Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/12—Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
  • B32B27/281—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42 comprising polyimides
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4326—Condensation or reaction polymers
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/44—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling
  • D04H1/46—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling by needling or like operations to cause entanglement of fibres
  • D04H1/498—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling by needling or like operations to cause entanglement of fibres entanglement of layered webs
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/44—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling
  • D04H1/50—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties the fleeces or layers being consolidated by mechanical means, e.g. by rolling by treatment to produce shrinking, swelling, crimping or curling of fibres
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H13/00—Other non-woven fabrics
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
  • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
  • D06N3/0002—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate
  • D06N3/0015—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof characterised by the substrate using fibres of specified chemical or physical nature, e.g. natural silk
  • D06N3/0025—Rubber threads; Elastomeric fibres; Stretchable, bulked or crimped fibres; Retractable, crimpable fibres; Shrinking or stretching of fibres during manufacture; Obliquely threaded fabrics
  • D06N3/0031—Retractable fibres; Shrinking of fibres during manufacture
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
  • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
  • D06N3/12—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins
  • D06N3/125—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins with polyamides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2379/00—Other polymers having nitrogen, with or without oxygen or carbon only, in the main chain
  • B32B2379/08—Polyimides
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
  • D06N2201/00—Chemical constitution of the fibres, threads or yarns
  • D06N2201/02—Synthetic macromolecular fibres
  • D06N2201/0263—Polyamide fibres
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
  • D06N2209/00—Properties of the materials
  • D06N2209/06—Properties of the materials having thermal properties
  • D06N2209/067—Flame resistant, fire resistant
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
  • D06N2211/00—Specially adapted uses
  • D06N2211/12—Decorative or sun protection articles
  • D06N2211/26—Vehicles, transportation

