Imperial Chemical Industries Limited

Brian P Griffin

Frederic N Cogswell

John B Rose

Derrick S Bailey

Timothy G Ryan

Neil Carter

Eric Nield

Ronald George Feasey

Clive P Smith

David J Blundell

Alan W Jukes

Michael K Cox

Cyril S Wilkins

A thermoplastic polymer composition comprising a thermotropic polymer and 0.025 to 5% by weight of the composition of a finely dispersed particulate inorganic additive wherein the additive is a material having at least 95% by weight of particles with at least one dimension less than 1 micron and preferably less than 0.1 micron and is an organophilic or organophobic material which has a settling volume of at least 10 when measured in a liquid in which the particulate material is compatible. The presence of the inorganic additive in the thermotropic polymer gives rise to an improved processing behavior.

Thermotropic polymer

A process of polymerizing a polymerizable material in an inert organic liquid medium, in which the polymer formed from the monomer or monomers is insoluble, comprising dispersing the polymerizable material in the organic liquid in the presence of a finely, divided particulate material comprising an inorganic portion insoluble in the organic liquid medium and in combination therewith, preferably by covalent or ionic bonding, hydrocarbon chains containing at least 8 carbon atoms, the hydrocarbon chains being soluble in the organic liquid medium and heating the mixture to polymerize the polymerizable material to a required degree of polymerization. The process provides a means of stabilizing dispersion polymerizations which need to be carried out at very high temperatures to effect the polymerization.

Dispersion polymerisation process

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

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.

An anisotropic-melt-forming polymer having improved stiffness retention at elevated temperatures comprising residues selected from residues (A) of dihydric phenols, aromatic dicarboxylic acids, hydroxyaromatic acids, aromatic diamines, aminophenols and aminoaromatic acids wherein at least 40 mole % of the residues (A) have their chain extending bonds in either coaxial or parallel and oppositely directed relationship and sufficient of non-linear residues (B) selected from at least one of: ##STR1## to give a polymer having an improved retention of stiffness at elevated temperature compared with an otherwise similar polymer not containing said residues (B).

Anisotropic polyesteramide polymers having improved retention of

A melt-processable composition comprising at least one polymer capable of forming an anisotropic melt and at least one other melt-processable polymer characterized in that the temperature range over which the polymer can form an anisotropic melt overlaps the temperature range over which the melt-processable polymer may be melt processed. The melt viscosity of such compositions may be very much less than that of the melt-processable polymer in the absence of the anisotropic melt-forming polymer particularly at high shear rates, corresponding to those encountered during moulding and extrusion operations. On the other hand at low shear rates and particularly when the concentration of anisotropic melt-forming polymer does not exceed 5% by weight increases in melt viscosity are obtainable which are valuable in fabrication processes operated at low shear rate where retention of form stability is required.

Compositions of melt-processable polymers having improved processability

A melt-processable composition comprising at least one polymer capable of forming an anisotropic melt and at least one other melt-processable polymer characterized in that the temperature range over which the polymer can form an anisotropic melt overlaps the temperature range over which the melt-processable polymer may be melt processed. The melt viscosity of such compositions may be very much less than that of the melt-processable polymer in the absence of the anisotropic melt-forming polymer particularly at high shear rates, corresponding to those encountered during moulding and extrusion operations.

A polymer capable of forming an anisotropic melt characterized in that the polymer chain includes residues of cross-linking reactants at a concentration sufficient to give a polymer with a melt viscosity of not greater than 10.sup.7 Nsec/m.sup.2 measured by capillary rheometry at a shear rate of 10.sup.4 N/m.sup.2. The polymers exhibit favorable shear dependent viscosity characteristics in that the viscosity is high under low shear conditions and is low under high shear conditions, as judged by the viscosity characteristics of polymers of the same composition but not containing the residues of cross-linking reactants.

Anisotropic melt-forming polymer

Compositions containing a polymer of PTFE and a polymer capable of exhibiting an anisotropic melt characterized in that the compositions contain between 0.05 and 99.5% of PTFE and 0.5 to 99.95% by weight of the polymer capable of forming an anisotropic melt. The presence of a minor amount of the anisotropic melt-forming polymer, that is, from 0.5 to 50% by weight of the composition enables the processability of PTFE to be improved, even to the extent of providing an injection mouldable PTFE composition. Compositions containing 20 to 50% by weight of PTFE confer benefits on anisotropic melt-forming polymers, such as lubricity and greater versatility in fabrication operations. Concentration of 0.05 to 5.0% by weight of PTFE are particularly suitable for modifying the viscosity characteristics of the low melt viscosity anisotropic melt-forming polymers so that such anisotropic melt polymers are less subject to problems such as flashing and jetting during moulding.

Pipe compositions containing anisotropic melt-forming polymers

A melt-processable aromatic polyester anhydride characterized in that from 5 to 80% of the units linking the reactant residues in the polymer chain have the formula: ##STR1## the remaining linkages between the residues of the reactants being of the formula: ##STR2## optionally together with linkages of the formula: ##STR3## substantially all of said remaining linkages being disposed in coaxial or parallel and oppositely directed manner with respect to the residues to which they are linked, the polyester anhydride having a solubility of less than 5% by weight in dimethyl sulphoxide at room temperature.

Thermotropic polyester anhydride polymers

A polyester or polyesteramide capable of forming an anisotropic melt containing residues derived from dicarboxylic acids, dihydric phenols, hydroxyaromatic acids and aminophenols characterized in that at least 10 mole % of the acid residues of the polymer are radicals derived from fumaric acid or a substituted fumaric acid. Preferably at least 10 mole % of the residues other than the residues of fumaric acid or substituted fumaric acid are aromatic ring-substituted residues. The polyester or polyesteramides of the invention are particularly suitable for blending with chlorine-containing polymers at concentrations of up to 25% by weight of the polymer blend to improve the processability of the chlorine-containing polymer. A polyester in which the acid residues are entirely aliphatic is particularly suitable for blending with poly(vinyl chloride).

Anisotropic melt forming polyesters and polyesteramides

Fast crystallizing polyester compositions obtained by reacting a polyester having an intrinsic viscosity of greater than 0.3 which polyester comprises aromatic or cycloaliphatic residues obtained from diacids and/or hydroxyacids and aliphatic, aromatic or cycloaliphatic residues of diols with an ionizable metal salt of a compound containing a group of the formula &gt;NH, preferably selected from compounds of the formula: ##STR1## and acid amides, lactams, polyamides and sulphonamides.

Fast crystallizing polyester compositions

An aromatic copolyester capable of forming an anisotropic melt containing up to 75 mole % of recurring units of formula ##STR1## wherein R may be hydrogen, chlorine, bromine or alkyl groups containing from 1 to 4 carbon atoms.

Aromatic copolyesters capable of forming an anisotropic melt

The stability of a flash fibrillation process for converting thermoplastics materials into fibrils by flash extruding a hot pressurized dispersion of thermoplastics material in liquid through an orifice is improved by inserting a pressure-responsive valve in the orifice which ensures the dispersion is at a specified minimum pressure before it is extruded through the orifice. The minimum pressure should be sufficient to ensure the liquid does not volatilize prior to its extrusion through the outlet.

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St. Albans, United Kingdom

Brian P Griffin