Effect of co-additives on the flame/smoke suppression properties of zinc borates

Two zinc borates are useful partial replacements for the antimony oxide flame retardant normally used to flame retard flexible PVC products. The effect of using various co-additives with zinc borates on the flame retardancy and smoke formation of a model flexible PVC cable jacket was evaluated in an attempt to further improve the properties of the formulation. The use of ammonium octamolybdate with the borates yields products with improved properties. Highly flame retarded formulations that yield low levels of smoke can be prepared by using alumina trihydrate or magnesium compounds as replacements for the usual calcium carbonate filler. Replacement of part of the phthalate ester plasticizer with brominated ester, a phosphate ester, or a brominated phosphate ester also results in formulations with oxygen values as high as 39.5 which produce lower levels of smoke.     

Thermal behavior and flame retardancy of flexible poly(vinyl chloride) treated with zinc hydroxystannate and zinc stannate

The flame‐retardant and smoke‐suppressant properties of inorganic tin compounds such as zinc hydroxystannate (ZHS) and zinc stannate (ZS) were studied in comparison with those of alumina trihydrate and magnesium hydroxide through the limiting oxygen index test and a smoke density test. The thermal degradation in air of flexible poly(vinyl chloride) (PVC) treated with the above compounds was studied by thermal analysis from ambient temperature to 800°C. The activation energy was calculated by using the Vyazovkin model‐free kinetic method and the Kissinger method. The results showed that tin compounds such as ZHS and ZS could be used as highly effective flame retardants for flexible PVC; these flame retardants enhanced the stability and the activation energy of the oxidation of the char. J. VINYL ADDIT. TECHNOL, 2008. © 2008 Society of Plastics Engineers     

Zinc hydroxystannate and zinc stannate as flame‐retardant agents for flexible poly(vinyl chloride)

The flame‐retardant and smoke‐suppressant properties of inorganic tin compounds such as zinc hydroxystannate (ZHS) and zinc stannate (ZS) were investigated in a comparison with alumina trihydrate, magnesium hydroxide, and Sb₂O₃ through the limiting oxygen index test and smoke density test. The flame‐retardant mechanisms were studied through the char yield test, SEM, quantitative analysis, thermogravimetry and differential thermal analysis. The thermal degradation in air of flexible PVC treated with the above compounds was studied by thermal analysis from ambient temperature to 800°C. The results showed that tin compounds such as ZHS and ZS could be used as a highly effective flame retardant for flexible PVC, and it appears that the tin compound may exert its action in both the condensed and vapor phases, but mainly in condensed phases as a Lewis acid. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1469–1475, 2005     

Enhanced flame retardancy and thermal stability of zinc borate and magnesium carbonate as a promising alternative for Sb2O3 toward polyvinyl chloride

Inorganic zinc compounds such as zinc carbonate (ZC) and zinc borate (ZB) are considered as promising alternatives for harmful antimony trioxide in the future, but may result in poor thermal stability for flexible polyvinyl chloride (PVC). To enhance the flame retardancy and static thermal stability of flexible PVC, zinc compounds with environmentally friendly magnesium carbonate (MC) were introduced into PVC matrix. Findings reveal that the simultaneous use of 5 phr ZB and 5 phr MC for flexible PVC exhibits satisfactory properties containing pronounced flame retardancy with a limiting oxygen index of 30.2% and a UL-94 V-0 rating without dripping, enhanced static thermal stability with high color stability by discoloration tests, reduced smoke emission, and decent mechanical properties, which are advantageous over the standalone use of ZC, ZB, and MC. The enhancement mainly due to that the incorporation of ZB can accelerate the dehydrochlorination and promote the charring of flexible PVC in the early stage of flame burning, and MC can perform the long-term static thermal stability due to the HCl absorption capacity.     

