Abstract

Synthetic wood adhesives, consisting of urea-formaldehyde resins (UF), phenol-formaldehyde resins (PF), melamine-formaldehyde resins (MF), and polyurethane resins, are widely used. For UF and MF, most investigations are concerned with reducing free formaldehyde content; for PF, most studies focused on finding new alternative chemicals to replace phenol. These adhesives come under the Carcinogenic, Mutagenic, and Reprotoxic chemicals (CMR) category. Due to global energy issues and dependency on petroleum sources, the focus has shifted to look for alternative and renewable raw material sources for wood adhesives. Conventionally available wood adhesives are polyvinyl alcohol (PVA) stabilized, with drawbacks like poor water resistance, poor heat resistance, low-temperature workability, and it’s based on petroleum resources. Polyvinyl acetate (PVAc) is non-resistant to moisture polymer, and if such adhesive joints are exploited in a moist environment, its strength substantially decreases. Sufficiently moisture-resistant adhesive joints are obtained by modifying PVAc dispersion with special compounds like reactive comonomer, Silanes, and modified PVA. To improve the workability at low temperature, Vinyl acetate (VAc) is copolymerized with specific comonomers like butyl acetate without affecting the performance properties. Here, we aim to present an overview of the research trend of PVAc-based adhesives in the wood industry. The review summarizes the current state of research PVAc-based adhesives.

Highlights

  • Wood adhesive Wood is a porous material with many inherited anatomical characteristics

  • Polyvinyl acetate (PVAc) is non-resistant to moisture polymer, and if such adhesive joints are exploited in a moist environment, its strength substantially decreases

  • Polyvinyl acetate (PVAc) emulsion is an odorless and non-flammable adhesive widely used in furniture and other wood product manufacture at room or low temperatures [46] [47]

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Summary

Introduction

Wood adhesive Wood is a porous material with many inherited anatomical characteristics. To that end, developing environmentally benign materials that can replace CMR-based wood adhesives is a vital objective [20]. Animal glue has to fight against instability and resistance to hot water and microorganisms, and the lack of block board limits their usage, though the use and application of synthetic resin in plywood production eliminate these drawbacks [24]. From this art, animal and fish glues were refined, and other adhesives were developed, such as an adhesive from egg whites to bond golf leaf. In addition to egg whites, other natural ingredients were used to prepare the glue, such as blood, bones, hide, milk, cheese, vegetables, and grains [25] [26]

Classification of Adhesives Based on Chemistries
Polyvinyl Acetate Emulsion
Current Issues Using Conventional Polyvinyl Acetate Emulsion Adhesive
Limitations
Conclusion
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