Imperial Chemical Industries Limited

Frederic N Cogswell

Brian P Griffin

David J Hezzell

John B Rose

Jiri G Tomka

Umakant Measuria

Peter J Williams

Peter J Meakin

Philip A Staniland

David Mitchell

Derrick S Bailey

Geoffrey R Belbin

Eric Nield

Geoffrey Cowen

Roger M Turner

Clive P Smith

Martin S Swerdlow

David J Blundell

Ernest A Cole

Jonathan Huxtable

A structural thermoplastic composite material comprises a laminate of a first layer of a fibre reinforced thermoformable crystalline polymer composite and an adherent layer of a second thermoformable polymer which has been applied to the first layer at a temperature above the melting point of the polymer of the first layer. The second polymer comprises an amorphous polymer having a Tg which is at least 10.degree. C. lower than the Tm of the other polymer, which is crystallisable in a subsequent annealing process, and which has a peak crystallisation time of at least 1 minute. Such a material can be bonded to itself or to a different material by the adherent layer at temperatures below the Tm of the matrix polymer.

Fibre reinforced stuctural thermoplastic composite materials

Fibre-reinforced structures comprising a thermoplastics polymer and containing at least 30% by volume of reinforcing filaments extending longitudinally of the structure which have been produced in a continuous process and which have exceptionally high stiffness. The exceptionally high stiffness results from thorough wetting of the reinforcing filaments by molten polymer in the continuous process. The thorough wetting gives rise to a product which can be further processed even in vigorous mixing processes such as injection moulding with surprisingly high retention of the fibre length in the fabricated article. The continuous processes for producing the reinforced structures employ thermoplastics polymers having lower melt viscosities than conventionally considered suitable for achieving satisfactory physical properties.

Fibre-reinforced compositions and methods for producing such compositions

A structural thermoplastic composite material comprises a laminate of a first layer of a fibre reinforced thermoformable polymer composite containing reinforcing filaments and an adherent layer of a second thermoformable polymer. The thermoformable polymer of the adherent layer comprises either a crystalline polymer having a melting point at least 10.degree. C. below that of the first layer, or is an amorphous polymer having a glass transition temperature which is at least 10.degree. C. lower than the melting point of the polymer of the first layer, or is an amorphous polymer which may be crystallizable in a subsquent annealing process. The adherent layer is applied to the first layer at a temperature above the melting point of the thermoformable polymer of the first layer.

Fibre reinforced thermoplastic composite structures

Fiber-reinforced structures comprising a thermoplastics polymer and containing at least 30% by volume of reinforcing filaments extending longitudinally of the structure which have been produced in a continuous process and which have exceptionally high stiffness. The exceptionally high stiffness results from thorough wetting of the reinforcing filaments by molten polymer in the continuous process. The thorough wetting gives rise to a product which can be further processed even in vigorous mixing processes such as injection moulding with surprisingly high retention of the fiber length in the fabricated article. The continuous processes for producing the reinforced structures employ thermoplastics polymers having lower melt viscosities than conventionally considered suitable for achieving satisfactory physical properties.

Fiber reinforced compositions and method of producing such compositions

A process of producing a structural network from a semicrystalline, melt crystallizable polyarylene ether or polyarylene thioether comprising providing a molten mixture of at least one semicrystalline polymer in the presence of a melt plasticizer for the polymer which melt contains at least some polymer entities having a crystalline form, the total polymer concentration being between 5 and 50% by weight of the mixture of polymer and melt plasticizer, and heating the mixture of polymer and melt plasticizer at a heating rate of between 1.degree. C./hour and 1000.degree. C./hr, preferably between 10.degree. C./hour and 100.degree. C./hour until the mixture is at a temperature in the range 10.degree. C. below to 20.degree. C. above its clearing point and cooling the mixture until it solidifies whereby an open cell structure essentially free from granular superstructure is obtained.

Process for making microporous products and the products thereof

Shaped articles are provided containing a polymer which is capable of exhibiting anisotropy in the melt characterized in that the ratio of the stiffness in any two directions at right angles in the shaped article differs by at least 10%, and preferably by at least 50%, from the ratio in the same two directions for a control sample made from a melt consisting entirely of the polymer in anisotropic form. These may be obtained by a variety of methods including disturbing the normal flow pattern of flow into a mould by including obstacles to flow in the mould, disturbing the pattern of flow by foaming in the mould, by including fillers or by using polymers capable of existing as a bi-phase anisotropic and isotropic melt and forming shaped articles in which the two-phase disposition is retained.