Definitions

• This invention relates to layered fibre structure and has particular reference to fibre structures having layers of material with different physical properties.
• One particular aspect of the present invention relates to a fibrous structure having a substantially continuous skin incorporated within the structure in which both core and skin compositions have flame retardent, high temperature resistant properties, said structure being capable of being processed into a number of specific novel products.
• fibres such as those formed from polyolefins, polyesters, polyvinylchloride or polyamides shrink between about 10% and 50% when subjected to treatment with heat.
• the strong inter-molecular forces which are due to Van der aals interactions and, in some materials, dipole - dipole interactions or even hydrogen bonds, however, can be overcome at elevated temperatures by entropic relaxation allowing the fibre to reach a state whereby a contracting force develops and the fibre shrinks.
• the article should be flame retardent and exhibit "non-melting" characteristics at high temperatures, on exposure to fire, the article should retain at least some semblance of integrity and should prevent hot molten material being generated by the fire itself.
• a fibre structure comprising an assemblage of rigidified or rigidifiable fibres, characterised in that said assemblage is provided in at least one surface thereof with a matrix layer of a thermoplastic material which is compatible with said fibres and imparts a substantially continuous surface to said assemblage.
• compatible a thermoplastic material that is capable of wetting the surface of the fibres to allow adhesive forces to be effective between the material and the fibres.
• matrix layer as used herein is to be understood a substantially continuous layer of a thermoplastics material, at least part of which matrix layer includes fibres of the surface lamina of the assemblage.
• the matrix layer is disposed substantially wholly within a surface lamina of the fibre assemblage; the fibres of the assemblage extending substantially throughout the layer with the thermoplastics material of the layer entering the interstices of fibre structure of the assemblage.
• the matrix layer comprises a substantially continuous skin of said thermoplastic material which is disposed externally of the surface of said assemblage, in which case the fibres of the assemblage extend only partially into the matrix layer.
• the assemblage may comprise at least a major proportion of heat shrinkable fibres.
• the fibres constituting at least a major proportion of the fibre assemblage may be selected from heat shrinkable synthetic fibre materials; typical fibres are polyamide fibres, acrylic fibres, polypropylene fibres, polyphenylene sulphide fibres, polyimide fibres, aromatic polyether ketone fibres, polyetherimide fibres and polyester fibres.
• the fibre assemblage may include discrete fibre groups as described in our copending British Patent Application No. 8904069.5 the disclosure of which is incorporated herein by reference.
• the fibre structure may be capable of heat treatment to produce a structure of increased density in which the density of said discrete fibre groups is greater than that of the remainder of the fibre assemblage.
• Such a densified fibre structure may be produced by forming an assemblage comprising at least a major proportion of heat shrinkable fibres; locating the assemblage contiguous a shaping surface; constraining the structure against shrinkage in at least one direction and subjecting the assemblage to heat at a temperature and for a time sufficient to shrink the fibre and to obtain fibre-to-fibre bonding to increase the rigidity of the assemblage; and thereafter removing said shaped article from the surface.
• the density of the fibre structure after heat treatment may be non-uniform and the structure may have a plurality of longitudinal elements therein, each element comprising a group of fibres oriented in a plane and densified by heat treatment.
• the fibre assemblage may be woven, knitted, or non-woven. Fibres ' lengths within the assemblage may be oriented or partially oriented to provide substantially uni-directional properties.
• the fibre assemblage may be a batt layer or a paper mat.
• the assemblage in particular, may comprise a plurality layers of fibre material which layers have been extensively needle punched to produce cohesion between the fibres, both within a particular layer and between fibres of different layers.
• assemblage may be provided with densified pillars, or elements, disposed therein and extending in a direction generally transverse to the plane of the fibre structure.
• the fibre structure when subjected to heat treatment, may be constrained in at least two dimensions so that the only direction in which the material is free to shrink is the third dimension, that is to say, substantially perpendicular to each of the constrained dimensions.
• a fibre structure has been produced which is provided with densified pillars, or elements, disposed within the assemblage and extending generally othogonal to the plane of the fibre structure. This results in a substantial stiffening and increase in the compressional strength of the material.
• This feature of core structure and fibre structure is again described at some length in our copending British Patent Application No. 8904069.5.
• the assemblage may be formed from polyimide fibres, typically those which at the time of writing, are produced under the reference P84 by Messrs. Lenzing Aktiengesellschaft of Austria.
• the fibre structure produced in accordance with the present invention permits a number of different layers and components of different densities, rigidities and properties which can be molded either separately or in combinatio .
• the assemblage of a fibre structure produced in accordance with the present invention may comprise, for example, a layer of high shrink polyimide fibres combined with a layer of non-shrinkable polyimide fibre batting, the two layers being united by needling.
• the combined bi-layer structure may then be molded with substantial lateral constraint at temperatures of the order of 600°F (316°C) . This results in the formation of a molded structure having a high density, thin, rigid layer on one side and a softer, less dense, non-rigid product intimately attached to the dense layer on the other side.
• a fibre assemblage which is produced by locating a web of said assemblage juxtaposed a forming surface with a layer of the thermoplastic material interposed therebetween, and thereafter applying heat and pressure to the assemblage such that said thermoplastic material impregnates a surface of the fibre assemblage juxtaposed said forming surface to form said matrix layer.
• the matrix layer may be caused to enter the surface lamina of the fibre assemblage by utilising the natural shrinkage capability of the fibrous material itself.
