降低聚氨酯固化剂中游离TDI含量的方法研究

采用工艺与装备一体化的思路进行了TDI-TMP聚氨酯固化剂的合成与分离研究。研究了适合在薄膜蒸发器中进行游离TDI分离的聚氨酯预聚物的合成工艺,讨论了TDI/TMP的配比、反应温度和加料方式对TDI-TMP预聚物合成工艺的影响。研究了高真空两级薄膜蒸发器分离预聚物中游离TDI的分离工艺,讨论了进料速率、二级蒸馏温度、二级绝对压力和二级刮板转速对分离效果的影响。研究表明:在TDI与TMP质量比在5:1,反应温度在50℃,反应时间5h的合成条件下,得到的预聚物分子量小、黏度低、流动所需温度低,适合在薄膜蒸发器中进行游离TDI的分离。优化的分离工艺条件是进料速率为1.6kg·min-1,二级蒸馏温度为170℃,二级蒸馏绝压为80Pa,二级刮板转速为180r·min-1。合成与分离后的聚氨酯固化剂色泽浅、游离TDI含量和-NCO含量符合设计要求。     

高真空两级分离聚氨酯固化剂中游离TDI的研究

采取高真空两级蒸馏分离聚氨酯固化剂中的游离TDI，在MD-S80内冷式薄膜蒸发器设备上通过调整真空度和温度，将游离TDI单体降低到0．28％以下，考察了影响分离的主要因素，达到用内冷式薄膜蒸发器分离TDI的目的。得到的TDI加成物和三级蒸馏相比，工艺简单，设备投资小，说明内冷式薄膜蒸发器设备采用两级分离聚氨酯预聚物中的TDI是可行的。     

采用薄膜蒸发器从聚氨酯预聚物中分离TDI(英文)

从聚氨酯预聚体分离游离的二异氰酸酯的方法有许多种,最好的方法是使用薄膜蒸发器进行分离。采用内冷凝式薄膜蒸发器和二次蒸馏技术研究了从甲苯二异氰酸酯(TDI)/三羟甲基丙烷(TMP)型聚氨酯预聚体分离游离TDI的方法及影响TDI分离的主要因素。研究工作通过使用MD-S80内冷式薄膜蒸发器,并调整蒸馏温度和真空度使产物中游离TDI低于0 5%。相应的蒸馏参数是:原料流速1 0kg/h,原料Ⅰ温度100℃,原料Ⅱ温度110℃,一次蒸馏温度150℃,二次蒸馏温度200℃,第一次蒸馏余压5000Pa,二次蒸馏余压35Pa;刮板转动速度150r/min。二次蒸馏后用醋酸丁酯稀释成质量分数为75%的溶液。预聚体中TDI质量分数为0 4%。异氰酸基含量高于12 7%,达到了分离的目标。结果表明内冷式薄膜蒸发器进行二次蒸馏有效地从TDI TMP预聚体分离了游离的TDI。     

用薄膜蒸发器制备低游离TDI聚氨酯固化剂

在高真空两级蒸馏分离聚氨酯固化剂中游离TDI小试基础上,确定了中试的工艺路线和条件。本实验考察了进料流量、分离温度、分离真空压力等对分离效果的影响。通过实验,确定了中试最优化条件:进料流量20 kg/h,分离温度180℃,分离真空度200 Pa,在此条件下,用薄膜蒸发器可以制得低游离TDI聚氨酯固化剂。中试实验表明,温度对实验结果影响很大。温度低,分离后聚氨酯固化剂中游离TDI达不到要求,分离温度不能低于170℃,而当温度高于190℃,容易使固化剂在分离过程中发生凝胶,使装置发生堵塞。在中试设备上验证了用薄膜蒸发器制取低游离TDI聚氨酯固化剂的可行性,并对进一步工业化积累了宝贵资料。     

