Seikei-Kakou
Online ISSN : 1883-7417
Print ISSN : 0915-4027
ISSN-L : 0915-4027
Volume 13, Issue 11
Displaying 1-14 of 14 articles from this issue
Index
Preface
Technical Note : Special Issue on Control of Heat Transfer and Sandwich Molding Process
Special Lecture
Technical Reports
Reports from Universities and Institusions in Japan : 99
Reports from Oversea Universities and Institutions : 46
Visiting Active Companies
Original Papers
  • Haruo Shikuma, Kiyohito Koyama
    2001 Volume 13 Issue 11 Pages 746-750
    Published: November 20, 2001
    Released on J-STAGE: November 18, 2009
    JOURNAL FREE ACCESS
    The viscoelastic properties of ethylene/alpha-olefin copolymers (LLDPE) produced by the metallocene catalysts have been studied. Effects of long chain branchings and molecular weight distribution on rheological properties were investigated on four types of polymers produced using the different kinds of catalysts. The following conclusions were obtained through two types of polymers produced by CGC (Constrained-Geometric Catalyst) and mono-Cp (mono-Cyclopentadienyl) types. The effect of very long relaxation times based on the long chain branching of the sample obtained by CGC and mono-Cp type appeared in dynamic viscoelastic functions, creep recovery and elongational viscosity. The critical stress in shear flow property of the samples showed much lower stress compared with the polymer having no long chain branching.
    Especially, it was found that a long chain branching and a high molecular weight component cause strong effects on the steady state recoverable compliance and elongational viscosity from measuring creep recovery and elongation flow in LLDPE produced using mono-Cp catalyst.
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  • Kimitoshi Sato, Yasuo Kurosaki, Takushi Saito
    2001 Volume 13 Issue 11 Pages 751-758
    Published: November 20, 2001
    Released on J-STAGE: November 18, 2009
    JOURNAL FREE ACCESS
    The development of a novel precision replication procedure having two stages: a molding process and a replication process assisted by an infrared radiation from an external source is described in this paper. As a preliminary process, an injection molding system is used to process blank components by a conventional procedure; the components in this stage not always require a high degree of accuracy. A component molded in the first stage is inserted into the cavity, and is covered with an infrared-transparent glass plate. An infrared radiation is applied to heat the inserted resin components for a certain duration about a few tens seconds. Since the temperature of the thin layer of resin near surface rises due to absorption of radiation, the fluidity of polymer consequently increases. The information on the window is replicated onto the work piece by means of heat supplied with the external radiation. In this replication process, the system is able to be in a low temperature, and therefore cooling is rapidly accomplished. Further, it is expected that the residual birefringence remained within the injection molded products by such a reheating process. In this process, two kinds of precise mold were adopted; a ZnSe mold wall on the surface of which a few precise fine grooves were formed and a thin metallic stamper plate for CDs pasted on the surface of ZnSe were used for replication. The temperature distributions within the plastics were obtained by numerical calculation in order to estimate the validity of the proposing experimental system. The proposed process showed remarkable performance on the micro-and sub-micro-scale replication keeping rapid cooling after heat supplying with the external radiation.
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