Preparation And Application Of Formaldehyde-free Flame-retardant Adhesive For Plywood

With the rapid development of the wood industry,the shortage of wood resources worldwide has become increasingly serious.The development of comprehensive utilization of wood with artificial technology and wood-based panels as its core technology has become one of the important ways to solve the serious shortage of wood resources.Soy protein has attracted people’s attention as a safe and environmentally friendly green energy source,and soy protein adhesive is a green,non-polluting,functional adhesive that can be widely used in the rapidly growing wood industry.In this paper,a soybean-based aldehyde-free flame-retardant wood adhesive was produced using commercially available high-temperature soybean meal as raw material.The formula design was completed and the application process of plywood was explored.The main research contents of this paper are:Preparation of soybean-based aldehyde-free adhesives:This article produced soy protein powder(DF),examined the difference between DF and market soybean protein powder(SF),and examined the effect of the amount of modified solution KZDY1 on the mechanical properties of plywood.The experimental results show that when KZDY1:DF=1:1,the modification effect is the best,and the wet strength,static bending strength,and elastic modulus of the plywood reach the maximum,which meets national standards.Preparation of formaldehyde-free flame retardant adhesive:The effects of single flame retardant and compound flame retardant on the mechanical properties and flame retardant effect of plywood are compared through experiments,and a performance flame retardant is selected.Experiments show that the flame retardant effect is best when the compound flame retardant KZDF1 is 0.75 times the amount of DF added.The plywood has a burning time of 5s,a burning time of 30 s,a carbonized length of 37 mm,and a limiting oxygen index of 31.7%.With the addition of this kind of flame retardant,the plywood has a bonding strength of 1.21MPa,far exceeding the national standard.Process exploration of formaldehyde-free flame-retardant plywood:the application of formaldehyde-free flame-retardant adhesives to the production of plywood,and the single-factor experiment method was used to explore the application process of wood-based panels to determine the best application process.The best process for plywood application is:aging time 1 h,glue application amount 250 g/m~2,cold pressing time 60 min,hot pressing temperature 110℃,hot pressing pressure 1.2 MPa,and hot pressing time 8 min.At this time,the plywood’s wet bonding strength reached 1.12 MPa in compliance with national standards.