Discovered during the 19th century, and industrialised in the first half of the 20th century, methacrylates form a family of monomers comprising methacrylic acid (MAA) and its esters derivatives.
Methacrylates are used as building blocks to make a wide range of polymers. These polymers are then used as raw materials or components in the manufacture of a wide range of formulations or objects that we use in our everyday life, especially when stability, durability, hardness and scratch resistance are needed. Today, it is estimated that more than three million tons of methacrylates are produced and transformed every year in the world
Methyl methacrylate (MMA) is by far the most produced methacrylate monomer. Its versatility allows it to be used to produce a pure homopolymer (poly-methyl methacrylate or acrylic glas - PMMA) or, in combination with other monomers, to obtain a series of polymers with various and valuable properties. Other methacrylate monomers are produced by using MMA as a key raw material.
MMA can be manufactured using different industrial processes based either on ethylene (C2), Ppopylene (C3) or isobutylene (C4) petrochemical feedstock. In Europe, MMA is industrially produced from acetone cyanohydrin (ACH), itself obtained from acetone (C3) using a process known as the ACH Process.
The main applications of MMA are:
- PMMA also called ‘acrylic glass’ is a highly transparent long lasting plastic which is used in many end products and appliances where it stays for a long time with unchanged properties. Hardly any other plastic can provide these unrivalled properties (optical transparency, stability against sunlight and air-oxidation, no discoloration). Of specific interest is the ability of PMMA to split back into its monomer under suitable conditions (Back-cracking) thereby offering excellent recycling opportunities.
In the form of pellets or beads, PMMA can be moulded into an almost infinite range of end use products such as: rear-lights and instrument clusters for vehicles, appliances and lenses for glasses.
PMMA in the form of sheets, affords shatter resistant panels for building windows, skylights, bullet proof security barriers, signs & displays, sanitary ware (bathtubs), LCD screens, furniture and many other applications.
PMMA sheets can be produced as cast sheets (direct polymerisation of MMA) or as extruded sheets using molten PMMA beads or pellets as starting material.
- Coating Polymers (or Coating Resins) made based on MMA and other co-monomers like butyl methacrylate, butyl acrylate and some other (meth)acrylates provide outstanding stability against environmental conditions Therefore they are preferred for long lasting high quality applications like protective coatings highly resilient to weather, sunlight and other factors that can cause failure of other types of coatings. This durable property is important in all applications and contributes positively to the reduction of the (sustainability) footprint of these paints and coatings.
Relevant examples are residential, road-marking and industrial paints as well as powder coatings and inks. Some coating systems are also made of formulations that are directly polymerised on site. Methacrylates provide access to end use coatings that can be applied with reduced emissions of volatile organic compounds (VOCs).
- Other methacrylates:
MMA is a raw material for the manufacture of other methacrylates. These derivatives include ethyl methacrylate (EMA), butyl methacrylate (BMA) and 2-ethyl hexyl methacrylate (2-EHMA) which are mainly found in various types of coating polymers or formulations to which they bring some unique properties. Methacrylic acid (MAA) is used as a chemical intermediate as well as in the manufacture of coating polymers, construction chemicals and textile applications.
Because of the wide array of valuable properties it affords, MMA –often in combination with other methacrylates- can be used in many other applications, notably as plastics modifiers and processing aids, medical equipment and dental objects (fillings, dentures, bridges, dental prosthetics). It is a key ingredient in the manufacture of artificial marble and is also found in the composition of products adding value to several other industries including electronics, paper, leather, floor polishes or adhesives and sealants.