Wax treated article and method of making
Water swellable articles are treated with wax by applying a molten wax to the article, the wax having a kinematic viscosity of between about 0.1 cSt to 20 cSt at 100° C., wherein the temperature of the article at the time of applying is about 40° C. to 200° C., with the proviso that the temperature is not less than 30° C. below the melting point of the wax. Using this method of treatment, swelling of the article in water is reduced by at least 25% compared to the same article treated with molten wax wherein the article is at ambient temperature at the time the wax is applied.
1. A process for making a container, the process comprising:
placing a fiber mixture in a mold, the fiber mixture comprising a fiber and a binder, the fiber and the binder being biodegradable, edible, or both;
forming a self-supporting container by application of heat and pressure to the fiber mixture in the mold, the container having an interior container surface and exterior container surface;
removing the container from the mold;
upon removing the container from the mold, applying a molten wax to the container, the wax having a kinematic viscosity of between about 0.1 cSt to 20 cSt at 100° C., wherein the temperature of the container at the time of applying is about 40° C. to 200° C., with the proviso that the temperature is not less than 30° C. below the melting point of the wax; and
cooling the container to a temperature below the melting point of the wax.
2. The process of claim 1 wherein the fiber comprises wood fiber, straw, corn husks, sorghum stalks, soybean hulls, peanut hulls, or a combination of two or more thereof.
3. The process of claim 1 wherein the binder comprises soy flour.
4. The process of claim 1 wherein the container is coated on at least a portion of the exterior surface thereof.
5. The process of claim 1 wherein the container is coated on both the interior and exterior surfaces thereof.
6. The process of claim 4 wherein swelling of the container in water is reduced by at least 25% compared to a container having a wax coating wherein the temperature of the container at the time of applying the wax is ambient temperature.
7. The process of claim 1 further comprising bringing the container to the temperature of about 40° C. to 200° C. by pre-heating the container in an oven, by use of microwave radiation, or by use of infrared radiation.
8. The process of claim 1 wherein the temperature of the container at the time of applying is about 50° C. to 190° C., with the proviso that the temperature is not less than 20° C. below the melting point of the wax.
9. The process of claim 1 wherein the melting point of the wax is from 55° C. to 90° C.
10. The process of claim 1 further comprising pre-heating the wax to a temperature that is about 5° C. to 50° C. above the melting point of the wax at the time of the applying.
11. The process of claim 1 further comprising pre-heating the wax to a temperature that is about 15° C. to 30° C. above the melting point of the wax at the time of the applying.
12. The process of claim 1 wherein the applying comprises dipping the container in the molten wax.
13. The process of claim 1 wherein the applying comprises curtain coating the container with the molten wax.
14. The process of claim 1 wherein the container has a surface roughness R a of from 1 μm to 2 cm before the applying.