After two years experimental work (from 2009 to
2011) in Wuxi Foundry, Bangni resin was put into production officially, and good comments were obtained from its customers. According to production trials and after evaluating its application results, a national confer- ence on steel casting sand was held in Wuxi Foundry in November 2010. Conference delegates visited the pro- duction site and Bangni resin sand received wide acclaim from the delegates. Since 2011, Bangni resin sand has undergone further
development and application. At the moment, nine met- alcasting facilities use this resin in production and a fur- ther 10 metalcasters are undertaking trials with the inten- tion of progressing to production. Good results have been obtained in environmental protection, emission reduction, cost reduction and steel casting quality improvement.
The Main Characteristics of Bangni Resin Production trials confirmed Bangni resin has the fol-
lowing features: • It has the features of resole phenolic resin sand; during stripping, the sand is not very strong and has a certain toughness; the stripping property is better than that of other resin-bonded sand.
• The resin contains high molecular alkene genus carbon chains. The resin sand molds and cores have good stability and the surface of resin sand molds and cores is smooth and tough. When coating, no loose sand appears on the surface of cores and molds. After coating, the surface is hard and smooth without any loose sand.
• Due to the second hardening effect after pouring, molds have good rigidity.
• After pouring, the break-down properties are good and similar to those of furan resin sand.
• The reclamation and recyclability of used sand are good; the recycling rate can reach around 95%. Wuxi Foundry uses Chinese, dry attrition reclamation equip- ment, and the loss-on-ignition value of reclaimed sand can be controlled to below 1.5%. The molding sand, prepared with 95% reclaimed sand, 5% new sand, 1.2% resin and 0.3% hardening agent, has a final strength above 1.0 MPa.
• Since this resin does not contain formaldehyde and phenol, and when treated with the special purpose acid hardening agent, the gas, smoke and odor produced from this resin sand during pouring are much less than that with other resin-bonded sands. Various organic sub- stances have been tested by the China Building Material Test and Certification Centre; the conclusion is that free formaldehyde, benzene, methylbenzene, dimethylbenzene (xylene) and free phenol could not be detected.
Application Results/Effects of Bangni Resin Operational conditions and environmental protec-
tion—Using Bangni resin sand, the gas, smoke and odor emitted after pouring are markedly reduced. Te metal- casting facilities that use Bangni resin in production agree
分子的烯属碳链，因而硬化后具有脂肪族化合物的柔 性。
使这种酚和醛在特定的条件下发生加成反应、缩聚 反应，同时再加入多种材料，进行改性处理。 从2005年起，经实验室及中试基地进行了两年左右 的试验、研究，邦尼树脂于2007年基本定型。 2006年至2008年，曾陆续在7个铸造企业进行了生 产性的试验、考核，都取得了良好结果。 2009年至2011年在无锡铸造厂经试验后正式投入 生产，并得到了客户的赞许。根据实际生产中的考 核，对其应用效果进行了比较全面的总结与评估后， 于2010年11月在无锡铸造厂召开了全国性的铸钢型砂 会议，请与会代表参观了生产现场，受到了与会代表 的广泛关注。
2011年以后，邦尼树脂砂得到了进一步的应用与发 展。目前，已有9个铸造企业正式用于生产，还10余 个企业正在进行试验，即将陆续投入生产。在环保、 节能、减排、降低生产成本及提高铸钢件质量等方 面，都取得了良好的效果。
2、邦尼树脂的主要特点
经实际生产的考核，已确认用邦尼树脂配制的自硬 砂有以下特点： • （1）具有甲阶酚醛树脂砂的特点，起模时型砂的 强度不太高，而具有一定的韧性，起模性能优于 其他各种自硬砂；
• （2）树脂中含有高分子的烯属碳链，砂型、芯子 的表面滑润、柔韧，稳定性好，上涂料时，不出 现浮砂；
• （3）由于受热后有二次硬化作用，铸型的刚度较 好；
• （4）浇注后的落砂性能很好，与呋喃树脂自硬砂 基本相当；
• （5）旧砂再生、回用的性能好，旧砂的回用率可 达95%左右。无锡铸造厂用国产的干式摩擦再生 设备，再生砂的灼烧减量可控制在1.5%以下。 用95%再生砂、5%新砂，加树脂1.2%、硬化剂 0.3%配制的型砂，终抗拉强度在1.0 MPa以上；
• （6）由于树脂中不含甲醛和苯酚，在采用专用酸 性固化剂的条件下，浇注过程中产生的烟和气味 远低于其他各种树脂自硬砂。经国家建筑材料测 试中心对邦尼树脂中各种有机物含量进行检测， 结论是：游离甲醛、苯、甲苯、二甲苯和游离苯 酚等均未检出。
February 2013
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