. The three-dimensional depth visual effect of Curv® can also be combined with different surface textures for unique appearance.
In one application, 1mm thick Curv® sheets are thermoformed into helmets for recreational and competitive sports. The compression of Curv® in the heated state at an elongation of about 50%, allow achievement of the desired shell geometry. A helmet of 100% polypropylene can be produced by the proper selection of other components. Thanks to Curv®, the 300g helmet weight is much lighter than many comparable helmets for cycling, skiing and roller skating made from carbon fiber composites.
Protective equipment made of Curv® is also used in various other sports. It is valued for its combination of light weight and impact resistance. Our self-reinforced composite provides reliable protection of the athlete. Soccer shin guards are a classic field of application. Another field is American football. Shoulder pads made of Curv®, 1.5mm to 2 mm thick, are the lightest pads on the market. In ice hockey, Curv® is used in shoulder pads, elbow pads and shin guards and other protective applications. For these applications, in general, typical material processing methods are sufficient and conventional forming plants can achieve very good results.
The excellent multi-hit resistance is also utilized by the leading manufacturer of paddle racquets, the rackets of a tennis-like sport. As a liner or outer layer of a complex hybrid construction, Curv® gives the racket the impact resistance, resilience and longevity unmatched by other composite materials. Curv® can be used in a lot of hybrid constructions. The material can be customized to bond to a variety of other materials or to modify the mechanical properties to achieve the desired result.
Curv® is also found in equipment for water sports, where the low density of polypropylene (0.92 g /cm³) and the negligible water absorption of the material are valued.
Curv® gives ultra-light support and dynamic comfort to a kite waist harness. Its high stiffness helps transferring the pull of the kite to the body.
A Curv® sandwich panel, in a polypropylene honeycomb structure, is the material used to construct a canoe. A sturdy, two person, origami-style boat is fabricated using bending technology and a special design. The canoe can be folded to suitcase size and easily transported and stored due to its low weight.
Our thinnest Curv®, from 0.35mm to 0.66mm thickness, is perfect for speaker cones. It combines the advantages of paper, fiber composite and standard polypropylene (PP) membranes at a moderate price level. As a high tech material, Curv® achieves outstanding audio performance when compared to other materials, due to the stiffness and low weight. Glass filled polypropylene, aramid or carbon fiber speaker cones are heavier than those using light weight Curv® material.
Paper membranes are subject to water absorption, which increases the weight and degrades the acoustic performance. Curv®, a 100% polypropylene composite, is also more stable than paper membranes. Curv® demonstrates the high degree of damping typical of a thermoplastic material, which improves the acoustic performance and ensures first-class resonance behavior. These benefits are appreciated by our current customers.
Curv® has 30% higher stiffness when compared to glass filled polypropylene, due to the unique production process. Curv® is made from specially manufactured polypropylene drawn tapes. The Curv® composite is formed by selective melting of several layers of fabric made of these special tapes resulting in a self-reinforced material with improved mechanical properties. This allows Curv® membranes to be about 30% thinner than extruded PP membranes.
The typical Curv® look also creates a visibly attractive part. For example, in the high end segment of the market, this special look has been used by Wilson Benesch for more than 10 years. The black version also has the added benefit of UV stabilization.
Different finishes are available for the product range of audio equipment. Areas of application for loudspeaker membranes made of Curv® are in the automotive sector, outdoor speakers, home theater woofers and satellite mid-bass woofers.