moisture vapor transmission rate

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moisture vapor transmission rate

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MVTR

The rate at which a barrier permits moisture to penetrate or escape. In pharmaceutical packaging the moisture vapor transmission rate is one element that determines the shelf life and expiration of a medication.
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A combination of the absorbent barrier structure and the outer cover has a hydrohead value of at least about 25 mBars and a convective air permeability of at least about 10 Darcy/mm; a liquid impact transmission value of less than about 20 gpsm; and MVTR of no more than 3500 gpsm/24 hrs.
BASF claims its materials also make films with 50% lower MVTR than other biodegradables.
In laboratory tests, Dureflex PT 1710S--which Deerfield terms the "workhorse" of its breathable TPU film line--reportedly moves 3500 G/m2d using test method E-96E in a MVTR 38[degrees]C/90% RH upright cup desiccant.
MVTR tests moisture resistance over a 24-hour period under controlled conditions.
The new resin has a flex modulus of 560,000 psi, tensile strength of 33,000 psi, and MVTR of 0.
With an MVTR of 600 g/m2/24 hr (ASTM E-96B upright test), the new TPU film provides fabric with a layer that is "breathable," allowing moisture vapor to escape--but also waterproof, preventing water, blood, or such liquids from penetrating, Ticona reports.
Unlike the traditional cup test method in which ambient moisture and temperature created constantly changing conditions and require longer test times, the LYSSY MVTR tester works within a sealed chamber that features a controlled humidity and temperature environment.
Color Guard MVTR can be used in sheet extrusion, thermoforming, injection molding, and blow molding.
According to Equistar, the resin has an improved MVTR, which, combined with high stiffness, makes it potentially useful in such applications as a bun over-wrap.
psi 185,000 -- 475,000 61,600 OTR (c) 370 10 93 303 MVTR (d) 1.
Unlike the traditional cup test method, in which ambient moisture and temperature create constantly changing conditions and require longer test times, the LYSSY MVTR tester works within a sealed chamber.
30 shows that Finacene mPPs have comparable or better tensile strength relative to nonmetallocene PPs, plus improved stiffness, clarity, and MVTR.