Multi-layer technologies

Rgure 7.2 shows the design of a thermoelectric gas sensor device manufactured according to planar ceramic multi-layer technology.The heater brings the tip of the sensor to operation temperature by applying a heater voltage,... 

Multi-layer technology for pipes has been on the market for about one and a half years and has been widely accepted for extrusion of large-diameter pipe for sewer ducts. Today, virtually no pipe of this type is produced without a core of foamed PVC between the inner and outer skins. The three-layer structure, in which the central core constitutes about 60% of the total material, reduces the weight of the pipe by about one-third, compared with conventional technology for production of a pipe of the same diameter. The blowing agent is nitrogen, directly metered into the machine as azodicarbonamide. 

Polypropylene (PP) bottles have the advantage that they are inherently hot-fillable (at 85°C) and retortable to 120°C. The bottles are normally extrusion blow-moulded, and can also be made with multi-layering to include barriers against oxygen permeability. This technology is commonly used for sauce bottles and juice products. Since most of the bottles are of an oval shape, product contraction resulting in volume reduction is countered by allowing die bottle to become more oval under the effects of vacuum. 

The multi-layer structure of cartons continues to be an environmental issue. However, much has been done to develop recyclable technology for drinks cartons. One output uses a chipboard-effect material of the type used to make furniture at the other end of the lifecycle is incineration with reclaimed heat. 

Nonlinear polymers in which second harmonic active molecules are incorporated into a polymer matrix offer interesting possibilities for waveguide SHG by virtue of their fabrication technology. The multi-layer films needed for waveguiding can be fabricated by simple spinning techniques already in use for decades in the electronics industry, and systematic calibration of the process al-... 

In the early 1980s, a multitude of patents and patent applications were registered in the field of coextrusion of multi-layer pipes. Meanwhile, a number of pipe products representing a composite of several layers are established products on the market. The technology of the coextruded foam core pipe builds on these developments. The foam core type of PVC plastic pipe today takes the largest volume share of all coextruded foam core products. This product has developed into an important and very competitive alternative for non-pressure applications such as drain pipes, sewer pipes and cable ducts. France has played the role of a pacesetter in this development. Today, over 80% of all pipes for non-pressure applications are produced in the form of foam core pipes in that country. Since the common market realised within the EU is connected with a strong market equalisation tendency, other European countries are following. 

Ilford uses nearly exclusively resin-coated true photobase for their wide format and desktop media. The ink-receiving layers (IRL) are based on proprietary technology and are apphed in a multi-layer photo-like cascade or curtain coating process. Ilford developed ink receiving layers which are based on either polymers (e.g., gelatin CMC, PVA) or microporous layers based on sUica or lanthanum doped boehmite, or a combination of both. ... 

Rapra Technology Ltd has undertaken a detailed investigation into the migration of species from different types of adhesives used with laminated multi-layer materials (Barber et al, 2003). Migration of aromatic amines, BADGE, bisphenol A and polyols were examined. A description of the samples used and a brief summary of some of the results obtained from this analytical work are given below. 

Whereas all conventional thermoplastic fabrication techniques have been successfully employed to convert pellets of HIPS into useful articles, extrusion (film, sheet, profile and multi-layer) and injection molding (solid, structural foam and gas-assist) are the predominant processing technologies. Innovative hardware technologies, in both extrusion and injection molding, have provided means to combine less expensive materials, such as polystyrene, with polymers or structures offering key performance characteristics. 

Abdul S, Poddar SS. A flexible technology for modified release of drugs multi-layered tablets. J Control Release 2004, 7 Jul 97(3) 393-405. 

The above heading has been selected to include all variants which may be now used for both flexible and rigid applications. Whereas previously these may have been introduced under flexibles , film, foils and laminates , etc., the use of new technology such as coextrusions, metallisation and different coating techniques has produced some confusion as to what terminology should be employed, so the word multi-layer may be more appropriate. 

M. Chan. The potential and realization of multi-layers three-dimensional integrated circuit. Int l Solid-State and Integrated-Circuit Technology, 2001, 40 - 45. 

The fast growth in emerging new technologies for starch utilization as a thermoplastic material, such as multi-layered composites, nanocomposites... 

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