Various new technologies were exhibited in the largest plastics industry exhibition of the millennium "NPE2000" held in Chicago USA during the second half of June 2000. Among them, one of the most unique new technologies that attracted a lot of attention was that of the "MuCell ® Process".

This technology was invented in Massachusetts Institute of Technology, and at present a related venture company called Trexel Inc. has the basic patent and has entered into licensing agreements with eight injection molding machine manufactures in the world.
A feature of this technology is that in a special mixing and kneading cylinder, nitrogen (N2) gas or carbon dioxide (CO2) is sealed in the supercritical state, injected into the mold in a manner similar to ordinary injection molding, filled, cooled, and the molded product is taken out.

Although no differences can be observed between the obtained injection molded product and an ordinary injection molded product, you will recognize the difference once you take the product in your hands. That is, the product will clearly be lighter (by about 12%) than an ordinary molded product. If you cut the product to know the reason for this difference, you will find that although the surface is solid, the interior has innumerable very fine bubbles generated in it and the material will have a sponge shape (with a honeycomb structure).

In this manner, since the surface is solid but the inside has air bubbles, it is possible to achieve a lighter weight compared to the ordinary molded product which is completely solid. In addition, since this is a collection of very fine bubbles (with the bubble diameter being 50 micrometers or less), there is the unique feature that there is no marked decrease in the mechanical strength.

The features of this technology are the following.

1.Lightweight molded products can be obtained.

2.The molding cycle is made shorter, because the solidification time of the central part becomes shorter.

3.It is possible to set the screw heating temperature to a lower value, which results in energy saving.

4.It is possible to lower the viscosity of the plastic. Therefore, it is possible to fill at a low pressure.

5.The pressure maintenance time can be shortened.

6.It is possible to reduce warping and deformation substantially. The principle of operation is similar to gas assisted molding.

7.There is no difference in the outer appearance of the surface between the molded product and an ordinary molded product.

8.A wide range of plastics such as PS, ABS, PP, PA6, PPS, glass fiber reinforced plastic, etc., can be used.

9.It is possible to increase the number of products molded using the mold during its life.

As explained above, this new molding technology has technical content that needs to be mentioned particularly, and it appears that this technology is very highly likely to be applied in various fields from now on.
A license agreement is necessary in order to use this technology, and at present, it is necessary to enter into an implementation rights contract with Trexel via the manufacturers of the molding machine.