Methyl methacrylate adhesive
Methyl methacrylate adhesives are two-component reaction adhesives in which the monomer used, methyl methacrylate - the methyl ester of methacrylic acid - is polymerized by a radical chain reaction .
To start the polymerization reaction , a reactive radical is required, which usually arises from a peroxide when an accelerator (usually an amine ) is added to it. This means that ultimately you only need the 2K system to start the radical reaction at room temperature, in which the peroxide and accelerator come together and form the starting radicals.
It is therefore possible to market both the peroxide in the methyl methacrylate monomer as one component and the accelerator dissolved in the base monomer as a second component. Mixing both components initiates the radical chain reaction and the adhesive hardens.
Another variant combines the entire monomer and the accelerator in one component and uses only the peroxide as the second component (often diluted with a solvent for easier processing). This means that the previous mixing of the two components - and the associated pot life - can be dispensed with if the main component is applied to one part and the peroxide is applied to the other part. By joining the surfaces, the two components come into contact and the radical reaction starts.
Practical use
Methyl methacrylate adhesives are mainly used for the structural bonding of metals and plastics. For some time now there have been specially formulated systems from various manufacturers that enable high-strength bonding even of low-energy plastics such as B. allow polyethylene or polypropylene without a special surface treatment would be required. Due to allergic reactions, methyl methacrylate is either banned or warned against use in nail modeling agents in some countries outside the EU.