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TITLE Development of biodegradable foaming resin and its producing technology
(Joint Program to Promote Technological Development with the Private Sectors)
AUTHOR qhsd|gnet k`anq`snqx in Kanebo Gohsen, ltd.

The purpose of this theme is to develop the packaging materials(especially, foamed packaging materials), that is compatible to environment and to give the contribution into global environment.

We have studied about this subject since August, 1996 for putting to practical use and have come to e nd at march,1999.

In this three years, we have gained the remarkable results below.

1996: We have mainly studied to choose the raw PLA(poly-lacticacid) resin, foaming agents , foaming conditions and to increase the molecular weight o f PLA resin by crosslinking agent to fit for foaming, and got the basic technology of foaming.

1997: We have studied the producing technology under the above basic technology gotten in 1996.

We got the effective results, those are, the provisional spec of PLA resin, conditions of compounding, suitable classes and amount of foaming agents, foaming assistant agents and nuclear agents, foaming and molding conditions.

In addition, we evaluated the modified PLA resins by crosslinking agents, and have confirmed the biodegradability of those.

1998: We studied to brush up the producing technology and to improve the subjects, which are the results of evaluation by several customers.

And we obtained the anticipated results below.

1) To use butane, having low boiling point, made the ratio of foaming sharply increase and the size of cell critically decrease.

2) Also to use butane made the conditions easy to foam/mold almost like those of EPS(expandable polystyrene).

3) The results of evaluation the foamed/molded articles by some customers were low ratio of foaming, narrow condition of foaming/molding, low expandin g during molding. But we conquer them by choosing the resin having suitable molecular weight, molecular distribution, also choosing butane for foaming agent and impregnation condition of butane (foaming agent) and methanol (foaming assisting agent) etc.

We have some subjects to develop, those are to raise up the r atio of foaming, occurring problems by scale up producing and so on, but commercializatio n are near at hand after this 3 years' R&D.

We will continue to study and realize the commercialization after the end of this R&D.