浅述BMC注射成型技术

介绍ＢＭＣ注射成型技术的特点与原理，讨论了ＢＭＣ注射成型设备的性能特点及工艺条件，并分析了ＢＭＣ注射制件常见的缺陷及其原因等。     

注塑参数对聚碳酸酯成型收缩率的影响研究

研究了注塑参数对聚碳酸酯(PC)成型收缩率的影响，从理论上探讨了注塑参数—制品结构—收缩率之间的关系。试验结果表明，对PC成型收缩率影响最大的注塑参数是料温，其次是模具温度、注塑压力和注射速率，而保压时间、冷却时间、预塑速率在实验范围内对PC成型收缩率影响较小。     

轿车扶手表皮材料——旋转模塑用聚氯乙烯增塑糊粘度稳定性研究

ＰＶＣ增塑糊粘度稳定性是指粘度随时间的变化，是影响糊制品加工工艺的重要因素，本文利用ＮＤＪ－１型旋转粘度计，通过测定糊粘度随时间的变化，对影响ＰＶＣ增塑糊粘度稳定性的各种因素进行了较为详细的研究。     

剪切控制取向注射成型概述

对比了剪切控制取向注射成型（ＳＣＯＲＩＭ）与普通注射成型（ＣＩＭ）的基本原理，剪切控制技术（ＳＣＯＴ），可消除制品熔接缝，改善外观质量，还可消除内在应力和空隙等缺陷，提高制品内在质量。     

热固性塑料注射成型模具设计中的一些体会

注射成型(又称注塑成型)的方法是将塑料置于注射机的料筒内,使受热软化,然后用推杆或螺杆施加压力,使呈熔融状态的塑料在高压下以一定速度射入模具,通过浇口、分浇道到达型腔,冷凝脱模后,即成所需形状的制品。 我厂塑压车间几年前便开始采用注射成型工艺。在有关部门的大力配合下,先后设制了几台卧式热固性塑料注射成型机     

计算机辅助成型技术在共注射成型中的应用

诸如Moldflow MPI 5．0软件这样的计算机辅助成型技术在注射成型中的应用正变得越来越重要，尤其是对于像共注射成型这样复杂的成型。该软件中的共注射模块能够帮助技术人员对共注射成型过程及制品进行模拟预分析，从而使他们避免了只凭经验的弊端，可以快速地解决成型中的难题。     

PP注射成型中的压力及熔体流动过程

讨论了聚丙烯在注射成型中充模、增密、保压、冷却各个阶段的压力变化情况和熔体流动过程，以及二者对制品成功质量的影响。认为在聚丙烯注射成型过程中，要保证制品成型质量，不应以升温的办法来降低熔体的粘度，而应以提高注塑压力和剪切速率为主。     

旋转模塑用聚氯乙烯增塑糊粘度稳定性研究

ＰＶＣ增塑糊粘度稳定性是影响糊制品加工工艺的重要因素，本文利用ＮＤＪ－１型旋转粘度计，通过测定糊粘度随时间的变化，对影响ＰＶＣ增塑强粘度稳定性的各种因素进行了较为详细的研究。     

由中间相炭微球制备高密度各向同性炭

以中间相炭微球（ＭＣＭＢ）为原料,在常温下压制成型。所用ＭＣＭＢ由不同一次吡啶不溶物含量的煤焦油在不同条件下聚合反通过热过滤及吡啶抽提分离而得。考察了不同原料、成型压力、热处理温度及升温速率对炭制品的密度及收缩率的影响。１０００℃下炭化后炭制品的表观密度最高达１．７５ｇ／ｃｍ＾３。     

树脂传递模塑成型用高性能双马来酰亚胺改性树脂基体的研究

本文以烯丙基对甲酚醚（ＡＭＰＥ），作为双马来酰亚胺（ＢＭＩ）／二烯丙基双酚Ａ（ＤＡＢＰＡ）树脂体系的活性稀释剂，获得了适合树脂树脂传递成型（ＲＴＭ）工艺的三元共聚树脂体系。通过对该树脂体系及其固化物的粘度－温度－时间曲线，凝胶化特性、ＤＳＣ（微分扫描式量热）ＩＲ（红外光谱）、ＳＥＭ（电子显微镜扫描）和力学性能测试，表明该体系在ＲＴＭ成型 中，注射温度可取７０℃，该温度下，粘度仅０．３Ｐａ．ｓ，贮存     

影响块状模塑料均匀流动的主要因素

采用Brabender转矩流变仪，并结合同心圆取样测定块状模塑料（BMC）中玻纤质量分数的方法，讨论了预混料在模压中的流动性能；研究了温度、玻纤的质量分数及长度、填料粒度、增稠剂用量等因素对BMC预混料的流动粘度和玻纤在BMC材料中分布的影响。     

团状模塑料（BMC）反射镜注射成型技术的研究

从团状模塑料（BMC）注射成型机、辅助设备、模具、BMC材料及工艺条件,分析BMC注射成型车灯反射镜的技术与要求。     

Shear and extensional flow of reinforced plastics in injection molding. I. Effects of temperature and shear rate with bulk molding compound

Capillary flow studies on bulk molding compound (BMC) using an instrumented injection-molding machine are reported. The significance of extensional flow effects with fiber-reinforced materials is emphasized. The extensional flow behavior in converging dies is modeled, and a means of evaluating both extensional and shear viscosity from capillary flow data is proposed. Methods of correcting results for the effect of deformation heating are discussed. The shear and extensional flow behavior of BMC in the temperature region 18 to 58°C can be fitted to a simplified Arrhenius Law.     

