Abstract: To provide a polyester resin container with a fracturable portion that has improved openability and to provide its production method. In the polyester resin container with a fracturable portion, in which the material of the container is polyester resin, which comprises a mouth portion 20 contiguous to the container body and a fracturable portion 30 located above the mouth portion 20 integrally, which is equipped with a fracturable structure that can be opened by fracturing the boundary part between the opening end 22 of the mouth portion 20 and the fracturable portion 30; a groove 40 is formed approximately perpendicular to the outer surface of the boundary part between the opening end 22 of the mouth portion 20 and the fracturable portion 30 of the container, and the intrinsic viscosity of the polyester resin located at the periphery of the groove 40 is lowered than the intrinsic viscosity of the polyester resin located at a location other than the periphery of the groove 40.

Abstract: To provide an imide oligomer, excellent in thermal moldability, having excellent heat resistance as a thermally-cured polyimide resin, and that is obtainable easily and inexpensively. An imide oligomer including a nonaxisymmetric site derived from one nonaxisymmetric aromatic diamine molecule represented by below formula (1), only at a central portion of the oligomer chain, in the formula (1), W is a direct bond, —O—, —CH2—, —C2H4—, —C(CH3)2—, —CF2—, —C2F4—, —C(CF3)2—, —C(?O)—, —NH—, —NH—C(?O)—, —S—, —S(?O)—, or —S(?O)2—.

Abstract: A laminate has a core layer and a skin layer on either side of the core layer, wherein the skin layer is formed of a copolymer having a glass transition point of 85° C. or more and 115° C. or below and consisting of 2,6-naphthalene dicarboxylic acid or its lower alkyl ester, terephthalic acid or its lower alkyl ester and ethylene glycol or a polymer alloy having a glass transition point of 85° C. or more and 115° C. or below and consisting of polyethylene terephthalate and polyethylene-2,6-naphthalate. Thus, it can be used suitably as a packaging container for food and drink, such as jelly containers, which has flavor resistance and aroma retention sufficient not to be limited by types of flavor used for jelly or the like, excels in sealing properties with a lid body, can be hermetically sealed with an easy-peel transparent lid body, and is also superior in gas barrier properties, impact resistance, heat resistance, cost efficiency and transparency.

Abstract: A laminate has a core layer and a skin layer on either side of the core layer, wherein the skin layer is formed of a copolymer having a glass transition point of 85° C. or more and 115° C. or below and consisting of 2,6-naphthalene dicarboxylic acid or its lower alkyl ester, terephthalic acid or its lower alkyl ester and ethylene glycol or a polymer alloy having a glass transition point of 85° C. or more and 115° C. or below and consisting of polyethylene terephthalate and polyethylene-2,6-naphthalate. Thus, it can be used suitably as a packaging container for food and drink, such as jelly containers, which has flavor resistance and aroma retention sufficient not to be limited by types of flavor used for jelly or the like, excels in sealing properties with a lid body, can be hermetically sealed with an easy-peel transparent lid body, and is also superior in gas barrier properties, impact resistance, heat resistance, cost efficiency and transparency.

Abstract: A laminate has a core layer and a skin layer on either side of the core layer, wherein the skin layer is formed of a copolymer having a glass transition point of 85° C. or more and 115° C. or below and consisting of 2,6-naphthalene dicarboxylic acid or its lower alkyl ester, terephthalic acid or its lower alkyl ester and ethylene glycol or a polymer alloy having a glass transition point of 85° C. or more and 115° C. or below and consisting of polyethylene terephthalate and polyethylene-2,6-naphthalate. Thus, it can be used suitably as a packaging container for food and drink, such as jelly containers, which has flavor resistance and aroma retention sufficient not to be limited by types of flavor used for jelly or the like, excels in sealing properties with a lid body, can be hermetically sealed with an easy-peel transparent lid body, and is also superior in gas barrier properties, impact resistance, heat resistance, cost efficiency and transparency.

Abstract: A laminate has a core layer and a skin layer on either side of the core layer, wherein the skin layer is formed of a copolymer having a glass transition point of 85° C. or more and 115° C. or below and consisting of 2,6-naphthalene dicarboxylic acid or its lower alkyl ester, terephthalic acid or its lower alkyl ester and ethylene glycol or a polymer alloy having a glass transition point of 85° C. or more and 115° C. or below and consisting of polyethylene terephthalate and polyethylene-2,6-naphthalate. Thus, it can be used suitably as a packaging container for food and drink, such as jelly containers, which has flavor resistance and aroma retention sufficient not to be limited by types of flavor used for jelly or the like, excels in sealing properties with a lid body, can be hermetically sealed with an easy-peel transparent lid body, and is also superior in gas barrier properties, impact resistance, heat resistance, cost efficiency and transparency.

Abstract: 1. An ester copolymer resin having a general formula ?I!.HO.paren open-st.COArCOORO.paren close-st..sub.n H ?I!wherein Ar represents 2,6-naphthalene group or phenylene group, R represents ethylene group or 1,4-cyclohexylene group, and n is a number of 100 to 1000 and a polymer alloy having a solubility parameter of 10.8 to 11.9 consisting essentialy of the ester copolymer and a polycarbonate resin are provided. The ester resin and the alloy are transparent and has a heat resistance and a hot water resistance (resistance to whitening) resisting sterilization of food, a good heat sealebility to aluminum closure, and recycling ability with PET resin.

Abstract: 1. An ester copolymer resin having a general formula ?I!. ##STR1## wherein Ar represents 2,6-naphthalene group or phenylene group, R represents ethylene group or 1,4-cyclohexylene group, and n is a number of 100 to 1000 and a polymer alloy having a solubility parameter of 10.8 to 11.9 consisting essentialy of the ester copolymer and a polycarbonate resin are provided. The ester resin and the alloy are transparent and has a beat resistance and a hot water resistance (resistance to whitening) resisting sterilization of food, a good heat sealability to aluminum closure, and recycling ability with PET resin.