金属配合物对软聚氯乙烯的阻燃消烟作用

利用热分析的方法研究了以Al(OH)3和Mg(OH)2为基础，含有Fe、Co、Ni或Cu的金属配合物的复合阻燃剂对软聚氯乙烯(PVC)的阻燃消烟作用。研究了软PVC从室温到1073K的热降解过程。利用Kissinger方程给出了其动力学参数。结果表明：阻燃处理过的软PVC具有较好的阻燃消烟性能，如较高的氧指数和剩炭率，较低的烟密度等级和最大烟密度，力学性能有所降低。     

Recent studies on the use of zinc borate as a flame retardant and smoke suppressant in PVC

By the Oxygen Index test, zinc borate alone is an effective flame retardant in rigid PVC. In flexible PVC formulations containing 50 phr of dioctyl phthalate as the plasticizer, zinc borate in combination with antimony oxide displays a synergistic effect at a total loading of more than 10 phr (1-to-1 ratio). In the presence of 30 phr of alumina trihydrate, this synergism increases significantly at a total loading as low as 5 phr. Zinc borate also shows strong synergism with alumina trihydrate. Zinc borate acts as a smoke suppressant in plasticized PVC. With alumina trihydrate, a strong smoke-reducing synergism is created. Zinc borate in a flexible PVC formulation markedly increases the amount of char formed, whereas the addition of antimony oxide, a vapor phase flame retardant, has little effect on char formation. Zinc borate is a good afterglow suppressant. Volatilized zinc derived from the zinc borate probably contributes to flame retardancy but not to smoke suppression. Zinc compounds can alter the pyrolysis chemistry by catalyzing dehydrohalogenation and promoting crosslinking, resulting in increased char formation and a decrease in both smoke production and flaming combustion.     

高分子粘结膜与金属化合物对PVC树脂的协同阻燃消烟作用

研究了铝塑复合板中高分子粘结膜与Mg(OH)_2和CaCO_3复合阻燃剂对PVC树脂的协同阻燃消烟作用。通过NBS烟箱等仪器测试的有关参数对PVC体系中的金属化合物及填料的抑烟、阻燃效果进行了分析和研究。结果表明：在高分子粘结膜和金属化合物协同作用下能使烟密度(MSD)和生烟速率显著降低,而且有效地推迟了发烟时间。各种金属化合物对PVC体系的氧指数(LOI)影响不大,对烟密度的影响差异很大。     

Aryl phosphate ester fire‐retardant additive for low‐smoke vinyl applications

Additives that act as flame retardants can contribute significantly to smoke generation because they decrease the efficiency of the fuel source and, as a result, create a sooty combustion. Work on a new phosphate ester material has shown interesting results and synergies that complement both flame retardancy and low smoke generation in flexible vinyl compositions. This new proprietary aryl phosphate was examined in both neat and blended systems and compared to other typical phosphate ester fire‐retardant (FR) compounds for vinyl. Additionally, the flammability and smoke effects were measured with and without other common vinyl FR additives (zinc borate and ammonium octamolybdate). J. Vinyl Addit. Technol. 10:187–192, 2004. © 2004 Society of Plastics Engineers.     

软聚氯乙烯的阻燃抑烟研究

本文借助氧指数法，差热分析，热重分析研究了Ａｌ（ＯＨ）３，Ｍｇ（ＯＨ）２，Ｓｂ２Ｏ３对软质ＰＶＣ的阻燃作用和锌化合物对软ＰＶＣ的抑烟作用。结果表明，Ｓｂ２Ｏ３对软ＰＶＣ的阻燃效果优于Ａｌ（ＯＨ）３和Ｍｇ（ＯＨ）２的；由Ｓｂ２Ｏ３，ＣａＣＯ３和锌化合物组成的阻燃抑烟体系，对软ＰＶＣ具有良好的阻燃抑烟效果。     

Metal hydroxystannates as flame retardants and smoke suppressants for semirigid poly(vinyl chloride)

Metal hydroxystannates were studied as flame retardants and smoke suppressants for semirigid poly(vinyl chloride) (PVC). The flame‐retardant and smoke‐suppression mechanisms were investigated by using limiting oxygen index (LOI), smoke density rating (SDR), the solid yield test (SY), scanning electron microscopy (SEM), thermogravimetry, differential thermogravimetry, and differential thermal analysis. Results showed that semirigid PVC treated with the flame retardants had a higher LOI, and solid yield, but a lower SDR and maximum smoke density, thereby indicating that the flame‐retardance and smoke‐suppression properties of the treated PVC were improved and that the hydroxystannate compounds could be used as highly effective flame retardants. The tin compounds may exert their action in both the condensed and vapor phases, but mainly in the condensed phase as Lewis acids. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.     

