Developments in polymer composites

In line with the general spirit of optimism and industry growth at the event, presenters at ACMA’s technical conference shared some insights on current research and development efforts. American Composites Manufacturers Association’s (ACMA) annual exhibition and convention was held in February 2012. A few of the highlights as per
Ashland Performance Materials highlighted its new strategic alliance with Acell in North America to promote Acell’s sheet molding compound (SMC)-based sandwich panel processing technology, and its Hetron FR 650T-20 resin, developed in response to the need for a versatile, high-performance fire retardant polyester. The new high-strength resin is a low-viscosity, promoted, thixotropic polyester with exceptional fire retardant properties. According to the company, properly fabricated laminates made with Hetron FR 650T-20 resin can achieve Class I flame spread rating in ASTM E-84 testing without the use of antimony synergists. The resin is suitable for hand lay-up, spray-up and filament winding applications. It exhibits excellent wet out properties and low drainage when applied to vertical surfaces. Its flame retardant properties make it especially attractive for use in mass transit, architectural, electrical and ducting applications.
Bayer MaterialScience LLC emphasized its polyurethanes, focusing on the process flexibility of this material. Dominating the booth was a large (121 ft2/11.2 m2) combine roof module, molded by Romeo RIM using its new long-fiber injection press from KraussMaffei. Also on display was a composite wind turbine root ring, two prototype airfoils and a high-pressure hydrogen storage tank, molded via resin transfer molding (RTM) and resin infusion.
BYK USA Inc. exhibited the composite pallet, manufactured by Plastics Research Corp. BYK supplied the additives, including wetting and dispersing additives and coupling agent that improve the performance of the finished pallet part, which is made with sheet molding compound (SMC) in a compression molding process. The pallet, weighing 54 lbs or about 25% less than a standard wooden version, has a maximum rated rack load of 2,800 lbs/1,272 kg.
Cerex Advanced Fabrics Inc. exhibited its line of N-Fusion continous filament nylon surfacing veils, designed for pultrusion. According to the company, the N-Fusion veils provide a better product surface and gloss retention, better UV and corrosion protection compared to polyester materials, a high melting point above 260°C/505°F for processes that require high temperature, and improved impact resistance compared to other veil products.
Chomarat North America featured its new, trademarked C-PLY bi-angle reinforcements, developed in cooperation with Dr. Steven Tsai of Stanford University and his consulting group Think Composites. Chomarat says it is committed to turning Prof. Tsai’s theory of using unbalanced laminates as building blocks for composite structures subjected to bending and twisting into industrial reality. C-PLY, in 0-25° configuration, is available in several fabric forms and a variety of fiber types, and can also be purchased as a prepreg. The 2-angle fabric offers benefits not possible with traditional balanced and symmetrical laminate architecture, such as increased strength and rigidity, less scrap during manufacturing and fewer microcracks.
Continental Diamond Tool featured its diamond-plated saw blades for cutting composites. Known for natural diamond as well as cubic boron nitride (CBN) tools made in an electroplating process, the company stressed the long manufacturing life of its tools, ability to maintain shape and dimensions longer than carbide tools, and faster task completion with less heat generation. The tools are up to the task of cutting fiberglass, carbon fiber or other composite materials.
Specialty chemical company Dixie Chemical attracted interest for its technical paper presentations regarding the company’s “green” products: maleinated acrylated epoxidized soybean oil (MAESO), maleinated acrylated epoxidized linseed oil (MAELO), and methacrylated fatty acid (MFA) made from renewables such as palm, kernel or coconut oils, as a diluent or styrene replacement. The company says that when compared to standard petroleum resins, MAESO and MAELO perform comparably to iso-unsaturated polyester, and that resin performance can be customized by varying the type and amount of oil-based resin and the diluent used, that is, traditional diluents are compatible with the resins. Dixie’s products have been shown to be suitable for sheet molding compound (SMC), bulk molding compound (BMC) and infusion processing, for customers wanting to reduce their product’s carbon footprint.
Dustcontrol Inc. exhibited the DC 2800 EX mobile dust extractor suitable for use in explostive atmospheres. Intended to capture dusts from handheld power tools and small table saws, the 2800 unit is equipped with a 115-volt motor and slightly longer cyclone compared to the 1800 model, which increases suction power. The 0.5 micron HEPA-certified filter is easily washable, says the company, and collected material can be recycled if appropriate.
Entropy Resins displayed its pine-based epoxy resin, Super Sap, reportedly the industry’s first USDA BioPreferred-certified plant-based epoxy system. Super Sap 100/1000 has 37% of its resin backbone made up of naturally-occurring industrial pine oil, as documented by the USDA, and reportedly has good adhesion with reinforcements and better elongation properties than traditional petroleum-based epoxies. The company is currently targeting sporting goods applications.
Eurovac Inc. featured its new Eurovac II Grinding Portable, outfitted with a new motor design for more power, producing more cubic feet per minute than any 110 volt motor on the market. It’s on/off feature means it turns on automatically when pneumatic grinders are activated, reducing energy costs. And, the dust filtration system includes a built-in cyclone, so that particulates are forced to move to the cyclone where 85% of the matter is removed before the air hits the secondary cartridge filter, for much greater efficiency and less filter cleaning time.
Fiberlay has improved its DraGun meter/mix head, introduced last year that can be driven by an electric hand drill or a few select ½-inch portable battery drills. Intended as a low-cost solution for small shops, the cost-effective DraGun now has a variable mix ratio, from 1:1 to 1:100, is gear-driven, pumps up to half a gallon per minute, and can pump thicker materials with an optional pressure tank, says the company. It can spray everything from polyurethane foam to casting materials.
