注塑工艺对哑光PC/ABS光泽度的影响

研究了注塑工艺对哑光PC/ABS光泽度的影响。皮纹面的光泽度与材料复制模具的能力有关。注塑温度和模具温度升高,材料流动性提高,复制模具的能力提高,获得低光泽度。提高射胶速率和压力也会降低光泽度。光泽度随着保压压力的提高及保压时间的延长而降低。     

注塑工艺对哑光PC/ABS冲击性能的影响

通过不同注塑工艺对哑光级聚碳酸酯(PC)和丙烯腈–丁二烯–苯乙烯(ABS)共聚混合物进行注塑成型,通过改变不同的注塑条件(注塑温度、模具温度、注塑压力、注塑速度),研究不同的注塑工艺对哑光PC/ABS材料抗冲击性能的影响。研究结果表明,注塑工艺变化,会引起材料冲击性能变化。其中注塑温度与模具温度对结果影响较大,注塑温度240℃,模具温度80℃时,哑光PC/ABS的冲击强度最高;在合适的注塑压力范围内,压力变化对材料冲击影响不大;合适的注塑速度范围内,注塑速度变化对材料冲击影响不大。工艺选择注塑温度240℃,模具温度80℃,注塑压力2.6~6.1 MPa,注塑速度13.9~32.3 g/s时,哑光PC/ABS冲击性能最好。因此,选用合适的注塑工艺可以提高材料的冲击性能。     

注塑工艺对ASA光泽的影响

采用双螺杆挤出机加入消光剂等助剂制备了不同光泽的高耐候丙烯腈–苯乙烯–丙烯酸酯塑料(ASA),并研究了注塑温度、注射速度、模具温度、保压压力以及保压时间等注塑工艺对ASA注塑制品表面光泽的影响。结果表明,消光剂在ASA中有很好的哑光效果,通过控制其添加量可以获得力学性能和低光泽综合性能优异的哑光ASA。注塑工艺对ASA光泽研究结果显示,模具温度和注塑温度是影响ASA表面光泽的最主要工艺参数。在合理的注塑加工范围内,适当地提高注塑温度、模具温度和保压压力,以及适当地延长保压时间可以获得低光泽效果优异的注塑件。     

注塑工艺对聚丙烯EP548N光学性能的影响

采用不同的工艺条件对无规共聚聚丙烯EP548N进行注塑成型,测试注塑件表面光泽度、黄色指数和透光率,分析了注塑成型条件对制品光学性能的影响。确定聚丙烯EP548N的最佳注塑工艺为:熔体温度200℃,模具温度40℃,注射速度210mm/s、保压压力4.6MPa、注射压力4.9MPa,注塑工艺条件改变对聚丙烯EP548N注塑件透光率影响较小。     

成型温度对PP和ABS试样表面颜色和光泽度的影响

以K31皮纹为例,研究了成型温度对聚丙烯(PP)和丙烯腈-丁二烯-苯乙烯塑料(ABS)试样表面颜色和光泽度的影响。结果表明,随着模具温度和熔体温度的升高,无论是PP还是ABS,其试样颜色的L值均呈增加趋势而光泽度均呈降低趋势,且ABS试样的光泽度降低程度比PP试样高。注塑温度和模具温度升高,材料的流动性提高,冷却时间延长,试样复制模具皮纹的能力提高,使得PP和ABS试样表面皮纹深度均有所增加,从而使试样的光泽度降低、同时L值升高。与PP结晶型材料不同,ABS作为非结晶型材料,其流动性受温度影响更为显著,随着成型温度的升高,使得ABS试样的光泽度降低的程度更大。     

汽车低光泽内饰件用无机填料改性ABS材料的研究

研究了不同无机填料对ABS(丙烯腈–丁二烯–苯乙烯共聚物)材料的光泽度和力学性能的影响,同时研究了注塑工艺对ABS复合材料表面光泽的影响。结果表明:无机填料对ABS材料的光泽度影响显著,对比材料光泽度和力学性能发现,添加滑石粉改性后的ABS具有较好的表观和综合力学性能;可通过调整模具温度和保压压力等注塑工艺参数,获得表面低光泽效果的注塑件。     

