Preparation And Characterization Of Binders For Water-based Ultra-thin Intumescence Fire Retardant Coatings

The fire seriously endangers the safety of human life and property. Application of fireretardant coatings is one of the most effective ways to improve fireproof performance of thebuildings. At present, the common water-based ultra-thin intumescence fire retardant coatingsexhibit some disadvantages such as short fireproof time, and the char layer has low degree ofexpansion as well as bad adhesion to the base material. The binder is one of the keycomponents for the fire retardant coatings. The binder is not only used for adhering othercomponents together, but also participates in the charring process of the coatings on fire. Thethermal decomposition temperature, softening temperature and melt viscosity of the bindershave important influence on the fireproof performance. Hence, it has a great theoreticalsignificance and practical value to study the binders of fire retardant coatings. In this paper,binders which are suitable for water-based ultra-thin intumescent fire coatings are prepared,and the main studies are as follows:(1) The ternary acrylic copolymer emulsion of AN/VAc/2-EHA and thephosphorus-containing copolymer emulsion were synthesized. Firstly, the synthetic processconditions of the ternary acrylic copolymer emulsion, such as the reaction temperature, thetype and amount of emulsifier and initiator were explored. Then the phosphorus-containingcopolymer was synthesized, and the effects of phosphorus-containing vinyl monomerPAM-100content on the properties of emulsion were studied. The results showed thatAN/VAc/2-EHA copolymer emulsion with high quality could be obtained when the reactiontemperature was75oC, the amounts of emulsifier SDS/OP-10and initiator KPS/NaHSO3were2.5-3.5%,0.71%respectively, and the quality ratio of anionic and non-ionic emulsifierwas2:3. The introduction of PAM-100enhanced the chemical stability of the latex, loweredthe initial decomposition temperature and thermal decomposition rate of copolymer, andimproved the high-temperature thermal stability and carbon residue of polymer at the sametime.(2) The VAc/Veova-10copolymer emulsion was synthesized. The synthetic processconditions, such as the polymerization technique, the reaction temperature, the type andamount of emulsifier and initiator, the type of protective colloid, the amount and adding means of MAA, were studied. The results showed that the VAc/Veova-10latex with highquality could be obtained when the reaction temperature was75oC, and the amounts ofemulsifier CO-436, initiator KPS/NaHSO3and MAA were3%,0.65%,3%, respectively. Theintroduction of reactive emulsifier ANPEO10-P1and protective colloid could enhance thechemical stability of the latex remarkably, but the particles size of VAc/Veova-10polymerincreased in those cases.(3) The effects of phosphorus-containing copolymer on the properties of water-basedultra-thin intumescence fire retardant coatings were investigated. The fire retardant coatingsusing AN/VAc/2-EHA/PAM-100emulsion as binders were prepared. The results revealed thatPAM-100could increase the fire-resistant time of fire-proof coatings, but the effect was notobvious. The fire retardant coatings using VAc/Veova-10/P emulsion as binders were alsoprepared. The results showed that the fire-resistant time based on this binder was9min longerthan the coatings based on non-phosphorus VAc/Veova-10emulsion.(4) The effects of the binder types on the performances of fire retardant coatings wereinvestigated. The fire retardant coatings using acrylate, styrene-acrylat andVAc/Veova-10/PVA emulsion as binders were prepared. Dynamic mechanical analysis (DMA)results demonstrated that VAc/Veova-10/PVA copolymer has lower Tg and softening meltingtemperature. The coatings using VAc/Veova-10/PVA as binders presented outstanding fireretardant performance (52min).(5) The effects of composite viscosity of binders on the performances of fire retardantcoatings were investigated. The rheological properties of VAc/Veova-10latex with differentmolecular weights were tested, and the water-based ultra-thin intumescence fire retardantcoatings using VAc/Veova-10as a binder were prepared. The results indicated that with theincrease of the composite viscosity of binders, the structural strength and compactness of theintumescent layer was enhanced, and the fire-resistant performance of the coatings wasimproved.(6) The therrmogravimetric analysis results of binders, intumescent fire retardantsystem and coatings showed that the synergistic effect of VAc/Veova-10/PVA copolymer andthe intumescent fire retardant system were helpful for forming the char layer.