Film Breathable

Lower-density E-plastomers have found alternate use in cast film processes to make elastic film laminates with good breathability which contain laminates of liquid impermeable extensible polymeric films with extensible-thermoplastic-polymer-fiber nonwovens and nonwoven webs of polyethylene-elastomer fibers as the intermediate layers. The development relates to a breathable film including an E-plastomer and filler that contributes to pore formation after fabrication and distension of the film. The method and extent of distension is designed to produce a breathable film by stretching the film to form micropores by separation of the film of the E-plastomer from the particulate solids. This film is useful for manufacture of absorbent personal-care articles, such as disposable diapers and sanitary napkins and medical garments. In detail, these constructions comprise a liquid impermeable extensible film comprising polyolefins. The outer layer contains extensible-thermoplastic-polymer-fiber nonwovens, and an elastic intermediate layer contains nonwoven webs of fiber E-plastomers. The intermediate layer is bonded to the film layer and the outer... 

The formation of microvoids (or micropores) in drawn /3-PP is a well-known feature, used successfully to produce breathable films and membranes. Macroscopically their occurrence is correlated with an opacification (i.e. whitening) of the specimen. Their amount can, for example, be measured at given strain rate/draw ratio by liquid porosimetry (e.g. mercury intrusion), gas absorption or by the determination of the density of the deformed sample [129,177,178]. 

The damage process is accompanied by numerous microvoids, the development of which has been utilized for waterproof and/or breathable films. Other interesting segments are fibers, glass-fiber reinforced PP, thermo-formable grades and piping systems. 

Table 43-01. Film Properties of Atofina Pebax Breathable Films...

Breathable Films, Pebax, Elf Atoehem, R-04.96, Atofina Chemieals, Ine. 

Fig. 2.8 Types of laminates (a) outer fabric laminate (b) insert laminate (c) lining laminate (d) three-layer laminate 1, outer fabric, 2, breathable film, 3, insert fabric, and 4, lining material.

Anon. Nonwoven backing gives new strength to breathable films. BPR 2001. p. 20-1. 

This coextrusion techniqne has been applied to the fabrication of breathable films, using polyethylene oxide and polyolefin fiUed with CaC03. As the layer thickness decreased, the water vapor transmission rate changed dramatically due to changes from a continuous to discontinuous layer structure. Microlayer extrusion of a number of polymers has been accomphshed, including combinations of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE), ethylene-styrene copolymers and low-den-... 

Breathable film n. A film that is at least somewhat permeable to gases due to the presence of open cells throughout its mass or to minute perforations. Shah V (1998) Handbook of plastics testing technology. John Wiley and Sons, New York. 

Breathable film can also be used in construction for films that are inserted under roof tiles, and in wallcoverings. Omyafilm is claimed to give high film extrusion speeds, with less frequent changes of screen packs. Horticultural film can have its optical characteristics modified by mineral fillers. 

Porous PE nonwoven, breathable fabric is used as the strength component and starting material for both a perforated housewrap as well as several non-perforated breathable films in many other applications. These products are designed to offer the end nser a range of products and performance up to the highest grade of breathable film housewrap. 

Other areas where mLLDPE is making an impact are heavy-duty shipping sacks, food packaging (especially fresh produce packaging) (117-120), and breathable films for personal care use, eg diaper backsheet. Elastomers find application as modifiers in LLDPE and ULDPE to improve impact strength, low temperature toughness, and sealability (121). 

New sectors are also growing outside biodegradability, driven by the unique technical performance of some Mater-Bi products versus traditional materials, as in the case of breathable films with silky hand for diapers, chewable items for pets, or biofillers for tires. The new tire Biotred GTS, laimched by Goodyear in 2001 and recently adopted by BMW and Ford, is an example of the high tech performances reached by Mater-Bi products (164). 

In some cases, it is desirable to increase the permeability of a polymeric material. One example is breathable films. For example, calcium carbonate filled PP films are first made by solvent casting, or extrusion casting or as blown film and subsequently stretched to delaminate the filler - polymer interface [57]. High filler loadings are used to ensure interconnecting voids, giving unimpeded diffusion [58]. 

Fig. 3 Images of hydrogel (a) without covering, (b) covered with breathable film [viewed smooth surface of BF], (c) covtaed with breathable laminate [viewed rough surface of BL]...

Particulate-filled composites are widely used in many fields of application. The filler used in largest quantity is CaCOs, which is added mainly to poly(vinyl chloride), but significant amounts are used also in polypropylene, polyethylene and other polymers. Typical products prepared from CaCOs-filled composites are sewer and drainage pipes, garden furniture and breathable films [1]. The properties of particulate-filled polymers are determined by several factors, of which interfacial interactions are extremely important [2, 3]. Particle-particle and... 

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