Study On Preparation And Application Of Flame Retardant Adhesive

There are some problems on the fire retardant technology of wood materials,1) theprocess is complicated,2) the flame retardant has negative effect on bonding properties of resin,3) the effect is easily decreased because the flame retardant is easily lost. It was one of the keyto overcome above-mentioned problems and simplify the flame retardant technology in theresearch field of the flame retardant wood materials. In this study, flame retardant MUF wasprepared by using mechanical mixture from intumescent flame retardant and self-mademelamine modified urea formaldehyde resin adhesive (MUF) as row materials to explore theproperties of MUF and flame retardant MUF. A series of studies were conducted to make athorough discussion on bonding and flame retardant properties of the flame retardant MUF.Meanwhile, the preparation technology of flame retardant MUF combined bonding propertieswith flame retardant properties was determined, and the flame retardant plywood, flameretardant blockboard and flame retardant composite wood floor were developed making use offlame retardant MUF,also conducted the production test.Firstly, the synthesis techniques of MUF were discussed and studied. Six kinds of themelamine-urea-formaldehyde resin (MUF) were synthesized by using modified and improvedsynthesis technology on the base of the original reference. The comprehensive performance ofthe resins was detected. The research showed that the condensation temperature was increasedfrom60℃to85℃, condensation time to30min, which could get the six stable resins. In thesix MUF, when n(F)/n(M+U)=1.5, n(M)/n(U)=1.0, the corresponding MUF3soakingdelamination performance and bonding strength had reached the national standard for class Irequirements, and the bonding strength was up to1.04MPa. It had a good fluidity placed atroom temperature.more than1months, whicn laid the foundation for the development of flameretardant resin. On the basis of synthesing MUF had excellent bond performance, the flame retardantMUF was prepared by intumescent flame retardant (APP, PER) and MUF by using mechanicalmixture. In the paper, the flame retardant MUF was prepared by intumescent flame retardantand MUF (in terms of solid content of resins) according to the mass ratio was respectively0.7:1,0.9:1,1:1.The physicochemical properties, bonding properties and flame retardantproperties of flame retardant MUF were emphasis studied, and the main conclusions aresummarized as follows:(1) Physicochemical properties research showed that the flame retardant MUF resinadhesive had good physicochemical properties, in the experimental range, with the increase ofamount of flame retardant, The viscosity of the flame retardant MUF was increased, the curingtime was prolonged, the pH was decreased.and application period was larger than6h;(2) Study on bonding performance indicated that the flame retardant MUF resin adhesivehad good bonding performance and water resistance. It can reache the national standard IIrequirements. With the increasing amount of flame retardant, the bonding strength of flameretardant MUF was reduced. When the mass ratio of flame retardant and MUF was0.9:1, themaxmum of flame retardant MUF bonding strength was up to1.35MPa; When the the massratio of flame retardant and MUF was1:1, the minimum of flame retardant MUF bondingstrength was up to1.03MPa.(3) Study on flame retardant properties demonstrated that flame retardant MUF resin hadgood flame retardant ability. With the increase of the quantity of flame retardant and coating offlame retardant MUF, the flame retardancy significantly growed. When the mass ratio ofintumescent flame retardant and MUF reach1:1, the coating of the flame retardant MUF reachs250g/m~2(single) on the surface of MDF, the ignition time of MDF was prolonged from32.2sto253.3s, the peek heat release rate was reduced from262.6KW/m~2to19.91KW/m~2, the totalheat release of300s was reduced from34.25MJ/m~2to0.91MJ/m~2.(4) Study on the preparation and properties of the flame retardant MUF clearly stated thatThe flame retardant MUF was prepared by intumescent flame retardant and MUF, when theirmass ratio between0.7:1and1:1, not only the bonding strength beyond the requirements of the national class II standard, but also it had good flame retardant effect and physicochemicalproperties. It may be possible to realize that the wood materials had a good flame retardance ifthe flame retardant MUF was used reasonably.In order to verify the good bonding properties and flame retardant ability of the flameretardant MUF, the fire retardant plywood and its preparation technology were developed,which used flame retardant MUF by the way of building a flame retardant layer on the surfaceof ordinary plywood. The factors which influenced on the flame retardance of flame retardantplywoods were studied. Such as flame retardant adhesive layer amounts, the ratio of MUF andflame retardant single board flame retardan or not.The conclusions are as follows:(1) The flame retardant protective layer has good protective effects on ordinary plywoodbecause of significantly ability to resist external heates source to internal radiation.(2) With the increase of the flame retardant additives and the number of flame retardantMUF layers in the flame retardant layer, the heat release rate and total heat release of flameretardant plywood are significantly reduced, and the flame retardance is improved significantly.After the single board was fire retardant treated, which is beneficial to further improve theflame retardant performance of flame retardant plywood. But it will increase the complexity ofprocess.(3) In actual application process, we can change the factors of flame retardant additives,flame retardant adhesive layer amounts, single board was flame retardanted or not, in whichorder to meet the requirements of the flame retardant grade.On the basis of laboratory studies, the prepared technology and application performanceof flame retardant MUF were studied in the production. Without changing the originalproduction technology, the fire retardant wood materials, such as flame retardant plywood,flame retardant blockboard and flame retardant composite wood floor were developed by flameretardant MUF in production. The flame retardant properties of them have got up to theGB/T8624-2006(GB/T8624-1997) B(B1) level, the bonding strength has reachedGB/T17657-1999class II level, the formaldehyde emission has reached the national standardE1requirement. The test results showed that the synthetic process of MUF is stability, the preparation technology of flame retardant MUF could meet the requirements of industrialproduction, and it has the feasibility for the industrial production.