Collagen Modified Hardener for Melamine-Formaldehyde Adhesive for Increasing Water-Resistance of Plywood

Improving coating properties of shellac–epoxidised-novolac blends with melamine formaldehyde resin

Pigment & Resin Technology ◽

10.1108/prt-02-2016-0022 ◽

2017 ◽

Vol 46 (2) ◽

pp. 92-99 ◽

Cited By ~ 1

Author(s):

Mohammad Fahim Ansari ◽

Gautam Sarkhel

Keyword(s):

Metal Surfaces ◽

Water Resistance ◽

Coating Material ◽

Alkali Resistance ◽

Formaldehyde Resin ◽

Coating Properties ◽

Melamine Formaldehyde ◽

Novolac Resin ◽

Content Type ◽

Melamine Formaldehyde Resin

Purpose The purpose of this study is to improve the coating properties of shellac–epoxidised novolac blends by treatment with melamine formaldehyde resin (MF) at ambient temperature for its use as a coating material. Design/methodology/approach Epoxidised-novolac resin was synthesised by epoxidation of novolac resin with epichlorohydrin. Novolac resin was synthesised by reaction of phenol with formaldehyde in acidic medium. Shellac was blended with the epoxidised-novolac resin in solution in varying ratios and treated the blends with MF resin in fixed ratio. Coating properties of the treated compositions were studied using a standard procedure. The compositions were characterised with Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopic (SEM) spectroscopy. Findings Treatment of shellac–epoxidised-novolac blends with MF resin improved water and alkali resistance of the blends, besides enhancing gloss. Gloss in all the blends was uniformly increased on treatment with MF resin. Water resistance of the blends tremendously improved after treatment with MF resin. Contact angle of the blends against water increased while decreased against ethylene glycol and dioxane. The compositions were more resistant to polar solvent than non-polar ones, suggesting that the compositions shifted to hydrophobic (lipophilic) nature on treatment with the MF resin. Research limitations/implications A specified concentration of MF resin was used in the study. Different concentrations of the MF resin can also be tried for treatment of shellac–epoxidised-novolac blends to see the effect of the resin on the blends. Practical implications Treatment of shellac–epoxidised-novolac blend with MF resin improved the coating properties of the blends. The formulation SeNB-64 is the best with high gloss, good impact, scratch hardness and water resistance, and hence can be used as coating material for metal surfaces. Originality/value Blending of shellac with epoxidised-novolac resin and treatment of the blends with the MF resin was done for the first time. The formulation SeNB-64 can be used as coating material for metal surfaces.

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Emulsifier-Free Acrylate-Based Emulsion Prepared by Reverse Iodine Transfer Polymerization

Polymers ◽

10.3390/polym12030730 ◽

2020 ◽

Vol 12 (3) ◽

pp. 730

Author(s):

Tao Huang ◽

Qing-Xia Yuan ◽

Shu-Ling Gong

Keyword(s):

Molecular Weight ◽

Emulsion Polymerization ◽

Water Resistance ◽

Solid Content ◽

Chain Extension ◽

Mass Ratio ◽

Melamine Formaldehyde ◽

One Pot ◽

Moderate Amount ◽

Iodine Transfer

The self-emulsifying acrylate-based emulsions with solid content 45 wt.% were prepared in 3.5 h by reverse iodine transfer polymerization (RITP), and the polymer molecular weight (Mn) could be 30,000 g·mol−1. The influences of methacrylic acid (MAA) amount, soft/hard monomer mass ratio, and iodine amount on polymerization and latex were investigated. A moderate amount of ionized MAA was needed to stabilize the emulsion. Glass transition temperature (Tg) was decreased with the increasing mass ratio of soft/hard monomer. A higher iodine amount resulted in lower Mn. The increased Mn after chain extension of the polymer with water-insoluble monomers in iterative one-pot method proved the living of polymer. Compared with conventional emulsion polymerization, molecular weight (Mn) could be controlled, and Mn of polymer synthesized in RITP emulsion polymerization is higher; emulsion of polyacrylate-containing hydroxyl monomer units prepared by RITP emulsifier-free radical polymerization is more stable. Good properties, such as hardness, water resistance, adhesion, and increased value of maximum tensile of films modified by reaction of polyacrylate with melamine–formaldehyde (MF) resin, indicated potential application in baking coating.

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