注塑工艺对PC/ABS合金电镀性能的影响研究

对聚碳酸酯(PC)/丙烯腈-丁二烯-苯乙烯(ABS)合金采用使用不同的注塑工艺注塑后电镀。研究了注塑工艺对PC/ABS合金粗化性能和镀层结合力的影响。结果表明:注塑工艺对PC/ABS合金的粗化性能和镀层结合力影响较大,注塑温度过低、压力和速度过高以及模具温度过低都会降低PC/ABS合金的粗化性能和镀层结合力。     

注塑工艺参数对高抗冲聚苯乙烯产品光泽度的影响

通过改变注塑工艺参数,研究了注塑工艺对高抗冲聚苯乙烯(HIPS)产品的光泽度的影响。结果表明:随着熔体温度的升高,产品的光泽度明显提高;当模具温度为65℃时,产品的光泽度达到86.6%,可以满足厂家对高光制品的需求;当注射压力控制在7.5MPa左右时,产品的光泽度最好;随着注射速度的增加,产品的光泽度不断增加;当保压压力在7 MPa左右时,产品的光泽度最好;延长保压时间,可提高产品的光泽度,当保压时间超过20s后,产品的光泽度几乎不变。     

制样方式及注塑工艺对聚酰胺6抗冲击性能的影响

通过改变注塑压力、注塑速度、模具温度、注塑温度等注塑成型工艺参数,研究了两种制样方式对改性聚酰胺(PA)6抗冲击性能的影响.结果表明:相同注塑成型工艺条件下,自带缺口试样的冲击强度都高于自制缺口的试样;注塑压力和注塑速度对自带缺口试样的冲击强度影响较大,但对自制缺口试样的冲击强度影响不大;模具温度和注塑温度对两种制样方...     

聚碳酸酯注塑工艺条件研究

以双酚A型聚碳酸酯(PC)为原料,对其进行注射成型,主要探讨了注射成型温度对其成型性能和力学性能的影响,同时讨论了注塑压力及模具温度对其成型性能的影响。结果表明,随着注塑温度升高,PC试样的拉伸强度、弯曲强度、断裂伸长率及缺口冲击强度升高,当注塑温度超过290℃后,力学性能总体上变化不大,注塑温度过高或过低都会使试样透明性下降、缺陷增多,而过高或过低的注塑压力及模具温度均会劣化PC的成型性能。PC的最佳注塑工艺条件为注塑温度290℃,注塑压力100 MPa,模具温度100℃。对在最佳注塑工艺条件下注塑的PC试样通过退火的方式进行热处理,发现在一定范围内,随着热处理温度提高,PC试样的拉伸强度和弯曲强度总体上升高,断裂伸长率和缺口冲击强度下降。当对PC的强度要求较高而对韧性要求相对较低时,125℃是较为适宜的热处理温度;而当对其韧性和强度都有一定要求时,热处理温度不宜太高。     

Variations in surface gloss on parts made by gas assisted injection moulding

Abstract

Gas assisted injection moulding has proved to be a breakthrough in moulding technology for thermoplastic materials. However, there are still unsolved problems that limit the overall success of this technique. The aim of this work was to study the phenomenon of gloss variations occurring across the surfaces of gas assisted injection moulded parts. Experiments were carried out on an 80 t injection moulding machine equipped with a high pressure, nitrogen gas injection unit. The materials used were pigmented acrylonitrile/butadiene/ styrene and polypropylene. A plate cavity with a gas channel across its centre was used to mould the parts. Various processing parameters were varied: melt temperature; mould temperature; melt filling speed; short shot size; gas pressure; and gas injection delay time. After moulding, a glossmeter was used to determine the effects of these processing parameters on the surface gloss profiles of the parts. A roughness meter and scanning electronic microscope were also employed to characterise the surface quality of moulded parts. In addition, a numerical analysis of the filling process was carried out to help better understand the mechanisms responsible for the phenomenon of surface gloss variations. It was found that the surface gloss difference occurs mainly in the transition area between channel and plate in the moulded parts, which might be the result of the shear stress gradient in the polymer melt during the filling process. Surface roughness of moulded parts might also be another factor resulting in the gloss difference problem. PRC/1720     

Polycarbonate/acrylonitrile–styrene–acrylic elastomer terpolymer blends with enhanced interfacial adhesion and surface gloss

