Surface embossing

Elimination of gloss by surface embossing has been practiced but requires a separate step and adds cost. Moreover, subsequent abrasion may remove the embossed surface and cause the gloss to reappear (31). 

Wood-grain effects colorants for wood-plastic composites have been commercialized, with recently improved formulations reported by Americhem. These formulations are said to produce deep wood-grain effects for more naturallooking building products, serving as a durable low-cost altemahve to surface embossed graining or laminated films [9-39]. 

Fig. 6.1. Schematic illustration of the manufacturing processes for textured geomembrane surfaces embossing and embossed stracture (1), impingement and impinged texture (2) and co-extrasion and co-extraded texture (3). All three processes are capable of manufacturing double-sided textured geomembranes...

Curved surfaces, embossing, and scoring affect the spectrum of a tablet as positioning is varied, but the effect of such factors can be reduced by the methods just discussed. Natural variations in tablet mass and hardness also affect a tablet s spectrum through baseline shifting. 

Pan W. J., Furniss D., Rowe H., Miller C. A., Loni A., Sewell R, Benson T. M., and Seddon A. B., Fine embossing of chalcogenide glasses First time submicron definition of surface embossed features,/ Non-CrysL Solids, 353,1302-1306 (2007). 

In the case of nonwoven geotextiles made from continuous filaments, a heat process using calendering is most often used. The filament web spread on the feed apron is directed to a calendar where it will be compressed at a high temperature by two heated metal rollers. The heat and pressure cause the filaments to fuse together where they touch in this way, they form a cohesive filament stmcture. Depending on the product required, the calendar can be smooth or have a surface embossing pattern which... 

Sheet can be produced by melt extmsion, but in this case a three-roll stack of quenching roUs is generally used (Fig. 2). More than three roUs may be used where necessary. The roUs may be mounted vertically or horizontally. The web is extmded through a slot die in a thickness close to the desired final thickness. The die is in very close proximity to the first chill roU or chill-roll nip. The web may be cast horizontally directly onto the upper chill roU of the stack as shown (Fig. 2), or it may be extmded into the first nip directly. The roUs quench the sheet and provide the surface polish desired. In some applications, matte or embossed roUs maybe used to impart special surface characteristics for certain functions. Where the utmost in optical (glazing) quality is desired the trend has been to mount the roU stack horizontally. The hot melt is then extmded vertically down into the first nip. This avoids problems associated with sag of a horizontal hot melt no matter how short the distance between die and quench. 

Miscellaneous Types. Various decorative effects have been developed which meet specific aesthetic requirements. These laminates may have special visual appeal, such as gloss finish, deeply embossed textures, and metallic surfaces. They are designed for specific installations and may not be suitable for all apphcations. For this reason, they are not included in these standards. Information concerning thein proper appHcation, properties, and care should be requested from the manufacturer. 

Specific terms have been designated according to the function and composition of various roUs. Steel roUs that impose pressure, transmit heat, and emboss a pattern onto the fabric are known as pattern roUs. Flexible surface roUs that transport the fabric and permit pressure transmission to the fabric are termed bowl roUs or bowls. Bowl roUs are usually larger in diameter than pattern roUs. The material used to make these types of roUs is chosen according to the depth of surface smoothness to be placed on the fabric being calendered, and must be compatible with the pattern roU. Cellulose pulp, cotton, wool, cotton—wool mixtures, com husk, and various polymer materials are used as fillers for the roU surface compound. 

Asphalt-coated glass fiber venting base sheet with fine mineral surfacing on the top side and coarse granules on the bottom side perforated/embossed or not. The coarse granules provide an open, porous channel in the horizontal plane (5,11). 

The surface finish of the specimen may also affect impact behaviour. Machined surfaces usually have tool marks which act as stress concentrations whereas moulded surfaces have a characteristic skin which can offer some protection against crack initiation. If the moulded surface is scratched, then this protection no longer exists. In addition, mouldings occasionally have an embossed surface for decorative effect and tests have shown that this can cause a considerable reduction in impact strength compared to a plain surface. 

Figure 10-158A. Styles of Mueller Temp-Plate heat transfer plates. (1) Double-embossed surface, inflated both sides. Used in immersion applications, using both sides of the heat transfer plate. (2) Single-embossed surface, inflated one side, used for interior tank walls, conveyor beds. (3) Dimpled surface (one side), available MIG plugwelded or resistance spot welded. Used for interior tank walls, conveyor belts. (Used by permission Bui. TP-108-9, 1994. Paul Mueller Company.)...

Nowadays, however, zinc-coated steel sheets, either continuously galvanised or electroplated, are often used as a basis material for overcoating with plastic materials or paints. The coatings are usually applied continuously and have a range of uses both externally and internally. Many surface finishes are obtainable, e.g. plain or embossed, and in an extensive range of colours, to suit almost any requirement . 

I. Baudelot coolers (see Figures 7.7 and 7.8a). The evaporator stands above a collection tank, and the water runs down the outside surface in a thin layer. Evaporator construction can be pipe coils or embossed plates. The latter are now usually of stainless steel, to avoid corrosion troubles. Evaporators maybe flooded or dry expansion. During operation, a Baudelot cooler... 

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