Lamellar mold

Direct Tooling So-called lamellar molds are made from steel with the layer laminate processes. They quickly create volume, but must be machined due to the surfaces, and are also very limited in their complexity. For metal parts, spreading film will also be used without reworking. 

Returning now to composition B, in which the PS block distribution is less severe than in C, we note that evidently both rod-like and lamellar morphologies are about equally probable. The morphologies shown in Figures 7 and 8 were obtained on presumably identically prepared samples they appear to be the result of small adventitious variations in molding technique and/or thermal history. The data of Table II, which... 

With this technology a substantially improved surface quality can be achieved of injection-molded parts containing lamellar pigments and fibers. 

In a practical fabrication method, such as injection molding, the mold temperature affects the degree of crystallinity, Xc, of SPS and the morphology [35]. When neat SPS is molded at high mold temperatures, a well developed lamellar structure is observed, and macroscopically spherulites are observed (Figure 18.14), and Xc stays constant across the whole cross-section of the molded part (Figure 18.15). 

In contrast, when SPS is molded at low mold temperatures far below the Tg, crystallization of SPS is restricted at the surface owing to fast cooling, resulting in a lower Xc and a poorly developed crystalline lamellar structure at the surface. However, in the center of the molded parts, spherulites are formed because the slower cooling allows the crystallization of SPS. The Xc profile across the cross-section is very different from what was molded at high mold... 

If so, then PE chains had to exist in the PP phase to start with, i.e., under high shear rate in injection molding machine PP and PE could be locally miscible. Upon removal of the shear field the PE chains crystallized in PP-rich matrix. Also note that in the PE phase, there are the highly disordered regions in which normal PE lamellar growth may be prevented by the presence of PP chains as impurities. This implies that shear-induced mixing took place in the PE-rich phase as well. 

LameUar Injection Molding Injection molding of individual fliermoplastics or their blends, e.g., with liquid-erystal polymers, that produees a lamellar (platelike crys-talUte) skin texture of the molding for decorative purposes or enhanced surface properties. 

Rio Tlnto has also looked at how very fine lamellar talcs allow thtn-waH blow-molded HDPE bottles and packaging. Here, extra fine 1- to 2-itm Luzenac talc reportedly stiffens and strengthens the resin efficiently without excessively reducing... 

Mica flakes embedded in a polymer and properly oriented in a plane can provide a tortuous path to vapors and liquids, similarly to the natural composites shown in Figure 1.1. Barrier properties can be imparted in blow-molded containers, packaging films, and corrosion-resistant coatings not only by mica but also by other impermeable lamellar fillers, including glass flakes, talc, and nanoclays. In blown LDPE film, the addition of 10% mica was found to reduce the oxygen permeabihty from 4.16 to 3.03 Barrer [37]. Assuming an impermeable, fully oriented lamellar filler, Eq. (8.1), [38] maybe used to predict the composite permeability. Pc, perpendicularly to the filler plane as a function of the matrix permeability, P , filler volume fraction, V(, matrix volume fraction, V , and filler aspect ratio a... 

Hyperfom HPN 210 M is a new nucleating agent for injection molded high-density polyethylene apphcations. It improves mechanical performance to the levels approaching those of polypropylene impact copolymers. It increases stiffness by up to 50%, heat distortion temperature by 10-40°C, and productivity. It has ability to create lamellar crystal orientation of PE in the polymer flow direction reducing shrinkage. ... 

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