METHOD OF RECYCLING PACKAGE-CUSHIONING MATERIAL, AND PELLETS AND INJECTION-MOLDED ARTICLES MADE THEREFROM

Abstract: Package-cushioning material are recycled by the steps of: recycling waste PS foam into recycled PS pellets; recycling waste copolymerized PE + PS foam into recycled PE + PS pellets; mixing the recycled PS pellets and the PE + PS pellets; extruding the mixed pellets into recycled mixed pellets; and cutting the mixed recycled pellets extruded at the extruding process to predetermined sizes.

Description: METHOD OF RECYCLING PACKAGE-CUSHIONING MATERIAL, AND PELLETS AND INJECTION-MOLDED ARTICLES MADE THEREFROM FIELD OF THE INVENTION The present invention relates to the cycling of package-cushioning materials, such as materials formed of PS (polystyrene) foam, or a copolymerized material formed of PE (polyethylene) plus PS. DESCRIPTION OF THE PRIOR ART Environmental pollution poses serious problems these days, so strong emphasis has been placed on effectively collecting used plastic package-cushioning materials and on making the most of recycled materials or products for the purpose of environment protection by decreasing the amount of disposed synthetic package materials to be land- filled or burned and by saving natural resource to make new plastic products. In general, only disposed PS has been collected and recycled to make window or picture frames by being mixed with new high quality polystyrene (HIPS). However, other package-cushioning materials like copolymerized PE + PS foam or PE foam have been excluded in the recycling efforts because the reclaiming industry has found it difficult to process the PE + PS and PE. It has been known that resin of PE and PS cannot be properly mixed together, with a dominating notion that a mixture of PE resin and PS resin is impossible. The copolymerized PE + PS foam product and PE foam product have more difficulty in the recycling process because use of the PE + PS foam or PE foam is less popular, and the melting temperature of PE is higher than that of the PS. Therefore, the copolymerized PE + PS and PE foam waste are not usually collected to be recycled. However, in consideration of hazardous environment problems caused by the plastic wastes that are burnt as a way of disposal, it is necessary to do much research on developing recycling methods for those plastic wastes. The use of PE + PS package-cushioning material consistently gains in popularity because of higher reliability and effectiveness in distribution, which are attributed to better physical properties of the copolymerized PE + PS in impact absorption, resiliency, durability against repeated use and to an advantage of occupying smaller volume, when packages are accumulated, resulting in reduction in distribution costs. Therefore, it is necessary to develop a new recycling method of the copolymerized PE + PS, since as the use of the PE + PS, as a package-cushioning material is on the increase. SUMMARY OF THE INVENTION The present invention is disclosed to solve the aforementioned problems and it is an object of the present invention to provide a method of recycling package-cushioning materials. It is another object of the present invention to provide a method of recycling package-cushioning material including copolymerized foam of polyethylene (PE) and polystyrene (PS). It is still another object of the present invention to provide pellets formed by method of a recycling package-cushioning material including the copolymerized foam of PE and PS, and also to provide articles injection molded therefrom. In accordance with the objects of the present invention, there is provided a method of recycling package-cushioning material, the method comprising the steps of: recycling wasted PS foam into recycled PS pellets; recycling wasted copolymerized PE + PS foam into recycled PE + PS pellets; mixing the recycled PS and PE + PS pellets along with new PS pellets; extruding the mixed pellets into recycled mixed pellets; and cutting the mixed recycled pellets extruded at the extruding process predetermined. BRIEF DESCRIPTION OF THE DRAWINGS For fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawing in which; Fig. 1 is a recycling flowchart of package-cushioning material in accordance with the present invention. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION The recycling method of the present invention is described in detail with reference to Fig. 1. First of all, synthetic package-cushioning materials are used to protect items from being damaged or destroyed in transportation. Then, the used package-cushioning materials are usually separated and disposed of after delivery of the items. The reclaiming industry collects those waste plastic package- cushioning materials and classifies them into types of waste, such as paper, vinyl, PS (polystyrene) foam and the copolymerized PE (polyethylene) + PS foam. The waste PS foam and the PE + PS foam go through a series of sequential processes or steps 20, namely pulverizing 30 → fusing (i.e., liquefying 40) → ingoting 50 → extruding 60 (following another fusing step) → pellet cutting 70, 80, to respectively make recycled PS pellets 70 and recycled PE + PS pellets 80. Then, the recycled PS pellets 70 and the PE + PS pellets 80 and new high quality PS pellets 90 are