Q: "We have a small case, molded in two halves, from Ultem (GE or SABIC). Is there an adhesive that will pass the following autoclave profile: 127°C, 50 minutes, steam based?"
A: A few options come to mind. Ultem, or polyetherimide, can be a little difficult to bond to, and autoclaving is fairly aggressive against an adhesive. Dymax 1161-M light-curable adhesive is a one-component medical grade adhesive with some adhesion to Ultem, which can be improved with air plasma treatment or flame treatment. The conditions listed are a little longer than a normal 15-minute autoclave cycle, and approximately 3x. The 1161-M will typically survive 1-3x autoclave cycles, if the bond line is wide enough, (perhaps) a tongue and groove design, and enclosed within the plastic. Large bond gaps or a fillet bond will be more difficult. There are other options out there, but this might be a good starting point.