The purpose of this study is to explore methods to suppress hydrogen chloride gas generation during the recycle injection molding process of glass cloth coated with polyvinyl chloride (PVC) resin. Hydrotalcite compound was added to PVC as a halogen scavenger before injection molding. Two types of experiments were performed on ground injection molded samples to examine the suppression effects of HT on hydrogen chloride gas generation. First, the time elapsed before gas generation at 180°C was measured by using Congo-red test paper. Second, a corrosion test was performed by exposing an iron clip in the 180°C test chamber. In addition, tensile tests were carried out on injection molded samples to investigate the effects of adding HT to PVC on mechanical properties. It is concluded here that HT is effective for protecting injection molding machines from corrosion during the recycling of glass cloth coated with PVC.

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Flowing meso-phase structures of binary polymer blends with and without viscoelastic features are simulated using a two fluid model with modified Cahn-Hilliard equation and double reptation mixing rule. The calculated system is thermodynamically unstable under quiescent conditions and tends to separate into two phases automatically. The modified Cahn-Hilliard model with viscoelastic network stress in simple shear flow predicts that phase separation leads to a co-continuous structure at early time and then decomposes into a layered structure, that is mixed in flow direction and separated into two phases in shear direction at near steady state. Furthermore, the ratio of shear modulus between a droplet and surrounding matrix influences the nature of the layer structure attained at steady state. When the droplet's shear modulus is larger than that of the matrix phase, the droplet causes a layer structure perpendicular to the flow direction.

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The low strength of the Integrated Thermocouple Sensor has been already reported was improved, furthermore, a new Integrated Thermocouple Sensor with improved pattern shape which can prevent errors due to thermal conduction was fabricated, and the melt temperature distribution along the cavity thickness direction was measured in a broad range of injection rates and for high viscosity materials such as short glass fiber reinforced thermoplastics which were difficult to measure with the previous sensor. The following conclusions were obtained.
(1) When the crystalline polymer with high viscosity is injected at high injection rates, a protruding type of temperature peak caused by shear heating is generated at the vicinity of the cavity wall. On the other hand, the resins with low viscosity and amorphous polymers, this peak does not occur easily.
(2) The reinforced polypropylene with short glass fiber, it was confirmed that when the base resin is high viscosity polypropylene, though the generation of the temperature peak is marked except for high injection rate, the temperature distribution including the temperature peak generation area does not change considerably even if the glass fiber content changes sharply regardless of the change in the base resin viscosity and injection rate.
(3) The above temperature distribution did not change considerably even if glass fibers are mixed with the base resin, because of the following two opposite effects offset each other. (a) the viscosity increases, promoting shear heating which raises the temperature, (b) the thermal conductivity in the molten state increases, promoting cooling at the vicinity of the cavity wall, which lowers the temperature.
(4) These results (1) (2) indicate that the temperature peak generation is affected by the viscosity characteristics of resins near the crystallization temperature “Tc” or the glass transition point “Tg, ” latent heat, and thermal conductivity. Furthermore, the heat resistance between the resin surface and cavity surface may also be an important factor which influences temperature peak generation.

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