“I need to attach this 1.58 mm polyethylene to another type of material such as wood-plastic-metal of various types. Any ideas?”
Polyethylene is a polyolefin and very difficult to achieve strong adhesion to. A common method to overcome this issue is to pre-treat the surface via corona discharge, gas plasma, flame treatment, or priming. These methods typically increase the surface energy of the substrate and the potential to adhere to it. Utilizing any of these pre-treatment methods will open up the choice of possible adhesive products. To bond surface-treated polyethylene to wood, plastic, or metal you can use a cyanoacrylate (RX-50 from Pacer, available through DYMAX), epoxy (Master Bond EP21), or polyurethane (Master Bond EP30D12).
The right adhesive choice for you is not only dependent on the dimension, design, and substrates you are trying to assemble, but also the environment the device/item is being subjected to. Is it being used indoors with no contact to moisture or outdoors with consistent contact to water? For a dry environment, a cyanoacrylate might be the right choice, whereas an epoxy might be better for a moist environment.
“We need to bond a Mylar film with a PET backing to extruded ABS sheeting. We are looking for a liquid and/or PSA. The criteria we need to achieve:
• Adhesion for a period exceeding five years
• The finished product will be in high-humidity environments and exposed to fresh/salt water spray
• Temperature variation -20 to 180ºF (or very close)”
A silicone sealant/adhesive (Pt curable) or silicone pressure-sensitive/lamination adhesive would all be good options to evaluate. A PSA like Dow Corning Q2-7406 (solvent based, peroxide cure) would be applied to the Mylar film by draw down bar/myer rod, drive off the solvent at 65oC for two minutes, cure at 150°C for two minutes, and then apply to the ABS. You could also devolatilize the solvent, apply the film and uncured PSA to the ABS, and then cure at 150°C in more of a lamination-type application. If a lower temperature is required, then Platinum-curable DC 7657 & Syl-Off 4000 catalyst could be mixed and then cured between 80-130°C (after driving off the solvent). For a solvent-free option, DC 2013/Syl-Off 4000 would be a good option.
“I have an application where I insert a 6 mm square shaft into a 6 mm + square hole to a depth of 6 mm. I need a product to bond these so the shaft does not pull out axially. There is very little force axially. Torque will be taken care of by the square. This is a veterinary medical instrument that does not stay in the body. Adhesive should be able to withstand 500-600 autoclavings and also be usable in ethylene oxide sterilization. “
To achieve a strong bond between two pieces of stainless steel and withstand 500-600 cycles of autoclaving, the best option would be a two-part or heat-curable epoxy. I would suggest trying Master Bond EP42HTMED, which is a two-component epoxy that cures at room temperature or via heat. Another supplier to contact is Epotec, who also offers medical-grade epoxies that will resist autoclaving and ETO sterilization.
“Which type of cyanoacrylate can be used for bonding skin/tissue together instead of suturing small wounds or incisions? Does DYMAX supply such a material? “
There are four types of cyanoacrylates. Two of them can be used for closing wounds and are available from different suppliers:
- Butyl cyanoacrylate is used to bond skin and close wounds and is available from Henkel (Indermil), Advanced Medical Solutions Group (LiquiBand), and B. Braun (Histoacryl). All versions are FDA approved.
- Octyl cyanoacrylate is a newer-generation cyanoacrylate for bonding skin and closing wounds. It is supposed to provide higher breaking strength and be less irritating to skin than the butyl-type adhesive. This type of cyanoacrylate is available from Adhezion Biomedical (SurgiSeal), Ethicon (Dermabond), and Chemence Medical Products (derma+flex QS). All products are FDA approved.
- Ethyl cyanoacrylate is the most commonly used adhesive for assembly purposes and the type of cyanoacrylate supplied by DYMAX.
- Methyl cyanoacrylate is used for assembly purposes.