VISIOMER® Specialty Methacrylates for Plastics & rubber
Methacrylate monomers are used in the production and modification of a wide variety of polymers – mainly in cast sheet, graft copolymers as impact modifiers for thermoplastics.
Further application fields include artificial marble, PVC modifiers and PVC plastisols. Molding compounds based on unsaturated polyester resins may also contain multifunctional methacrylates as crosslinking agents.
Artificial marbles based on methacrylates are widely used as materials for kitchen countertops, wash basins, dressing tables, bathtubs, tabletops, walls, interior fixtures, etc. They combine outstanding aesthetics and high-end texture with excellent durability. MMA is the most widely used monomer in this application field. Besides MMA, specialty methacrylate monomer such as VISIOMER® IBOMA can impart additional properties, such as excellent dimension stability and hot water resistance to the finished products. Multifunctional methacrylates such as VISIOMER® 1,3-BDDMA, 1,4-BDDMA EGDMA, TRGDMA, and TMPTMA are used to enhance thermal stability and other mechanical properties of cast plastic sheets.
PVC plastisols are PVC powder emulsions in plasticizers, e.g. aromatic or aliphatic dicarbonic esters. Depending on the application envisaged and properties required, PVC/plasticizer ratios vary between 80:20 and 50:50. Without additives, PVC plastisols show only moderate adhesion to polar substrates, such as metal. Partially substituting the plasticizer with multifunctional methacrylates causes a substantial improvement in plastisol adhesion to these substrates. Moreover, peroxides added for plastisol gelation effectively initiate polymerization of the multifunctional methacrylates. This in turn leads to increased hardness and higher tensile strength in the end product. Shore hardness also depends on the type of multifunctional methacrylate used. It decreases in this order by up to 40% at the same monomer content: VISIOMER® 1,3-BDDMA > EGDMA > TRGDMA > PEG 200 DMA. The main applications for PVC plastisols containing multifunctional methacrylates as adhesion promoters and hardeners include the following: anti-noise compounds, car underseals, finish compounds for PVC flooring, and coil coatings.
PMMA molding compounds are mainly used in the car industry for the production of headlamps, taillights and transparent panes for dashboards as well as household appliances, optical media (DVDs, lenses) and electronics. They are used in illuminated advertising applications and shop interior displays. PMMA sanitary ware is suitable for the production of bathtubs and shower trays. MMA is the principal monomer used for acrylic plastic casting. Multifunctional methacrylates, such as VISIOMER® 1,3-BDDMA, 1,4-BDDMA , EGDMA, PEG200DMA and TRGDMA, are used in smaller quantities to enhance thermostability and other mechanical properties of cast plastic sheets.
Crosslinking agents traditionally used for vulcanization, such as sulfur donors, only work with unsaturated polymers. Saturated elastomer polymers need to be crosslinked by means of energy-rich radiation or peroxides, which can also be used for crosslinking unsaturated polymers.
Compared to sulfur vulcanization, peroxide or radiation crosslinked technology improves thermal stability and ozone resistance in the end product. Using co-agents in conjunction with peroxide to cure elastomers makes it possible to reduce the content of costly peroxides. This way, crosslinking density and curing speed can be accelerated as well.
Those co-agents are typically multifunctional monomers that are highly reactive in the presence of free radicals and graft to elastomer chains, forming a complex crosslinked network. Depending on the desired crosslinking density, they are typically used in quantities of 0.5 to 5 wt. % in the polymer.
VISIOMER® 1,4 BDDMA, VISIOMER® EGDMA and VISIOMER® TMPTMA are, co-agents for rubber cross-linking, can replace volatile plastisizers in plastisols or improve mechanical properties of plastic films and artificial marble resins.