Methods for improving the resistance of fumigant sorption in a produce container and a related produce containers

Abstract

Methods for improving the resistance of fumigant sorption in produce containers made from expandable polystyrene particles in a fumigation process, and related produce containers. An embodiment involves pre-expanding the expandable polystyrene particles to form pre-expanded particles; applying a coating comprised of a chemical selected from the group consisting of mineral oil, polyethylene wax, ethylene vinyl alcohol copolymer, and polyethylene glycol to the pre-expanded particles and in amount of 0.05 to 5.0 parts per hundred; and forming the container from the pre-expanded particles. A further embodiment involves applying the chemical coating to the expandable particles; pre-expanding the expandable polystyrene particles to form pre-expanded particles; and forming the containers from the pre-expanded particles. Other methods involve increasing the cell size of the expandable particles used to form the produce container.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing the methyl bromide concentrations (ounces/1000 feet³) versus fumigation time (minutes) for the USDA minimum requirement for the present (old) EPS containers indicated at “A” and for the inventive (new) EPS containers indicated at “B”.

Claims

1. A method for improving the resistance of fumigant sorption in a produce container in a fumigation process, the steps comprising: pre-expanding expandable polymer particles to form pre-expanded particles with a density ranging from about 12.0 pounds per cubic feet to 1.0 pounds per cubic feet to form pre-expanded particles;applying a coating to said pre-expanded particles, said coating comprised of a chemical selected from the group consisting of mineral oil, polyethylene wax, ethylene vinyl alcohol copolymer, and polyethylene glycol in an amount ranging from about 0.05 to about 5.0 parts per hundred; andforming said produce container from said pre-expanded particles.

2. A method of claim 1, wherein said chemical is selected from the group consisting of mineral oil and ethylene vinyl alcohol copolymer.

3. A method of claim 1 wherein said polymer particles are polystyrene particles.

4. A produce container made by the method of claim 1.

5. A method for improving the resistance of fumigant sorption in a produce container in a fumigation process, the steps comprising: applying to expandable polymer particles a coating comprised of a chemical selected from the group consisting of mineral oil, polyethylene wax, ethylene vinyl alcohol copolymer, and polyethylene glycol in an amount ranging from about 0.05 to about 5.0 parts per hundred;pre-expanding said expandable polymer particles to form pre-expanded particles with a density ranging from about 12.0 to about 1.0 pounds per cubic feet to form pre-expanded particles; andforming said produce container from said pre-expanded particles.

6. A method of claim 5, wherein said chemical is selected from the group consisting of mineral oil and ethylene vinyl alcohol copolymer.

7. A method of claim 5, wherein said polymer particles are polystyrene particles.

8. A produce container made by the method of claim 5.

9. A method for improving the resistance of fumigant sorption in a produce container in a fumigation process, the steps comprising: increasing the cell size of expandable polymer particles; andusing said expandable polymer particles to mold said produce container.

10. A method of claim 9 wherein said polymer particles are polystyrene particles.

11. A produce container made by the method of claim 9.