Hot Fill

Thin wall plastics are used to hot fill (injection and blow molded bottles, thermoformed containers, etc.) without sagging during filling and maintaining mechanical properties such as impact strength and stiffness in temperatures from at least —40°F to 250°F (—40°C to 120°C). Plastic used includes special grades of PEN, PET, PP, PS, and PVC. 

They use principally polyethylene and polystyrene foam in different shapes such as peanuts and pretzels. 

---

Types of internal enamel for food containers include oleoresins, vinyl, acryflc, phenoHc, and epoxy—phenoHc. Historically can lacquers were based on oleoresinous products. PhenoHc resins have limited flexibiHty and high bake requirements, but are used on three-piece cans where flexibiHty is not required. Vinyl coatings are based on copolymers of vinyl chloride and vinyl acetate dissolved in ketonic solvents. These can be blended with alkyd, epoxy, and phenoHc resins to enhance performance. FlexibiHty allows them to be used for caps and closures as weU as drawn cans. Their principal disadvantage is high sensitivity to heat and retorting processes this restricts their appHcation to cans which are hot filled, and to beer and beverage products. 

PEN film for audio- and videotape and various electronic appHcations and blow molded PEN containers for hot-fill appHcations are already being marketed in Japan. NDA is unlikely to ever become as inexpensive as terephthaUc acid but novel NDA-based polyesters will become available if a market need exists. One example could be the experimental polyester PBN (Celanese Corp.) this is the NDA analogue of PBT, poly(l,4-butylene naphthalene-2,6-dicarboxylate) [28779-82-0]. It has a high rate of crystallization, faster even than that of PBT, and its combination of physical properties is weU-suited for injection molding. 

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... 

The main applications for CPVC arise from the fact that the material has a softening point of about 100% and very good chemical resistance. Particular interest has been shown in waste and soil systems which may pass hot water effluents. Calendered sheet may be vacuum formed for uses where hot filling techniques are employed, for example in jam packing. 

Glass transition 108°C withstand top load of filling, stacking Allows hot fill (juices, drinks),... 

High-performance films and fibers, hot-fill containers... 

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... 

Hot-filament chemical vapor deposition (HFCVD), 17 214-215 Hot-fill market, 20 50-52 Hot-film anemometers, 11 676 Hot flocking, 7 59... 

However, there remain numerous end-use applications which require significant improvements in the properties PET has to offer. These include higher tensile strength and modulus for tyre reinforcement yams and monofilament applications, higher temperature resistance for hot-fill containers and films, and greater gaseous barrier for longer shelf-life requirements (e.g. fruit juice and beer markets). 

Many evaluations have led to the commercial utilization of PEN, its copolyesters and blends in some commercial applications. The cost effectiveness is especially apparent in retumable-refillable applications, which take advantage of PEN s chemical resistance in commercial washing operations, so ensuring an increased number of re-fill trips [26], Other applications benefit from PEN s increased gaseous barrier, UV absorption, thinner and lower weight potential. Considerable effort is underway to enable utilization of PEN, its copolyesters and blends for beer, higher hot-fill and heat-pasteurizable containers [27],... 

Jenkins, S. D., PET/PEN copolymers and blends for hot-fill and high barrier packaging applications, presentation given at the Specialty Polyesters 95 Conference, Brussels, June 27-28, 1995, Schotland Business Research Inc., Skillman, NJ, 1995. 

The other severe problem in the application of PET regarding food containers or bottles is that these products cannot be hot-filled. This limitation is caused by the low Tg of PET, which causes shrinkage during hot-filling. Alternatively, multilayer containers can overcome the problems, but, however, at higher manufacturing costs. PET in combination with an intermediate layer of poly(ethylene-co-vinyl alcohol) (PEVOH) or polybutylene has been used in such... 

Clear or drop impact resistant containers, boxes, hot filled bottles, dessert pots, horticultural pots, integrated hinge boxes, bottles and other cans up to several litres, caps and closures for beverage and cosmetic applications, medical disposable trays, containers for irrigation, parenteral, haemodialysis solutions. .. 

The temperature resistance is sufficient to allow the hot filling of certain foodstuffs. 

Amorphous polyesters are used in bottle manufacturing for their transparency to light, impermeability to carbon dioxide, and possibilities for hot filling. For other packaging purposes, amorphous PET is also appreciated for its transparency to microwaves (for packaging that will be reheated). 

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. 

Hot-Fill Applications. A growing market for blow-molded containers is the so-called hot-fill market. This covers such items as tomato... 

Country Carbonated soft drink containers Hot-fill containers Returnable containers Mineral water containers Edible-oil containers Other3... 

PB film is usually made by the blown film process, but also can be cast oil drill lolls. Film applications include food and meat packaging, compression wraps, and hot-fill containers. The material can be formulated to provide a wide range of seal strengths for peelable or easy-opening packaging. 

For all other fruit juice and nectar products either frozen storage or in-pack pasteurisation will be used, although some manufacturers who employ a hot fill process. 

Glass bottles will normally be pasteurised using either the hot fill method or in-pack pasteurisation. 

There is some limited use of plastic bottles for juice packing - mostly related to short-shelf-hfe products sold from the chill cabinet. Plastics are now available to support aseptic filling or even hot fill operations, but they have found limited support for the sale of fruit juices. 

In hot filling product is heated (in a heat exchanger), sent to the filler hot and filled into containers. The containers are closed and held at or above the required temperature for a specified time prior to being cooled, usually in a tunnel with water sprays. In this system not only has the product been heat treated but so has the container. 

---