METHOD OF RECYCLING PACKAGE-CUSHIONING MATERIAL, AND PELLETS FORMED THEREOF AND ARTICLES INJECTION MOLDED FROM THE PELLETS

Abstract: Package-cushioning materials are recycled by the steps of: drying waste copolymerized PE + PS form, pulverizing the dried foam fusing the pulverized foam, forming the fused foam into ingots, extruding the ingots, and cutting the extrudate into pellets. The pellets can be injection molded into articles at a temperature of 160-200 degrees Celsius.

Description: METHOD OF RECYCLING PACKAGE-CUSHIONING MATERIAL, AND PELLETS FORMED THEREOF AND ARTICLES INJECTION MOLDED FROM THE PELLETS FIELD OF THE INVENTION The present invention relates to the recycling 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 that a 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 amount of disposed synthetic package materials to be supposedly 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 and 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 resins of PE and PS cannot be properly mixed together with a dominating notion that mixture of PE and PS resin is impossible. The copolymerized PE + PS foam product and the PE foam product together, have more difficulty in the recycling process because use of the PE + PS and PE foam or the PE foam is less popular and the melting temperature of PE is higher than that of the PS. Therefore, the copolymerized PE + PS foam waste and the 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 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 recycling method of package-cushioning materials. It is another object of the present invention to provide a method of recycling package-cushioning material including a copolymerized foam of polyethylene (PE) and polystyrene (PS). It is still another object of the present invention to provide pellets formed by a method of 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 treating waste packaging cushioning material of copolimerized polyethylene (PE) + polystyrene (PS) foam, comprising recycling that foam into PE + PS pellets. The recycling preferably comprises pulverizing the waste copolymerized PE + PS foam; fusing the pulverized PE + PS; forming an ingot from the fused foam; extruding the ingot; and cutting the extrudate into pellets. The waste copolymerized PE + PS foam should be dried out before being input to the recycling processes to remove any moisture therefrom. Appropriate pigments can be added during the extruding step to achieve a wide range of colors from white to black. Articles can be injected molded from the pellets under a temperature of 160-200 degrees Celsius to prevention discoloring. 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. 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 waste types, i.e., paper, vinyl, PS (polystyrene) foam and copolymerized PE (polyethylene) + PS (polystyrene) foam. The waste PE + PS foam goes through a series of sequential processes or steps 20, namely pulverizing 30 - fusing 40 → ingot forming 50 extruding 60 (following another fusing step), and thereafter be cutting into recycled PE + PS pellets 70. Then, the recycled PE + PS pellets 70 are injection molded at 80 to form functional parts 90 for distribution to a manufacturer. It is preferable that the waste PE + PS foam is dried by a drying process 100 prior to the recycling process 20. In addition, some pigments (e. g., titanium, carbon or their mixture) are added, if necessary, for a wide range of colors from white to black while recycled PE + PS resin is being extruded by the extruding process 60. During the injecting process 80, the recycled PE + PS resin should be injected at a temperature of 160 - 200 degrees Celsius to prevent combustion thereof for maintaining a predetermined color. Therefore, the recycling method of the present invention is found to be effective in producing a regenerated functional material by using waste PS + PE. Table 1 shows similar physical properties of the regenerated functional materials similar to those of the conventional ABS resin or 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 extrusions formed therefrom, according to the present invention in that recycled pellets of waste copolymerized PE + PS is 100% used to produce regenerated functional 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 treating waste package-cushioning material of copolymerized PE + PS foam, comprising the step of recycling the waste copolymerized PE + PS foam into PE + PS pellets. 2. The method as defined in claim 1 , wherein the step of recycling comprises: A. pulverizing the waste copolymerized PE + PS foam; B. fusing the pulverized PE + PS foam; C. forming an ingot from the fused PE + PS; D. extruding the ingot; and E. cutting the extrudate into pellets. 3. The method as defined in claim 1 , wherein the waste copolymerized PE + PS foam is dried to remove residual moisture therefrom before being converted into pellets. 4. The method as defined in claim 2, wherein pigments are added during step D. 5. A pellet formed by recycling waste package-cushioning material of copolymerized PE + PS foam into PE + PS pellets. 6. A pellet as defined in claim 5 formed by the steps of: A. pulverizing the waste copolymerized PE + PS foam; B. fusing the pulverized PE + PS foam; C. forming an ingot from the fused PE + PS; D. extruding the ingot; and E. cutting the extrudate into pellets. 7. An article formed by recycling waste package-cushioning material of copolymerized PE + PS foam into PE + PS pellets and injection molding the pellets. 8. The article defined in claim 7 wherein the injection molding is performed at a temperature in the range of 160-200 degrees Celsius. 9. The article defined in claim 7 wherein the recycling comprises the steps of: A. pulverizing the waste copolymerized PE + PS foam; B. fusing the pulverized PE + PS foam; C. forming an ingot from the fused PE + PS; D. extruding the ingot; and E. cutting the extrudate into pellets.

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