Composites Fabricators show aims at boat builders.

Despite long-depressed sales of pleasure boats, exhibitors of new resins, additives and equipment for FRP processing focused on marine applications at the recent Fabrication '92 show in Reno, Nev., sponsored by the Composites Fabricators Association. Among the products introduced were new polyester, vinyl ester and modified epoxy resins; fillers, catalysts, air releases and mold releases; and new equipment for spray-up, mechanized lay-up, RTM and filament winding.

A FEW NEW RESINS

Still high on the minds of resin makers is the need to reduce the styrene emissions of their products. With that goal in mind, a few suppliers introduced new materials with lower styrene content. Ashland Chemical Inc., Columbus, Ohio, introduced corrosion-resistant Hetron 980/35, an unpromoted, highly crosslinked vinyl ester with a styrene content of less than 35%. An upgraded version of the company's Hetron 980, the new vinyl ester has a heat-distortion temperature of 271 F--20|degrees~ higher than its predecessor. Other reported benefits include a resin flexural strength of 21,700 psi and strong solvent and acid resistance.

Ashland has also lowered the styrene content of one of its epoxies. New AME 5000 is a high-solids (66%), thixotropic, acrylic-modified epoxy for marine applications that contains less than 35% styrene. Ashland says the physical properties of cured laminates are better than those made with many polyesters.

Reichhold Chemicals Inc., Research Triangle Park, N.C., also showcased a new series of low-VOC resins for marine applications, as well as a new vinyl ester. The Hydrex 33254 series of marine resins are high-solids polyesters that reportedly provide improved blister resistance, better profile and increased durability. Reichhold says the two resins in the new line--33254-00 and 33254-02--both have less than 35% VOC, water absorption of 0.12% (24 hr at room temperature), and HDT of 212 F. The difference is in their gel times--33254-00 gels in 21 min, 33254-02 in 32 min.

Reichhold's new Polylite 33346-00 is a prepromoted, thixotropic vinyl ester designed for high production rates at room temperature. It contains 47% styrene, has an HDT of 210 F, and has a compressive strength at yield of 15,400 psi.

A new vinyl ester primer was introduced by Hawkeye Industries, Inc., Marietta, Ga. Duratec primer is designed for osmosis and blister repairs of boat bottoms. It can be sprayed, rolled or brushed onto both composite and metal surfaces and is formulated to allow addition of low-density fillers, Hawkeye says. Typical properties include 1000-1100 cps viscosity; 13-16 min gel time; and 180 g/liter of VOCs.

FILLERS & OTHER ADDITIVES

Two series of sprayable granite-effect fillers were introduced by R.J. Marshall Co., Southfield, Mich. The SG series is for use behind a gelcoat. The SGU series can be used without a gel-coat. They are designed to be sprayed at a 45% loading and come in colors from gray with black and white highlights to dark green with black and light-green highlights.

Two new cumene hydroperoxide-based initiators were introduced by the Argus Div. of Witco Corp., Marshall, Texas. CHP-158 is an 89%-pure, low-color solution of cumene hydroperoxide for room-temperature and heat-assisted curing processes as well as applications where lower exotherms are required, as with thick sections. Witco says the pot life and gel time with CHP-158 are usually longer than those for MEKPs. The other initiator, CHP-5 is designed for faster reactions than CHP-158 and is said to eliminate gassing in vinyl esters. Witco says CHP-5 can be used in place of MEKP for room-temperature cures of polyesters, giving more moderate exotherms.

Akzo Chemicals Inc., Dobbs Ferry, N.Y., showed off its recently commercialized ketone peroxide initiator, Trigonox 63, for open molding, RTM and filament winding. It also debuted a new line of cobalt accelerators for polyesters and vinyl esters. These new accelerators reportedly can reduce gel-time drift and provide quicker cures than equal amounts of accelerators based on other chemistries. Also, the company says fillers absorb only minimal traces of the cobalt in the accelerators.

