New Adhesives Compete With Fasteners, Welding
The ASSEMBLY Show featured not only the machinery needed to assemble parts, but also the supplies, such as fasteners and adhesives. It may not be as “sexy” as a robot or a high-speed automated assembly system, but one of the most interesting new products that was introduced at the show last fall was actually an adhesive.
Henkel Corp. introduced Loctite 4090, a “hybrid adhesive” that combines the strength of an epoxy with the speed of a cyanoacrylate. Versatile enough to be used in both indoor and outdoor applications, the new adhesive greatly expands the capabilities of cyanoacrylates, especially in applications where traditional instant adhesives offer too little strength or are too brittle.
The adhesive produces high-strength bonds on a variety of substrates, including metals, most plastics and rubbers, and it can be used to bond dissimilar materials. A high-viscosity gel, the adhesive fixtures in 3 to 5 minutes when applied to gaps of 0.2 inch or less. The low-blooming product is ideal for appearance-sensitive applications. Because it resists moisture, impact, vibration, UV light and temperatures of up to 300 F, the adhesive is an excellent choice for outdoor and marine applications.
Henkel was one of at least 13 adhesive suppliers exhibiting at the show. In addition, there were at least 14 companies displaying equipment to dispense and cure adhesives. The following are just some of the new adhesives seen on the show floor.
Modified Epoxy Sealants
Permabond Engineering Adhesives will be displaying an array of anaerobic adhesives, cyanoacrylates, epoxies, structural acrylics, polyurethanes, and UV light curable adhesives and coatings.
Among the company’s newest materials are two modified epoxy sealants, MT382 and MT3821, that form strong bonds with many plastics, wood, metals and composites. MT382 is self-leveling and MT3821 is nonflowing.
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Both cure to form durable, strong, flexible bonds that are weather resistant. They absorb and distribute stress caused by thermal expansion, broadening the range of material choices for engineers.
Featuring 2-to-1 mix ratio formulas, these UV-resistant sealants remain flexible down to -40 F and can withstand temperatures up to 400 F for brief periods. Their shrinkage is low enough that thin panels can be bonded with no read-through. Elongation is 100 to 200 percent.
Epoxy Cures Quickly
Hernon Manufacturing Inc. will be showing anaerobic adhesives, cyanoacrylates, epoxies, acrylics, methacrylates, UV and visible light curing adhesives, and customized dispensing and curing technologies.
For example, Hernon Tuffbond 305 is a modified epoxy adhesive that cures in approximately 4 minutes at room temperature. Specially formulated for rapid, in-line assembly of loud speakers, the epoxy resists moisture, chemicals and heat. It is also recommended for bonding metals, wood and ceramics, and it can be used for potting and encapsulation of electrical and electronic components.
Part A has a viscosity of 10,000 to 16,000 centipoise at 25 C; part B has a viscosity of 12,000 to 18,000 centipoise. The mix ratio is 1-to-1. It has a working life of 4 to 7 minutes at a temperature of 22 C.
When cured, it has a Shore D durometer hardness rating 80 to 90, and resists temperatures of -54 to 82 C. Shear strength on aluminum lap-shear specimens exceeds 2,400 psi after 24 hours and 2,600 psi after 30 days.
Adhesive for Catheter Assembly
Dymax Corp. has introduced MD 215-CTH-UR-SC, an LED-curable adhesive for assembling next-generation catheter designs using Nylon 12 and PEBA.
Formulated with new Encompass technology that combines the company’s See-Cure color change and Ultra-Red fluorescing technologies, the adhesive provides secure bonds with the added benefits of easy cure confirmation and post-cure bond-line inspection. The adhesive is ideal for a number of catheter assembly applications, including bonding the lumen to the balloon or hub, marker band assembly, and manifold bond joints.
While in an uncured state, this adhesive is blue in color for easy verification of placement. As the product cures with sufficient exposure to UV light, its blue color transitions to colorless and provides obvious visual confirmation that the adhesive is fully cured and the bond site is secure.
The adhesive fluoresces bright red under low-intensity black light (365 nanometer wavelength), contrasting extremely well on plastics that naturally fluoresce blue in color (like PVC). This allows manufacturers to incorporate automated or manual quality inspection to verify complete and accurate placement of the adhesive after cure.
Silicone Adhesive and Sealant for RV Assembly
Novagard Solutions formulates single-component, neutral-cure, oxime silicone adhesives and sealants for a variety of industrial applications.
The company has recently introduced a new material, Novaflex RV, for bonding and sealing applications in the manufacture of truck trailers, truck bodies, cargo containers, travel trailers, manufactured housing, and recreational vehicles. It has excellent expansion and contraction properties and will withstand joint movement and temperature changes associated with transporting manufactured units.
Permanently flexible, this solvent-free, low-odor silicone adhesive produces weather-tight seals and adheres well to most building substrates. It resists mold and mildew, and it’s AAMA-verified for all window installations. It can be used on interior and external surfaces.
Easily dispensed at all temperatures, it cures tack-free in 10 minutes and cures completely in 48 hours. Removable tips ensure no wasted material.
Eco-Friendly Adhesive Dots
RS Industrial Inc. will be showing ECO-Squares, the first-ever adhesive dots conscientiously developed from biodegradable materials.
“Meeting market expectation for a biodegradable adhesive dot has been a central focus of RS Industrial,” says Matthew Ingerson, sustainability advisor at RS Industrial. “As our customers focus on having biodegradable labels, bottles and packaging, we want to ensure their adhesive is just as environmentally responsible.”
The squares create less waste through biodegradation and are formulated in a high tack level, making it possible for customers to enjoy high-performance adhesion without compromising the environment. During 34 days of bio-methane potential testing, 35 percent biodegradation of ECO-Squares was shown to occur in an anaerobic environment.
Unlike hot melts, ECO-Squares do not require heat for application. This reduces the risk of burns and saves energy costs.
Fast-Setting Epoxy
Star Technology has introduced a fast-setting epoxy, called ER1005, for bonding, potting or tacking almost anything. The epoxy has a convenient one-to-one mix ratio and cures in about five minutes.
Star Technology can package the epoxy into convenient, resealable 50-milliliter mix-packs for easy dispensing. Mixing guns and static mixers are also available.