Novel adhesive for label derived from peanut meal and MDI

Abstract

Peanut meal (PM) as the raw material was crosslinked modification by different mass fractions of 4,4′-diphenylmethane diisocyanate (MDI), to prepare adhesives for label. The properties of the adhesives, including water resistance, the viscosity and solid content were investigated. The performance of the label adhesive modified using MDI were significantly higher than those of the unmodified adhesive, making it suitable for applications in the labels. The water resistance duration was up form 3 h to 77 h when the modifier was added at 15 wt.% (based on PM). Further, the viscosity of the modified adhesive increased to an appropriate 82.2 Pa·s, and its solid content increased from 16.01% to 18.16%. In addition, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD) were used to characterize the chemical interactions in the cured adhesives, and the thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were used to analyze the reason of adhesive performance improvement. It was found that incorporating MDI into the adhesives resulted in the formation of a dense crosslinking network structure because of chemical reactions between MDI and active groups on the protein molecules and the introduction of hydrophobic groups in the adhesives; these factors effectively prevented water penetration, thus improving the water resistance of the cured adhesives.

Keywords:

• Adhesive
• label
• peanut meal
• water resistance

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors’ contributions

All authors contributed to this paper. Y.K., F.C. and B.L. designed the research study. Y.K. performed the assay and analysed the data and wrote this paper. F.C. and B.L. reviewed the manuscript. All authors gave final approval for publication.

Data accessibility

• Our data are deposited in the Dryad Digital Repository: https://doi.org/10.5061/dryad.41ns1rnc2

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant no. 21676073], and the 13th Five-year National Key Research and Development Plan [grant no. 2018YFD0401100].