A blend of bisphenol A polycarbonate (PC) and an acrylonitrile–styrene–acrylic elastomer (ASA) terpolymer with high surface gloss and excellent interfacial properties was developed for automobile applications. Because PC and the styrene‐co‐acrylonitrile (SAN) copolymer that formed the matrix in the PC/ASA blend were not miscible, two different types of compatibilizers were examined to improve the compatibility of the blend. A diblock copolymer composed of tetramethyl polycarbonate and poly(methyl methacrylate) (PMMA) was more effective than PMMA in increasing interfacial adhesion between PC and SAN. The surface gloss of the PC/ASA blend was always lower than that of the pure ASA included in the blend because of PC existing at the surface of the injection‐molding specimen. The PC/ASA blend with optimum surface gloss and enhanced interfacial adhesion was developed through the control of the molecular weight of PC and the compatibilizer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2097–2104, 2005     

Effects of injection‐molding conditions on the gloss and color of pigmented polypropylene

The effects of processing conditions on appearance characteristics of injection‐molded mineral‐filled polypropylene (compounded with pigments giving differing intensities of a beige color) have been studied; characteristics studied included gloss, color, and texture. A mold cavity embossed with smooth, fine, and coarse surface patterns was used. In‐mold rheology and gate‐seal analysis were used to select the filling and postfilling processing parameters. Interest was focused on the effects of filling rate, holding pressure, and mold temperature on the appearance characteristics, and a significant influence of these processing conditions on the gloss and color was found. For all the surface patterns examined, a better replication of the mold texture was obtained with a low melt viscosity at a high shear rate (high injection speed or short injection time) and a high mold temperature. This gave a higher gloss in the smooth surface regions and a lower gloss in the textured regions. An increase in the holding pressure had an effect similar to but smaller than increasing the filling rate or mold temperature. The gloss (or surface topography) had a significant effect on the color; an increase in gloss was associated with an increase in the color coordinate b* and a decrease in the lightness L*. POLYM. ENG. SCI. 45:1557–1567, 2005. © 2005 Society of Plastics Engineers     

Variations in surface gloss on rubber‐modified thermoplastics: Relation to morphological and rheological behavior

The parameters that promote the formation of surface defects on multi‐phase polymer systems during injection molding are not yet clearly understood. The objective of this work is to establish the influence of composition, particularly the role of rubber, on the rheological properties of such multi‐phase systems and relate that to variations in gloss that appear on the surface of ASA and PC/ASA blends. Analysis of morphology by micro‐thermal analysis (μTA?) in combination with oscillatory rheology, time‐temperature‐superposition (TTS), creep recovery and PVT testing revealed distinct trends of surface gloss with each material's viscoelastic behavior and surface finish. It has been shown that influential properties such as rubber content, particle size and distribution, molecular weight, viscosity ratios and the degree of acrylonitrile mismatching play key roles in each material's rheology, developed morphology and subsequent trends in surface gloss after injection molding.     

基于非连续超临界N2注气系统的聚丙烯发泡注塑工艺参数

将聚丙烯与1%的滑石粉混合造粒,使用N2作为物理发泡剂,通过自行搭建的非连续超临界N2注气系统,研究发泡注塑工艺过程中注射行程、注射速度、螺杆转速、熔体温度对制品表面质量、减重和泡孔结构的影响。结果表明:注射行程引起的熔体填充量变化是影响制品减重的首要因素,随着填充量的增加,减重下降明显;高压力降速率能够得到均匀泡孔分布且泡孔密度较高的制品;螺杆转速导致停留时间改变对制品表面质量影响较大;熔体温度影响到发泡剂在聚合物熔体中的溶解,螺杆转速130～150 r/min、熔体温度200℃时,能够得到减重、制品表面质量和泡孔结构俱佳的制品。     

Characteristics of mould separation and its effects on qualities of thin wall injection moulded parts

