PET/PET-co-PEN共混物的中空吹塑研究

介绍聚对苯二甲酸乙二酯(PET)／PET共聚聚萘二甲酸乙二酯(PET—co—PEN)共混物的成型加工特性，探讨利用加工PET的设备、两步法注射拉伸吹塑工艺，生产耐热和阻隔PET／PET-co-PEN共混物制品的可行性。结果表明，为了得到理想的制品外观和性能，需要对挤出螺杆、加工工艺参数、型坯设计和拉伸比进行改进。     

高阻隔耐热PET/PEN饮料瓶的研制

用双螺杆挤出机研究了熔融挤出工艺、原料的选择及配比对聚对苯二甲酸乙二酯(PET)/聚对萘二甲酸乙二酯(PEN)共混物耐热性和阻隔性的影响,并利用差示扫描量热仪、核磁共振仪进行了性能表征。结果表明,PET与PET-PEN共聚酯容易熔融共混,即在无定形态相容;随挤出时间和温度的增加,PET/PEN共混物的冷结晶温度升高、熔点降低、阻隔性降低而玻璃化转变温度不变;随PET-PEN含量的增加,共混物的阻隔性和耐热性得到改善。用注-拉-吹工艺成型可得到PET/PEN共混物饮料瓶,其耐热性和对氧气的阻隔性比纯PET瓶高,且随PET-PEN含量的增加而提高。     

聚酯瓶问题分析(二)

讨论瓶用聚酯的乙醛值、阻隔性及啤酒包装用的聚酯瓶;聚酯的结晶熔点与瓶坯注塑之间的关系,指出结晶熔点增高的原因主要是采用较高增黏工艺温度的结果;聚酯瓶耐应力开裂时间的提高对聚酯树脂来说,主要是控制切片[η]和它的稳定性([η]降小)。     

空调器室外机塑料壳体的研制和应用

研制了一种空调器室外机塑料壳体,该塑料壳体由聚酯瓶破碎料经改性造粒后注塑成型或者由聚酯瓶破碎料经改性后挤出成板材,再将板材热压成型加工制作而成。试验结果表明,该空调器室外机塑料壳体耐老化、免油漆、耐雨水冲刷、耐腐蚀、绝缘性能好、加工工艺简单、生产制作成本低廉,综合性能优于金属材料制作而成的空调器室外机壳体。     

Studies on the thermal and mechanical behavior of PLA‐PET blends

The increasing use of bio‐sourced and biodegradable polymers such as poly(lactic acid) (PLA) in bottle packaging presents an increasing challenge to the polyethylene terephthalate (PET) recycling process. Despite advanced separation technologies to remove PLA from PET recyclate, PLA may still be found in rPET process streams. This study explores the effects of PLA on the mechanical properties and crystallization behavior of blends of PET containing 0.5–20% PLA produced by injection molding. SEM indicates an immiscible blend of the two polymers and TGA confirms the independent behavior of the two polymers under thermal degradation conditions. Temperature‐modulated DSC studies indicate that adding PLA to PET increases the rigid amorphous fraction of the PET moiety. Critical amounts of PLA induce stress oscillation behavior during mechanical testing. The mechanical behavior of the samples is explained by antagonistic interaction between increased rigid amorphous fraction and decreased fracture strength arising from an increased population of PLA microparticles. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44147.     

Blends of a bottle grade polyethylene terephthalate copolymer and a liquid crystalline polymer. Part I: Injection molding morphology and rheological properties

Blends of a bottle grade polyethylene terephthalate copolymer (PET) with a liquid crystalline polymer (LCP) were prepared by injection molding. The thermal transitions, the morphology and the rheological properties of the pure components and of the blends were measured by dynamic mechanical analysis (DMTA), scanning electron microscopy (SEM) and capillary and parallel plates rheometry, respectively. The blends displayed only one T_g; the B60 and B80 compositions showed the highest LCP β‐transition, which has been correlated to good barrier properties. In all the blends a “skin‐core” type morphology was observed; the core region had two phases while the skin region showed only one fibrillar phase. The viscosity measurements gave an indication that the interface was strong, probably due to transterifications reactions that occurred during the tests. On creep recovery, the increasing addition of the LCP to the PET increased the blends elastic recovery. On stress growth, the highest stress overshoot was displayed by the pure LCP; this polymer actually presented two overshoots that were also observed in some of the blends at high shear rates.     

