Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Patent
1993-08-06
1995-03-07
Cannon, James C.
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
66196, 66198, 66202, 428101, 428298, 428302, B32B 708
Patent
active
053956842
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to thermal insulation materials and to a method of manufacturing such materials.
BACKGROUND OF THE INVENTION
There is a need for a lightweight flexible sheet material which has low thermal conductivity, but which can be fabricated into thermal insulation blankets or panels. Ideally such flexible sheet materials should be safe to use and not produce dust or fibre particles which can be inhaled or cause irritation to the skin of anyone who comes into contact with the material. There are some applications which require such sheet material to be re-useable many times.
In some applications, the material has to withstand exposure to very high temperatures and also provide a thermal insulation barrier, and there are few materials which possess both resistance to high temperature and low thermal conductivity.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a flexible thermal insulating fabric comprising a double-faced weft knitted structure formed by knitting yarn which comprises strands of air-textured glass fibre to produce two spaced knitted faces interlinked by yarn which passes from one knitted face to the other.
In a further aspect of the present invention there is provided a method of making a flexible thermal insulation fabric comprising the steps of weft knitting a double faced glass fibre fabric using yarn which comprises strands of air-textured glass fibre on a double needle bed weft knitting machine and interconnecting the faces of the fabric with at least one linking yarn which passes from one knitted face to the other. The or each linking yarn may be formed by tuck stitches which pass from one face of the fabric to the other.
In a preferred embodiment of the present invention, the thermal insulation material is knitted on a double needle bed weft knitting machine which uses a "V" bed with 2.5 gauge needles.
The spacing between the front bed needles and the back bed needles is suitably about 10 mm, and this dimension affects the overall thickness of the finished fabric as will be explained below. If desired the spacing between the front and back needle beds could be greater than 10 mm if thicker fabrics are required.
Preferably linking yarn in the form of tuck stitches are created by wrapping the at least one linking yarn around selected needles of both needle beds.
Preferably the or each linking yarn is a glass fibre thread.
In a preferred embodiment of the invention glass fibre threads are converted to silica by leaching the fabric in an aqueous solution containing hydrochloric acid.
In yet a further embodiment of the invention a leached fabric has a finish applied to at least one of the faces. The preferred finish is applied by immersing the fabric in a solution comprising 50% by weight vinylacetate ethylene copolymer latex and an aqueous silicone elastomer emulsion
The preferred yarn for knitting comprises a plurality of strands of air-textured glass fibre (each of which is about 1700 decitex) fed to a yarn feeder of the knitting machine.
Preferably the thermal conductivity of the fabric, measured in a direction normal to both faces, is of the order of 0.01 to 0.20 w/m.degree.k. Ideally the thermal conductivity is in the range of 0.10 to 0.125 w/m.degree.k.
In one embodiment of the invention, the thermal insulation material may comprise a first substantially silica fabric joined to a second glass fibre fabric.
In a further embodiment of the invention the thermal insulation material may comprise a core fabric made of glass fibre and a silica fabric joined to the surfaces of the core fabric.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be further described, by way of example, with reference to the accompanying drawings in which:
FIGS. 1 to 5 illustrate schematically the stitch patterns for knitting five thermal insulation materials in accordance with the present invention, and
FIGS. 6 to 8 show schematically the cross-section of three materials made in accordance with the present i
REFERENCES:
patent: 5027618 (1991-07-01), Robinson et al.
patent: 5166480 (1992-11-01), Bottger et al.
patent: 5284031 (1994-02-01), Stoll et al.
World Patent Index Latest, Section Ch, Week 8903, Derwent Publ. Ltd., London, GB; Class F, AN89-019789 and JP, A, 63-295,746 (Nippon Muki) Dec. 2, 1988.
Fairchild's Dictionary of Textile, published 1967--see entry on "glass fibre" on pp. 256-257.
Robinson Frank
Solomon Patricia A.
Cannon James C.
Courtaulds Aerospace Limited
LandOfFree
Thermal insulation materials does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thermal insulation materials, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermal insulation materials will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1404993