TY - JOUR

T1 - Causes of the Gloss Transition Defect on High-Gloss Injection-Molded Surfaces

AU - Gim, Jinsu

AU - Han, Eunsu

AU - Rhee, Byungohk

AU - Friesenbichler, Walter

AU - Gruber, Dieter P.

PY - 2020/9/15

Y1 - 2020/9/15

N2 - The gloss transition defect of injection-molded surfaces should be mitigated because itcreates a poor impression of product quality. Conventional approaches for the suppression of thegloss transition defect employ a trial-and-error approach and additional equipment. The causes ofthe generation of a low-gloss polymer surface and the surface change during the molding processhave not been systematically analyzed. This article proposes the causes of the generation of alow-gloss polymer surface and the occurrence of gloss transition according to the moldingcondition. The changes in the polymer surface and gloss were analyzed using gloss andtopography measurements. The shrinkage of the polymer surface generates a rough topographyand low glossiness. Replication to the smooth mold surface compensates for the effect of surfaceshrinkage and increases the surface gloss. The surface stiffness and melt pressure influence thedegree of mold surface replication. The flow front speed and mold temperature are the main factorsinfluencing the surface gloss because they affect the development rate of the melt pressure and therecovery rate of the surface stiffness. Therefore, the mold design and process condition should beoptimized to enhance the uniformity of the flow front speed and mold temperature.

AB - The gloss transition defect of injection-molded surfaces should be mitigated because itcreates a poor impression of product quality. Conventional approaches for the suppression of thegloss transition defect employ a trial-and-error approach and additional equipment. The causes ofthe generation of a low-gloss polymer surface and the surface change during the molding processhave not been systematically analyzed. This article proposes the causes of the generation of alow-gloss polymer surface and the occurrence of gloss transition according to the moldingcondition. The changes in the polymer surface and gloss were analyzed using gloss andtopography measurements. The shrinkage of the polymer surface generates a rough topographyand low glossiness. Replication to the smooth mold surface compensates for the effect of surfaceshrinkage and increases the surface gloss. The surface stiffness and melt pressure influence thedegree of mold surface replication. The flow front speed and mold temperature are the main factorsinfluencing the surface gloss because they affect the development rate of the melt pressure and therecovery rate of the surface stiffness. Therefore, the mold design and process condition should beoptimized to enhance the uniformity of the flow front speed and mold temperature.

UR - http://www.scopus.com/inward/record.url?scp=85092081502&partnerID=8YFLogxK

U2 - 10.3390/POLYM12092100

DO - 10.3390/POLYM12092100

M3 - Article

VL - 12.2020

JO - Polymers

JF - Polymers

IS - 9

M1 - 2100

ER -