Mechanical properties of poly(ε‐caprolactone) and poly(lactic acid) blends

The aim of this work was to better understand the performance of binary blends of biodegradable aliphatic polyesters to overcome some limitations of the pure polymers (e.g., brittleness, low stiffness, and low toughness). Binary blends of poly(ε‐caprolactone) (PCL) and poly(lactic acid) (PLA) were prepared by melt blending (in a twin‐screw extruder) followed by injection molding. The compositions ranged from pure biodegradable polymers to 25 wt % increments. Morphological characterization was performed with scanning electron microscopy and differential scanning calorimetry. The initial modulus, stress and strain at yield, strain at break, and impact toughness of the biodegradable polymer blends were investigated. The properties were described by models assuming different interfacial behaviors (e.g., good adhesion and no adhesion between the dissimilar materials). The results indicated that PCL behaved as a polymeric plasticizer to PLA and improved the flexibility and ductility of the blends, giving the blends higher impact toughness. The strain at break was effectively improved by the addition of PCL to PLA, and this was followed by a decrease in the stress at break. The two biodegradable polymers were proved to be immiscible but nevertheless showed some degree of adhesion between the two phases. This was also quantified by the mechanical property prediction models, which, in conjunction with material property characterization, allowed unambiguous detection of the interfacial behavior of the polymer blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

关于我国PET瓶成型设备科学发展的探讨

分析了我国PET瓶成型设备的现状,研究了国际上先进的PET瓶成型设备的技术进展和发展趋势,提出了我国PET瓶成型设备的科学发展方向。以科学发展观为指导,重新认识符合市场发展规律的PET瓶成型设备的新特点,创新开拓。自主创新是PET瓶成型设备科学发展的理念,高速率成型是PET瓶成型设备性能研发的首要重点,节能环保是PET瓶成型设备功能研发的重点。     

瓶级PET“注射-吹塑”成型生产技术

简述了瓶级 PET切片及 PET瓶性能特点 ,介绍了仪化瓶级 PET“注射 -吹塑”成型生产技术以及今后的发展趋势     

饮料瓶坯注射模具的热流道设计

对饮料瓶坯注射模具的热流道结构进行了设计,并从理论上计算了热流道的加热功率。对于注射成型加工温度范围较窄的ＰＥＴ塑料,可利用热流道板实现一模多腔热流道注射成型。热流道板的设计成功,为ＰＥＴ瓶坯多烧口注射成型奠定了基础。     

一步法生产PET瓶

介绍了PET树脂、PET瓶的性能特点 ,并阐述了注 -拉 -吹法 (即注塑 -拉伸 -吹塑成型 )生产PET瓶的工艺技术及生产控制要点。     

Polyethylene terephthalate/low density polyethylene/titanium dioxide blend nanocomposites: Morphology,crystallinity, rheology,and transport properties

Physical features of polyethylene terephthalate (PET)/low density polyethylene (LDPE) immiscible blends, rich in PET, with and without titanium dioxide (TiO₂) nanoparticles are studied. These materials are of industrial interest, because they can be obtained by recycling PET bottles containing TiO₂ with their corresponding polyethylene made caps. Their potential application in packaging is investigated. Droplet-matrix morphology is observed by scanning electron microscopy; coalescence occurs during compression molding. Transmission electron microscopy results show that TiO₂ nanoparticles are located at the interface between PET and LDPE, forming a physical barrier that favors development of smaller droplets. Thermal analysis results are compatible with the morphology of the blends and the location of the TiO₂ nanoparticles. Viscosity obtained by extrusion continuous flow and oscillatory flow measurements in the linear regime show that some of the blends have viscoplastic behavior. Permeability results reveal that 80PET/20LDPE/TiO₂ blend nanocomposite shows a balanced barrier character to both oxygen and water vapor. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46986.     

Morphological development during injection molding of self‐reinforcing composites. II: Numerical simulations and analytical predictions

In this study, combined numerical simulation of injection molding and analytical calculations have been used to determine the velocity and elongational strain in the advancing melt front (AMF) region, during the molding of PET/LCP blends, at various injection molding conditions. A model is proposed that establishes the relationship between the aspect ratio of LCP fibers and elongational strain, based on the assumption of an affine deformation of the LCP domains. This model enables us to predict the processing dependent morphology of injection molded PET/LCP blends. The effect of processing parameters on the morphology development during injection molding were investigated. The studies show that injection speed and mold temperature have significant effects on the morphological development of the blends, compared with the effect of the melt temperature. A good correlation between calculated and scanning electron microscopy results was obtained.     

