Abstract:
A thermoformable acoustic sheet formed by a compressed fibrous web includes high melt fibres and adhesive thermoplastic fibres in which the adhesive fibres are at least partially melted so that in the compressed web the adhesive fibres at least partially coat the high melt fibres and reduce the interstitial space in the fibre matrix. Also included are methods of producing a thermoformable acoustic sheet which includes heating a fibre web including high melt and adhesive thermoplastic fibres to at least partially melt the adhesive fibres and compressing the web to form a sheet so that the adhesive fibres at least partially coat the high melt fibres to reduce the interstitial space in the fibre matrix.
Abstract:
Blended fluoropolymer compositions are provided. In one embodiment, a liquid dispersion of a first fluoropolymer is blended with a liquid dispersion of a second fluoropolymer. The first fluoropolymer may be polytetrafluoroethylene (PTFE), such as a low molecular weight PTFE (LPTFE) that has been polymerized via a dispersion or emulsion polymerization process, and which has not been agglomerated, irradiated, or thermally degraded. The LPTFE may be in the form of an aqueous dispersion, having a mean particle size of less than 1.0 microns (μm), with the LPTFE having a first melt temperature (Tm) of 332° C. or less. The second fluoropolymer may be a melt processible fluoropolymer (MPF), such as methylfluoroalkoxy (MFA), fluorinated ethylene propylene (FEP), or perfluoroalkoxy (PFA), for example, in the form of an aqueous dispersion, and having a mean particle size of less than 1.0 microns (μm). Blending of the dispersions facilitates interaction of the LPTFE and MPF on a submicron level to facilitate intimate blending such that, when the blended fluoropolymer composition is dried, a crystal structure representing a true alloy of the fluoropolymers is formed, having melt characteristics that differ from those of the individual fluoropolymers. The blended fluoropolymer composition may be used to provide a coating having improved impermeability, stain resistance, abrasion resistance, smoothness, and higher contact angles.
Abstract:
Blended fluoropolymer compositions are provided, in which a liquid dispersion of a first fluoropolymer is blended with a liquid dispersion of a second fluoropolymer. The first fluoropolymer may be polytetrafluoroethylene (PTFE), such as a low molecular weight PTFE (LPTFE) in the form of an aqueous dispersion having a mean particle size of less than 1.0 microns (μm) and a first melt temperature (Tm) of 332° C. or less. The second fluoropolymer may be a melt processible fluoropolymer (MPF), such as methylfluoroalkoxy (MFA), fluorinated ethylene propylene (FEP), or perfluoroalkoxy (PFA), for example, in the form of an aqueous dispersion having a mean particle size of less than 1.0 microns (μm). When the blended fluoropolymer composition is dried, a crystal structure representing a true alloy of the fluoropolymers is formed, having melt characteristics that differ from those of the individual fluoropolymers.
Abstract:
Fluoropolymer particles are subjected to high energy treatment so as to change the chemical functionality of the particle surfaces and thereby change the surface characteristics of the particles. These characteristics improve the usefulness of these particles and can make them highly dispersible, even in water. The surface treated fluoropolymer particles are subject to a chemical crosslinking process, or alternatively, are subject to a high energy treatment process, and may optionally be pretreated with a macromolecular chemical species prior to the foregoing processes. The high energy treatment can be used to both surface treat the fluoropolymer particles and in some embodiments, may also cause chain scission of the fluoropolymers to thereby reduce the molecular weight of the fluoropolymer particles. The surface treated fluoropolymer particles can be used to form fluoropolymer coatings on various substrates.
Abstract:
A fluoropolymer block copolymer containing a hydrofluorocarbon and a polyamide-based crosslinking agent crosslinked at a temperature above about 500° F. (about 260° C.). The crosslinked-block copolymer has compatibility with both non-hydrofluorocarbon-based fluoropolymers and engineered resins. Additionally, the block copolymer has unexpectedly high temperature stability, higher than each of the individual components.
Abstract:
Fluoropolymer particles are subjected to high energy treatment so as to change the chemical functionality of the particle surfaces and thereby change the surface characteristics of the particles. These characteristics improve the usefulness of these particles and can make them highly dispersible, even in water. The surface treated fluoropolymer particles are subject to a chemical crosslinking process, or alternatively, are subject to a high energy treatment process, and may optionally be pretreated with a macromolecular chemical species prior to the foregoing processes. The high energy treatment can be used to both surface treat the fluoropolymer particles and in some embodiments, may also cause chain scission of the fluoropolymers to thereby reduce the molecular weight of the fluoropolymer particles. The surface treated fluoropolymer particles can be used to form fluoropolymer coatings on various substrates.
Abstract:
A thermo-formed acoustic product formed from an acoustic sheet with a relatively high flow resistance, and a layer of porous flow resistive spacer material attached to one side of the acoustic sheet and having a flow resistance substantially smaller than the acoustic sheet. The acoustic product has locally reactive acoustic behavior and an overall air flow resistance of between 2800 Rayls and 8000 Rayls. A decorative facing can be applied to the acoustic sheet.
Abstract:
Fluoropolymer powder particles which are surface treated so as to change the chemical functionality on their surfaces which in turn changes the surfaces characteristics. These characteristics improve the usefulness of these powders and can make them wettable. The surface treated fluoropolymer particles are subject to an atmospheric plasma treatment process, and preferably pretreated with a macromolecular chemical species prior to the atmospheric plasma treatment. The atmospheric plasma treatment enhances adhesion to the powder surface and can also enhance cross-linking of the macromolecular chemical species. The surface treated fluoropolymer powders can be used to form fluoropolymer coatings on various substrates.
Abstract:
A miscible polymer blend of superior mechanical strength, hardness and abrasion or mar resistance comprising PVDF and at least one compatible aromatic polyimide. The aromatic polyimide in the miscible polymer blend acts as a nucleating agent for PVDF crystallization. The miscible polymer blend comprising PVDF and aromatic polyimide does not exhibit the negative characteristic of reduced mechanical strength encountered in PVDF and polymer alloys known in the art. The PVDF/aromatic polyimide alloy is prepared by dissolving, separately, PVDF and the aromatic polyimide in a solvent and blending the solutions to form the required composition.
Abstract:
A method for the preparation of a modified fluoropolymer powdered material is disclosed. A suspension of solid fluoropolymer particles together with SiC particles in an aqueous carrier, is frozen and the frozen carrier is then removed by sublimation at sub-atmospheric pressure to produce a dry powder of modified fluoropolymer particles.