Strictly-Extrusion

Berstorff, Germany, has fundamentally reworked its machine concept for processing of solid silicone rubber. At the heart of the new concept is a hot air oven, where re-circulating air can be used in addition to the electrical infrared energy to achieve vulcanisation. Upstream of the hot air oven is a modular-design shock oven and a cold-feed extruder. Silicone rubber tubes and profiles of widely varying Shore hardness values can be produced for use in many different applications. Each of the three treatment chambers of the Berstorff hot air oven has an integral air circulation system. The energy produced by ceramic black-body radiator units is continuously fed to the vulcanisation process by means of circulating air. Only 20% of fresh air needs to be introduced into the oven and only 20% of the process air is exhausted to remove any by-products that might be created during vulcanisation. This saves energy and at the same time increases the efficiency of the vulcanisation.

The 18th World Congress “Speciality Plastic Films 2002″ will be held in Zürich, Switzerland, from 29 to 30 October 2002. Maack Business Services is organising the conference on topics such as global film markets and developments for food and non-foold applications. Contacts: Fax 0041-1- 7811569; e-mail MBSpolymer@bluewin.ch

Extrusion Dies: New Ultracoat slot die

Advances in precision and uniformity achieved with a new generation of Ultracoat (R) slot dies enable web converters to apply consistent, distortion-free fluid coatings even at very low coat weights or onto very thin substrates, it was announced today by Extrusion Dies, Inc. (EDI),USA.

Key to the improvements is a new die design. As in standard dies, the wet or wiping lip (the lip passed by the substrate after coating has been applied) is on the upper section of the die; the profile and surface properties of this lip play a critical role in coating quality and consistency. Unlike standard dies, however, EDI’s new Ultracoat V die has the flexible lip and lip-adjusting system (used to change the size of the exit gap) on the lower section. This prevents the flexible lip from interfering with wet-lip functions and causing distortions in the coating, according to Jeffrey Seckora, EDI product manager for coating dies.

Kiefel Extrusion, Germany, a technology leader in the area of blown film lines, has already sold 20 of its new Kirion generation machines, introduced for the first time at the K 2001 fair, worldwide. Against this background, Kiefel Extrusion booked an above average order intake, contrary to the general market trend in plastics machinery and is well above its operative plan. One of the company objectives, which is aimed at worldwide expansion and an increase in market share, has now been impressively confirmed. Several of the lines sold, which have a variety of different configurations — from HDPE monolayer lines up to complex barrier film lines with working widths up to a maximum of 3,000 mm — have already been successfully installed, accepted and produce with the highest customer satisfaction.

Flexible packaging giant Bemis Co. has agreed to sell its global pressure-sensitive materials business, known as MACtac, to Finland’s UPM-Kymmene for US$420 million. In a separate transaction, Bemis will acquire the Walki Films division of UPM-Kymmene, a Helsinki-based paper products supplier, for US$70 million. The sales are expected to be finalized by year’s end. Acquisition of Walki Films, which makes high-barrier vacuum and modified-atmosphere packaging for meat, cheese, and other fresh foods, will more than double the level of Bemis’ flexible packaging sales in Europe, Bemis says. Walki’s reported annual sales are now about US$120 million. The division has two manufacturing plants, located in Valkeakoski, Finland and Epernon, France, which Bemis says it will continue to operate.
Bemis has recently been moving to bolster the size and scope of its flexible packaging operations. Earlier this year the company purchased DuPont’s Clysar shrink-film business for $142 million. Last year, Bemis acquired Duralam Inc., an Appleton, WI, manufacturer of barrier films for food packaging, for a reported $69 million.

