Troubleshooting and mitigating gels in polyethylene film products

Abstract

The term “gel” refers to any small defect that distorts a film product. Eliminating gel defects from extruded polyethylene film products can be difficult, time consuming, and expensive due to the problem's complexity and the off-specification product produced. This paper discusses how to: identify gel types, common root causes, and technical solutions for mitigating gels in film products produced using single-screw extruders.

Keywords

Gels unmixed gels unmelts film defects single-screw extruders screw design mixers

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References

Campbell

Spalding

. Analyzing and troubleshooting single-screw extruders, Munich: Hanser, 2013.

Butler

Gel Troubleshooting. In: Butler

(ed). Film extrusion manual, Atlanta, GA: TAPPI Press, 2005, pp. 275–286. .

Scheirs

. Compositional and failure analysis of polymers, New York: Wiley, 2000.

Kodjie

Guerra

Savargaonkar

. Analytical techniques for characterizing defects and morphology of polymer films. 2012 Microsc Microanal 2012, pp. 715, .

Garcia-Meitin

Bar

Blackson

et al.

High resolution polymer imaging using scanning transmission electron microscopy. Microsc Microanal 2008; 14: 1380, .

Blackson

Garcia-Meitin

Darus

. High resolution scanning electron microscopy examination of polymer morphology. Microsc Microanal 2007; 13: 1062.

Hemsley

. Applied polymer light microscopy, London: Elsevier Applied Science, 1989.

Hyun

Spalding

Powers

. Elimination of a restriction at the entrance of barrier flighted extruder screw sections. SPE-ANTEC Tech Papers 1995; 41: 293.

Spalding

. Metering channel flows and troubleshooting single-screw extruders. SPE-ANTEC Tech Papers 2004; 50: 329.

10.

LeRoy G. Apparatus for extrusion of thermoplastics. Patent 3,486,192, USA, 1969.

11.

Andersen

Shih

C-K

Spalding

et al.

Breakthrough inventions in polymer extrusion. SPE ANTEC Tech Papers 2009; 55: 668.

12.

Sun

Gou

Spalding

et al.

Optimization of maddock-style mixers for single-screw extrusion. SPE-ANTEC Tech Papers 2016; 62: 898.

13.

Sun

Spalding

Womer

et al.

Optimization of maddock-style mixers for single-screw extrusion. SPE-ANTEC Tech Papers 2017, pp. 63.

14.

Hyun

Spalding

. Troubleshooting TPU resin extrusion rate limitations due to solids in the discharge. SPE-ANTEC Tech Papers 2012, pp. 58.

15.

Maddock

. A visual analysis of flow and mixing in extruder screws. SPE J 1959; 15: 383.

16.

Spalding

Dooley

Hyun

. The effect of flight radii size on the performance of single-screw extruders. SPE-ANTEC Tech Papers 1999; 45: 190.

17.

Moffat

. Viscous and resistive eddies near a sharp corner. J Fluid Mech 1964; 18: 1.

18.

Najarzadeh

Abdellah Ajji

. Role of molecular architecture in interfacial self-adhesion of polyethylene films. J Plastic Film Sheeting 2017; 33: 1.

19.

Spalding

Womer

. Mitigating gels in polyethylene products produced using grooved-bore, single-screw extruders. SPE-ANTEC Tech Papers 2017, pp. 63.

20.

Recommended Dimensional Guideline for Single Screws. The Society of the Plastics Industry, Inc.

21.

Maillefer C. Patent, 363,149 Swiss, 1962.

22.

Gale GM. Extruder mixer. Patent 4,419,014, USA, 1983.

23.

Wang

Manus-Zloczower

. Flow field analysis of a cavity transfer mixer. Polym Eng Sci 1994; 34: 1224.

24.

Neubrech

Karrenberg

Wortberg

. Virtual and experimental comparison of different dynamic mixing devices for single-screw extrusion. SPE-ANTEC Tech Papers 2017, pp. 63.

25.

Spalding

Powers

. Elimination of defects from injection molded parts via screw modifications. SPE-ANTEC Tech Papers 2009; 55: 2463.

26.

Spalding

Campbell

. Using hypothesis setting to optimize the troubleshooting process for single-screw plasticators. SPE-ANTEC Tech Papers 2011; 57: 1392.