Abstract: A double container including an outer container having flexibility and communicating with the outside air, and an inner bag holding contents, with a space defined between the outer container and inner bag. The contents include a component which generates gas by decomposition and a volatile component and the inner bag has permeability to decomposition gases evolved by the decomposing component of the contents. The decomposition gases evolved permeate through the inner bag without difficulty for easy discharge into the outside while the volatile gases evolved from the volatile components are allowed to stay in the space on the outer side of the inner bag, making it difficult for the newly evolved volatile gases to permeate through the inner bag, thereby limiting dispersion of the volatile gases and effectively suppressing deterioration of hairdye.

Abstract: A double container (11) comprising an outer container (13) having flexibility and communicating with the outside air, and an inner bag (14) holding contents, with a space (20) defined between the outer container (13) and inner bag (14), wherein the contents include a component which generates gas by decomposition and a volatile component and the inner bag (14) has permeability to decomposition gases evolved by the decomposing component of the contents. The decomposition gases evolved permeate through the inner bag (14) without difficulty for easy discharge into the outside while the volatile gases evolved from the volatile components are allowed to stay in the space (20) on the outer side of the inner bag (14), making it difficult for the newly evolved volatile gases to permeate through the inner bag (14), thereby limiting dispersion of the volatile gases and effectively suppressing deterioration of hairdye.

Abstract: A process for producing a polyester container having a higher strength than usual and a reduced wall thickness, whereby the polyester is present in a reduced amount contributing to resource savings, which includes preparing a polyester resin composition containing a polyester resin and 0.1 to 10 parts by weight, based on 100 parts by weight of the polyester resin, of an additive compound selected from the group consisting of compounds represented by the formula (I): ##STR1## and compounds represented by the following formula (II): ##STR2## and subjecting the resin composition to stretch blow molding.