锡酸锌对软质聚氯乙烯的阻燃和抑烟作用

采用氧指数法、热重分析及烟密度测试法就锡酸锌对软质PVC的阻燃抑烟行为进行了研究。发现锡酸锌不仅是软质PVC的良好阻燃剂，更是一种性能优异的抑烟剂，添加15份时，最大烟密度只是空白试样的32．5％，氧指数为30．8，有可能代替三氧化二锑用于软质PVC的阻燃和抑烟。     

活性炭模板制备铝酸铁及其在软PVC中的阻燃应用

以硫酸铁和硫酸铝为原料,以磷酸处理过的活性炭为模板制备铝酸铁阻燃剂。并通过X射线衍射（XRD）和红外吸收光谱（FT-IR）对合成铝酸铁阻燃剂做了表征。用极限氧指数、烟密度测试其对PVC的阻燃消烟性,当铝酸铁阻燃剂的添加量为5%（质量分数）时,阻燃后软PVC的极限氧指数达到32.8%,烟密度等级为55.45%,拉伸强度为18.36 MPa,断裂伸长率为214%,并通过热重分析对阻燃前后PVC的热降解行为做了研究。结果表明：以活性炭为模板制备的铝酸铁阻燃剂对软质PVC具有较好的阻燃消烟性能。     

阻燃剂在低烟无卤电线电缆料中的应用

通过对低烟无卤电线电缆燃烧特性和阻燃剂的阻燃机理的分析,论述了无机金属化合物、磷系、氮系、磷氮系阻燃剂等不同类型阻燃剂的阻燃特性、发展动向及新型阻燃技术,指出无卤、高效、低烟、低毒、多功能的新型阻燃剂合成及其新型阻燃技术的研究是阻燃剂的发展方向。     

Poly(vinyl chloride) and its fire properties

This work provides an up‐to‐date review of the fire properties of poly(vinyl chloride) (PVC) materials, both rigid (unplasticized) and flexible (plasticized). The fire properties addressed include ignitability, ease of extinction (oxygen index), flame spread (small scale and intermediate scale), heat release, smoke obscuration, smoke toxicity, hydrogen chloride emission and decay, and performance in real‐scale fires. This comprehensive review includes a wide selection of references and tables illustrating the properties of PVC materials in comparison with those of other polymeric materials, including, in many instances, wood materials. The work puts these fire properties in perspective, showing that the heat release rate (the key fire property) of rigid PVC (and that of properly flame‐retarded flexible PVC) are among the lower values found for combustible materials. This work also shows that the smoke toxicity and smoke obscuration resulting from burning PVC materials in real‐scale fires is in the same range as those of other materials.     

PVC阻燃抑烟的研究进展

介绍了聚氯乙烯(PVC)的热降解机理及燃烧特性。综述了PVC阻燃抑烟剂(如阻燃增塑剂、金属化合物、含硼阻燃剂、微胶囊红磷和无机填料等)的研究,特别提及了一些过渡金属(如Mo、Cu与Fe的化合物)在PVC抑烟中的明显作用。比较了各种阻燃抑烟方法的优缺点。采用阻燃剂和抑烟剂复合对PVC协同阻燃抑烟是未来的研究方向。     

