Laminated films

In other areas, POD has been used to improve the wear resistance of a mbber latex binder by incorporation of 25% of Oksalon fibers. Heat-resistant laminate films, made by coating a polyester film with POD, have been used as electrical insulators and show good resistance to abrasion and are capable of 126% elongation. In some instances, thin sheets of PODs have been used as mold release agents. For this appHcation a resin is placed between the two sheets of POD, which is then pressed in a mold, and the sheets simply peel off from the object and mold after the resin has cured. POD-based membranes exhibit salt rejection properties and hence find potential as reverse osmosis membranes in the purification of seawater. PODs have also been used in the manufacturing of electrophotographic plates as binders between the toner and plate. These improved binders produce sharper images than were possible before. 

Strength they are of interest as a streteh film for meat packaging and for cling-wrap purposes. Some EVA is used in coextrusion processes for the manufacture of laminated film. 

Films stretch film, laminated film, shrinkable film... 

Union Carbide Corp produced the first of the synthetic papers in the late 1960s. Since that time other examples of synthetic papers include DuPont s Tyvek nonwoven paper and Van Leer s Valeron cross-laminated film. This market is now dominated by a few large, worldwide ventures with proprietary processing techniques that extend the use of single and multilayer extruded blown film or cast film. 

Development of biodegradable laminate films derived from naturally occurring carbohydrate polymers. Carbohydrate polymers, 60, 39-42. 

The commercial process for the production of vinyl acetate monomer (VAM) has evolved over the years. In the 1930s, Wacker developed a process based upon the gas-phase conversion of acetylene and acetic acid over a zinc acetate carbon-supported catalyst. This chemistry and process eventually gave way in the late 1960s to a more economically favorable gas-phase conversion of ethylene and acetic acid over a palladium-based silica-supported catalyst. Today, most of the world s vinyl acetate is derived from the ethylene-based process. The end uses of vinyl acetate are diverse and range from die protective laminate film used in automotive safety glass to polymer-based paints and adhesives. 

In this example a polymer laminate film (for packaging) was examined, which was composed of nine layers (see Table 2), by both FTIR imaging and Raman line scan. For the IR measurements thin sections (5 pm) were cut. The central ethylene/vinyl acetate (EVA) copolymer layer is very soft, and holes can be seen in the visible image (Figure 12). 

Many polymer products are constructed as laminated films, with each layer imparting a particular property to the end product, whether it be, for example, a... 

Polystyrene can be moulded, cast or extruded in sheets, rods and tubes. It can be easily pigmented. It finds wide, application in making household goods, lenses, plastic moulds, toys, wood laminates, films, battery boxes and electrical components. Expanded polystyrene is used as thermal insulating material and packaging. It is also used in lifejackets and floats. 

Patent Number US 5968630 A 19991019 LAMINATE FILM-FOAM FLOORING COMPOSITION... 

Instead of the simultaneously extmded polymer film, a pre-extmded or laminated film can be laminated on the substrate (e.g., paper or paper board). In this case, the extruder can be used to extrude the polymer providing adhesion (e.g., Ecoflex ) in a thin layer between the polymer coating film or laminate and the substrate. Another option is to apply a dispersion or heat in the laminator (Fig. 10, 4) to obtain adhesion. After thickness measurement and second subsequent corona treatment, substrate and polymer coating are wound on a winder (Fig. 10, 6) in order to obtain rolls for transport to subsequent processes (e.g., printing, cutting, cup forming, box making). 

Specimen preparation Film thickness 0.3 mil (7.7 im) the substrate was corona treated to 42 dynes/cm adhesive cured through the laminate film using a 300 wpi (120 W/cm) mercury lamp. 

There are two basic ways of using this form, fill seal process with laminates, films, or sheets in reel form. 

Multi-layer films can be produced, composed of different polymers. For each polymer a separate extruder is applied the extruders discharge into an accumulator, in which the separate streams are guided to their own position in the film. A laminated film can thus be made, in which one of the layers provides the strength, another one acts as a gas barrier, other layers promote adhesion and weldability, etc. This laminating process is applied with flat film extrusion as well as with film blowing. 

After the removal of solvents not more than 10 g of polyurethane should be applied per 1 m2. Residual solvents and amines may not be detected in foods or food simulants coming in contact with the laminate films. 

Diffusion through a barrier layer is a special case of diffusion through a laminate film composed of several layers with different thicknesses and diffusion coefficients. The mathematical treatment of the non-steady state case is complicated. The steady state permeation case allows the overall transport to be simply treated. Let n films with thicknesses dpi, dp2,..., dpn with corresponding diffusion coefficients DP1, Dp2,..., Dpn be bound together in a laminate. Because in steady state, the flux J of the diffusing substance i is the same through every individual component of the laminate, one obtains an expression for the concentration gradient ... 

A precondition for the optimization of a package having a specified minimum shelf life date for a food with a known oxygen and/or water sensitivity is the calculation of the permeability of laminate structures. The total permeability Qv of a laminate film made from n different plastic layers with thicknesses d, and having permeability coefficients of Pj can be calculated using the following formula ... 

Example 9-8. A pouch is made from 5 dm2 of a heat sealable laminate film material. The film has the following structure 25 pm PP, 5 pm EVOH and 50 pm LDPE. How much oxygen permeates into this pouch at room temperature ... 

A complaint of an off-odor that smelled like cat urine occurred practically simultaneously in two different cooked ham products. Both products were cooked and packed in polyamide/ionomer laminate films coming from different film manufacturers with different sources for the PA but the same source for the ionomer. One of the two cooked ham producers used two different printing inks on the same laminate and received complaints only for one of the two packages. 

Corresponding model studies in which DAA-saturated laminate films as well as DAA-saturated mono films were heated under the cooking conditions confirmed the suspected dehydration reaction of DAA by the ethylene ionomer. This gave an logical explanation for the mechanism of formation for the 4-methyl-4-mercaptopentane-2-one off-odor (Fig. 13-5). 

A finished packaging material for a specific food, e.g. a roll of printed laminate film, often possesses a certain individual odor. Even though from a food regulatory view only the transfer of odor substances to the food is important and not the individ-... 

FIGURE 6.12 Drug diffusion through a laminated film with drug concentration C, on the donor side and C0 on the receiver side. 

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