Abstract

Precision injection moulding of thin walled parts has become an important concern in the computer, communication, and consumer electronics plastics industry. Previous studies in precision injection moulding control focus on the injection screw and the associated operations. In the present study, the influence of relevant parameters including injection speed, melt temperature, mould temperature, filling-packing switchover, and packing pressure on the mould plate separation under different clamping pressure were investigated as part of precision moulding control. A two cavity tensile test specimen mould equipped with four linear variable displacement transducers across the parting surfaces of the mould was used. A computer based monitoring system was built to detect the mould separation signals. Mould separation can also be identified from part weight and thickness variation and exhibits relevant correspondence with them. It was found that owing to the high injection speed required for thin wall moulding, mould separation is not negligible. In all situations, mould separation decreases with increasing clamping pressure. As melttemperature andmouldtemperatureincrease,mouldseparationincreases, resulting in an increase in part weight and thickness. Similarly, when packing pressure and injection speed increase, mould separation also increases. Earlier switchover from filling to packing can decrease mould separation as well as part weight and thickness. Among all the parameters studied, packing pressure exhibits the greatest influence on mould separation and on the associated weight and thickness change. This influence also becomes larger when the moulded part becomes thinner, owing to the larger injection moulding pressure. PRC/1746     

长玻纤增强聚甲醛注塑成型工艺的研究

制备了长玻璃纤维(LGF)增强聚甲醛(POM)复合材料。通过6因素2水平的正交试验,探讨了注射压力、注射速度、模具温度、保压压力、保压时间、冷却时间等工艺条件对LGF增强POM复合材料的制品表观和拉伸强度的影响。结果表明:注射压力、注射速度、保压时间和模具温度等4个工艺条件对LGF增强POM制品表观和拉伸强度的影响最大,当注塑成型条件分别为料筒温度180¹90℃、注射压力60 MPa、注射速度60 mm/s、模具温度80℃、保压时间15 s时,制品具有最佳的表观和力学性能。     

Effects of injection molding conditions on the electrical properties of polycarbonate/carbon nanotube nanocomposites

Polycarbonate/Carbon nanotube (PC/CNT) nanocomposites containing various CNT contents (0–5 wt%) were prepared by injection molding. The effects of CNT contents, injection speed (V) and injection temperature (T) on the electrical resistivity of the PC/CNT nanocomposites were investigated. It was found that the tensile strength of nanocomposites was enhanced slightly with increased CNT contents, and the tensile modulus was 29% greater after the 5 wt% CNT addition, but the brittle tendency became stronger. Aside from tensile properties, the electrical resistivity of the nanocomposites dropped 12 orders of magnitude after the 5 wt% CNT addition. Also, there was a tendency that the electrical resistivity was lower in the case of higher injection temperature and lower injection speed. Scanning electron microscope (SEM) images and the distribution of surface layer electrical resistivity, clearly showed a notable influence by surface layer microstructures on the electrical resistivity, and the injection conditions affected both the value of the maximum electrical resistivity and the position where it occurred. This study offers an alternative green and simple molding process to prepare conductive PC nanocomposites and to achieve the industrialization of PC/CNT nanocomposite products which can be used in electromagnetic shielding and anti‐static fields. POLYM. COMPOS., 37:3245–3255, 2016. © 2015 Society of Plastics Engineers     

Gloss and surface topography of ABS: A study on the influence of the injection molding parameters

Acrylonitrile butadiene styrene is used in applications where the surface appearance is important. Plates with surface texture, varying from highly smooth to very rough, were injection molded with various processing conditions. Morphology, roughness, and gloss of the surface were assessed in relation to the processing parameters. The surface characterization of the moldings was done using reflected differential interference contrast microscopy and laser microtopography. It was observed that the surface properties are affected by the molding parameters. The mold temperature, followed by the injection temperature and the holding pressure are the more influent parameters. The contribution of each parameter to the gloss varies with the type of surface, but for most of the surfaces the contribution of the mold temperature was above 90%. In general, higher values of these parameters improve the replication accuracy that reduce the roughness (and increase the gloss) of very smooth surfaces and cause the opposite effect in other surfaces. In surfaces with an anisotropic texture the gloss depends on the measuring direction. POLYM. ENG. SCI. 46:1394–1401, 2006. © 2006 Society of Plastics Engineers.     

成型工艺对表面特殊效果材料表观缺陷改善的研究

通过对不同的注射成型工艺条件及模具温度的研究表明,注塑温度、注塑压力对表面特殊效果材料中铝粉的堆积现象无明显影响,提高注射速度则能大幅度改善铝粉堆积现象;由光学显微镜观察可知,提高模具温度可以明显改善熔接痕,当模具温度从40℃提高至75℃时,熔接痕宽度从16 μm降至7 μm,进一步升高温度至120℃,熔接痕则完全消失...