Maleic anhydride was grafted onto poly(propylene) (PP)-type thermoplastic elastomer PER by reactive processing with a screw extruder and a maleated PER (MPER) was prepared. With the intent of ionic crosslinking, metal compounds such as aluminum stearate (AlSt), magnesium stearate (MgSt), calcium stearate (CaSt), zinc stearate (ZnSt), potassium stearate (KSt), sodium stearate (NaSt), magnesium hydroxide (MH), zinc oxide (ZnO), and zinc sulfide (ZnS) were added to the MPER and meltmixed with the screw extruder, and crosslinked compounds were obtained. The degree of crosslinking estimated from the gel fraction was in the order AlSt, MgSt, CaSt, ZnSt Ͼ NaSt, KSt Ͼ MH Ͼ ZnO, ZnS Ͼ MPER. The rheological properties, such as capillary flow properties and dynamic viscoelasticities, of the compounds were measured and their melt processabilities were evaluated. The viscosity increased with increasing the content of the metal compounds and the increase was higher at the lower shear rate. The increasing effect of the viscosity at low shear rates was AlSt Ͼ MgSt Ͼ ZnSt Ͼ NaSt Ͼ KSt Ͼ MH Ͼ ZnO Ͼ ZnS Ͼ MPER. Namely, the viscosity increasing effect of the metal salt of stearic acid is the higher for the larger ionic charge and the viscosity increasing effects of other compounds are lower than those of the metal salts of stearic acid. Accordingly, by changing the kind and content of the metal compounds, the viscosity can be freely controlled. Considering also other rheological characteristics, these ionically crosslinked compounds are assumed to show ideal flow processabilities except for the extrudate appearance. To improve the appearance, it is necessary to dilute the compound with unmodified PER, PP, or fillers.

Maleic anhydride was grafted onto a polypropylene-type thermoplastic elastomer PER by reactive processing with a screw extruder, and a maleated PER (MPER) was prepared. Aiming at ionic crosslinking, magnesium 12-hydroxy stearate (MgStOH), zinc oxide (ZnO), and zinc sulfide (ZnS), and aiming at covalent crosslinking, melamine as an amino compound, and Epocizer and GRYCI-ALE as epoxy compounds, were added to the MPER, melt-mixed by use of the screw extruder, and crosslinked compounds were obtained. The rheological properties such as capillary flow properties and dynamic viscoelasticities of the compounds were measured and their melt processabilities were evaluated. The degree of crosslinking was in the order of epoxy compounds Ͼ MgStOH Ͼ melamine Ͼ ZnO, ZnS Ͼ MPER (blank). In the case of the compound with MgStOH of a moderately high degree of crosslinking, the nonNewtonian behavior is remarkable and the die swell ratio is low and suitable for extrusion. However, in the case of compounds with epoxy compounds of an excessive degree of crosslinking, fine extrudate cannot be obtained due to the lack of fusion and the control of degree of crosslinking is necessary.

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