高性能聚乙烯管材的開發

Research and Development of High Performance Polyethylene Pipes

王瑞棠(Jui-Tang Wang)

《石油季刊》 45卷4期 (2009/12) Pp. 67-86

https://doi.org/10.30128/JP.200912.0005

摘要

聚乙烯是一種熱塑性、半結晶型的功能性高分子，由於具有低成本、優異物性及多樣化的特性，因此能夠覆蓋各種領域的應用。聚乙烯也是一種應用在戶外曝曬相當具有潛力的材料，特別是密度範圍940到960kg/立方公尺的中密度與高密度聚乙烯。在管材的應用領域上，具高規格的韌性與衝擊強度的樹脂通常需要使用高分子量與雙峰分子量分佈的高密度聚乙烯為材質。
如吾人一向所知，以最小要求強度(MRS)作為定級標準且應用於給水管與燃氣管（壓力管）的第一代管材與第二代管材的環向應力值分別為6.3MPa及8.0MPa，即所謂的PE63等級與PE80等級管材，而當第三代管材料的環向應力值為10MPa時，即稱PE100等級樹脂，該定級標準是根據ISO/TR9080的測試方法，強調由這些材料所製造的混摻料管材必須能夠在20℃條件下承受連續受到10MPa的環向應力達50年而不被破壞。通常，高性能管材樹脂屬於高密度聚乙烯材質，具有優異的抗慢速裂紋增長(SCG)、極佳的抗快速裂紋擴長(RCP)和極高的抗蠕變等性能。
文中主要著墨於台灣塑膠公司的高性能聚乙烯管材（PE100等級）之研發過程、創新製程生產技術、專利現況及樹脂特徵等，其次，利用如TREF-DSC與TREF-GPC等交叉分級技術的微結構手段研究分子結構和樹脂加工性的關連性，並以自主創新的多段重合製程與高活性觸媒的組合方式優化分子量、分子量分佈及共重合單體分佈的生產條件。最新的研究結果指出，高性能聚乙烯管材台塑烯8001牌號的PENT值已經超過25,000小時，較開發初期時的PENT值僅200小時大幅地提高。

關鍵字

高密度聚乙烯 ； PE100等級管材 ； 慢速裂紋增長 ； 快速裂紋擴長 ； 聯結分子

並列摘要

Polyethylenes (PE) acting as performance materials is a thermoplastic semi-crystalline polymers. They can cover a very wide range of applications owing to their low cost, good physical properties and versatility. It is also a material with potential for applications in outdoor explosure, particularly medium and high density polyethylene resins having the density range of 940 to 960 kg/m^3. In the pipe application field, high requirements of stiffness and impact strength of the resin require the use of high density polyethylenes with higher molecular weight and bimodal molecular weight distribution.
It has been well known that first-and second-generation PE pipes for water and gas distributions (pressure pipes) have minimum required strength (MRS) ratings for respective hoop stresses of 6.3 and 8.0 MPa, and are known as PE63 rating and PE80 rating individually. The third-generation materials, which are known as PE100 rating resins with hoop stress of 10 MPa. The rating is based upon the ISO/TR 9080 test method, which specifies that PE pipes manufactured from these materials should withstand a circumference stress of 10 MPa for up to 50 years at 20℃. Generally, high performance pipe resins are high density polyethylene products that exhibit exceptional resistance to slow crack growth (SCG), excellent rapid crack propagation (RCP) resistance and very high creep resistance.
This paper will mainly focus research and development history, state-of-the-art process technology, proprietary patents status quo and its physical characteristics of high performance polyethylene resins pipe (PE100 rating) made by Formosa Plastics Corporation. In addition, we investigate the relationship between molecular architecture and resin processing properties by means of micro approach such as TREF-DSC and TREF-GPC cross-fraction chromatography (CFC) techniques, and optimize the molecular weight, molecular weight distribution and comonomer distribution using our innovative multi-stage tandem (MT) polymerization process together with high-milleage activity catalyst. Recent investigations have pointed out that the measured PENT value for our new Taisox 8001 (PE100 rating resin) designed to improve SCG performance is over 25,000 hrs compared to only 200 hrs for the initial Taisox 8001 resin.

並列關鍵字

High Density Polyethylene ； PE100 Rating Pipe ； Slow Crack Growth ； Rapid Crack Propagation ； Tie Molecule