多层板材料的技术动向

概述了多层板材料的技术动向和特性。     

锥板粘度计法测定树脂及其预浸料的凝胶时间

介绍了用锥板粘度计测定树脂及其预浸料凝胶时间的方法,并通过实验与现行的电热板法进行了比较.结果表明锥板粘度计法具有设备简单、测试速度快、消除人为影响、重现性好和数据准确的特点.适于预浸料生产过程中间控制以及树脂及其预浸料的质量表征.     

H300碳纤维及其预浸料性能研究

对H300碳纤维性能进行了测试,结果表明H300碳纤维与T300碳纤维力学性能基本相当。试验了3238A/H300碳纤维热熔预浸料制造工艺,制造出合格预浸料。测试了3238A/H300碳纤维复合材料物理力学性能,结果表明3238A/H300碳纤维复合材料满足要求。     

厚铜PCB用高填充性半固化片的研制

一般地,106半固化片的树脂含量（简称RC）只能达到75％左右。因厚铜（铜厚达到105μm及以上）印制电路板的线路间需要更多的树脂来填充,故普通工艺制造的半固化片就很难满足厚铜印制线路板的填胶性。因此,本文研究了提高半固化片RC的新工艺方法,从而改善半固化片对厚铜印制线路板的填胶性能。     

预浸渍液pH值对阳山水蜜桃汁色泽的影响

采用不同pH值预浸渍液对打浆前的水蜜桃进行预处理,以水蜜桃亮度(ΔL)、红度(Δa)、黄度(Δb)、总色差值(ΔE)、色泽饱和度(ΔC)等为色泽指标,考察预浸渍对水蜜桃汁色泽的影响。结果表明:pH 4.8时,水蜜桃汁ΔL值由参照样品的-3.16升高到-1.23,Δa值由1.21下降到-0.83,Δb值由-1.4升高到0.05,ΔE值由3.67下降到1.49,而ΔC值基本保持稳定。证明经pH值4.8的预浸渍液处理水蜜桃30min,可以有效遏制水蜜桃汁的褐变。     

零吸胶工艺复合材料层板成型质量与预浸料特性关联分析

针对3种国外产碳纤维/环氧预浸料,测试表征了预浸料的工艺特性,并采用热压罐零吸胶工艺制备了复合材料层板,考察了工艺条件对层板厚度和内部缺陷的影响,分析了成型质量与预浸料特性之间的关联性,进一步研究了层板弯曲性能、层间剪切性能对成型质量变化的敏感性。实验结果表明,由于零吸胶工艺树脂流动受到很大限制,预浸料树脂含量不均容易造成所成型层板厚度不均、表面不平整,另外,预浸料树脂流动性小的体系在层间容易出现明显富树脂现象;零吸胶工艺夹杂空气主要在真空作用下通过铺层内的通道排出,因此预浸料气体渗透率和成型封装方式对孔隙缺陷有重要影响;实验范围内,工艺条件的改变没有显著影响所成型层板的短梁剪切性能和弯曲性能。研究结果对于预浸料选择和国产高性能预浸料的开发具有重要参考价值。     

用DMA研究环氧预浸料的等温固化过程

采用动态力学分析法(DMA)对648环氧预浸料的等温固化过程进行了表征分析。以储能模量E′的相对增长率作为动态力学性能增长的指标,研究了不同恒温温度下E′的增长规律,并用Hsich非平衡热力学涨落理论、Avrami方程和等转变率 3种方法研究了预浸料的等温固化动力学。结果表明：648环氧预浸料等温固化过程中E′的增长分为高温和低温2种增长模式,低温下包含一个高温下没有的模量增长的过渡阶段,该阶段与测试频率具有明显的相关性。Hsich非平衡热力学涨落理论、Avrami方程可以对648环氧预浸料等温固化过程储能模量的相对变化进行分段描述。对活化能的计算结果表明,不同温度范围内恒温储能模量增长过程中活化能的数值及其变化趋势不同。     

半固化片的基础知识

本文主要介绍半固化片的分类、相关特性与指标、保存条件及生产流程,希望能给PCB生产者带来帮助。     

Research on the Shear Behaviour of Plain Weave Prepreg at Lateral Compaction Stage

Abstract:  An investigation of the shear behaviour of plain weave prepreg at lateral compaction stage was undertaken by the picture-frame test. A unit cell of weave prepreg was modelled and three moments were assumed in the unit cell: (i) the moment of shear force that picture frame applies on the unit cell; (ii) the friction moment at crossover of yarns; and (iii) the compaction moment between the yarns. Through moment balance, a relationship between the load and the shear rate was deduced. A plain sheet shearing film resin model was established to obtain the friction moment at crossover. To get the compaction moment, a constitutive equation of a single prepreged yarn was deduced and a transverse viscosity coefficient equation was given. Moreover, through an equivalent cross-sectional area model, the lateral contact thickness between the yarns was obtained. The comparison between the experimental and theoretical results shows that the presented model can describe the shear behaviour of weave prepreg at lateral compaction stage well.     

Effect of NBR on epoxy/glass prepregs properties

Solid acrylonitrile‐butadiene rubber (NBR) was used in epoxy resin for toughening and also for increasing the tack of epoxy/glass prepregs. The NBR used in this study was a rubber with 33% acrylonitrile content. The changes in thermal and mechanical properties such as glass transition temperature (T_g), curing characteristics and lap‐shear strength have been studied. For this purpose, three types of prepregs with two levels of NBR content of 3 and 5%, were prepared. Prepregs were made by solvent type impregnation apparatus. In this method, resin impregnates satin textile glass fiber under the controlled and constant condition of line speed and oven temperature. Prepregs were B‐staged for about 3%. The cure characterization, T_g and flow behavior were evaluated using differential scanning calorimetry and rheological analysis. Results showed that increasing the rubber content caused the following effects: (a) delay in gel time of prepregs, (b) increase in activation energy of prepregs, and (c) decrease in total heat of curing reaction. It is interesting that NBR increased the tack of epoxy/glass prepreg but, had no effect on its resin flow behavior. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012