• Resources Recycling
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• v.23 no.5
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• pp.68-79
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• 2014

Since 1990s, efforts to recycle the waste plastics by chemical methods have increased. And in accordance with this trend, attempts have become active to use the waste PET as raw materials of chemical industries. In this article, the patents and papers for development of commercial technology for feedstock recycling and high end products from PET wastes were collected and analyzed. The open patents of USA (US), European Union (EP), Japan (JP), and Korea (KR) and SCI journals from 1974 to 2013 were investigated. The patents and papers were collected using key-words and filtered by the definition of the technology. The patents and papers were analyzed by the years, countries, companies, and technologies and the technical trends were discussed in this paper.

• Resources Recycling
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• v.12 no.5
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• pp.16-22
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• 2003

Lightweight aggregate for concrete was manufactured from recycling the waste PET bottles (PET Bottle Lightweight Aggregate, LAPET). The qualities of LAPET and its mortar were investigated. Specific gravity and unit weight of LAPET was very low in comparison with river sand like as 1.39, 844 kg/㎥ respectively. In addition, compressive strength of concrete significantly decreased because of specific gravity of aggregate decreased with increases in containing ratio. When LAPET was contained to 25% and 50％ of river sand, compressive strength of concrete at 28 days was indicated more 30MPa. Most of LAPET was generally showed to round shape and fluidity of mortar increased significantly due to sleeking the surface texture of LAPET. On the other hand, capillary absorption of mortar with LAPET was greatly increased in comparison with that of mortar without LAPET because of LAPET was composed of singular gradation. Absorption of LAPET was 0％ because the interior structure of LAPET consists of PET like as organic high polymer. Therefore the fault of normal lightweight aggregate, absorption, will be improved. It could expect several advantages that the pollution of environment will be previously prevent and the waste resources could be recycled if LAPET is reused as aggregate for Lightweight concrete.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.17-25
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• 2014

Wide spread application and non-biodegradability of the poly(ethylene terephthalate) generate a huge amount of waste and disposal, posing serious environmental problems. Disposal of the PET wastes also can be thought as an economic loss of valuable chemical resources. We present various ways of feedstock recycling of PET waste to deal with environmental and economic problems. Feedstock recycling is one of promising technologies. It is based on the concept of depolymerizing the condensation polymer such as PET through solvolytic chain cleavage into low molecular products which can be purified and reused as raw materials for the production of high quality chemical products.

• Resources Recycling
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• v.17 no.3
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• pp.21-28
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• 2008

Using the post-consumer waste and edge scrap mixed PET with small amount PP air filter elements of automobiles. It was studied that these mixed waste plastics of the various types of the PET were practicable for the material recycling. Various waste PET/PP plastics were collected, crushed, dried in vacuum, and extruded to recycled PET/PP chips. These chips were mixed with three kinds compatibilizers, EVA, MBS, and recycled PVB of the ratio of $3{\sim}10wt.%$ for the purpose of the compatibility for the post-consumer waste and edge scrap. We investigated mechanical and thermal properties of PET/PP mixtures which were compound with the weight ratio of compatibilizers. Compatibilizer, MBS application was showed the most excellent mechanical properties in the range of the $3{\sim}5wt.%$ EVA application was displayed good impact strength and thermal property in the range of $3{\sim}5wt.%$ Last, recycled PVB application was showed poor mechanical properties in the whole range ratio of the PVB.

• Resources Recycling
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• v.16 no.5
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• pp.51-56
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• 2007

Plastics are widely used in everyday life as very useful material. In Korea, about 4 million tons of plastic wastes are generated annually. However, recycling ratio is below 30%, and most of plastic wastes are disposed by landfill and incineration. Hence, the development of material separation technique that can recycle plastic wastes is a necessary situation. In this study, Triboelectrostatic separation for recovery of PET from final plastic wastes obtained from the sink product after wet-type gravity separation has been carried out. In the charging properties, the charge polarity and charge density of PET and PVC were very effective with the tirbo-charger made of PP and HDPE with the decrease in relative humidity. In material separation using HDPE cyclone charger, a PET grade of 96.80% and a recovery of 85.0% were achieved at 30 kV and the splitter position -2cm from the center. In order to obtain PET grade of 98.5%, PET recovery should be sacrificed by 24% with moving the splitter from the center to -6cm position.

