Compositions comprising low molecular weight polyhydroxyalkanoates and methods employing same

Abstract

Polyhydroxyalkanoate compositions including hot melt adhesive compositions, biodegradable wax compositions, and protective coating compositions are provided and include a low molecular weight polyhydroxyalkanoate, a terminally-modified polyhydroxyalkanoate, or both. The compositions are biodegradable and environmentally friendly. Methods of protecting an article, such as a food product like cheese, are also provided and include coating or encapsulating the article with a composition containing a low molecular weight polyhydroxyalkanoate, a terminally-modified polyhydroxyalkanoate, or both.

Description

[0001] This application is a divisional of U.S. patent application Ser. No. 09 / 999,782, filed Oct. 25, 2001 (now allowed), which in turn is a divisional of U.S. Patent Application No. 60 / 243,818, filed Oct. 27, 2000, which are incorporated in their entirety by reference herein. BACKGROUND OF THE INVENTION [0002] The present invention relates to hot melt adhesive compositions, wax compositions, and coating compositions, and methods of using the same. [0003] With a view to the environment, a serious need has arisen for biologically degradable products. Various plastic and wax materials, such as hot melt adhesives and protective coatings, are so often used and in such great volume that these products have a significant impact on the environment. A need exists for biodegradable hot melt adhesive and protective coating materials. [0004] Hot melt adhesives are used in a great number of applications and are particularly employed in packaging materials for all sorts of goods. Unfortunately,...

AI Technical Summary

Benefits of technology

[0009] It is therefore an object of this invention to provide degradable polymeric compositions, particularly oligomeric compositions, having improved hydrophobic biodegradation characteristics and that can be used as hot melt adhesives, protective coatings, surface active agents, and solvents.

[0010] It is another object of the present invention to provide hydrophobic biodegradable compositions suitable for use in a wide range of processing conditions.

[0021] The biodegradable wax compositions of the present invention can contain, in addition to the polyhydroxyalkanoate oligomer, at least one other component such as a wax component. The biodegradable waxes of the present invention preferably exhibit at least one of the following properties: a crystalline to microcrystalline structure; a capacity to acquire gloss when rubbed; a capacity to produce pastes or gels with suitable solvents or when mixed with other waxes; a low viscosity at just above the melting point; and a low solubility in solvents for fats at room temperature.

Problems solved by technology

Unfortunately, most conventional hot melt adhesives are non-biodegradable, thus adversely affecting the environment.

The plastic of such a rind cannot be recovered or recycled and thus presents a problem for the environment.

Furthermore, such a coating must fulfill a large number of functions and a large number of requirements.

Although biologically degradable and compostable coatings exist, they are generally water-soluble polymers which are consequently water-sensitive.

In the past, it has not been possible to use polyhydroxyalkanoate films as coatings in the foodstuffs industry because of the use of organic solvents and because of the need to heat the polyhydroxyalkanoates to the melting point thereof, which could unnecessarily damage the product.

Current biodegradable surfactant systems either do not meet required technical specifications or have a significant price disadvantage that make them uncompetitive with synthetic based systems.