Mechanical properties of injection molded blends of poly(ethylene-terephthalate) and poly(amide-6,6)

Data have been obtained regarding the tensile and impact behavior of pure poly(ethylene terephthalate) (PET) and polyamide 6,6 (PA) and blends of PA in PET in concentrations of 5, 10, 25, 30 and 35 percent by weight of PA. The measurements were carried out at ?40, 23 and 70°C. Dispersion and sample preparation were carried out in a reciprocating screw injection-molding machine. All blends exhibited brittle behavior and low strength, when compared to pure components. Although some enhancement of mechanical properties might be realized by orientation, it is suggested that the observed behavior might be attributed to the low quality of dispersion achievable in injection molding process. This conclusion is supported by microscopic evidence.     

新型注塑螺杆性能研究

随着注塑技术的不断发展以及注塑物料种类的不断丰富,注塑螺杆的性能越来越引起人们的重视.通过自行开发的可视化实验装置和在线数据测控系统,研究了各种新型注塑螺杆的熔融、温度均匀性、塑化能力等性能,并和三段式通用螺杆进行比较.结果表明新型注塑螺杆的性能比普通三段式螺杆有较大的提高.     

微注射成型机螺杆参数的优化设计

借鉴传统注射成型技术,对微注射成型机的注射螺杆进行了结构优化设计.螺杆类型选择三段式渐变型结构,先初步设定符合微注射成型机要求的螺杆结构参数,通过建立数学模型对其进行优化设计,在获得优化螺杆结构参数的基础上,利用聚合物成型计算软件对物料的塑化过程进行数值模拟,分析熔体温度、固体剩余量、剪切速率等参数,最终得到螺杆的最优...     

Rapid thermal cycling with low thermal inertia tools

Solid freeform fabrication processes offer the manufacturing flexibility for tools with low thermal inertia and internal conformal channels for rapid thermal cycling in injection molding. This article analyzed each step of a rapid thermal cycling process and provided quantitative guidance for tooling design. The proposed design methodology was tested on a three‐dimensional (3D) printed benchmark tool with truss support. Rapid cooling test on the benchmark tool resulted in the mold time constant shorter than 2.3 s and the cavity temperature uniformity better than 3°C. Preliminary tests demonstrated the technical feasibility of using a solid freeform fabrication process to fabricate low thermal inertia tools for improved heat management in injection molding. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers     

Properties of reactively blended soy protein and modified polyesters

The compatibilizing effect of anhydride groups attached to a polyester was examined while blending soy protein and a biodegradable polyester. Three different polyesters grafted with anhydride functional groups were used as compatibilizers for blending with soy protein concentrate, soy flour, and soy isolate. The processing conditions for these blends in a twin screw extruder and injection‐molding machine were evaluated and the physical and mechanical properties of these blends were determined. The concentrations of soy protein and compatibilizer were varied to achieve optimum mechanical properties, exploring the various limits of operating conditions. The dynamic mechanical properties were determined using a rheometric mechanical spectrometer (RMS‐800). The enthalpy of fusion was determined using a differential scanning calorimeter. Blends containing compatibilizer gave enhanced tensile strength when compared to blends without compatibilizer. The morphology of these blends was investigated with the help of an optical microscope and X‐ray diffraction was used for crystallinity studies. Water and oil absorption by these blends were determined for a period of 25 days. © 1999 Society of Chemical Industry     

药用塑料包装瓶模具结构设计

介绍了一步法单工位注吹成型药用塑料包装瓶的模具结构设计。该模具一模8腔,结构紧凑,操作维修简单,从型坯到制品用普通注射机一步完成,克服了二步法和一步法三工位生产工艺环节多、设备投资大的缺点,产品成品率高。     

Correlations between extrusion and injection molding process variables for PVC dry blends

Although thermoplastic extrusion and injection molding have been extensively studied by a large number of authors, very little is known about the correlations between the extrusion and injection molding process variables. This paper describes the various comparable process variables between extrusion and injection molding of PVC dry blends. The Brabender extruder of 19 mm diameter and 25:1 length to diameter ratio and the Szekeley reciprocating single screw injection molding machine were used. PVC dry blends of industrial importance were prepared using a high speed mixer. The four mix formulations based on a commercial grade of PVC were used. Process variables studied during the injection molding were the melt temperature near the nozzle, injection pressure, injection speed, and energy consumption. Process variables studied during extrusion were the melt pressure at the die, power consumption, and the melt temperature at the die orifice. The correlations between the extrusion and injection molding process variables for PVC dry blends have been established.