Abstract:
A delivery system containing an active agent within a polymeric material formed from a thermoplastic composition is provided. Through selective control over the particular nature of the thermoplastic composition, as well as the manner in which it is formed, the present inventors have discovered that a porous network can be created that contains a plurality of micropores and nanopores. The ability to create such a multimodal pore size distribution can allow the delivery rate of an active agent to be tailored for a particular use.
Abstract:
Fibers that are formed from a thermoplastic composition that contains a rigid renewable polyester and has a voided structure and low density are provided. To achieve such a structure, the renewable polyester is blended with a polymeric toughening additive in which the toughening additive can be dispersed as discrete physical domains within a continuous matrix of the renewable polyester. Fibers are thereafter formed and then stretched or drawn at a temperature below the glass transition temperature of the polyester (i.e., "cold drawn"). Without intending to be limited by theory, the present inventors believe that the deformation force and elongational strain of the drawing process causes debonding to occur in the renewable polyester matrix at those areas located adjacent to the discrete domains. This creates a network of voids (e.g., micro-voids, nano-voids, or a combination thereof) located adjacent to the discrete domains, which as a result of their proximal location, can form a bridge between the boundaries of the voids and act as internal structural "hinges" that help stabilize the network and increase its ability to dissipate energy.
Abstract:
A method for forming biodegradable fibers is provided. The method includes blending polylactic acid with a polyepoxide modifier to form a thermoplastic composition, extruding the thermoplastic composition through a die, and thereafter passing the extruded composition through a die to form a fiber. Without intending to be limited by theory, it is believed that the polyepoxide modifier reacts with the polylactic acid and results in branching of its polymer backbone, thereby improving its melt strength and stability during fiber spinning without significantly reducing glass transition temperature. The reaction-induced branching can also increase molecular weight, which may lead to improved fiber ductility and the ability to better dissipate energy when subjected to an elongation force. To minimize premature reaction, the polylactic acid and polyepoxide modifier are first blended together at a relatively low temperature(s). Nevertheless, a relatively high shear rate may be employed during blending to induce chain scission of the polylactic acid backbone, thereby making more hydroxyl and/or carboxyl groups available for subsequent reaction with the polyepoxide modifier. Once blended, the temperature(s) employed during extrusion of the blended composition can be selected to both melt the composition and initiate a reaction of the polyepoxide modifier with hydroxyl and/or carboxyl groups of the polylactic acid. Through selective control over this method, the present inventors have discovered that the resulting fibers may exhibit good mechanical properties, both during and after melt spinning.
Abstract:
A biodegradable fiber for use in forming a nonwoven web is provided. The fiber is formed from a thermoplastic composition comprising at least one polylactic acid in an amount from about 75 wt.% to about 99 wt.% and at least one polyether copolymer in an amount from about 1 wt.% to about 25 wt.%, wherein the polyether copolymer contains from about 40 mol.% to about 95 mol.% of a repeating unit (A) having the following formula. wherein, x is an integer from 1 to 250, the polyether copolymer further containing from about 5 mol.% to about 60mol.% of a repeating unit (B) having the following formula. wherein, n is an integer from 3 to 20; and y is an integer from 1 to 150. Such polyether copolymers have been found to improve a variety of characteristics of the resulting thermoplastic composition, including its ability to be melt processed into fibers and webs, as well as its sensitivity to moisture.
Abstract:
A method for forming a composition that includes mixing an antimicrobially active botanical oil (e.g., thymol, carvacrol, etc.) and a modified starch polymer within a melt blending device (e.g., extruder) is provided. Unlike the problems associated with proteins, the use of starch polymers allows for a greater degree of flexibility in the processing conditions and is still able to achieve good properties in the resulting composition. The present inventors have also discovered that a plasticizer may be employed to facilitate melt processing of the starch, as well as to enhance the ability of the botanical oil to flow into the internal structure of the starch where it can be retained in a stable manner. The composition is also typically generally free of solvents. In this manner, the starch will not generally disperse before use and prematurely release the botanical oil. Due to the water sensitivity of the modified starch, however, it may be subsequently dispersed by moisture when it is desired to release the botanical oil.
Abstract:
Novel polymer blends useful for manufacturing breathable, environmentally stable, and water weakenable disposable films, fibers, and articles, and methods for making the blends are disclosed. The films, fibers and articles manufactured from these novel blends demonstrate improved stability and enhanced strength when exposed to environmental conditions of increased humidity and elevated temperature. Films, fibers, and articles manufactured from the novel polymer blends are particularly useful for the manufacture of disposable products.
Abstract:
The present invention relates to shape deformable materials, which are capable of (1) being deformed, (2) storing an amount of shape deformation, and (3) recovering at least a portion of the shape deformation when exposed to electromagnetic radiation (EMR) energy. The shape deformable materials can advantageously be in the form of films, fibers, filaments, strands, nonwovens, and pre-molded elements. The shape deformable materials of the present invention may be used to form products, which are both disposable and reusable. More specifically, the shape deformable materials of the present invention may be used to produce products such as disposable diapers, training pants, incontinence products, and feminine care products.
Abstract:
The present invention relates to shape deformable materials, which are capable of (1) being deformed, (2) storing an amount of shape deformation, and (3) recovering at least a portion of the shape deformation when exposed to electromagnetic radiation (EMR) energy. The shape deformable materials can advantageously be in the form of films, fibers, filaments, strands, nonwovens, and pre-molded elements. The shape deformable materials of the present invention may be used to form products, which are both disposable and reusable. More specifically, the shape deformable materials of the present invention may be used to produce products such as disposable diapers, training pants, incontinence products, and feminine care products.
Abstract:
A method for forming an antimicrobial composition that includes mixing an antimicrobially active botanical oil (e.g., thymol, carvacrol, etc.) and protein within a melt blending device (e.g., extruder) is provided. Despite the problems normally associated with melt processing proteins, the present inventors have discovered that the processing conditions and components may be selectively controlled to allow for the formation of a stable, melt-processed composition that is able to exhibit good mechanical properties. For example, the extrusion temperature(s) and shear rate employed during melt blending are relatively low to help limit polypeptide dissociation, thereby minimizing the impact of aggregation and embrittlement. While the use of such low temperature/shear conditions often tend to reduce mixing efficiency, the present inventors have discovered that a carrier fluid may be employed to enhance the ability of the botanical oil to flow into the internal structure of the protein where it can be retained in a stable manner. The composition is also typically anhydrous and generally free of solvents. In this manner, the protein will not generally disperse before use and prematurely release the botanical oil.
Abstract:
A method for forming a fiber is provided. The method comprises supplying at least one aromatic polyester to a melt processing device and modifying the aromatic polyester with at least one polyether copolymer within the device to form a thermoplastic composition having a melt flow rate that is greater than the melt flow rate of the aromatic polyester. The polyether copolymer contains a repeating unit (A) having the following formula (A) wherein, x is an integer from 1 to 250, the polyether copolymer further containing a repeating unit (B) having the following formula (B) wherein, n is an integer from 3 to 20; and y is an integer from 1 to 150.