Near-Infrared Spectroscopic Monitoring Technique of Physical Blowing Agent Concentration in Foam Injection Molding Processes

Hosoe, Shunsuke; Hikima, Yuta; Ohshima, Masahiro; Watari, Masahiro; Naito, Akihiro

doi:10.4325/seikeikakou.33.176

Cited by 1 publication

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“…A similar tendency was observed for CO 2 foaming with a low-pressure foam injection molding machine. 47,48 This BP effect is attributed to a decrease in the surface area of the polymer-gas phase at the starvation zone as the back pressure increased. When the back pressure was increased, the length of the starvation zone decreased.…”

Section: Resultsmentioning

confidence: 99%

In-Line Near-Infrared Spectral Monitoring of Dissolved Nitrogen in Molten Polymers during Foam Injection Molding

Yoshikawa,

Hikima,

Ohshima

2024

Ind. Eng. Chem. Res.

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Polymeric foams offer significant benefits in terms of resource conservation. Foam injection molding (FIM) is a common mass-production technique used for preparing polymeric foams. Recently, we developed an inline near-infrared (NIR) spectroscopic sensor to monitor the concentrations of blowing agents dissolved in the polymers during the process. The proposed technique was suitable for measuring concentrations of carbon dioxide (CO 2 ); however, for nitrogen (N 2 ), it is still challenging because N 2 is infrared-inactive. A scheme developed in this research overcame this problem by estimating the N 2 concentration from changes in the polymer density resulting from N 2 dissolution. The NIR absorption peak of the polymer density was changed by the dissolution of N 2 during polymer processing. A multivariate model and an equation of state were combined to estimate the N 2 concentration from the NIR spectrum. The method provides precise concentrations for N 2 dissolved into the polymer as the physical blowing agent.

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Section: Resultsmentioning

confidence: 99%