摘要:
A method and system for melt processing a thermoplastic composition that contains a starch and plasticizer is provided. The composition is melt blended and extruded through a die to form an extrudate, which is thereafter cooled using a multi-stage system of the present invention that includes at least one water-cooling stage and at least one air-cooling stage. More particularly, the extrudate is initially contacted with water for a certain period time so that it becomes partially cooled and solidified on its surface. After the water-cooling stage(s), the extrudate is also subjected to at least one air-cooling stage in which a stream of air is placed into contact with the extrudate.
摘要:
A film that contains a thermoplastic polyurethane and water-soluble polymer is provided. The film is both elastic and water-sensitive (e.g., water-soluble, water-dispersible, etc.) in that it loses its integrity over time in the presence of water. The dual attributes of elasticity and water-sensitivity may be achieved by reducing the tendency of the thermoplastic polyurethane and water-soluble polymer to form separate phases. Namely, phase separation may cause the elastomer to act as a barrier and limit the ability of the water-soluble polymer to contact water and thereby disperse. To minimize such phase separation, a variety of aspects of the film construction may be selectively controlled, such as the nature of the thermoplastic polyurethane and water-soluble polymer, the relative amount of each component, and so forth.
摘要:
A biodegradable and renewable film that may be employed in a wide variety of applications is provided. The film is formed from a thermoplastic composition that contains at least one starch and at least one plant protein. Even at a high renewable material content, the present inventors have discovered that films may be readily formed from plant proteins and starches by selectively controlling the individual amount of the starch and plant proteins, the nature of the starch and plant proteins, and other components used in the film. Balancing the amount of starches and plant proteins within a certain range, for instance, can reduce the likelihood of plant protein aggregation and enhance the ability of the composition to be melt processed. The composition also contains at least one plasticizer that improves the thermoplastic nature of the protein and starch components. The selection of the plasticizer may also help reduce the tendency of the plant protein to aggregate during melt processing. For example, a relatively acidic plasticizer (e.g., carboxylic acid) may be employed in certain embodiments to minimize the formation of disulfide bonds in a gluten protein, and thereby decrease its tendency to aggregate.
摘要:
A biodegradable, substantially continuous filament is provided. The filament contains a first component formed from at least one high melting polyester and a second component formed from at least one low melting polyester. The low melting point polyester is an aliphatic-aromatic copolyester formed by melt blending a polymer and an alcohol to initiate an alcoholysis reaction that results in a copolyester having one or more hydroxyalkyl or alkyl terminal groups. By selectively controlling the alcoholysis conditions (e.g., alcohol and copolymer concentrations, catalysts, temperature, etc.), a modified aliphatic-aromatic copolyester may be achieved that has a molecular weight lower than the starting aliphatic-aromatic polymer. Such lower molecular weight polymers also have the combination of a higher melt flow index and lower apparent viscosity, which is useful in the formation of substantially continuous filaments.
摘要:
A film that contains a core layer positioned adjacent to an outer layer is provided. The core layer contains a relatively high percentage of thermoplastic biopolymers that are both biodegradable and renewable. Despite being biodegradable and renewable, many biopolymers tend to be relatively stiff in nature. The present inventors have discovered, however, that through selective control over the components in the core and outer layers, a film can be readily formed having good mechanical properties. Among other things, this is accomplished by blending the biopolymer in the core layer with a polyolefin. A polyolefin is also employed in the outer layer. In addition to providing functionality to the film (e.g., heat sealing, printing, etc.), the polyolefin-containing outer layer also helps counteract the stiffness of the biopolymer in the core layer, and helps improve processability, stiffness, and ductility.
摘要:
A film that contains a thermoplastic polyurethane and water-soluble polymer is provided. The film is both elastic and water-sensitive (e.g., water-soluble, water-dispersible, etc.) in that it loses its integrity over time in the presence of water. The dual attributes of elasticity and water-sensitivity may be achieved by reducing the tendency of the thermoplastic polyurethane and water-soluble polymer to form separate phases. Namely, phase separation may cause the elastomer to act as a barrier and limit the ability of the water-soluble polymer to contact water and thereby disperse. To minimize such phase separation, a variety of aspects of the film construction may be selectively controlled, such as the nature of the thermoplastic polyurethane and water-soluble polymer, the relative amount of each component, and so forth.
摘要:
A method for forming a thermoplastic composition that contains a combination of a renewable biopolymer with a polyolefin is provided. The biopolymer and polyolefin are supplied to the extruder at a feed section. The plasticizer is directly injected into the extruder in the form of a liquid so that it forms a thermoplastic biopolymer in situ within the extruder and then a homogeneous blend. The in situ addition of the plasticizer is facilitated by the use of a compatibilizer that has a polar component with an affinity for the biopolymer and a non-polar component with an affinity for the polyolefin.
摘要:
A film that is both elastic and water-sensitive (e.g., water-soluble, water-dispersible, etc.) in that it loses its integrity over time in the presence of water is provided. To achieve these dual attributes, the film contains an olefinic elastomer and a water-soluble polymer. Although these polymers are normally chemically incompatible due to their different polarities, the present inventors have discovered that phase separation may be minimized by selectively controlling certain aspects of the film, such as the nature of the polyolefin, water-soluble polymer, and other film components, the relative amount of the film components, and so forth. For example, certain water-soluble polymers may be selected that have a low molecular weight and viscosity to enhance their melt compatibility with nonpolar polyolefins. This, in turn, may result in a film that is generally free of separate phases, which would otherwise limit the ability of the water-soluble polymer to contact water and disperse.
摘要:
An injection molding material that includes a renewable resin containing a combination of renewable polymers (e.g., starch and plant protein) and a plasticizer is provided. Although such compounds are normally difficult to process into thermoplastics, the present inventors have discovered that injection molding materials may nevertheless be formed by melt blending the renewable resin with a synthetic resin (e.g., polyolefin) while selectively controlling the nature of the resins and their relative concentrations. In this manner, a morphology may be achieved in which the renewable resin is present as a discontinuous phase that is dispersed within a continuous phase of the synthetic resin (e.g., “island-in-the-sea” morphology). The discontinuous and continuous phases may each constitute from about 30 vol. % to about 70 vol. %, and in some embodiments, from about 40 vol. % to about 60 vol. %. With such a morphology, the continuity of the synthetic resin can minimize the aggregate properties of the renewable resin such that the molding material possesses melt properties similar to that of the synthetic resin. Further, this morphology may also minimize the need to use different molding tools as the shrinkage properties of the overall composition may be substantially similar to that of the synthetic resin.
摘要:
A film that contains a thermoplastic polyurethane and water-soluble polymer is provided. The film is both elastic and water-sensitive (e.g., water-soluble, water -dispersible, etc.) in that it loses its integrity over time in the presence of water. The dual attributes of elasticity and water-sensitivity may be achieved by reducing the tendency of the thermoplastic polyurethane and water-soluble polymer to form separate phases. Namely, phase separation may cause the elastomer to act as a barrier and limit the ability of the water-soluble polymer to contact water and thereby disperse. To minimize such phase separation, a variety of aspects of the film construction may be selectively controlled, such as the nature of the thermoplastic polyurethane and water-soluble polymer, the relative amount of each component, and so forth. For example, thermoplastic polyurethanes are polar in nature and thus may be generally compatible with water-soluble polymers (e.g., polyvinyl alcohol), which are also polar in nature. Further, water-soluble polymers having a relatively low molecular weight and viscosity typically possess better melt compatibility with polar thermoplastic polyurethanes. By carefully controlling the nature of the polymers used to form the film, the present inventors have discovered that a film may be formed that is generally free of distinct phases.