无卤阻燃抑烟ABS材料的制备及性能研究

采用熔融共混法,以二乙基次膦酸铝（ADP）为主阻燃剂,聚磷酸铵（APP）为协效阻燃剂,对丙烯腈?丁二烯?苯乙烯共聚物（ABS）实现了良好的阻燃抑烟改性。利用极限氧指数测定仪、烟密度测试箱和锥形量热测试仪对复合材料的燃烧性能进行了测试,通过扫描电子显微镜、差示扫描量热仪等分析表征了复合材料的微观结构和热性能。结果表明,当ABS/ADP/APP质量比为100∶16∶4时,复合材料的极限氧指数（LOI）可提高到29 %,烟密度等级下降到68.5,火点指数（FPI值）提高到0.215 s/（kW·m^-2）;复合材料在燃烧过程中会分解产生磷氧自由基,抑制基体燃烧的链式反应,并在材料表面形成大量细小空穴、膨胀疏松的炭层,取得了气相阻燃和凝聚相阻燃之间的良好协效。     

纳米CaCO3对阻燃型软质聚氯乙烯的增韧增强作用

通过氧指数(LOI)、剩炭率、烟密度等级(SDR)、冲击强度、拉伸强度和断裂伸长率等参数的测定,研究了氢氧化物和金属配合物复合阻燃体系对软质PVC阻燃、消烟性能和力学性能的影响;通过冲击强度、拉伸强度、断裂伸长率以及材料流变性能的测定对比研究了纳米级CaCO3和微米级CaCO3对阻燃型软质PVC的力学性能和加工性能的影响。结果表明:氢氧化物和金属配合物复合阻燃体系在提高软质PVC阻燃、消烟性能的同时会恶化材料的力学性能;纳米CaCO3能明显提高阻燃型软质PVC的冲击强度、拉伸强度和断裂伸长率,对材料具有明显的增韧、增强作用,同时对材料的流变性能及阻燃、消烟性能影响不大。     

Zinc hydroxystannate‐coated metal hydroxides as flame retardant and smoke suppression for flexible poly vinyl chloride

Zinc hydroxystannate (ZHS)‐coated metal hydroxides were prepared. The effects of ZHS‐coated metal hydroxides on flame retardancy and smoke suppression of flexible poly vinyl chloride were studied by means of the limiting oxygen index, smoke density rating and the char yield test. The mechanism was investigated by thermogravimerty (TG), differential thermal analysis, and differential TG analysis and scanning electron microscopy. The results showed that ZHS‐coated metal hydroxides are more effective flame retardant and smoke suppressant than metal hydroxides, and it appears that tin compound may exert its action in both the condensed and vapor phases, but mainly in condensed phases as a Lewis acid. Copyright © 2009 John Wiley & Sons, Ltd.     

ZnO与Mg(OH)_2在软PVC中的协同阻燃消烟作用

用热分析的方法研究了ZnO和Mg(OH)2复合阻燃剂对软PVC的协同阻燃消烟作用,考察了经阻燃处理的软PVC从室温到800℃的热降解过程,用Kissinger方程给出了热降解反应的活化能。通过极限氧指数(LOI)、剩炭率、烟密度等级(SDR)和最大烟密度(MSD)的测定以及用电子扫描显微镜(SEM)对燃烧后所生成炭层的观察,探讨了协同体系阻燃抑烟的机理。结果表明:经阻燃处理的样品尤其是加入适量ZnO和Mg(OH)2复合阻燃剂的样品具有较高的极限氧指数(LOI)和剩炭率、较低的烟密度等级(SDR)和最大烟密度(MSD),与未处理的样品相比具有较好的阻燃和消烟性能。ZnO的加入可改变PVC的热降解过程,使起始降解温度降低,并且使反应的活化能增大,可能属于固相Lewis酸催化机理。     

阻燃抑烟剂对软聚氯乙烯材料燃烧性能的影响

针对氢氧化镁、硼酸锌、三氧化二锑等常用的阻燃抑烟剂对在软聚氯乙烯燃烧时的热释放速率和一氧化碳释放量进行了研究 ,发现氢氧化镁和硼酸锌虽然可以降低材料的热释放性能和发烟量 ,但是会大大增加烟气中一氧化碳的释放量 ;而三氧化二锑会增加材料的发烟量 ,但却能大大降低烟气中的一氧化碳的释放量