• Resources Recycling
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• v.3 no.1
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• pp.44-51
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• 1994

PET bottles were composed of several different materials such as PET, HDPE, PVC and PP, it is necessary for recycling of PET bottles to precede seperation of each material. This study is purposed of recycling of PET bottles by separation using float and sink method. Pure PET is obtained a proportion of 94% on condition that bottle labels were removed by using tap water. In case the labels were attached on the bottles, PET was unable to obtain because of PVC and PET sink, and PP and HDPE float. Therefore, the labels should be removed before separation of PVC lebels substituted for PP or PE material. The various physical properties of recovered PET and HDPE were measured and compared with the original PET and HDPE, and it is identified that recycling is possible as a result.

• Resources Recycling
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• v.7 no.5
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• pp.26-32
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• 1998

Recycline of used plastics is rather restricted due to their variety and difficulties in their separation. In this study, a reliable and economical method for the separation of PVC which utilizes an appropriate control of surface chemistry of pariticles was suggested. this method consists of modification of PET surface from hydrophobic to hydrophilic by NaOH solution and subsequent separation by a froth flotation technique. Flotation results were in terms of NaOH concentration, digestion temperature and time, temperature and pH of solution, PVC concentration. They could be separated up to 95~100% by this method.

• Resources Recycling
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• v.12 no.4
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• pp.44-50
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• 2003

Separation of mixed plastics is not a simple task due to similarities of specific gravity and limitations of sizes, etc. In this study, a new technique was developed to separate plastics selectively by a thermal adhesion method using the different softening or melting temperatures of various types of plastics. Tests were conducted to investigate softening or melting temperatures and adhesion probabilities of plastics with change in temperature. Tests also were conducted to analyze the operating variables, including contact times, size and color pigment. It was founded that LDPE, HDPE and PVC, PET, etc among mixed plastics could be separated selectively according to the change of temperature.

• Resources Recycling
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• v.32 no.3
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• pp.57-67
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• 2023

The treatment of waste plastic has primarily been entrusted to small companies, which has resulted in challenges in obtaining an accurate overview of the current state of affairs and ensuring profitability. Consequently, despite the presence of recycling technology, their practical application has proven to be challenging. In this study, as part of the waste plastic material recycling plan, it is assumed that the PET/OPP laminated waste film is peeled off at the waste film generation site for the second use. The recycling rate of PET/OPP delaminated waste film is assumed to be 2%, 10%, and 30% referring to the figures suggested by "Life-cycle Post Plastic Measures" from the Korean government. In this study, a physical separation method was developed as a recycling approach for waste PET. A result of cost-benefit analysis was conducted to evaluate the economic viability of the recycling process based on changes in the recycling rate. The findings indicated that a recycling rate of waste PET was 30% or higher resulted in a cost-benefit ratio (Benefit-cost ratio, BCR) of 1.32, exceeding the threshold of BCR ≥1, which is considered to meet the minimum requirement for cost-benefit balance. As the government's allocation ratio and unit price are expected to increase in the future, the cost-benefit ratio is expected to increase further. This case is expected to serve as a pilot initiative for waste PET recycling and foster profit creation for businesses in similar industries.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.05a
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• pp.418-421
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• 2003

경량ㆍ고강도 기능성 Composite는 경량구조재료로 차량, 항공기, 선박 및 각종 설비의 안전구조재로 그 용도가 다양하게 사용되고 있다. 특히 폐플라스틱을 이용한 경량구 조재는 가격 경쟁력이 높고 또한 환경 및 자원 재활용 측면에서 관심이 고조되고 있다. 고강도, 안전성 확보를 위해 사용가능한 폐플라스틱 소재로는 가공성이 용이한 폐Polyethylene(PE), 폐Polypropylene(PP), 폐Polyethyleneterephthalate(PET) 등을 주원료로 가공되나, 기계적 특성이 저하되어 이의 개선을 위해 여러 가지 형태의 충진재의 혼합을 통해 개선하고자 하는 연구가 진행되어 왔다.(중략)