A new type of non-machine-sewn (zero stitch) MLI blanket has been developed to achieve high thermal performance while maintaining workability of production and assembly equivalent to the conventional type. Tag-pins, which are widely used in commercial applications to hook price tags to products, are used to fix the films in place. The pin material is changed to polyetheretherketone (PEEK) for use in space. Thermal performance is measured using a boil-off calorimeter, in which a rectangular liquid nitrogen tank is used to evaluate the degradation at the bending corner and joint of the blanket. A test piece of zero-stich MLI shows significantly improved thermal performance (eff is smaller than 0.0050 at ordinary temperature) despite having the same fastener interface as traditional blankets, while the venting design and number of tag-pins are confirmed as appropriate in depressurization test.