Shaped articles formed from polymers capable of exhibiting anisotropic

A method of producing a fibre reinforced structure by melt impregnation of continuous fibres with a thermoformable polymer melt comprising pre-wetting the filaments of the fibres with a composition containing a melt plasticizer for the thermoformable polymer, prior to introducing the pre-wetted fibres into the melt, optionally removing the plasticizer when the composition contains a polymer miscible with plasticizer to leave polymer coated filaments and introducing the pre-wetted filaments into a polymer melt, optionally a polymer melt containing a metal plasticizer for the melt and preferably removing the plasticizer from the composition by volatilization. The pre-wetted polymer coated filaments are useful materials as reinforcing fibres for use in processes other than direct melt impregnation. They can be used in the process known as film stacking impregnation or in processes involving initial impregnation using particulate polymers or alternatively in conventional extrusion compounding.

Process for making fibre reinforced products

A process for impregnating a fibrous product, said fibrous product being a fabric woven from reinforcing fibres or a fabric of randomly disposed fibres, with a matrix polymer comprising causing partial impregnation of the fibrous structure by introducing the fibrous structure into a molten composition comprising the matrix polymer and a melt plasticizer for the matrix polymer and subsequently causing substantially complete wetting of the filaments of the fibrous structure by volatilizing the melt plasticizer from the partially impregnated structure at a temperature at which the polymer is molten, the melt plasticizer being thermally stable at the temperature of the melt and having volatility characteristics such that the plasticizer can be removed below the decomposition temperature of the melt but sufficiently involatile at the temperature of the melt to permit the viscosity of the melt to be reduced by comparison with the melt viscosity of the polymer at the same temperature. When a woven fabric is employed thermoformable composites can be obtained having short beam shear strength values at least 0.7 times the tensile strength of the plastics matrix material of the composite.

Reinforced fibre products and process of making

A reinforced composite structure comprising parallel, aligned continuous filaments extending along the maximum dimension of the structure, said fibres being bonded together with a thermoplastic matrix polymer which intimately contacts substantially the whole of the surface of the filaments characterized in that the reinforcement of the structure comprises at least 30% by volume of filamentary reinforcing material and from 1% up to 30% by volume, preferably from 5 to 15% by volume of particulate filler. The preferred process for producing the product use a mixture of polymer, filler and melt plasticizer for the polymer to effect impregnation of the continuous fibres with the melt plasticizer subsequently being volatilized at a temperature at which the polymer is molten.

Reinforced composite structures

Reinforced fibre products

Fibre-reinforced structures comprising a thermoplastics polymer and containing at least 30% by volume of reinforcing filaments extending longitudinally of the structure which have been produced in a continuous process and which have exceptionally high stiffness. The exceptionally high stiffness resluts from thorough wetting of the reinforcing filaments by molten polymer in the continuous process. The thorough wetting gives rise to a product which can be further processed even in vigorous mixing processes such as injection moulding with surprisingly high retention of the fibre length in the fabricated article. The continuous processes for producing the reinforced structures employ thermoplastics polymers having lower melt viscosities than conventionally considered suitable for achieving satisfactory physical properties.

Fibre reinforced compositions and methods for producing such compositions

Method for impregnating filaments with thermoplastic

A process of producing a fibre-reinforced composition comprising drawing a plurality of continuous filaments through a melt comprising a mixture of a thermoplastic polymer and a plasticizer for the polymer in the weight ratio between 1:4 and 99:1 of polymer to plasticizer, preferably in the weight ratio 1:1 to 19:1, the plasticizer being thermally stable at least up to the temperature of the melt and having volatility characteristics such that the plasticizer can be volatilized from the composition below the decomposition temperature of the composition but has a sufficiently low volatility at the temperature of the melt to plasticize the polymer in the melt and give a melt of reduced viscosity compared with the melt viscosity of the polymer alone. The process enables higher molecular polymers to be used in the pultrusion process and enables higher fibre contents to be achieved.

Method of producing fibre-reinforced composition

Shaped articles are provided containing a polymer which is capable of exhibiting anisotropy in the melt characterized in that the ratio of the stiffness in any two directions at right angles in the shaped article differs by at least 10%, and preferably by at least 50%, from the ratio in the same two directions for a control sample made from a melt consisting entirely of the polymer in anisotropic form. These may be obtained by a variety of methods including disturbing the normal flow pattern of flow into a mould by including obstacles to flow in the mould, disturbing the pattern of flow by foaming in the mould, by including fillers or by using polymers capable of existing as a bi-phase anisotropic and isotropic melt and forming shaped articles in which this two-phase disposition is retained.

A process of producing a fibre-reinforced shaped article comprising extruding a composition comprising a settable fluid as a carrier for fibres at least 5 mm in length through a die so that relaxation of the fibres causes the extrudate to expand to form an open fibrous structure with randomly dispersed fibres as the extrudate leaves the die characterized in that the porous extrudate is compressed while the carrier is in a fluid condition into a shaped article. The process enables moulded articles to be formed having a random distribution of fibres the majority of which are at least 5 mm long.

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Welwyn Garden City, United Kingdom

Frederic N Cogswell