Flow analysis of conical spiral mandrel dies

2020 ◽  
pp. 875608792096976
Author(s):  
N Bouzari ◽  
F Goharpey
Keyword(s):  
Pressure Drop ◽  
Fluid Model ◽  
Flow Analysis ◽  
Flow Distribution ◽  
Film Extrusion ◽  
Blown Film ◽  
Initial Clearance ◽  
Blown Film Extrusion ◽  
Flat Spiral ◽  
Cylindrical Spiral

Spiral dies are divided into three categories, namely: Flat Spiral Die (FSD), Cylindrical Spiral Mandrel Die (SMD), and Conical Spiral Mandrel Die (CSD). These dies are used to produce films via blown film extrusion and multilayer films via co-extrusion. The goal is to improve the flow distribution and to decrease the pressure drop which will result in uniform film thickness and reduced energy dissipation. A viscous power-law fluid model shows that low-pressure drop and proper flow distribution can be achieved in a CSD simultaneously. As the number of grooves and the initial channel depth increases, the flow distribution becomes more uniform and the pressure drop decreases. Also, there is an optimum initial clearance and clearance increment angle. The model results show that the pseudo-plastic fluid has more appropriate performance than the Newtonian and dilatant fluids in improving the flow distribution and reducing the pressure drop.

Numerical investigation of the temperature influence on the melt predistribution in a spiral mandrel die with different polyolefins

2016 ◽  
Vol 36 (7) ◽  
pp. 751-760 ◽  
Author(s):  
Christian Hopmann ◽  
Nafi Yesildag
Keyword(s):  
Flow Distribution ◽  
Simulation Models ◽  
Thermal Design ◽  
Optimized Design ◽  
Temperature Influence ◽  
Film Extrusion ◽  
Blown Film ◽  
Melt Distribution ◽  
Shear Heating ◽  
Blown Film Extrusion

Abstract The main goal in the design of spiral mandrel dies for blown film extrusion is to achieve a homogeneous velocity distribution of the plastics melt at the die outlet. However, thermal inhomogeneities in the die can lead to an uneven flow distribution despite a rheologically optimized design of the die. The thermal inhomogeneities are especially dominant in the predistributor of spiral mandrel dies. Against this background, the temperature influence on the melt distribution in the predistributor is investigated for different polyolefins with the help of flow simulations in Polyflow (Ansys). The simulation models the whole predistributor and takes both the heat transfer in the predistributor and the shear heating in the melt into account. Afterwards, simulations are conducted in which the thermal design measures for the homogenization of the flow in the die are applied. With the combination of heating cartridges, brass inserts, and isolating gaps in the die, a significant homogenization of the predistribution can be achieved. Finally, the simulation results are validated in practical tests, whereby a good agreement between simulation and measurement can be observed.

scholarly journals Biodegradable Polymer Compounds Reinforced with Banana Fiber for the Production of Protective Bags for Banana Fruits in the Context of Circular Economy

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 242
Author(s):  
Pablo Bordón ◽  
Rubén Paz ◽  
Carolina Peñalva ◽  
Gisela Vega ◽  
Mario Monzón ◽  
...  
Keyword(s):  
Circular Economy ◽  
Environmental Problem ◽  
Ecotoxicity Test ◽  
Banana Fiber ◽  
Film Extrusion ◽  
Blown Film ◽  
Blown Film Extrusion ◽  
Environmentally Friendly Process ◽  
Test Requirements ◽  
Better Than

Bags used to protect and accelerate the ripening of bananas are a clear example of the environmental problem of packaging waste. Small pieces of these non-biodegradable bags are frequently disposed on the soil by accident (environmental conditions and poor handling during the harvest) and remain there for years. This work focuses on the development of protective biodegradable bags reinforced with banana fiber, obtained from waste of the banana plants, thus promoting a circular economy and a more environmentally friendly process. To achieve this, different bio-based composites were tested (processability) by compounding extrusion (biopolymer and banana fiber with different process steps) and blown film extrusion. The bags produced were tested in field and sequentially improved in three generations of biofilms. The results showed that the maximum processable fiber content was 5 wt %. Additionally, the micronizing of the compounds was crucial to simplify the blown film extrusion and improve the smoothness of the bags (scratches avoidance on the banana surface). The final bags (Mater-Bi biopolymer, 5% combed and sieved banana fiber, and 2.5 wt % TiO2 for ultraviolet light filtration), performed better than the conventional ones (faster maturing, i.e., earlier harvest, and easier handling) and fulfilled the biodegradability, composting and ecotoxicity test requirements.

