Since EVOH has an -OH group in its molecular structure, defects (particularly whitening) caused by water absorption occur during retort treatment (e.g., at 121deg C for 30 minutes). This, along with maintaining good long-run processability, were the challenges Nippon Gohsei faced in developing a retortable EVOH. At its Processing Technique Development Center, Nippon Gohsei worked to overcome these difficulties and has succeeded in developing the next-generation retortable EVOH, SoarnoL™ RB7405B. With this improved grade there are few surface defects after retort treatment and long-run processability is maintained
Industrial and consumer pouches for soups, sauces, and pastes.
Change of Appearance after Retort Treatment
Retort condition: 121deg C-30mins (content is water)
Structure of pouch: (PP/Tie/EVOH/Tie/PP)=(10/10/10/10/10)m
Evaluation: Check the transparency of the pouch by placing a black sheet with the word “Clear” in white letters behind the pouch.
Standard SoarnoL™ shows a decrease in transparency due to whitening of the pouch, so the background letters “Clear” cannot be read. With retortable SoarnoL™ RB7405B, however, the background letters “Clear” can be read easily.