폴리프로필렌 수지의 유변물성을 고려한 사출성형공정 전산모사

지호석; 정현욱; Ho Suk Ji; Wook Jung

Polymer(Korea), Vol.47, No.1, 99-107, January, 2023

DOI10.7317/pk.2023.47.1.99 Export Citation

폴리프로필렌 수지의 유변물성을 고려한 사출성형공정 전산모사

Simulation of Injection Molding Process Considering Rheological Properties of Polypropylenes

지호석^{1, 2}, 정현욱 ^{1, †}

¹고려대학교 화공생명공학과
²S-OIL Chemical TS&D Center

Ho Suk Ji^{1, 2}, and Wook Jung^{1, 3, †}

¹Department of Chemical and Biological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea
²Chemical TS&D 31, S-Oil, Magokjungang 8-ro 1-gil, Gangseo-gu, Seoul 07793, Korea
³, Korea

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초록

폴리프로필렌(PP)의 유변물성을 오프라인 레오미터(회전형, 모세관)로 측정하여 인라인 레오미터로 측정한 결 과와 비교 분석하였다. 오프라인 및 인라인 레오미터로 측정한 유변물성 결과는 고전단속도 영역에서는 유사하였으 나, 저전단속도 영역에서는 유의미한 차이를 확인하였다. 측정한 유변물성 결과의 유효성 검증을 위해 spiral mold 및 flat mold의 사출성형 실험과 수치 모사를 수행하였다. 종합적으로 판단하였을 때, 오프라인 레오미터로 측정한 PP의 유변물성을 반영한 사출성형 유동 해석 결과가 인라인 레오미터를 활용한 결과 대비 실제 사출 실험 결과를 잘 예측하였는데 특히, flat mold에서의 최대사출 압력은 실제 실험결과와 거의 일치하였다. 또한, 용융 고분자의 흐 름성에 영향을 미치는 열적 특성 중 전이 온도와 냉각수 온도의 영향을 살펴보았다. 고분자의 고형화가 빠를수록 spiral mold 내 고분자의 흐름성이 약하였고, flat mold의 최대사출압은 높아지는 결과를 확인하였다.

The rheological properties of polypropylenes were measured using offline rheometers (a rotational rheometer and a capillary rheometer) and compared with those measured using an inline rheometer (injection molding rheometer). Shear viscosities from both offline and inline rheometers were similar in the high shear-rate region, but a remarkable difference was found in the low shear-rate region. Experiments and numerical simulations with Spiral and Flat molds were conducted to validate rheological properties of polypropylenes (PPs) measured from both rheometers. Comprehensively, the numerical simulation considering offline rheological data accurately predicted the actual injection-molded products in comparison to the case considering inline rheological data. Additionally, the effect of thermal conditions such as transition temperature and cooling water temperature on the flowability of molten PPs was investigated using spiral and flat molds. It is found that faster solidification of PPs decreased their flowability in Spiral mold and increased the maximum injection pressure in the Flat mold.

Keywords:off-line rheometer;rheological properties;injection molding process;numerical simulation;polypropylene

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Münstedt H, Kunststoffe., 68, 92 (1978)

[Related Articles]

[1] Dealy JM, Broadhead TO, Polym. Eng. Sci., 33, 1513 (1993)

[2] Even RC, Slone RV, Coating Method. US Patent 6,524,656 B2, 2003.

[3] Dealy JM, Wissburn KF, Melt Rheology and its Role in Plastics Processing; Van Nostrand Reinhold: New York, 1990.

[4] Aho J, Syrjala S, Polym. Test, 30, 595 (2011)

[5] Pezzin G, Polym. Eng. Sci., 3, 260 (1963)

[6] Boronat T, Segui VJ, Peydro MA, Reig MJ, J. Mater. Process. Technol., 209, 2735 (2009)

[7] Khan AU, Mahmood N, Bazmi AA, Mater. Res., 12, 477 (2009)

[8] Hassan H, Regnier N, Pujos C, Defaye G, Polym. Eng. Sci., 48, 1199 (2008)

[9] Syrjala S, Aho J, Korea-Aust. Rheol. J., 24, 241 (2012)

[10] Macosko CW, Rheology Principles, Measurements and Applications; VCH Publications: New York, 1994.

[11] Kelly AL, Coates PD, Dobbie TW, Fleming DJ, Plastics Rubber Compos. Proc. Appl., 25, 313 (1996)

[12] Covas JA, Nobrega JM, Maia JM, Polym. Test, 19, 165 (2000)

[13] Chiu SH, Pong SH, Polym. Degrad. Stabil., 64, 239 (1999)

[14] Qin X, Thomson MR, Hrymak AN, Polym. Eng. Sci., 1108 (2005)

[15] Gou G, Xie P, Yang W, Ding Y, Polym. Test, 30, 826 (2011)

[16] Friesenbichler W, Duretek I, Rajganesh J, Kumar SR, Polymery, 56, 58 (2011)

[17] Szucs A, Belina K, EXPRESS Polym. Lett., 6, 672 (2012)

[18] Bariani PF, Salvador M, Lucchetta G, J. Mater. Process. Technol., 191, 119 (2007)

[19] Cox WP, Merz EH, J. Polym. Sci., 28, 619 (1958)

[20] Gradys A, Sajkiewicz P, Minakov AA, Adamovsky S, Schick C, Hashimoto T, Saijo K, Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process., 413-414, 442 (2005)

[21] Bird RB, Armstrong RC, Hassager O, Dynamics of Polymeric Liquids Vol.1: Fluid Mechanics, 2nd ed.; John Wiley and Sons: New York, 1987.

[22] Gurtin ME, An Introduction to Continuum Mechanics; Academic Press: San Diego, 1981.

[23] Hieber CA, Shen SF, J. Non-Newton. Fluid Mech., 7, 1 (1980)

[24] Münstedt H, Kunststoffe., 68, 92 (1978)