Fluorination or SMP Treatment  

The SCHUTZ SMP PROCESS, developed in close co-operation with the Linde Division of Union Carbide, is a new technology that reduces permeation of product through the HDPE is such an alternative. 

SMP, "SURFACE MODIFIED PLASTICS", is an off-line fluorination process which exposes plastic-containers on both sides with fluorine gas. Union Carbide holds several patents on this process. 

The SCHUTZ SMP-PROCESS  treats IBC's for safer storage.

LOWER ENVIRONMENTAL LOAD THROUGH SMP

Nitrogen and fluorine gas are blown into the evacuated treater, controlled through a process control computer. Fluorine concentration and treatment time can be adjusted according to permeation demands. Therefore, on the inner and outer surface a protection layer is created that is similar to PTFE (Teflon®). It greatly reduces the permeation of non-polar solvents.

SECURITY THROUGH SMP

With the SCHUTZ SMP-PROCESS plastic-containers are coated safely in a fluorination treater that is absolutely air-tight. Extra fluorine gas cannot escape from the treater but is always re-used. The double sided coating gives double protection against permeation through the plastic walls of the IBC. The excellent mechanical properties of HDPE such as tensile strength, expansion, hardness, stress cracking resistance, thermal properties and low temperature behavior are not influenced through the SMP-treatment.  Chemical resistance against inflammable, toxic and caustic materials is improved.

ECONOMICAL EFFICIENCY THROUGH SMP

Blowmolded plastic containers show decisive advantages in comparison to normal recepticals of glass or metal. For example: high range of application, low weight, high stability, extreme durability (sturdiness), high factor of security. SMP- treated plastic containers enlarge this range of application. The double-sided fluorine coating reduces the permeation of the contents to a minimum. It intensifies the chemical resistance against highly inflammable, toxic or caustic materials and, at the same time, it also builds an odor barrier.

The Chemistry of the Fluorination and the Barrier Effect
Fluorine is among all known elements, and it is also one gas with the highest capability of reaction (reactivity). Fluorine, as the strongest oxidation agent known, can react with all elements and compounds except light noble gases.
A treatment with fluorine serves to increase the barrier properties of HDPE against hydrocarbons. 
The basic reaction is a substitution of the hydrogen atoms with fluorine atoms on the chains of carbon atoms of the polyethylene macromolecules.
The permeation reduction is made in
three steps:
• Due to the treatment with fluorine the surface energy of HDPE is increased substantially. This reduces the wetting property - first permeation barrier.
• The second step: Liquid hydrocarbons and the fluorinated HDPE surface show cohesive-energy densities that lie far apart. The respective solubility is therefore very small. The dissolution of the solvent in HDPE is diminished, permeation is reduced.
• The third step: During the treatment with fluorine, cross linkings of the polymer chains emerge. Therefore the proper motion of the molecule chains, the clarity and - at the same time - the diffusibility are reduced.
Treatment with fluorine only changes the polymer molecules on the surface. As the chemically changed areas are only one part of the total wall cross section, the SMP-treated containers do not have a measurable change in regards to surface tension and impact resistance.

The new SCHUTZ-SMP-PROCESS opens new markets for plastic-containers as SMP-treated containers offer perfect transport security, an economical storage capability, extremely low permeation rates and a high solvent impact.