Crude acrylic acid has traditionally been used as the raw material for acrylate esters; methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate. These bulk acrylates were used to produce solvent-based acrylic resins but environmental concerns over solvent use led to the development of water-based acrylics. Applications for water-based acrylic acid (glacials) are primarily in decorative, masonry and industrial coatings, but other uses include adhesives, paper and leather coatings, polishes, carpet backing compounds and tablet coatings. Smaller volumes of acrylic acid are used in polyacrylates which are utilized as thickeners, dispersants and rheology controllers. Glacial acrylic acid is also employed as a co-monomer with acrylamide in anionic polyacrylamide and to produce hydroxyacrylates for use in industrial coating formulations.
From the mid-1980s, two new applications – super absorbent polymers (SAPs) and detergent polymers – have emerged, accounting now for nearly 40 percent of world glacial acrylic acid consumption. SAPs are cross-linked polyacrylates with the ability to absorb and retain more than 100 times their own weight in liquid.
Detergent polymers are essentially homopolymer polyacrylates and copolymers of polyacrylic acid and maleic anhydride that can be used with both zeolites and phosphates in washing powder formulations. They grew strongly in western Europe from the mid-1980s as phosphate-based detergents were phased out, and more recently, their use in the US has increased. However, the move to compact formulations in washing powders and a slowdown in phosphate replacement has diminished the growth of these polymers.
Acrylate esters are used in the manufacture of surface coatings/paints and resins, adhesives and plastics, dispersions and in some cases paper. They are readily polymerised if exposed in water, to form a latex (a dispersion of solid particles in water) such as latex paints. An associated product is methyl methacrylate. Acrylate esters are made from the reaction of an alcohol such as methyl to an acid such as acrylic acid. This process is called esterification.
Commodity acrylate esters are butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), ethyl acrylate (EA) and methyl acrylate (MA), in order of decreasing importance. Speciality acrylate esters are made from isobutanol, isooctyl alcohol and several polyols such as hydroxyalkyl, alkylalkanolamine. They are manufactured in minor quantities to produce specialty polymeric materials.
Major commercial acrylates are formed from the following alcohols: butanol, isobutanol, 2 ethyl hexanol, ethanol and methanol.
Acrylate esters are sold by roadcar or iso-container in liquid form or drums. They are colourless liquids with acrid odours, and are traded as technical grade (99% purity). MA & EA are toxic enough to require a hazardous shipping label, while BA and 2EHA are considered safe.
ICIS pricing quotes acrylate esters in Europe, Asia-Pacific and the US.
To find out moreAcrylic Acid-Acrylate Esters Methodology January 2013