采用分子蒸馏装置分离PU固化剂中的游离TDI

上海华生化工有限公司采用北京新特科技发展公司研制的分子蒸馏装置 ,成功地应用于聚氨酯固化剂中游离TDI的分离 ,经连续运转的结果表明 ,产品质量稳定 ,运行平稳 ,固化剂中游离TDI的含量控制在 0 5 %以下。目前该装置已能稳定地分离S 685固化剂 ,TMP/TDI加成物及TDI三聚体中的游离单体 ,产品质量达到了国际同等水平 ,目前用该固化剂配套的涂料已供应市场。该设备的正式使用 ,为我国涂料行业中固化剂的生产技术填补了一项空白采用分子蒸馏装置分离PU固化剂中的游离TDI     

短程蒸馏分离聚氨酯固化剂中游离TDI传质研究

合成完聚氨酯固化剂后,采用MD-S80短程蒸馏设备两级蒸馏聚氨酯固化剂分离TDI,研究了蒸馏温度、蒸馏压力、刮板转速、进料速率等条件对分离TDI的影响,结果显示提高蒸馏温度、刮板转速,降低蒸馏压力、进料速率都有利于分离TDI.针对聚氨酯固化剂物性数据不足的现状推导出半经验的传质模型公式,该公式对分离高粘度、需分离量不大、物性数据缺乏的体系具有较大的应用价值.     

甲苯二异氰酸酯单体的薄膜蒸发分离工艺

通过实验比较了3种甲苯二异氰酸酯-三羟甲基丙烷(TD I-TMP)预聚物中游离TD I单体分离的工艺,发现采用减压蒸馏和内冷式薄膜蒸发联用的工艺路线,不仅能保证物料在蒸发器系统中有较好的流动性,而且能保证TD I单体蒸气在高真空和刮板的搅动下极易从物料中蒸发出来,最终含量可降低到质量分数0.5%以下。实验还发现高真空内冷式刮膜薄膜蒸发分离预聚物中游离单体的关键因素是物料温度、压力和粘度的控制,它们最适宜的控制范围为:物料温度100—120℃、压力50—150 Pa、粘度500—1500 mPa.s。     

低残余TDI单体的PU预聚体的制备方法概述

简单介绍了低残余甲苯二异氰酸酯(TDI)单体的聚氨酯(PU)预聚体的制备方法,并对残余TDI单体的分离方法进行了讨论,说明采用分子蒸馏法对预聚体中游离TDI单体进行分离处理.能得到低残余TDI单体预聚体.     

合成低游离TDI预聚物时原料配比对CPU性能的影响

采用不同配比的甲苯二异氰酸酯(TDI)和聚四氢呋喃二醇(P TMG)合成了系列含不同游离TDI单体的预聚物,经分子蒸馏装置处理得到了低游离TDI预聚物,并以此制备了浇注型聚氨酯弹性体(CPU).讨论了n(TDI):n(PTMG)对低游离预聚物中NCO含量和最终CPU力学性能和动态力学性能的影响.结果表明,n(TDI):...     

分子蒸馏技术提纯茄尼醇的工艺研究

分子蒸馏技术是一种在高真空条件下进行的连续蒸馏过程,适合于分离高沸点、高粘性、热敏性及具有生物活性的混合物.应用刮膜式分子蒸馏装置对茄尼醇的提纯进行了研究,实验过程中茄尼酵粗品不需要进行脱色等方法预处理,通过两次分子蒸馏,即可得到高纯度茄尼醇.考察了多种分离工艺参数对茄尼醇纯度和收率的影响.得到了用分子蒸馏技术提纯茄尼醇的最佳工艺条件:进料速度350-400 mL·h-1,进料温度100℃,蒸馏温度为200～220℃,蒸发压力为10 Pa,刮膜器转速300～400 r·min-1,最终产品纯度和收率分别达到97.6%和 77.1%,达到了用分子蒸馏分离茄尼醇的目的,说明采用分子蒸馏设备提纯茄尼醇粗品是可行的.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。