Dynamic modeling of blown-film extrusion

2003 ◽  
Vol 43 (2) ◽  
pp. 398-418 ◽  
Author(s):  
J. Carl Pirkle ◽  
Richard D. Braatz
Keyword(s):  
Dynamic Modeling ◽  
Film Extrusion ◽  
Blown Film ◽  
Blown Film Extrusion

Real‐time wide‐angle X‐ray diffraction during polyethylene blown film extrusion

2008 ◽  
Vol 48 (8) ◽  
pp. 1487-1494 ◽  
Author(s):  
Giri Gururajan ◽  
H. Shan ◽  
G. Lickfield ◽  
A.A. Ogale
Keyword(s):  
Real Time ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Film Extrusion ◽  
Blown Film ◽  
Blown Film Extrusion

scholarly journals Development of PLA/EVA Reactive Blends for Heat-Shrinkable Film

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1925 ◽  
Author(s):  
Rattikarn Khankrua ◽  
Tanyawan Pongpanit ◽  
Ponchai Paneetjit ◽  
Rungnapha Boonmark ◽  
Manus Seadan ◽  
...  
Keyword(s):  
Ethylene Vinyl Acetate ◽  
Poly Lactic Acid ◽  
Elongation At Break ◽  
Blend Films ◽  
Film Extrusion ◽  
Blown Film ◽  
Twin Screw ◽  
Blown Film Extrusion ◽  
Reactive Blend

Heat-shrinkable films have widely been used for various applications such as shrinkable labels and cap seals. These plastics have generally a short life. The biodegradable polymers can thus be an ideal candidate for such applications. This work aimed to study the stretching and shrinking ratio of poly(lactic acid)/ethylene vinyl acetate through reactive blends system for heat-shrinkable films application. The reactive agents, Joncryl® and Perkadox were used as in situ compatibilizers. PLA/EVA with 100/0, 97/3, 95/5, 93/7, and 90/10 ratios were prepared in the twin screw extruder. Neat PLA and PLA/EVA films were fabricated by blown film extrusion. The results revealed that the elongation at break of PLA in the TD direction was improved when adding EVA. PLA and EVA film with 0.1 phr of Perkadox was found to be sufficient as evident by FESEM micrograph and DMTA results. The films were stretched and shrunk at a temperature of 70 °C. The percentage of shrinkage of the stretched PLA/EVA reactive blend films, two and three times were, 100%, approximately. On the other hand, the four-times stretched films shrunk less than 100% because of the excessive stretching, which resulted in film breakage and defect.

Mechanical Properties of Biodegradable Mulch Films Contained Poly(Lactic Acid) and Modified Natural Rubber Prepared by Blown Film Extrusion

2017 ◽  
Vol 873 ◽  
pp. 117-122
Author(s):  
Tarinee Nampitch ◽  
Thiti Kaisone ◽  
Pran Hanthanon ◽  
Chanon Wiphanurat ◽  
Sumate Ouipanich ◽  
...  
Keyword(s):  
Carbon Black ◽  
Poly Lactic Acid ◽  
Carbonyl Groups ◽  
Biodegradable Film ◽  
Film Extrusion ◽  
Blown Film ◽  
Biodegradable Mulch ◽  
Ester Linkage ◽  
Mulch Films ◽  
Blown Film Extrusion

The present research aimed to develop biodegradable mulch films that could resolve the environmental problem in agriculture. The research also compared the properties of transparent and black commercial mulch films. Blended films were prepared by blown-film extrusion, heating at 170 °C, and rotation at 55 rpm. The results revealed that the appearance of FTIR spectra were shown as functional groups of PBAT, described at 1710 cm-1 and 1267 cm-1, which corresponds to carbonyl groups in ester linkage and C-O in ester linkage, respectively. The presence of O-H carboxylic acids, attributed within the range 910-950 cm-1. The films containing 10% PLA loading showed peaks from 937 to 1712 cm-1, more than films containing 20% PLA loading. The carbon black contained in the biodegradable film could interrupt the mobility of the polymer chain, leading to decreased Tm, while the incorporation of carbon black in biodegradable mulch films could increase the tensile properties of blends.

Melt rheology and morphology of binary and ternary PS/HIPS blends for blown film extrusion applications

2017 ◽  
Vol 64 ◽  
pp. 277-286
Author(s):  
Karine Melro de Almeida ◽  
Ana Maria F. de Sousa ◽  
Fernando G. de Souza Junior ◽  
Luiz Carlos Bertolino ◽  
Marisa C.G. Rocha ◽  
...  
Keyword(s):  
Melt Rheology ◽  
Film Extrusion ◽  
Blown Film ◽  
Blown Film Extrusion
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