Stock material or miscellaneous articles – Hollow or container type article – Polymer or resin containing
Patent
1989-07-21
1993-11-23
Robinson, Ellis P.
Stock material or miscellaneous articles
Hollow or container type article
Polymer or resin containing
366336, 366337, 428222, 428221, 428292, 428105, 428107, 428108, 428112, 428113, 428114, 428297, 428303, 428401, 425200, 425204, 425205, 425206, 425461, 425465, 425466, 425467, 4253761, 4253824, 425542, 264108, 2641761, 264299, 26432818, 2642091, 2642097, 2642098, 2642106, B29C 4700, B29C 4712, B29C 4720, B29K10512
Patent
active
052642615
DESCRIPTION:
BRIEF SUMMARY
This invention relates to the manufacture of fibre reinforced polymer and prepolymer artefacts particularly (but not exclusively) those arising from extrusion, injection moulding and preimpregnated sheet or mat preparation.
It has long been appreciated that the addition of glass or other stiff fibres to a thermoplastic or thermoset in a suitable fashion usually brings increased stiffness and strength to the processed material. In the case of thermoplastics the glass fibre has until recently been short often in the range of 0.3-0.6 mm. In the case of thermoset compositions the fibres have either been long (c.25 mm) discrete fibres or continuous through a very considerable proportion of the artefact. If long discrete fibres are used they are usually either constructed into a loose woven mat and then impregnated with thermoset materials or scattered in a random overlapping fashion on to a layer of polymer with further polymer poured on top. In either case a form of semi-coherent fibre structure is obtained within the polymer liquid, this structure being maintained after the composite sets to solid. This coherent structure is one of the main reasons why fibre reinforced thermoset composites tend to show greater strength and stiffness than do the thermoplastic varieties based on shert fibres, which do not usually form such structures. Such short-fibre compositions have an advantage however in that they are processed in the same continuous or automatic ways which are used for thermoplastics on their own.
As will readily be appreciated the thermoset advantage carries with it a processing disadvantage by comparison with its thermoplastic competitor in that generally a good deal of semi-manual intervention is required.
Over the last few years polymer granules with relatively long (3-15 mm) glass fibres have become available for automatic processing, particularly by injection moulding. While these can show considerable advantages over their short fibre (0.3-0.6 mm) counterparts in some applications, the flow fields set up by the die or moulds to shape the artefacts exercise a major adventitious influence on the material properties of the finished artefact (as they do with short fibres). In particular, for flows with a predominant velocity component in one direction as in extrusion and many mouldings, fibres tend to be disposed very largely in that direction.
When reinforcement is required in all directions, as it usually is, such particular fibre orientations give rise to major weakness in the perpendicular direction.
Besides the objective (a) of increasing the strength and stiffness of organic polymer matrices, fibre structures may also be required in some applications to meet other objectives either singly or in combination. These include (b) improvements to the thermal conductivity of the composition so that for instance it may be cooled faster after shaping thereby permitting higher rates of production, (c) reduction of the net thermal expansion and contraction of an artefact subjected to environmental temperature changes, (d) with electrically conducting fibres, to permit the passage of appreciable electric current between two points of the artefact at moderate potential difference so that for instance parts of the artefact may be fused to other artefacts, (e) again with electrically conducting fibres to inhibit the passage of electromagnetic radiation through extended surfaces of an artefact (e.g. a panel or cylinder) in order to protect for instance an electronic system from interferences.
Hitherto such reinforcing structures (as distinct from the short-fibre compositions which do not form such structures) have been constructed before being brought into contact with a liquid resin or molten polymer. This method has two broad disadvantages in that first the reinforcing structure must be made to confirm to the artefact shape in a separate manufacturing step and secondly special steps must be taken in the shaping process to ensure that fibres are in sufficient contact with the resin or polymer, i.e. the fibres a
REFERENCES:
patent: 4087222 (1978-05-01), Noel
patent: 4100240 (1978-07-01), Bassani
patent: 4170446 (1979-10-01), Schutz et al.
patent: 4389361 (1983-06-01), Messerly
patent: 4500595 (1985-02-01), Gerteisen et al.
patent: 4627472 (1986-12-01), Goettler et al.
patent: 4692030 (1987-09-01), Tauscher et al.
patent: 4695509 (1987-09-01), Cordova et al.
patent: 4705660 (1987-11-01), Demarle
patent: 4789511 (1988-12-01), Bilgin
patent: 4883421 (1989-11-01), Morgan
Prosyma Research Limited
Robinson Ellis P.
Watkins III William P.
LandOfFree
Fibre reinforced polymer compositions and process and apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fibre reinforced polymer compositions and process and apparatus , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fibre reinforced polymer compositions and process and apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1847343