additives | Coupling agents Silicones ease WPC processing
In addition to coupling agents, additives such as lubricants and processing aids can also improve processing and properties WPC production. In collaboration with the Wood Competence Center at Linz in Austria, Wacker has developed processing aids for WPC containing 50 to 75% wood fibres in polymers such as PE, PP, or PVC. The company’s Genioplast additives, which were on display at K 2016, contain thermoplastic silicone elastomers that act as lubricants and reduce internal and external friction during extrusion. The additives are supplied as ready-to-use mixtures in PP and PE. WPC parts using the additive have higher impact strength and flexural toughness and are said to be more resistant to weathering. ❙
www.wacker.com
Wacker’s thermoplastic silicone-based Genioplast lubricants improve processing of WPCs Mixing is key for optimizing any coupling agent
performance in a compound. “Uniform distribution before the melt phase and high specific energy input to create maximum shear in the melt are needed for complete coupling at the filler-polymer interphase,” says Monte. “A common mistake made in test evalua- tions is to not lower temperatures compared to the control, as one must compound to equivalent torque, rather than temperature sets; work energy is defined as the area under the plot of torque vs. time.” 3M is studying surface modification of its boron nitride (BN) Cooling Fillers. Compatibilising the interface between BN particles and the matrix polymer should improve dispersion, processability, and compos- ite properties, explained Kristi Gangelhoff, Advanced Application Development Engineer in 3M’s Advanced Materials Division, in a presentation at AMI’s Conductive Plastics conference (held in September 2016 in Philadelphia, US). At the same conference, Péter Sebö, market
development manager at HPF The Mineral Engineers, a division of the Quarzwerke Group, described the company’s Silatherm aluminosilicate mineral fillers for providing thermal conductivity with electrical insulation and noted that they can be surface treated with various types of silanes depending on the intended matrix. Special coatings are used for viscosity reduction or for making the surface hydrophobic, which enables better incorporation into the polymer matrix. Gelest’s newly introduced Sivate A200 is a propri-
etary combination of a cyclic azasilane with an acrylate functional silane that reacts with more than three times as many hydroxyl groups as conventional ethoxy silanes and has a reaction speed more than 100 times faster than conventional silanes, providing immediate adhesion. The product was designed for thermosets (for
50 COMPOUNDING WORLD | November 2016
example, as a coupling agent for light-cured acrylic nanocomposites or an adhesion promoter for high- speed UV acrylated urethane cure systems), but Gelest says it may be used in thermoplastics on a limited basis in engineering resins (e.g., polyamide) or polyolefin copolymers of PP/acrylate or PP/maleic anhydride.
Nanomaterial modifiers Coupling agents or surface treatments, chosen for compatibility with the matrix polymer, can be used to improve bonding of carbon nanotubes (CNT), primarily to improve mechanical and fatigue properties, says Tushar Shah, CTO at Applied Nanostructured Solutions (ANS). “Polyethylene glycol works well with PE and PP, and polyurethanes work well with PC, PC/ABS, and nylons,” says Shah. ANS produces CNT flakes and chopped fibres impregnated with CNT flake. The company uses 1-3% of a coupling agent with its CNT flakes to bind the flake and increase its density for better handling during compounding, as required by the US EPA for safe handling. ANS considered surface treatment methods, such as cold plasma, but says adding coupling agents during melt compounding is an easier solution (and one familiar to compounders).
Click on the links for more information: ❙
www.michelman.com ❙
www.byk.com ❙
www.brueggemann.com ❙
www.arkema.com (
www.lotader.com) ❙
www.addivant.com ❙
www.4kenrich.com ❙
www.3m.com ❙
www.hpfminerals.com ❙
www.gelest.com ❙
www.appliednanostructuredsolutions.com
www.compoundingworld.com
PHOTO: WACKER
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98