Biomass resources which do not depend on oil as a raw material and effect carbon neutral that they do not increase the amount of carbon dioxide even when they are burnt are attracting a lot of attention due to problems such as concern about the depletion of oil resources and an increase in the amount of carbon dioxide in air which causes global warming. In the field of polymers, the development of biomass plastics produced from the biomass resources is now actively under way.
A typical example of the biomass plastics is polylactic acid. Since it has relatively high heat resistance and mechanical properties out of the biomass plastics, its use is spreading to dishes, packaging materials and miscellaneous goods, and further the potential of using it as an industrial material is now under study.
However, for use of polylactic acid as an industrial material, its heat resistance is not satisfactory and when a molded article thereof is to be obtained by injection molding having high productivity, it is inferior in moldability as its crystallinity is low as a crystalline polymer.
A polycarbonate resin which is produced from a raw material obtained from an ether diol residue able to be produced from sugar is under study as an amorphous polycarbonate resin obtained from a biomass resource and having high heat resistance. Especially, studies are being made to mainly use isosorbide as a monomer so as to incorporate it into a polycarbonate. There are proposed polycarbonate resins having excellent heat resistance and moldability which is prepared by copolymerizing isosorbide with an aliphatic dihydroxy compound (Patent Document 1 and Patent Document 2). However, as a polycarbonate resin containing isosorbide has a high water absorption coefficient, a dimensional change or warp occurs in a molded article thereof by water absorption. Use of this polycarbonate resin is limited in application fields such as disk materials, optical pick-up lenses and connectors used in optical systems thereof, and sheets whose warp by water absorption causes a problem, in which high-accuracy dimensional stability is required, and molded articles for use in an environment where water absorption and drying are repeated for a long time. Therefore, a resin having a low water absorption coefficient and high heat resistance is desired. Since packaging materials which are used to package food, medical and pharmaceutical goods and precision electronic parts must undergo boiling disinfection and pressure/heat sterilization, a resin having high boiling water resistance is desired.
Further, polycarbonate polymers containing an isosorbide unit, a C14˜49 aliphatic diacid unit and a C19˜44 aliphatic diol unit are disclosed (Patent Document 3, Patent Document 4). However, since these polycarbonate polymers have an extremely large number of main-chain carbon chains, HDT (deflection temperature under load) lowers.    (Patent Document 1) WO2004/111106    (Patent Document 2) JP-A 2008-24919    (Patent Document 3) JP-A 2011-500925    (Patent Document 4) WO2011/082103
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