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Title:: Development and application of injection molding grade polypropylene special material RM 060 T for milk tea cup

Author(s):: YAN Ling; YANG Jian; YANG Lei; HU Cong- yin; LUO Heng- Rong; ZHANG Jin- tang; Yunnan Yuntian Chemical and Petrochemical Co Ltd， Kunming 650000， China

Keywords:: polypropylene; food &; injection molding grade special material for milk tea cup; n-hexane dissolution; melt flow rate; mass fraction of ethylene; impact strength

摘要:: 在云南云天化石化有限公司15万t/a 的聚丙烯（PP）装置上，采用美国Grace公司开发的Unipol■无规共聚PP工艺及其C 702催化剂，开发生产出合格的食品注塑级奶茶杯PP专用料RM 060 T。结果表明：开发出合格RM 060 T的优化工艺条件为：催化体系的Al/Si，Al/Ti摩尔比分别为4.5~5.5，65~85，乙烯/丙烯的摩尔比为0.022~0.026，氢气加入量为6~8 kg/h，反应器的冷凝量为4%~9%；聚合条件为：反应温度60.0~64.0 ℃，反应压力3.00~3.20 MPa，循环气流速0.38~0.40 m/s，流化床床层料位高度18.5~20.0 m；其产品的熔体流动速率为5.5~6.5 g/min、弯曲模量不小于800 MPa、简支梁缺口冲击强度不小于3.7 kJ/m2、雾度不大于10%、正己烷溶出物质量分数为0.7%，二甲苯可溶物质量分数为10.2%。

Abstract:: The qualified food & injection molding grade polypropylene（PP） special material RM 060 T for milk tea cups was developed and produced in 150 kt/a PP unit of Yunnan Yuntian Petrochemical Co Ltd， by using the Unipol■ random copolymerization of PP process and its C 702 catalyst both developed by Grace Company of America. The results showed that: The comprehensive conditions for the development and production of qualified RM 060 T were: the molar ratios of Al/Si and Al/Ti in the catalytic system at 4.5-5.5 and 65-85， respectively， the ethylene feed measurement via the molar ratio of ethylene/propylene at 0.022-0.026， the hydrogen feed amount at 6-8 kg/h， the condensation volume control of the polymerization reactor at 4%-9%； and the polymerization reaction control conditions of reaction temperature at 60.0-64.0 ℃， reaction pressure at 3.00-3.20 MPa， the circulating gas flow rate at 0.38-0.40 m/s， and the material level height of fluidized bed at 18.5-20.0 m. The performance test results of RM 060 T product were as followed: the melt flow rate（MFR） at 5.5-6.5 g/min， the bending modulus not less than 800 MPa， the notch impact strength of simply supported beam not less than 3.7 kJ/m2， the haze level not more than 10%， the mass fraction of n-hexane dissolved matter and xylene soluble matter at 0.7%， 10.2% respectively.