In order to prevent formation of air bubbles, Byk-Chemie, Wallingford, Conn., has developed Byk A 555, the latest offering in the company's A 500 series of air-release additives. Byk says it is the first air-release additive that is usable in practically all FRP applications. It reportedly can eliminate almost all air bubbles at use levels as low as 0.4% by weight, while resulting in little or no haziness.

MOLD RELEASES

Three companies showed new release agents at the CFA show:

Axel Plastics Research Laboratories, Inc., Woodside, N.Y., displayed two of its newest 100% water-based mold releases--EM-1212SL and SFW-1000. Both are designed for use with polyesters, vinyl esters and phenolics; EM-1212SL is also recommended for epoxies. Axel says SFW-1000 is especially suited to filament winding and hot press molding; and is aimed at both ambient and moderately elevated curing temperatures including hand lay-up, spray-up, RTM and preform applications.

Chemlease Inc., Groveport, Ohio, showed its newest release agent, Chemlease 81S for RTM. Designed for multiple releases from a single application, solvent-based 81S can be used on both hot and cold molds, providing heat resistance up to 800 F. A water-based version, 81W, is just for hot-mold applications.

A liquid, semi-permanent thermoset release system, TR-900 Multi-Pull, was introduced by T.R. Industries, South Gate, Calif. The new release is said to be thermally stable up to 700 F and suitable for a variety of processes, including hand lay-up, spray-up, compression molding, injection molding, vacuum bagging or RTM.

FRP EQUIPMENT NEWS

There was also a modest amount of new processing equipment at the show. For example, both Binks Manufacturing Co. of Franklin Park, Ill., and its Poly-Craft Systems Div. in Burbank, Calif., introduced methods to optimize catalyst use. Poly-Craft's entry is called Unison, a system for precise catalyst metering. It's said to remove the "guesswork" that comes with using traditional slave-pump delivery systems. The Unison uses a self-adjusting rack-and-pinion drive to provide a smooth reciprocating motion, eliminating the use of unequal forces that can lead to imprecise catalyst measurements. By setting a dial, the unit can accurately meter as many as four fluids at levels from 0.5% to 3%.

Meanwhile, Binks introduced its Century HVLP gun, which reportedly reduces catalyst use by 20-30% through internal mixing rather than external atomization. This, Binks says, leads to an even dispersal of the catalyst to all edges of the material spray. Improved mixing efficiencies and lower VOC levels can cut catalyst flow to the gun by 30%, Binks says.

GS Manufacturing, Costa Mesa, Calif., introduced a new internal-mix chopper gun. It uses GS's catalyst slave system attached to the air motor of the resins pump. Its air-assisted pistol is fitted with modular fluid plates and a nozzle that can be adapted for use with saturator nozzles, wet-out rollers and RTM attachments.

An RTM system that uses low-pressure injection was debuted by Glas-Craft Inc., Indianapolis. The LPI System has a complete material and catalyst recirculation system to eliminate air entrapment in hoses. The injection gun has a battery-operated stroke counter and reset button, enabling the operator to determine how many strokes are needed to fill a mold. A new 3 1/4-in. air motor drives a 4:1 material pump with 2.5-gal/min output rate. Glas-Craft says its catalyst slave pump can accurately meter between 0.5% and 4.5% of catalyst.

A new remotely actuated valve for RTM dispensing guns comes from Venus-Gusmer, Kent, Wash. This valve not only controls the flow of resin into the mold, but it allows remote flushing without taking the gun off the mold. The valve's flush trigger, air purge and resin line are switched on and off a remote control panel. Computer control is optional. The valve is compatible with all Venus-Gusmer RTM equipment.

Also new from Venus-Gusmer was an 18-in. portable impregnator for mechanized wet-out and lay-up of woven roving. The new model handles fabric as wide as 18 in. and is designed for taping stringers and bulkheads in boat construction. Like the company's larger impregnators, the new model maintains catalyst percentages in the laminate to |+ or -~0.2%.

Engineering Technology Inc. (Entec) of Salt Lake City introduced a new filament winding machine, the Production Series 10. A 10-spindle machine, the Production Series 10 reportedly can wind at up to 1000 rpm and uses a two-axis tape delivery system.