mixed at a predetermined ratio of: 10- 40% recycled PS, 30-40% recycled PE + PS, and 40-50% new PS. The most preferred ratio is 30%: 30%: 40%, as shown in Table 1. The mixed pellets 100 are subsequently fused and extruded at 1 10 to make regenerated mixed pellets 120, which proceed to the injection molding process 130 to make a final regenerated mixed product 140 to be used as a raw material. It is preferable that after the separating process 10, the waste synthetic package-cushioning materials are dried by a drying process 150 prior to the recycling process 20. It is also preferable that in the mixing process 100, the recycled PS pellets 70, the recycled PE + PS pellets 80 and the new HIPS pellets 90 are of respectively similar sizes and are well mixed in order to ensure homogenous properties of a final regenerated mixed product. In addition, some pigments (titanium, carbon or their mixture) are added, if necessary, for a wide range of colors from white to black while recycled PS pellets 70, recycled PE + PS pellets 80 and new HIPS pellets 90 are mixed in the mixing process 100. During the injecting process 130, the recycled mixed pellets 120 should be injected at a temperature of 160 - 200 degrees celcius to prevent combustion thereof to maintain a predetermined color. Therefore, the recycling method of the present invention is found to be effective in producing a regenerated functional material 140 by mixing: (i) recycled PS (ii) PS+PE, and (iii) new PS at optimum ratios. Table 1 shows improved physical properties of the regenerated mixed materials at different mixing ratios, better than those of the conventional ABS resin or new HIPS resin. Table 1. Measurement of physical properties of various synthetic products according to the ASTM. There are advantages from the above-described method of recycling package-cushioning material, and mixed recycled pellet and injection articles formed therefrom, according to the present invention in that the waste PS material and PE + PS material are mixed with new HIPS material at optimum ratios to produce regenerated mixed material, thereby reducing environmental pollution caused by land-fill or burning of plastic products, saving natural resources and providing new functional products. Although the present invention has been described in connection with a preferred embodiment thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims: WHAT IS CLAIMED IS: 1. A method of recycling package-cushioning materials, the method comprising the steps of: A. recycling waste PS foam into recycled PS pellets; B. recycling waste copolymerized PE + PS foam into recycled PE + PS pellets; C. mixing the recycled PS and PE + PS pellets together and with new PS pellets to form a mixture, and D. extruding the mixture into recycled mixed pellets; and E. cutting the mixed recycled pellets extruded in step D into predetermined sizes. 2. The method as defined in claim 1, further including drying the waste PS foam and the waste copolymerized PE + PS foam prior to steps A and B by removing all residual moisture therefrom. 3. The method as defined in claim 1 wherein the recycled PS + PE pellets and the new PS pellets in step C are of substantially the same size. 4. The method as defined in claim 1 wherein the recycled PS pellets, PE + PS pellets and the new PS are mixed in step C at a ratio of 10-40%, 30- 40%, and 40-50%, respectively. 5. The method as defined in claim 1 wherein the recycled PS pellets, the PE + PS pellets, and the new PS pellets are mixed in step C at a ratio of 30%, 30%, and 40%, respectively. 6. The method as claimed in claim 1 wherein each of steps A and B comprises pulverizing the respective waste foam, liquefying the pulverized waste foam extruding the waste foam, and palletizing the extruded waste foam. 7. The method as claimed in claim 1 wherein pigment is added in step C. 8. The method as claimed in claim 7 wherein the added pigment is titanium. 9. The method as claimed in claim 7 wherein the added pigment is carbon. 10. The method as claimed in claim 7 wherein the added pigment is a mixture of titanium and carbon. 11. A pellet formed by the steps of: A. recycling waste PS foam into recycled PS pellets; B. recycling waste copolymerized PE + PS foam into recycled PE + PS pellets; C. mixing the recycled PS pellets and the PE + PS pellets together and with new PS pellets to form a mixture, and D. extruding the mixture into recycled mixed pellets; and E. cutting the mixed recycled pellets extruded in step D into predetermined sizes. 12. An article formed by the steps of: A. recycling waste PS foam into recycled PS pellets; B. recycling waste copolymerized PE + PS foam into recycled PE + PS pellets; C. mixing the recycled PS pellets and the PE + PS pellets; D. extruding the mixture into recycled mixed pellets; E. cutting the mixed recycled pellets extruded in step D into predetermined sizes; and F. injection molding the cut pellets of step E into articles. 13. The articles as claimed in claim 12 wherein step F is performed at a temperature in the range of 160-200 degrees Celsius.

Inventors: KIM JUNG HO, KIM, JUNG, HO
Applicants: KIM JUNG HO, SAMSUNG ELECTRONICS CO LTD, KIM, JUNG, HO, SAMSUNG ELECTRONICS CO., LTD.
Application year: 1998
Main classification: B29B17
IPC codes: B29B17, C08J9