Blow molding applications

Figure 11.24 Simulated axial pressure profile for the 152.4 mm diameter screw running HOPE resin in a high-speed blow-molding application...

LLDPE resins formulated for the blow molding applications have superior environmental stress-cracking resistance and low gas permeability. These features opened new bottle markets where such properties are important. A large variety of molded articles with a complex configuration... 

Pellets for injection-molding, extmsion, and blow-molding applications include mineral-filled, glass-filled, pigmented, and dame-retarded grades. 

Products SCLAIRTECH process can produce PE products with density range of 0.905-0.965 kg/m3, melt index (Ml) from 0.2 to in excess of 150, and narrow to broad molecular weight distribution (MWD). This allows producers to participate in the majority of the polyethylene market segments including among low-, medium- and high-density films, rotational, injection and blow molding applications. 

The most suitable properties for polyethylene used in each fabrication method vary. For example, for blow molding applications, it is preferred to use FFDPE having broad or bimodal molecular weight distribution. Figures 8.4-8.6 show how the major types of polyethylene are processed. 

AyV-bis(2-hydroxyethyl)alkylamine. Clear liquid used as an antistatic for blow molding applications for polyolefins. Approved for use in food packaging films. 

A number of commercially significant PC copolymers are produced. In addition to the previously discussed branched PCs (for extrusion and blow-molding applications) and copolymers of BPA with tetrabromo-BPA for enhanced flame retardancy, high-Tg polyester carbonate copolymers have been produced for a number of years (Bayer Apec , GE LEXAN PPC Tg approximately 190°C). Polyester carbonate copolymers can be produced via copolymerization of BPA with diacyl chlorides. Aromatic diadds produce high-Tg copolymers, while aliphatic diadds yield lower-Tg copolymers. A lower-Tg PC aliphatic polyester copolymer (GE LEXAN SP resin) exhibits enhanced flow and ductility in comparison to standard PC and is useful for thin-wall injection molding applications requiring ductility and ease of melt processability, such as personal communication devices. GE has recently introduced two new PC copolymers, a PC-siloxane copolymer (LEXAN EXL) and a copolymer of... 

FIGURE 71 Polymer grades made with Cr/silica catalyst can be tailored for a variety of diverse blow molding applications by varying the activation temperature. 

Silica-alumina has been widely investigated as a catalyst support [41-47,598,599]. The earliest Phillips catalysts used silica-alumina as a support rather than just silica, and Cr/silica-alumina is still used today for certain blow molding applications. These early polymerization catalysts, which used a cracking catalyst support, contained mostly silica with a small amount (13-25 wt%) of alumina added. 

Another difference that is sometimes apparent is a lower LCB level in polymers produced in fluidized-bed reactors. As noted in Sections 9 and 10, lower LCB is the result of use of a lower chromium loading on the catalyst, and of longer residence times, which improves the polymer yield. For example in blow-molding applications, resins produced in the fluidized-bed process are likely to exhibit higher die swell than resins made in the slurry process, when a similar catalyst is used. 

The effect of biaxial strain on the transport properties of semicrystalline polymers has been demonstrated for several systems (42) However, particular attention has been paid to poly(ethylene terephthalate)(47-49) because of its wide use in blow molding applications. 

Blends of engineering resins used in blow molding applications include systems based on PA, PC and PPE. When using impact modified PA-6, PA-66 or PA-6,12 Zytel ), the moisture content must be signihcantly lower (0.05%) than that required for injection molding (0.25%). 

For blow-molded products, HOPE, PP, and LDPE are used by the greatest percentage of companies—and they are even more commonly blow-molded than PET is. Large containers for industrial and agricultural chemicals and other nonfood bottles are the leading blow-molded applications for POs, though many of these applications are often so ubiquitous or so common that they are easily overlooked as important PO uses [2-22],... 

Glass T. Fundamentals of polyolefin structure/property relationships in blow molding applications. SPE Annual Blow Molding Conference, conference proceedings. Society of Plastics Engineers 2007. 

Figure 2.3 Tensile stress vs. strain for SABIC Innovative Plastics Cycolac EX39— highest impact extrusion ABS resin for sheet and blow molding applications.

For example, 5 to 20% acetal blended with TPU improves the overall processability of the TPU in extrusion and blow-molding applications. The blends of 30 to 50% acetal with TPU improve TPU s heat and humid age properties and solvent-resistance [41-43]. It was found that the higher the content of POM in the POM/TPU blend, the higher the heat distortion temperature (HDT) of the blend [44] (Figure 3). 

These linear polymers, in various molecular weights and with various monofunctional phenol end groups, dominate commercial polycarbonate production and sales. However, these products do not meet all requirements, particularly for extrusion and extrusion blow-molding applications where there is a need for polycarbonates that provide nonnewtonian, shear-dependent, viscoelastic flow properties. These desirable flow... 

Blow Molding. HDPE is the preferred resin for blow molding because of its combination of rigidity and barrier properties. LDPE is less commonly used, but does offer advantages in applications where clarity, flexibibty, and excellent ESCR are required. Typically, low melt index resins are used for blow molding applications (Table 19). 

Blong, T., Duchesne, D., Brandon, M. (1993) Processing Additives in High Density Polyethylene Extrusion Blow Molding Applications. SPE ANTEC 93. 

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