Emulsification, drying and film formation of alkyd emulsions

A method was developed and optimised for the emulsification of a conventional short oil alkyd resin which was solid at room temperature. The method was based on the emulsion inversion point (EIP) method whereby hot water (90°C) was added to molten alkyd resin (90°C) containing the emulsifier. Under slow mixing and addition of water, a point was reached where the emulsion instantaneously phase inverted from a water in oil emulsion (W/O) to an oil in water emulsion (O/W). Using optimum conditions, emulsions with droplet of diameters less than 0.8 μm were obtained. The drying and film formation of long oil alkyd emulsions were investigated with emphasis on loss of dry upon storage. The main reason for loss of dry was adsorption of the cobalt (drier) on pigment surfaces as a precipitated hydroxide. Titanium dioxides with alumina surface treatment and organic pigments were most detrimental to drying. Acrylate- and phosphate-based dispersants also deactivated cobalt presumably due to complexation and precipitation of cobalt. Emulsions prepared with an emulsifiable cobalt drier containing 2,2′-bipyridyl (complexing agent for cobalt) showed the best resistance to loss of dry. Films formed from the emulsions showed that surfactant migrated to the film surface which when washed with water leaves holes or pits in film. The pits were arranged in a hexagonal pattern, characteristic of Bénard cells which form due to interfacial tension gradients generated in the film during evaporation of water.     

涂料催干剂的进展与反应机理

涂料催干剂是涂料最重要的助剂。常用的是变价金属环烷酸盐和异辛酸盐。针对近年催干剂的发展做一些评述。重点在于对催干剂催干机理进行全面系统论述     

Bearing materials for small electric motors

Operation of small electrical machines with bearings under boundary lubrication conditions does not receive much attention in the literature. Yet there are some fifty million fhp (fractional horsepower) induction motors made every year. This article outlines the bearing types used in these motors and examines a new polymer lined bearing which seems attractive for many applications using sleeve or ball bearings     

Solar—drier—desiccator system evaluation

This paper discusses the design of solar drying systems which include a desiccator as part of the cycle. The influence of the desiccator investigated and the performance of a counter flow unit is discussed.     

Process engineering development for the manufacturing of manganese octoate on a pilot plant scale

A technically and economically feasible process is developed for the manufacturing of manganese octoate as a powerful paint drier in a pilot plant unit. Such material is an environmentally safe through drier, catalyzes cross linking within the whole coating layer and is highly recommended for both hard and durable finishes. Scaling-up is based upon successful studying, evaluation and optimization of all operating parameters affecting process chemical reaction kinetics, product recovery and purification, and finally the vacuum crystallization stage. The performance of the pilot unit, overall conversion of reactants (>85%) were in excellent conformity with laboratory results.     

醇酸涂料用钴催干剂的替代

介绍了代替醇酸涂料用钴催干剂的研究现状。     

成形烘干器的变形及防止措施

成型烘干器的变形,造成柱型暖气片大批报废,有时高达80％,通过八项预防变形的措施,消除了成型烘干器的变形,使铸件合格率稳定在85％,有时达到98％。     

浙73-1型烘茧灶给热装置的改进方法初探

本文简介了浙73-1型灶的特点,分析了该灶的供热和耗热情况。在此基础上,提出了该灶给热装置的改进方法:(1)炉胆外表面应覆盖一层辐射率较小的板料或贴一层1～3cm厚的绝热材料;(2)头冲、二冲的用煤量应作适当的调整,头冲为35～40kg/灶,二冲为27～32kg/灶。这样有利于保全茧质,提高烘茧效率。     

全热风干燥技术

提出带水平导流的全热风干燥的概念,通过合适的导流和诱导作用来合理组织干燥气流,使物烊适宜的热风温度和排湿工况下完成较为理想的热交换和湿（质量）交换,对当前常用的热风烘箱和烘道作出改进设计。     

气干型醇酸涂料的固化机理及催干剂

为了深入理解气干型醇酸涂料的固化反应机理及所用催干剂和催干机理,基于国内外最新文献,论述了气干型醇酸涂料的自动氧化固化机理,主要包括诱导阶段、过氧化物形成阶段、过氧化物分解阶段及聚合阶段;系统总结了催干剂的组成、制备方法、种类及催干机理;简述了水性醇酸涂料用催干剂研究现状。总结发现,高效无毒的环保型催干剂将是气干型醇酸涂料用催化剂的发展方向。