Gruber Systems highligted its “integrated process control capabilities” for composite part production, from mold design and production, to workplace soutions such as filler handling and metering equipment. Gruber produces molds for cast polymer parts, closed mold for light RTM and vacuum forming equipment. The company can design solutions for handling virtually any raw material; makes equipment for producing the parts, such as its automated remote casting mache with full recipe control system; and offers programmable logic controller (PLC) based control systems to ensure part quality control and consistency.
Gurit featured core materials for the marine and wind markets. Trademarked Corecell, PVCell, G-Foam, G-PET and Balsaflex, all with a distinct range of properties and attributes, are available in sheet form or as tailored pieces in kit format, which the company terms “B3 SmartPac.” B3 SmartPac is a construction solution developed by Gurit that contains all of the reinforcement and core materials required for a job, precut to exact shape and size to fit the mold, and clearly labeled for alignment and location, to ensure reduced waste and better quality for the boatbuilder.
HK Research introduced a new polymer called Revolution, a gel coat-like material that offers 6% elongation and excellent water and UV resistance. Company tests reportedly showed that Revolution, when it does crack, self-limits crack propagation and minimizes damage.
Huber Engineered Materials has developed Micral AM550 alumina trihydrate (ATH), a finely ground flame retardant and smoke suppressant with a median particle size of about 5.5 microns. Features of the ATH include viscosity stability, controlled thickening, fast dispersion, good mechanical properties and good process flow in glass fiber composites.
Interplastic Corp. displayed, among many other products, its trademarked Integrity high-performance gel coat, one of the company’s CoREZYN thermosets. The product, which is MACT-compliant, exhibits good resistance to sagging during application, outstanding weathering characteristics and good color stability, ease of spray-up, blister and crack resistance and low porosity. A wide range of colors are available, or custom colors can be created.
ITW SprayCore exhibited a new product, SC 4600 HTT, a sprayable, high-temperature mold-building resin. Designed for the tub/shower industry where metal molds are common, the vinyl ester-based material can be sprayed onto a pattern to quickly form a tool without surface distortion that, says the company, increases mold strength by up to 20% while reducing cost and time. The product makes a cost-effective alternative even with multiple part pulls.
Jushi USA, part of Jushi Group, reportedly the largest fiberglass reinforcement manufacturer in the world, highlighted three new products at the show. Single-end fiberglass roving 312T is designed for high performance pultruded profiles. Its combination of sizing chemistry and single-end manufacture makes it compatible with several resin systems and enables high mechanical properties. Also new were 568FR, fiberglass chopped strands for flame retardant engineering plastics, and 362K, which is fiberglass roving intended for long-fiber reinforced thermoplastics.
Fabricator Litek Composites Corp. showed its array of filament-wound and hand-layed fiberglass pipe, fittings and accessories for corrosion-resistant apps. Made in accordance with applicable ASTM standards, Litek’s filament-wound pipe, for example, incorporates a resin-rich veil for corrosion resistance and 55-degree helical winding architecture for maximum working strength in high-pressure applications.
Materials Innovation Technologies introduced MIT-RCF, a wet-laid, nonwoven blanket of randomly oriented, intermediate-grade carbon fibers, with areal basis weights of 50 g/m2 to 500 g/m2, which is made from unused prepreg scrap reclaimed from 787 Dreamliner productions and currently resold in roll-goods form. MIT is working on providing this material in several varieties, including one that commingles thermoplastic/carbon fibers, stitch-bonded forms from Vectorply Corp. (Phenix City, Ala.) and a prepreg. The carbon fiber prepreg in original form sells for about US$35/lb. MIT’s roll-goods product goes for US$20/lb. When it is molded with epoxy, it offers a tensile strength of 369 MPa, tensile modulus of 37.6 GPa, flex strength of 556 MPa and flex modulus of 36.4 GPa.
McLube, a division of McGee Industries Inc.’s MAC-1038 is a relatively new, easy to apply, fast air-curing semi-permanent mold sealer and release that is designed to provide enhanced surface finish and excellent release characteristics for multiple parts. MAC-1038 is compatible with epoxies, phenolics, polyesters and even thermoplastic resins.
Plasticolors Inc. showed a new pigmented and solvent-free urethane-based gel coat at its booth, developed in a joint venture with PPG Industries Inc., and intended as a tough in-mold coating for wind blades, nacelles and spinners. Thanks to Plasticolors’ additives, the “AGC-10000 Durablade” gel coat exhibits good UV stability and a customizable balance of flex strength and surface hardness.
Technical Fibre Products showed its huge range of technical, wet-laid non-woven mats and veils for composites. Trademarked Tecnofire provides passive intumescent fire protection through the use of exfoliating graphite combined with high-temperature resistant mineral fiber and a binder. When subjected to high heat, a char byproduct is produced that acts as an insulating layer to the underlying materials. Both flexible and rigid product forms are available, including sheets, rolls and narrow coils or cut shapes. Some grades include aluminum hydroxide (ATH) to further improve fire performance. Also on display were electrically conductive mats and veils for static dissipation, EMI shielding and lightning strike protection.
Thermwood Corp., manufacturer of both 3- and 5-axis CNC routers used for composites as well as many other industries, described a new line 5-axis machines under development that will be equipped with “high wall enclosures.” The enclosures bring greater dust and particulate control, for a cleaner shop and a higher level or worker safety, and follow an industry trend of increasing use of enclosures as CNC machining becomes more widespread.
TruStone Products displayed its capabilities in cultured marble manufactured by digitally embedding large-format high-resolution images of natural stone into the cast polymer surface; a process the company calls “Photofuzion.” A process involving dye sublimation printing, photofuzion imparts the look of real granite or marble to the product, at a price the company says is comparable to traditional chip and veining techniques employed by other manufacturers.

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