technology | LFTs Right: A laboratory
scale LFT line with glass side feeding at
Fraunhofer ICT in Germany
(LFT-D-CM). The organisations have worked together for over 15 years (parts of Dieffenbacher’s technical centre are actually within the Fraunhofer ICT campus). The LFT-D-CM technology uses a set-up involving two
twin-screw extruders, typically from Leistritz. The first one, typically a Leistritz ZSE, is used to compound various particulate additives into the melt (polypropyl- ene). This exits through a slot die into a shorter ZSG extruder running at low speed, where glass fibres are simultaneously fed, before the mix passes via a very low pressure die onto a conveyor belt feeding the press. Dieffenbacher says this “dual machine” technology ensures optimal compounding and gentle blending of reinforcement fibres, while the use of a highly efficient and precise hydraulic short-stroke press with very short pressure build-up time is key to production of good parts. Manfred Reif, Team Leader for Project Management
at Dieffenbacher, says the company has sold over 70 LFT-D-CM lines, mostly to automotive Tier Ones. The principal application for LFT-D-CM is for underbody shields, front end modules and trays, he says. More than 95% of production is understood to be in glass reinforced polypropylene, although he sees growth in systems based on polyamides. Numerous other twin-screw extruder suppliers
around the world are also looking to enter the LFT market. Taiwan-based Sino-Alloy Machinery is one among them. International representative Donald Stephens says the company is currently carrying out tests on a lab-sized line, but the intention is to offer design, manufacture, installation, commissioning, and after-sales service for full turn-key plants for produc- tion of LFT granules. Sino-Alloy Machinery can pair its PSM50A high
Below: Post impregnation cooling of LFT on a Protec line prior to pelletizing
speed co-rotating twin-screw extruder with a variety of different feeders and a specially designed closed impregnation die. The company’s PSH15B pelletizer is equipped with a long fibre cutter rotor specially designed for this particular application. Italian company Comac says its EBC co-rotating
twin-screw extruders are increasing in popularity for production of various types of glass fibre reinforced compounds, including LFTs. Pietro Zanotto, in the company’s export department, says there is growing interest in Comac lines for D-LFT configurations, mainly due to specific markets and demand for producing higher value added products. “The two most interesting regions for us are Europe and the Far East,” he says.
Sizing up LFTs Fibre manufacturers have developed grades specifically for LFT applications. PPG, for example, has its Tufrov range, which it expanded last year with Tufrov 4589 LFT for polyethylene, a roving that it claims provides a combination of processing and performance properties superior to current products in the marketplace. According to Kevin Richardson, PPG Global Business Manager, LFT Fibre Glass Products, “the tailored thermoplastic chemistry allows for enhanced mechani- cal properties for all LFT processes including tape production. The complete filament spread of this product results in exceptional impregnation and dispersion.” The E glass product is available in various Tex/yield options in filament diameters ranging from 12 to 17 microns. Owens Corning has introduced several new grades
of reinforcement glass fibres for PP LFTs over the past couple of years. Most recent offerings are Performax SE 4849 and SE 4850 Type 30 rovings, featuring improved resistance to fuzz generation, increased lubricity for lower strand tension, reduced strand stiffness for easier splaying, and improved splice tensile strength. The former is suitable for pultrusion-type processes and for D-LFTs, while the latter was specifically developed for D-LFTs. “We are actively developing two additional new reinforcements for LFT PA and for “wire coated” LFTP PP,” says Corey Melvin, Global Product Manager for Long Fibre Thermoplastics Reinforcements. Both are intended
38 COMPOUNDING WORLD | May 2016
www.compoundingworld.com
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
