Threadlockers fill the space between the threads which prevents vibration loosening. Anaerobic threadlockers are used for metal fasteners; they should not be used on plastics as metal ions are required to cure the material, and they can stress crack plastics. Anaerobic threadlockers (for metal) are available in a variety of strengths and viscosities. Although the need for plastic threadlockers is great, plastic threadlockers are not as common as metal threadlockers. This is likely because, until recently, the options for plastic threadlockers were not ideal.
Cyanoacrylate adhesives are one-part adhesives that cure by reacting with minute traces of moisture on the surface of the material being bonded. Cyanoacrylates are used as plastic threadlockers, but on many plastics, they create a bond that is too strong to be removed. Also, the brittle nature of cyanoacrylates leads to locking failure under impact.
New flexible cyanoacrylates from Permabond solve both issues.
Permabond 743 flexible cyanoacrylate is a very low viscosity, flexible adhesive which can be applied post assembly or at the interface between the fastener and the threads. The low viscosity allows it to wick between the threads very quickly. The soft, flexible nature permits removal on most plastics without destroying the fastener. The high elongation of the product allows much greater impact resistance.