Heat-sealing behavior

General Description Ticona Topas are amorphous, glass-clear copolymers of ethylene and norbomene. Ticona Topas cyclic olefin copolymers (COC) form strikingly clear films. When blended with polyethylene (PE), they enhance the stiffness and heat-seal behavior of blown and cast films and offer high moisture barrier, clarity, and stiflfiiess. The Tieona Topas product line features several grades differentiated by heat deflection temperatures ranging from 80° to 18o°c.[ioi5]... 

It is interesting to note here that with respect to heat-sealing behavior, some research indicates that a primary effect of surface pretreatments such as corona on... 

Syndiotactic PP is a thermoplastic with a slightly lower melting point (150-155 °C), lower crystallization rate, and higher flexibility (elastic modulus ca. 500) than iPP. It also has lower density, lower heat sealing temperature, but also better impact properties and better transparency. One of the difficult aspects of sPP as a material, but a great playground for polymer chemists and physicists, is its polymorphic behavior sPP has complex thermal properties and... 

Figure 8 shows the heat of fusion of the heat-sealed parts prepared at different heat-sealing temperatures. An increase in the heat of fusion is evident with increasing heat-sealing temperature, which peaked of at 140 C, thereafter a drastic drop in heat of fusion was observed. At this peak, the heat-seal temperature is still far from the T of OPP, hence the crystalhnity is preserved. At higher heat-seal temperatures, the orientation in OPP starts to relax while crystalhne regions in CPP starts to disintegrate, which lead to the drastic decreases in the heat of fusion. This contributes to the permanent adherence of the OPP and CPP, which ultimately lead to the E-type fracture behavior, as shown in specimens heat-sealed above 160 C. 

Fire Hazards - Flash Point (deg. F) 175 - 185 OC 178 CC Flammable Umits in Air (%) LEL 1.4 (ortho) 1.1 (meta or para) Fire Extinguishing Agents Water, dry chemical, carbon dioxide, and foam Fire Extinguishing Agents Not To Be Used Not pertinent Special Hazards of Combustion Products Flammable toxic vapors given off in a fire Behavior in Fire Sealed closed containers can build up pressure if exposed to heat (fire) Ignition Temperature (deg. f) 1110 (o-cresol) 1038 (m-or p-cresol) Electrical Hazard Data not available Burning Rate Data not available,... 

A change in size on scale-up is not the sole determinant of the seal-ability of a unit operation or process. Scalability depends on the unit operation mechanism(s) or system properties involved. Some mechanisms or system properties relevant to dispersions are listed in Table 2 (59). In a number of instances, size has little or no influence on processing or on system behavior. Thus, scale-up will not affect chemical kinetics or thermodynamics although the thermal effects of a reaction could perturb a system, e.g., by affecting convection (59). Heat or mass transfer within or between phases is indirectly affected by changes in size while convection is directly... 

The limited stability of 13 and 14 prepared according to method A is very likely caused by the presence of residual traces of NH4CI still present after reciystallization and capable of catalyzing condensation of the primarily formed aminosilane. Tliis assumption is substantiated by the condensation behavior of the less reactive monoamino derivative 9 (Scheme 4). Heating a hydrocarbon soluticHi of 9 prepared by method A in a sealed tube to 150 °C results in the quantitative formation of the condensation product 11. 

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