• the heating of the assemblage may be conducted at a temperature sufficient to cause or allow shrinkage of the fibres of the assemblage to occur; the thermoplastic material may have a softening point at or below the shrinkage temperture of the fibres of the assemblage such that, as shrinkage occurs, the assemblage shrinks and conforms to the forming surface thereby causing the thermoplastic material to enter the interstices between the fibres of the assemblage in a surface lamina thereof, juxtaposed said forming surface to form said matrix layer.
• the thermoplastic material may be a fibrous layer or a film. Where the thermoplastic layer is a film, it may be cast in place from solution or added as a separate free standing film. Where the thermoplastic layer is a fibrous layer, it may be in the form of a batt or a fleece. The thermoplastic layer may be cohered or adhered to the assemblage, or may be laminated therewith.
• the thermoplastic layer may be a fibrous layer which is needled together with the assemblage of heat shrinkable fibres prior to application to the forming surface.
• the forming surface may be any convexly shaped article, or it may be a mandrel of uniform or irregular shape.
• the web of fibres is located juxtaposed the forming surface and is clamped thereabout to prevent or restrain shrinkage in any direction other than perpendicular to the forming surface; a thermoplastic layer is interposed between the web and the forming surface.
• the fibre assemblage shrinks and seeks to "squeeze" the thermoplastic layer against the forming surface as the thermoplastic material itself is softened at the shrinkage temperature.
• the shrinkage forces act against the forming surface to produce a matrix layer of thermoplastic material in a surface of said assemblage and to impart a substantially continuous surface juxtaposed the forming surface, a portion of the thermoplastic material being forced into the interstices of the assemblage.
• the result is an article having the benefits of a substantially uniform, continuous surface formed in contact with a forming surface, whilst maintaining the advantages associated with a fibrous structure within the impregnated surface lamina; a portion of the thermoplastic material having entered the intestices of the fibrous assemblage in the said surface lamina.
• the fibre assemblage is a tube or closed web which is placed over a mandrel with the layer of thermoplastic material disposed between the forming of shaping mandrel and the heat shrinkable web.
• the web contracts about the mandrel, "squeezing" the thermoplastic layer, which has softened at the shrinkage temperature, between the shrinking web and the mandrel surface.
• the shrinkage forces exerted by the web ensures close conformity of the thermoplastic layer to the shaping surface of the mandrel and causes the thermoplastic material to enter the intestices of the assemblage in a surface lamina thereof.
• the tubular article produced in accordance with the present invention may be removed by severing, typically along an axis of a mandrel, thereby allowing the shaped article to be removed.
• the mandrel may be coated with release agents such as those typically used in thermoplastic moulding operations.
• release agents such as those typically used in thermoplastic moulding operations.
• various combinations of properties may be obtained by using different combinations of heat shrinkable fibre assemblages and thermoplastic matrix layers.
• thermoplastic matrix layer may be selected from any material that
• a) is compatible with the heat shrinkable fibres of the assemblage particularly in the environment in which the shaped article is subsequently to be used, and
• Typical fibres or films which may be used in the thermoplastic matrix layer include those formed from polyethylene, polypropylene, polyetherimide, polyester, polyarylate, polysulfone and polyperfluoroethylene propylene materials.
• the heat shrinkable fibres of the assemblage may be a polyimide material such as that which is commercially available under the trade name "P84" from Messrs. Lenzing AG of Austria; the thermoplastic material may be a polyetherimide such as that which is commercially available under the trade name "Ultem” .
• a fibre structure which is produced by the method of forming a self-supporting fibre assemblage of a rigidified or rigidifiable fibrous material, preparing a solution of a surface coating component comprising a compatible thermoplastic material, applying said solution to a surface of a fibre structure, and thereafter removing the solvent.
• the fibre assemblage comprises a major portion of a polyimide material; the thermoplastic matrix layer may be formed of polyetherimide.
• the polyethi ide can be prepared as a viscous solution in methylene chloride which is then applied to the assemblage surfaces to be treated. The methylene chloride may then be removed and, after application, calendering or heat treatments, may be used to modify the polyetherimide matrix layer to improve adhesion and to increase surface smoothness.
• the polyetherimide material can be applied either before or after the heat treatment of the heat shrinkable fibre assemblage.
• the subsequent heat treatment of the composite structure may permit the shrinkage of the fibres to effect further impregnation of a surface lamina of the fibre assemblage with thermoplastic material.
• the fibre assemblage is further treated by locating the assemblage juxtaposed a forming surface with said matrix layer towards said surface, and thereafter subjecting the structure to heat and pressure such that said thermoplastic layer further impregnates a surface lamina of the assemblage juxtaposed the forming surface.
• the shrinkage forces generated by the fibre assemblage act against the forming surface to 'squeeze' the thermoplastic material thereagainst and into the surface layer of the fibre assemblage.
• the method of this aspect of the present invention may be modified to the extent that the polyetherimide concentration in solution may be varied to change the continuity, density and depth of penetration of the resulting matrix layers, as well as generally to assist in carrying out the method.
• Concentrations of polyetherimide in methylene chloride of the order of 1 to 30% (w/w) and, more particularly, 15 to 25% (w/w) have been found to be exceptionally useful.
• the polyetherimide/methylene chloride solution can be applied to the fibre assemblage by a variety of methods such as spraying, dip coating and knife coating.
• the use of different coating methods will affect the polyetherimide density, the polyetherimide continuity and the depth of penetration of the matrix layer into the polyimide fibre assemblage.
• One aspect of the invention may permit the use of filled skins which may be obtained by adding a small portion of a fibre or particular agent to the polyetherimide/methylene chloride solution.
