In recent years, waste disposal of used synthetic resin molded articles (products) by land-fill or incineration sometimes causes a problem of environmental pollution. As a measure for solving this environmental pollution problem, use of biodegradable resins is attracting attention. Studies are also being made on the use of these biodegradable resins as the raw material resin for production of various packaging containers. For example, a container, biodegradable in a natural environment, and excellent in transparency and impact strength, has been proposed; such as a biodegradable container formed of a composition mainly comprising a copolymer of a polylactic acid or lactic acid and another hydroxycarboxylic acid (see, JP-A-6-23828 (the term “JP-A,” as used herein, means an “unexamined published Japanese patent application”), and a biodegradable container formed of a composition mainly comprising an aliphatic polyhydric alcohol and an aliphatic polybasic acid (see, JP-A-7-172425).
The label which is attached to a surface of the packaging container is also required to be made of a material, biodegradable in a natural environment, and use less generating heat of combustion when burned for disposal. In order to satisfy this requirement, there have been proposed, for example, a container comprising a biodegradable resin, where the container's outer peripheral surface is wound around by a shrinkable label made of the same biodegradable resin (see, JP-A-8-58797), and a method of molding a container by using a biodegradable polyester, where the container is molded by previously inserting a paper-made label in the mold (see, JP-A-8-58796 and JP-A-10-291247).
The paper label is biodegradable and generates less heat of combustion, but it is disadvantageously weakened by water, and is liable to be damaged during use. As a measure for improving the defects of paper label, a synthetic paper for label, for example, comprising polypropylene and polyethylene has been proposed (see, JP-A-2-84319), but this label is not biodegradable, and therefore, the problem of environmental pollution still remains. A label for in-mold forming, comprising a biodegradable resin-made film, and a biodegradable container attached with the label have heretofore not been proposed.
As a result of intensive investigations to provide a biodegradable label for in-mold forming, which is excellent in water resistance, printable to allow for printing letters, or the like, by various printing methods, and degradable in a natural environment, and also to provide a biodegradable container attached with the label, the present invention has been accomplished.
USPTO Backgrounds
USPTO Backgrounds