In situ flow state characterization of molten resin at the inner mold in injection molding

Online viscosity information on processing lines can reflect the material flow resistance and offer valuable guidance for manufacturing across various industries. Considering the accuracy, devices, and processes involved in injection molding, characterizing the melt's flow state during material processing poses a significant challenge. To reduce investment in viscometers, avoid influencing the components' surface aesthetics due to the installation of sensors, and make the flow state detect online in mold, this study designs a rheometric mold with cylindrical runners for identifying the in situ viscosity of molten resin during injection molding. The detection conditions of injection speed and cavity pressure variations, the entrance effect, and the viscous dissipation for Polycarbonate are analyzed under various conditions. The in situ viscosity is identified and compared with the standard cross-WLF model. The result shows that the melt velocity and cavity pressure variations during the filling process create a stable environment for in situ rheological characterization and the detected viscosity is related to the shear rate, melt temperature, and channel dimension in injection molding. The designed mold with cylindrical runners for determining the in situ thermal-rheological behavior of polymer is distinguished successfully and exhibits prospects for the development of low-cost, nondestructive, and inner-mold measurement in manufacturing applications.     

聚苯乙烯官能化及其在BMC中的应用

通过傅立叶变换红外光谱(FTIR)仪、旋转流变仪和示差扫描量热(DSC)仪测试官能化聚苯乙烯(FPS)的FTIR、复数黏度和玻璃化转变温度(Tg)。结果表明,聚苯乙烯(PS)经过官能化,FPS的FTIR在1 784 cm-1和1 808 cm-1处的峰明显变大,说明马来酸酐单体成功地接枝到PS大分子链上;熔体复数黏度较接枝前整体呈下降趋势,官能化反应对PS分子链有一定的降解作用,使分子量下降,Tg从100.35℃下降至93.77℃,但分子链结构未有大的转变。同时,还研究了FPS在团状模塑料(BMC)中的应用,结果表明,FPS作为低收缩添加剂添加在BMC中,其弯曲强度提高7.3 MPa,弯曲弹性模量提高517 MPa,拉伸强度提高2.4 MPa,冲击强度提高0.6 k J/m2,极限氧指数提高5%,但对BMC的抗收缩能力下降,BMC的线性收缩率从0.992%提升至1.260%。     

影响BMC注射制品强度的因素分析

从BMC的注射成型机理出发，分析、探讨了影响其注射成型制品强度下降的主要因素，并提出了一些解决问题的办法与建议。     

团状模塑料注塑成型"花斑"缺陷分析

本文从材料性能、注塑工艺、模具结构以及真空设备等方面分析了团状模塑料（Bulk Molding Composite简称BMC）注塑成型制品的“花斑”缺陷产生的原因与机理。     

Polyester molding compounds: Partial systems and related particulate composites

Several binary of ternary systems, consisting of an unsaturated polyester resin and one or two additives which are currently considered in formulating polyester molding compounds (such as BMC and SMC) were studied in relation to some of their relevant properties as a function of their composition. The additives were: MgO as a thickening agent; a thermoplastic polymer (PS or PVAc); and a fine CaCO₃ particulate filler. Measured quantities were, depending on the system physical state (fluid or crosslinked): viscosity, linear shrinkage, flexural modulus and strength, and fracture toughness and energy, besides SEM morphological characterization. Quantitative relations could in several instances be expressed; in particular, the relation between strength and filler volume fraction was found to follow the linear equation of the simplest area reduction “random model”.     

Polyethyleneterephthalate with increased viscosity by chemical crosslinking

An attempt is made to improve the processing and operation properties of polyethyleneterephthalate (PETP) containing chemically bound pentaerythrol as modifier by increasing its viscosity through slight chemical crosslinking in the solid state. It is established that thermal treatment in vacuum for 8 h at 240°C of PETP containing 0.3 mol-% pentaerythrol leads to an increase in its molecular weight from 20000 to 40000 mainly as a result of additional solid state polycondensation. Further more, annealing in vacuum for 6 h at 250°C of the polymer containing 0.4 mol-% pentaerythrol leads to the formation of a loose three dimensional network resulting from chemical crosslinking in the solid state. It is shown that this crosslinking material has improved processing behaviour during injection moulding due to the increased viscosity of the melt.