三层“核-壳”型环氧-丙烯酸酯乳液的合成及其室温固化反应

采用种子乳液聚合法合成了三层"核-壳"型环氧-丙烯酸酯乳液。研究了室温固化剂的种类和用量对乳液固化体系表干时间和适用期的影响,通过红外光谱(FT-IR)、扫描电镜(SEM)、硬度、耐酸碱性测试等方法对固化体系的性能进行了表征。结果表明:选用固化剂WH260,其用量为乳液固体组分的20%时,固化物的固化速率和适用期最佳,固化后的涂膜发生了自分层现象,并且为三层。与纯环氧树脂乳液固化体系相比,三层核壳结构环氧-丙烯酸酯乳液固化体系在延长适用期的同时固化性能不会有明显下降。     

LED光电显示器件用双组分有机硅灌封胶的研制

以α,ω-二羟基聚二甲基硅氧烷为基胶,配合处理的白炭黑、电子级硅微粉、硫化剂和偶联剂等,制得用于LED显示器件用的双组分有机硅灌封胶;研究了α,ω-二羟基聚二甲基硅氧烷的黏度、硅油用量以及A、B组分混合比例对灌封胶性能的影响;探讨了B组分中有机锡含量对灌封胶适用期和表干时间的影响.结果表明:随着α,ω-二羟基聚二甲基硅氧烷黏度的增加,灌封胶的拉伸强度和断裂伸长率增加,硬度降低;随着硅油用量的增加,灌封胶伸长率提高,强度下降,膨胀系数变大;随着A、B组分质量比的增加,灌封胶的剪切强度有所增加,同时线收缩率也变大;随着有机锡含量的增加,灌封胶适用期缩短、表干时间变快,当有机锡含量增加到0.15%～0.45%时,灌封胶适用期和表干时间趋于稳定.     

不同固化体系低毒脲醛树脂固化特性研究

采用不同固化体系对6种低毒脲醛(UF)树脂胶的固化速度、适用期及pH值变化情况进行了研究。研究表明：单组分固化体系中,过硫酸铵固化速度最快;磷酸与氯化铵组成的多元固化体系。固化速度虽然很快-但适用期较短;多元固化体系中加入2％～3％尿素对固化速度影响不大;乌洛托品对延长UF树脂胶的适用期效果较好。对加入固化剂后胶液pH值变化情况的研究表明。pH值在15min内下降较快。30min之后逐渐趋于稳定。     

低物质量比甲醛-尿素-三聚氰胺树脂快速固化剂研制

用普通固化荆对低物质量比甲醛-尿素-三聚氰胺树脂胶粘剂进行固化已不能满足实际生产需要,通过对单一和复合固化剂的反复试验,找出了一种能够使低物质量比甲醛-尿素-三聚氰胺树脂胶粘剂快速固化,适用期又能满足实际生产需要的固化剂。     

水性环氧树脂涂料适用期的研讨

研究探讨了水性环氧树脂涂料适用期方面的相关规律与特点。结果表明固化剂乳化型水性环氧树脂涂料的适用期一般较短;其与溶剂型环氧树脂涂料一样,可以用黏度变化来判断其适用期的长短;而对于水性环氧固化剂乳液与水性环氧树脂乳液所组成的水性环氧树脂涂料体系,其适用期较长,并且应以涂膜的性能,如涂膜光泽度的变化来确定。     

上海汉司推出高效双组分聚氨酯胶粘剂体系

正长适用期及快速后固化性能,一直是传统的双组分聚氨酯胶粘剂生产厂家所追求的目标。通常为保证较长的适用期,后固化速率就会下降,从而降低了生产效率。为此,上海汉司推出一系列可控固化型双组分聚氨酯胶粘剂体系。该体系的显著特点是:能根据客户需要调整适用期及后固化速率,即在保证胶粘剂具有较长适用期的同时     

