Polylactic Acid Resin Composition and Resin Molded Article Thereof

Abstract

Provided are a polylactic acid resin composition excellent in transparency, heat resistance, and migration resistance, and excellent in productivity at the time of the mold forming thereof, and a resin molded article thereof. The polylactic acid resin composition includes a polylactic acid; a reaction product of glycerin, an alkylene oxide mainly formed of ethylene oxide, and a fatty acid having 12 to 24 carbon atoms; and a fatty acid amide having a hydroxyl group.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 570,542, filed on Dec. 14, 2011, and Japanese Application No. JP2011-271595 filed on Dec. 12, 2011, the complete disclosures of which, in their entireties, are hereby incorporated by reference.BACKGROUND[0002]1. Technical Field[0003]The embodiments herein relate to a polylactic acid resin composition and a resin molded article thereof.[0004]2. Description of the Related Art[0005]While depletion of petroleum resources, a CO2 reduction, and the like have been perceived as problems, a polylactic acid using lactic acid obtained by fermenting a grain resource such as corn as a raw material has been attracting attention. Polylactic acid is a resin derived from a plant as described above and has the following characteristics: Polylactic acid has high rigidity, and is excellent in transparency. However, its applications have been limited as compared to an ordinary resin be...

AI Technical Summary

Benefits of technology

The present invention relates to a polylactic acid resin composition that is transparent, resistant to heat and migration, and has good productivity during molding. The inventors found that adding a specific reaction product (a mixture of glycerin, ethylene oxide, and a fatty acid) as a plasticizer, and a certain fatty acid amide (which acts as a crystal nucleating agent) to the composition, significantly improved its transparency. Additionally, the inventors found that when the content of the fatty acid amide was within a specific range, the resulting resin composition and molded article were even more transparent and productive during molding.

Problems solved by technology

While depletion of petroleum resources, a CO2 reduction, and the like have been perceived as problems, a polylactic acid using lactic acid obtained by fermenting a grain resource such as corn as a raw material has been attracting attention.

However, its applications have been limited as compared to an ordinary resin because of, for example, the following reasons: Polylactic acid generally has low heat resistance and low impact resistance, and hence typically cannot be used under a high-temperature condition.

However, the method involves, for example, the following problems.

The method is not practical owing to an extremely long heat treatment time and transparency of the polylactic acid reduces in association with progress of its crystallization.

However, generally the applications where the resin composition disclosed in WO2008 / 010318A can be used are extremely limited owing to its low transparency and low heat resistance.

Moreover, the resin composition involves a problem in that productivity at the time of its mold forming is poor because a molded article thereof is liable to deform upon its removal from the mold unless a molding time during the mold forming is set to be long.

However, a molded article excellent in transparency and migration resistance typically cannot be obtained from the resin composition because the resin composition is liable to be migrated in water or an alcohol.

Further, the resin composition still has room for improvement because its productivity at the time of the mold forming thereof is not sufficient.