Packaging applications blow-molded containers

Some corrosive chemical solutions which are inert to polyethylene that were packaged in blow-molded containers using LDPE are listed below and were some of the first applications for high-pressure LDPE. 

Hot-Fill Applications. A growing market for blow-molded containers is the so-called hot-fill market. This covers such items as tomato ketchup, pasteurized fmit juices, and salad dressings that are packaged while sti11 hot. The PET blow-molded bottie suffers from its relatively low T (70°C) which results in severe bottie distortion if the temperature of the contents approaches T (the maximum fill temperature is 60 65 C). A brief heat... 

Blow-molded containers, hot fill applications for, 20 50-52 Blow molded food packaging, 18 49-51 Blow-mold-fill-seal food packaging, 18 51 Blow molding, 10 179, 193-194 19 553-554 23 399 ABS, 1 427 HDPE, 20 171-172 LDPE, 20 237 LLDPE, 20 200... 

P.Y.212 is not recommended for exterior use, but provides an excellent value for interior applications such as packaging and household durables of all types. Pigment Yellow 212 is tinctorially quite strong as metallized azos go and exhibits very good dimensional stability, making it very useful in molded items such as blow molded containers. 

Packaging films (extruded, blown, and cast) are used in pressure-sensitive tapes and electrical applications and as replacements for cellophane and glassine films in liners for cereal boxes, wraps for snack foods, cigarettes, bread, and cheese. Blow-molded containers are used in applications where the higher use temperature of polypropene is needed (compared to HDPE), such as in packaging of syrups that are hot-filled. 

Extrusion. Sheet, film, and profiled articles are made by extrusion (20). The resin is melted and forced through a die plate or head. Variations include multilayer and blown film applications. In multilayer coextrusions, different combinations of plastics are separately but concurrently extruded to form layered sheet or film. In the packaging industry, specialty resins such as high barrier ethylene—vinyl alcohol copolymers are combined with heat- and impact-resistant thermoplastics for food packages. The properties of each resin layer are additive, as opposed to the "averaging of property" in blends. Multilayers are also used for blow-molded containers, films, and sheet products (see also Film AND sheeting materials). 

Due to its particularly good polymer characteristics PVC has an enormously wide spectrum of applications. From the consumption of more than 5.5 x 106 t in Western Europe (1997), 60% is in the building field, with a tendency to rise. Blow molded containers for packaging liquid products (beverages, edible oils, detergents, cosmetics and pharmaceuticals) receive special consideration, as do dishes for fatty foods (highly... 

The easy processability of the polyolefins permits ready fabrication by nearly all conventional processes. This versatility, plus their low cost, low density, and excellent balance of physical properties, gives them wide applicability in many different end-use fields. We now encounter polyolefins in our daily lives in the form of fibers (e.g., indoor-outdoor carpeting, underwear, and upholstery), film (packaging), blow-molded containers (squeeze bottles, detergent bottles), injection molded articles (housewares, appliance housings, auto parts), and extrusions (wire insulation, pipe). Statistics on major applications and accounts of new developments are published regularly (22). 

Table 2 shows how PE is used in Western Europe, Japan, and North America. LDPE and LLDPE are sold in the same market, primarily for thin film for packaging. HDPE is used for it s superior mechanical properties and hence resistance to enviromnental stress cracking in blow-molded containers, both for the domestic market (bleach, detergent, and milk) and for industrial containers also. All three types of PE are used in injection molding applications to produce housewares, toys, and industrial containers. LDPE is used if flexibility is required, HDPE is used if strength is more important. 

Many polymers are used in barrier applications, either to keep contents in or contaminants out. Food packaging is an excellent example of such usage. Plastic films and containers of many types are used to package food. Blow molded bottles often contain numerous layers, each of which provides specific benefits. Polyethylene layers are excellent water barriers, polyvinyl alcohol is a good oxygen barrier, and polyethylene terephthalate impedes the diffusion of carbon dioxide from carbonated drinks. Other barrier applications include toothpaste tubes, diaper backsheets, tarpaulins, and geomembranes, which are used to line containment ponds and landfill pits. 

HDPE accounts for about 42 percent of the domestic polyethylene market. It is harder, more rigid, and less waxy in appearance than HP-LDPE. Its higher density gives it better gas barrier properties. Because it softens above 100°C, containers made with HDPE can be sterilized, but those made with LDPE cannot. It is extruded into pipe, trash bags, food packaging, multiwalled sack liners, wire and cable coverings, and thick industrial film. A large application is for blow-molded containers and housewares. 

PET s broad range of properties make them ideal replacements in certain applications for such metals as die-cast aluminum or zinc also in thermoset switches, relays, sensors, etc. Applications include packaging (particularly stretched injection blow molded beverage bottles and film), appliances, electrical/electronics, etc. PET finds applications in such diverse end uses as fibers for clothing, films, botdes, food containers, and engineering plastics for precision molded parts.118-120 A wide range of applications is possible because of the excellent balance of properties PET possesses and because the degree of crystallinity and the level of orientation in the finished product can be controlled. 

EVOH can be extruded in films, blow molded, or injection molded. It can also be processed by coextrusion or lamination, in combination with PE, PP, PET, nylons, and other resins. Applications in packaging include flexible structures and rigid containers, as shown in Table 4.12. Typical applications are ketchup and barbecue sauce bottles jelly, preserves, vegetable juice, and mayonnaise containers and meat packages. Nonfood applications include packaging of solvents and chemicals. 

---