Hutchinson, one of the worlds leading concerns in the elastomer processing sector has recently placed an order with Berstorff, Germany, for a complete roller-head line for the manufacture of drive v-belts. The line consists of a GE 150 KS x 16D high-performance rubber extruder, a 2-roll calender and the associated downstream equipment. The core machine components of a Berstorff roller-head line include an extrusion unit consisting of a high-performance GE rubber extruder, drive, temperature control and hydraulics, with all the components mounted on a common baseplate; a wide slot die, its purpose is to distribute the extrudate from the screw diameter to the specified working width and to provide the calender with a constant extrudate feed; and a two-roll rubber calendar, which forms the material into the sheet and calibrates it to the closest tolerances. The patented hydraulic adjusting unit enables the calender gap to be precisely and rapidly re-set. Berstorff also delivers the matching downstream components such as wind-ups, cooling unit, and doubling and cutting equipment.

German based Windmöller and Hölscher, an international market leader in the field of machinery and equipment for the flexible packaging industry, has recently introduced a newly developed automatic roll handling system for increased printing press productivity, when handling small slit rolls primarily intended for use with automatic packaging systems. The Corematic lends itself to use downstream of both flexographic and gravure printing presses and permits the printed web to be slit and wound in a single pass, resulting in maximum production speeds, regardless of the web length being rewound and dispensing with separate slitting. The fully automatic roll handling unit removes the finished rolls from the winder of the printing press for transfer to downstream handling systems. The shafts are automatically removed from the rolls, recored and prepared for splicing and are immediately ready for the next winding cycle. Running at maximum speed, very short web lengths of up to 1000 metres can be wound up at cycle times of less than three minutes. The Corematic is designed to handle up to four slit rolls of diameters between 200 and 600 mm, with a maximum roll width of 300 mm.

Extruded building products manufacturer, Everwhite Plastics, UK, is investing GBP 2.1m over the next three years to treble the size of its premises and increase manufacturing capacity. GBP 600,000 of the investment is being provided by the National Assembly of Wales.Everwhite manufactures more than 40 types of rigid PVC fascia, soffit and cladding boards, window sills and architraves. It employs 75 staff and expects to increase sales of GBP 6.5m in 2001 to GBP 8m this year, assisted by a recent deal to supply extrusions to leading Belgian manufacturer Deceuninck, Belgium. By the end of the three-year investment programme turnover is forecast to have reached GBP 15m. In addition to expanding its extrusion activities from its existing 10 lines, Everwhite plans to develop an in-house tooling business. This will speed-up delivery times for tools internally and provide a tooling service to external customers. It also is establishing a separate company to carry out machining work and scrap recycling. Future options include entry into the guttering and downpipe market.

Syncroflow tooling from Guill Tool and Engineering Co. Inc., USA, can extrude plastics and rubber simultaneously. The plastic can be run on the inside or the outside later, since Syncroflow tooling is designed with a barrier that insulates and separates the extruded materials from each other. The extra layer facilitates the processing of two materials with widely differing processing temperatures. Syncroflow is available in diameters from one-eighth of an inch to 6 inches. By using a single die for both rubber and plastics, instead of a normal two-step process or in tandem, Syncroflow provides excellent adhesion of materials in their molten state. Also, there is less chance of contaminants being trapped between the layers of plastics and rubber.

Krauss-Maffei, Germany, is showcasing a new generation of counter-rotating twin-screw extruders with 36 L/D processing units, incorporating a radically new processing technology for PVC. The new 36 L/D extruders have two venting zones. In this double-venting process, the dry blend is fed to the processing unit, where it is compressed and preheated as usual. By the time it reaches the first venting zone, after 15 D, the material is compressed, but still powdery. In this zone, air that entered along with the material is allowed to escape via two long vents in the barrel. Then follows a further compression phase before the melt reaches the second venting zone, where a vacuum extraction system removes the remaining air and volatile constituents. The ratio of mechanical energy to heat energy applied to the melt is thus significantly reduced. As a result, although 36 L/D machines have 17% higher output, compression values in the restricted flow zone are much lower than in 26 L/D extruders. This innovation significantly reduces wear on the screws and barrel.