双组份水性涂料适用期判定方法的研究

针对配方研发的热点问题——涂料适用期,对与之相关的漆膜硬度、光泽、雾影等方面展开了研究。结果发现,针对不同的树脂体系,判断适用期的方法不同,即使对同一个树脂体系来说,不同方法测试得出的适用期的长短也不同,因此要综合不同测试方法来判断适用期的长短。研究还发现,从微观角度来看,双组分水性聚氨酯涂料中NCO含量的变化及其形成涂膜的表面微观形貌的变化对双组分水性聚氨酯涂料的适用期有重要影响。本文还对欧洲家装木器市场中双组分水性聚氨酯涂料的应用做了基本总结。     

封闭异氰酸酯与低毒脲醛树脂固化反应特性的探究

对不同固化体系下低毒脲醛树脂以及其与封闭异氰酸酯反应的固化速度、适用期及pH值变化情况进行了研究.结果表明,单组分固化体系中,硫酸铝固化速度最快.磷酸与氯化铵组成的双组分固化体系,固化速度虽然很快,但适用期较短;鸟洛托品对延长脲醛树脂胶的适用期效果较好.加入封闭异氰酸酯后会加快脲醛树脂固化速度,但其适用期有所缩短,而在硫酸铝和磷酸的固化体系中不明显.pH值在15min内下降较快,30min之后趋于稳定.     

长适用期丙烯酸酯结构胶黏剂的研究

室温固化丙烯酸酯胶黏剂由于适用期短,操作时间不够的问题限制了其在粘接较大面积材料中的应用。制备了一种适用期为40min的丙烯酸酯结构胶黏剂,并对其进行了含磷丙烯酸酯对适用期影响的研究,探讨了长适用期丙烯酸酯结构胶黏剂的耐温性能、耐热老化、耐水老化性能,采用热重分析对胶黏剂进行了分析。结果表明:含磷丙烯酸酯含量为3%时,胶黏剂适用期可达40min;制备的丙烯酸酯胶黏剂耐温性能较好,80℃和100℃剪切强度分别为11.75MPa、6.49MPa;丙烯酸酯胶黏剂经100℃老化8000h后,80℃和100℃剪切强度上升分别为14.04MPa、8.54MPa,室温和60℃剪切强度下降分别为14.76MPa、14.21MPa;在耐水老化8000h后,60℃和80℃剪切强度变化很小分别为17.62MPa、11.52MPa。     

硫化剂原料及配方对聚硫密封剂硫化性能的影响

研究了聚硫密封剂硫化剂配方中不同原材料和用量对密封剂适用期、不粘期和标准硫化期的影响。结果表明,不同的二氧化锰和促进剂对密封剂性能的影响亦不同。随着促进剂用量的增加密封剂适用期、不粘期和标准硫化期均表现不同程度的降低。硫化抑制剂中硬脂酸和油酸效果相当,随着硬脂酸、油酸含量的增加,密封剂的不粘期和标准硫化期显著延长,需控制硫化抑制剂用量在合理范围内。     

Automated determination of pot life of two-component reactive coatings

The process of pot life screening of two-component coatings is significantly accelerated by using an automated coating formulation system with viscosity measurement capability. High-throughput methods are revolutionizing the processes used in polymer and coatings development. A high-throughput approach to characterize the effect of formulation variables on pot life of two-component solventborne coatings is presented. Using an automated formulation system with viscosity measurement capability, the viscosity of the coatings formulations is measured periodically to determine the viscosity–time profile. As examples, variables such as catalyst type, catalyst level, polyol composition, polyol to isocyanate ratio, and pot life extender were selected as formulation variables and their role in pot life were explored. Compared to traditional pot life determination methods using efflux viscosity cups, the high-throughput approach greatly improves the speed and efficiency of the process and allows many more compositions to be explored.     

双组分水性聚氨酯汽车面漆的制备与性能研究

介绍了配制双组分聚氨酯涂料的工艺过程,并通过一系列的对比实验,考察了树脂、固化剂、n—NCO/n—OH配比、PVC和助剂对涂膜性能的影响,以及涂料的适用期。试验结果表明:羟基丙烯酸树脂Bayhydrol A XP 2695和固化剂Bayhydur XP 2655配用,n—NCO/n—OH为1.4,PVC为15%,润湿分散剂TG270和TG755配用,流平剂TG700和BYK380N配用,可获得综合性能优异的涂膜,满足汽车面漆的性能要求;涂料的适用期约为4 h。     

