Perforated film

The uses of spunbonded fabrics as coverstock in diapers and other personal absorbent devices will most likely remain unchallenged for the near term. Virtually any other nonwoven production method appears to be at a cost disadvantage opposite spunbonded polypropylene. There have been composite products developed from meltblown and spunbonded combinations, where areas of either improved hydrophobicity or hydrophilicity are desired. These products can be produced on-line at relatively low additional cost and offer high value to diaper manufacturers. Any competitive threat is likely to come from advances in film technology such as large improvements in perforated film used in segments of absorbent product appHcations, particularly sanitary napkins. 

Warehouse drying is normally aeeompllshed by providing an intermediate paekaging that breaths . In the ease of a rubber bale, the paekaging may eonsist of polyethylene perforated film wrap that enables the surfaee moisture to evaporate through the film wrap and achieve an acceptable moisture spec (typically less than 0.5 weight percent for products like EPDM or butyl rubber). 

Paraffin gauze dressing Perforated film absorbent dressing Polyurethane foam Burns, scaids, grafts Postoperative wounds Burns, ulcers, grafts. Any combination of dry heat, gamma-radiation and ethylene oxide... 

Fig, 7.17. Schematic illustrations of sub-crack propagation along the laminar interface of the composite intermittently bonded with perforated films. After Jea and Felbeck (1980). 

Ferreres, F., Gil, M.I., and Tomas-Barberan, F.A., Anthocyanins and flavonoids from shredded red onion and changes during storage in perforated films. Food Res. Int., 29, 389, 1996. 

The visual appearance, clarity in particular, of packed products with high water content (vegetables, fruits, various cheeses, fresh meat) in packaging can be impaired by fogging caused by condensation of water as small droplets on the inside surface of the plastic film. In applications where perforated films with effective water vapor transmission are undesirable, antifogging agents with the properties of surface active substances, such as poly(oxyethylene) sorbitan monooleate are effectively used. 

Wadas, W. Kosterna, E. Sawicki, M. (2007). Productivity of early potato cultivar in the cultivation under perforated foil and polypropylene fibre covers. Fragmenta Agronomica, No. 2, pp. 364-372, PL ISSN 0860-4088 Wadas, W. Kosterna, E. Sawicki, M. (2008). Effect of perforated film and polypropylene nonwoven covering on the marketable value of early potato yield. Vegetable Crops Research Bulletin, Vol. 69, pp.51-61, PL ISSN 1506-9427 Wadas, W. Kosterna, E. Zebrowska, T. (2006). The effect of using covers in cultivation of early potato cultivars on the content of some nutrients in tubers. Zeszyty Problemowe Post aw Nauk Rolniczych, No. 511, pp. 233-243, ISSN 0084-5477 Wadas, W. Sawicki, M. (2005). Estimation of early potato production profitability in mideastern Poland conditions. Pami tnik Pulawski, Vol. 139, pp. 2S9-297, ISSN 0552-9778... 

Siwek, P., Capecka, E., Kunicki, E., Kalisz, A. (2003). The effectiveness of new kinds of perforated film in cucumber cultivation. Folia Horticulturae. 15(2), 65—69. 

Currently, the top sheet of a disposable diaper is usually made from a hydrophilic nonwoven fabric. These nonwoven fabrics are broadly defined as sheet or web stractures bonded together by entangled fibres or filaments, and by perforating films mechanically, thermally, or chemically to form flat, porous sheets that are made directly from separate fibre or from molten plastic or plastic film. Therefore, the mechanical and smface properties of the hygienic nonwoven fabrics used as the top sheet of disposable diapers are important for the health and comfort of the skin (Hong, Kim, Kang, 2005). 

Modem tampons are mainly composed of ceUulosic absorbent material, either rayon or a mixture of these fibres. In most instances, the absorbent core is covaed by a thin, smooth layer of nonwoven or perforated film, helping to reduce loss of fibres and making the tampon easy to insert and remove. The withdrawal cord that is necessary to remove the tampon is usually made of cotton or other fibres, and can be coloured. 

As discussed later in details, the perforated and continuous films differ in their permeability characteristics for and CO. The perforated films will generate a higher partial pressure of CO for a given corrcentration of in the package and can increase... 

It is earlier mentioned that in continuous films packages, the permeability of the package to COj is usually 4-8 times that of Oj permeability. A common example is LDPE, where CO permeability is four times that of Oj. They can be used for less CO tolerant commodities such as banana, mango, apples, and so om In continuous films, the gas permeability is temperature dependent and is described by Arrhenius-type equations. In perforated films, the perforations serve as parallel paths for movement of gas and moisture. The rate of gas transfer is the sum of gas movement through the perforations and that through the film. For such films, an apparent permeability term is used, which depends on the number and size of perforations as well as the continuous film area and its permeability. The equation which gives the permeability of macroscopic films with equal size perforations is as follows (Mahajan et al., 2007)... 

The effect of change in temperature on the diffusion of gases is more pronounced in the continuous films than that in the perforations. The permeation through continuous LDPE film and perforations increases by 200% and 11%, respectively, when the temperature increases from 0-15°C (Beaudry, 2000). A combination of perforation and continuous films can be used to obtain permeability values in between those of the continuous and perforated films. 

Medical tapes are used for all kinds of fixing purposes. The carrier of medical tapes can be woven fabric, film, perforated film, laminates, and nonwovens. 

Plasters Viscose, polyester, polypropylene, perforated film Knitted, woven, nonwoven... 

The much enhanced water vapor transmission property allows non-perforated film structure to offer high moisture breathability. This unique performance capability could be used in food packaging applications where protection against contamination and atmospheric moisture control are important. It also provides breathability and comfort to protective apparels where a continuous layer is essential for protection. 

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