• glass fibres, ceramic fibres, carbon fibres, silica and glass beads - either solid or hollow - may be used in order to increase the strength or thermal resistance of the skins and of the entire fibre structure.
• the fibre structure produced in accordance with the present invention comprising a polyimide fibre assemblage and a polyetherimide matrix layer has an additional advantage in that it does not burn in air owing to the limiting oxygen index both for the polyimide and for the polyetherimide: in each case the limiting oxygen index exceeds 40.
• the structures may be light-weight and relatively rigid.
• the polyetherimide matrix layers produced in accordance with the present invention may serve as barriers to gas or liquid flow and, because of these characteristics, the structure may be utilized as self-insulating ductwork, thermal and acoustic insulation and as industrial building materials.
• the present invention also comprehends articles formed from a heat-shrunk fibrous material, having in at least one surface thereof a matrix layer of a compatible thermoplastic material.
• Some embodiments of the present invention may permit the production of novel articles that are particularly useful for ducting, tubing conduiting or decorative panels and the like in public buildings where a high level of fire retardance or resiliance is desirable.
• the articles produced in accordance with the present invention may permit the provision of continuous surfaces which allow ease of decoration.
• a disadvantage of many synthetic materials of this nature is that, when subjected to fire conditions, the thermoplastic material will melt and drip thereby constituting a further hazard.
• a fibre assemblage comprising flame retardent fibres which do not melt drip at elevated temperatures; and a matrix layer of a thermoplastic material in at least one surface of said assemblage which is present in a proportion with respect to the flame retardant fibres such that, on heating the structure towards the melting point of the thermoplastic material, melt dripping of the thermoplastic material is substantially inhibited.
• melt dripping of the thermoplastic material of the matrix layer in articles produced in accordance with some embodiments of the present invention is substantially inhibited when such articles are heated towards the melting point of the thermoplastic matrix layer material. It is thought that this may be due, at least in part, to the penetration of the thermoplastic material into the interstices between fibres in a surface lamina of the heat-shrinkable fibre assemblage.
• a felt was formed of polyimide P84 fibre. The felt was
• This structure was slit longitudinally of the pipe with a sharp knife and was removed from the pipe. On examination it was found that the layer of Ultem film had formed a smooth non-textured surface where it had been in contact with the pipe. Examination of the cut edge showed that the Ultem film had passed into a surface lamina of the assemblage of the polyimide fibres.
• Example 1 was repeated except that two layers of 1 mil (0.0025 cm) Ultem film were wrapped around the aluminium pipe. The heating procedure was also repeated and it was found that the layer and amount of Ultem entering the fibre assemblage had significantly increased.
• a solution of 25% by weight of polyetherimide in methylene chloride was prepared.
• a piece of needled felt having a thickness of 0.31 inches (0.79 cm) and
• the rigidified structure was removed from the mandrel and had the form of a cylindrical tube with an inner diameter of 8 inches (20.3 cm) a wall thickness of 0.11 inches (0.28 cm) and a density of
• the inner surface of the tube was a smooth impermeable skin of polyetherimide.
• a solution of polyetherimide commercially available under the trade name "ULTEM" was formed in methylene chloride solution in an amount of 18% by weight of Ultem based on the weight of the solution.
• the felt sample was coated on both surfaces with the Ultem solution and the felt plus coating, after evaporation of the methylene chloride, had a weight of 610 grams.
• the resulting coated felt was then wrapped around a pipe and was heated in an oven at 550°F (288°c) for 30 minutes and at 600-625°F (316 - 329°C) for a further hour.
• the pipe with the felt coating was removed and allowed to cool.
• the felt coating was slit along its longitudinal axis and was removed from the mandrel.
• the internal surface of the sample was found to have a smooth coating of polyetherimide, portions of which had migrated into the assemblage of polyimide fibres.
• EXAMPLE 5 A composite felt was prepared by needling a plurality of batt layers of P84 polyimide fibres to a batt layer of "Ultem” polyimide fibers.
• the needled felt therefore, had one surface composed substantially of Ultem fibres, and the remainder of the felt composed substantially of P84 polyimide fibres.
• the resultant felt had a density
• a piece of the needled felt having the dimensions of 0.30 x 13 x 38 inches (0.76cm x 33cm x 97cm) was cut and prepared for wrapping about an aluminium pipe having an 8.5 inch outside diameter with the Ultem layer disposed towards the surface of the pipe.
• the pipe was precoated with "Freecoat 33" release agent to assist in removal of the finished article.
• the pipe was then introduced into an oven and maintained at 630°F (332°C) for one hour. The pipe was then removed from the oven and it was found that the layer of polyimide P84 fibres had shrunk about the aluminium pipe.
• the structure was slit longitudinally of the pipe with a sharp knife and removed from the pipe. On examination, it was found that the layer of Ultem fibre in the composite felt had melted and formed a smooth non-textured surface where it had been in contact with the pipe. Examination of the cut edge showed that the fused Ultem fibres had impregnated a surface lamina of the fibre assemblage of P84 polyimide fibre.
• Example 5 was repeated except that the P84/Ultem fibre weight ratio of the needled composite felt was 4 to 1. Examination of the shaped article after subjecting the felt to the heat treatment revealed greater penetration of the Ultem thermoplastic fibre layer into a surface lamina of the P84 fibre assemblage.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Proteomics, Peptides & Aminoacids (AREA)
• Dispersion Chemistry (AREA)
• Laminated Bodies (AREA)

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Applications Claiming Priority (4)

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Family Applications (1)

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Cited By (2)

Citations (8)

• 1990
  • 1990-11-19 AU AU67338/90A patent/AU6733890A/en not_active Abandoned
  • 1990-11-19 WO PCT/GB1990/001778 patent/WO1991007541A1/en unknown
  • 1990-11-19 IE IE415990A patent/IE904159A1/en unknown
  • 1990-11-20 PT PT95930A patent/PT95930A/pt not_active Application Discontinuation

Patent Citations (8)

Non-Patent Citations (2)

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