基于ANSYS的侧加热锌锅厚度选择与温度控制模拟

利用ANSYS热应力分析模块对侧加热锌锅均匀加热时的锅壁进行稳态热分析,得到应力等值线分布图,通过对产生热应力原因的分析,得出不同厚度下侧加热锌锅外侧壁在允许屈服应力强度下所能承受的最大加热温度。为热镀锌生产线上延长锌锅寿命提供理论依据,同时也为锌锅制造厂家选择锌锅厚度与铸造锌锅时选择焊接位置提供参考。     

RTM工艺用双酚F型环氧树脂体系研究

本文选用二乙烯三胺和二乙氨基丙胺作固化剂,系统地研究了用于RTM工艺的低粘度双酚F型环氧常温固化体系的工艺特性及力学性能。研究结果表明,用二乙烯三胺固化双酚F型环氧时,其固化物力学性能优异,但适用期较短;用二乙氨基丙胺部分替代二乙烯三胺,得到了适用期为36m in的树脂体系(二乙烯三胺用量2phr、二乙氨基丙胺用量4phr),其树脂固化物拉伸强度为66.8MPa,弯曲强度为102.0MPa。用所确定的树脂体系制得的碳纤维复合材料综合力学性能优良,树脂与碳纤维界面粘结良好,将其应用于RTM成型某型号舱段的制备,制品综合性能优良。     

风电叶片用双组分聚氨酯胶粘剂的研制

考查了自制缓凝剂用量对混合后胶粘剂黏度和适用期的影响,以及多元醇对胶粘剂强度的影响,添加填料及其他助剂制备了双纽分聚氨酯结构胶。该胶混合后适用期达65min,本体拉伸强度迭39．5MPa,拉伸剪切强度达17．5MPa．且胶片韧性好,应用于风力发电行业的叶片粘接效果好,应用前号广阔。     

Anomalous but useful behavior of epoxy adhesive system

Freeze storage of adhesives has been an industry-wide practice for a long time. However, when the technique was applied to an epoxy adhesive, anomalous, but very useful results were obtained. Among other observations, the study showed that freeze storage changes the final properties of the epoxy. The epoxy was applied as an adhesive in the sealing of a component. Among adhesive candidates that were evaluated, the epoxy EA9396 was preferentially selected because it is amenable to room temperature cure and consequently it exhibits less stress and fracture upon cure. The formulation was frozen at −43 °C for different periods of time. A cure schedule consisting of 16 h at room temperature followed by two hours at 65 °C imparted shore D hardness of 80, shear strength of about 1800 psi and an extent of cure of 82% to the adhesive regardless of the length of the freezing time. Rheometry analysis of the thawed frozen formulation showed an anomalous trend whereby the pot life increased immensely in direct proportion to the duration of the freezing time. In this study pot life implies the working life after the frozen formulation is thawed. A pot life of 85 min was observed for samples cold-stored for three weeks. This method would offer advantages in applications requiring long pot and cold storage lives. This paper provides an insight into this phenomenon.     

A new epoxy/episulfide resin system for electronic applications — 2: pot life and prepreg storage life evaluation

A new epoxy/episulfide thermosetting resin was evaluated, using a dicyandiamide (DICY) curing agent. The system was found to exhibit a longer pot life and prepreg storage life than the standard epoxy system. The properties are attributable to the change in reaction mechanism caused by the addition of episulfide. The reaction mechanisms were studied using a mono-functional model compound system; the extent of episulfide-amine reaction is relatively high in the epoxy/episulfide system relative to epoxy-amine. A tert-amine salt is probably formed which does not act as a catalyst for the epoxy ring opening, resulting in a greater pot life.     

碳纤维片材加固胶黏剂的工艺性能改进研究

碳纤维片材加固胶黏剂已广泛应用于混凝土结构加固及改造领域,但对其工艺性能的改进研究一直未能引起足够的重视。本文研究了改性胺类固化剂对环氧树脂类碳纤维片材加固胶黏剂适用期的影响,同时也对触变剂进行了探讨,并提出了判定胶黏剂浸润性的方法。采用自制的固化剂复配得到了适用于不同季节使用的冬夏配方,工艺性能良好。