BARRIER FILMS : HYTIBAR

Since the International Montreal Protocol Agreement, there has been an increased demand for high barrier films for soil disinfestation with methyl bromide.

Already back in 1990 Hyplast developed a series of films called Hytibar with close to zero permeability to methyl bromide.
Via the blown film coextrusion process, different polymers are joined together in discrete layers, one of them having a very high barrier to CH₃Br permeation.

A lot of confusion arose when so called barrier films appeared on the market.
In nearly all cases it concerned LDPE or LLDPE films with a slightly higher density and consequently a minor difference in CH₃Br permeability.

In our presentation we will first explain the mechanisms of permeation through a polymeric membrane.
We will then give an overview of the possible polymer candidates with LDPE as reference material with poor barrier properties, versus polymers used in food packaging having barrier properties which per unit of thickness are a factor 1000 better.
Thirdly we will deal with the technical problems related to processing of these polymers into multilayer films of large widths needed for soil disinfestation.
Finally CH₃Br permeability results of these films will be discussed.

IV International Symposium on Soil and Substrate Infestation and Disinfestation

T.L.F. Daponte

https://doi.org/10.17660/ActaHortic.1995.382.5