Solvent bonding typically works with amorphous thermoplastics such as PVC, ABS, PC, PMMA, and PS. Pebax belongs to the family of thermoplastic elastomers and generally offers good resistance to solvents. Depending on its grade and softness, it may swell in certain solvents but will not behave like amorphous thermoplastics do. If you replace the ABS with Pebax, you need to switch to a new bonding process. UV-light curable adhesives are a good option, and I would recommend that you try Dymax medical-grade adhesives 204-CTH-F and 209-CTH. They both adhere well to PVC, Pebax, and several other commonly used plastics.

Without knowing what the plastic is, its size, and what type of environment the application will be exposed to, it is difficult to make an accurate recommendation. However, based on what you have provided, we would recommend looking at a cyanoacrylate, or instant adhesive.

I would suggest that you start trials with the Dymax 1180-M family. This series of products cures with UV and visible light, fluoresces for quality purposes, and is available in several viscosities. The adhesives are designed for bonding metal cannulae or wires into plastic parts made of polycarbonate, ABS, or other plastics.

For your first application, I would recommend 1180-M-UR, which has a nominal wicking-grade viscosity of 150 cp and fluoresces bright red.

For applications 2 and 3, Dymax 1180-M-T-UR could be a good candidate, with a nominal viscosity of 6,000 cp. This product also fluoresces red.

The optimum gap size for UV bonding applications in general is 0.002 to 0.006 in. In catheter bonding applications in which a Pebax tube is bonded into a polycarbonate Y-connector, we often see bond gaps of around 0.1 mm per side. The Dymax 204-CTH-F family is a good choice for this type of application and substrate combination. Another product to consider is 208-CTH-F.

A few chemicals will dissolve or swell 1184-M-T or any other light-curable acrylate, such as dichloromethane, MEK, or acetone. It may take some time for the solvent to migrate all the way in between the laminate, so the time depends on the size of your parts. A more gentle method is to soak the lenses in isopropyl alcohol (IPA) or even use warm IPA with the help of an ultrasonic cleaner. I would also suggest this method if your lenses are made of plastic, since plastic can withstand IPA but not other, more aggressive solvents.

Based on your choice of substrates—ceramic and stainless steel—and the room-temperature requirements, I would recommend looking at a cyanoacrylate (instant adhesive) or a two-part epoxy. Cyanoacrylates are available in very low viscosities. You may want to evaluate the Dymax 222 series. Low-viscosity epoxies are rare. One option could be two-part epoxy 301 from EPO-TEK, which has a viscosity of 100 to 200 cP.

For this type of application, I would suggest trying Dymax 1161-M. This adhesive cures using UV and visible light and exhibits good adhesion to ABS and PUR. It also fluoresces blue for quality purposes. If you are interested in our patented color-change technology, I would recommend trying See-Cure 1201-M-SC. This product is blue and therefore helps the user verify whether enough adhesive has been dispensed. Upon exposure to UV/visible light, it turns clear to confirm that the cure is complete.

Dymax provides a selection of adhesives that have been tested according to ISO 10993 standards and are biocompatible in the cured stage. However, such medical-grade materials are typically not needed for temporary masking applications in which the light-curing resin acts as a manufacturing aid only and will be removed before the end product is finalized.

To achieve better wettability, the dyne level of the substrate must typically be higher than that of the adhesive. Our adhesive chemistries (polyurethane-modified acrylates) have a dyne level of about 30 to 47. We haven’t come across any issues in which the dyne level of the substrate has been too high.

One option is Dymax’s 6-625-SV01-RevA, a flexible light-curing adhesive with secondary heat-cure and activator-cure capabilities for shadowed areas. Its high viscosity of 10,000 cps also enables it to be dispensed from the outside and act as an edge-bonding material.