GB2308094A - Securing flexible sheets in a stack - Google Patents

Securing flexible sheets in a stack Download PDF

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Publication number
GB2308094A
GB2308094A GB9525873A GB9525873A GB2308094A GB 2308094 A GB2308094 A GB 2308094A GB 9525873 A GB9525873 A GB 9525873A GB 9525873 A GB9525873 A GB 9525873A GB 2308094 A GB2308094 A GB 2308094A
Authority
GB
United Kingdom
Prior art keywords
sheets
stack
nets
thermoplastic material
net
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9525873A
Other versions
GB2308094B (en
GB9525873D0 (en
Inventor
Anthony Thomas Walsh
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Federal Mogul Technology Ltd
Original Assignee
T&N Technology Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by T&N Technology Ltd filed Critical T&N Technology Ltd
Priority to GB9525873A priority Critical patent/GB2308094B/en
Publication of GB9525873D0 publication Critical patent/GB9525873D0/en
Publication of GB2308094A publication Critical patent/GB2308094A/en
Application granted granted Critical
Publication of GB2308094B publication Critical patent/GB2308094B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

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
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
    • B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
    • 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
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • B32B7/14—Interconnection of layers using interposed adhesives or interposed materials with bonding properties applied in spaced arrangements, e.g. in stripes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41—WEAPONS
    • F41H—ARMOUR; ARMOURED TURRETS; ARMOURED OR ARMED VEHICLES; MEANS OF ATTACK OR DEFENCE, e.g. CAMOUFLAGE, IN GENERAL
    • F41H5/00—Armour; Armour plates
    • F41H5/02—Plate construction
    • F41H5/04—Plate construction composed of more than one layer
    • F41H5/0471—Layered armour containing fibre- or fabric-reinforced layers
    • F41H5/0478—Fibre- or fabric-reinforced layers in combination with plastics layers
    • 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
    • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
    • B32B2262/02—Synthetic macromolecular fibres
    • B32B2262/0261—Polyamide fibres
    • B32B2262/0269—Aromatic polyamide fibres
    • 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
    • B32B2305/00—Condition, form or state of the layers or laminate
    • B32B2305/10—Fibres of continuous length
    • B32B2305/18—Fabrics, textiles
    • 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
    • B32B2571/00—Protective equipment
    • B32B2571/02—Protective equipment defensive, e.g. armour plates, anti-ballistic clothing

Description

SECURING FLEXIBLE SHEETS IN A STACK This invention is concerned with a method of securing a plurality of sheets of flexible material together in a stack.
In various applications, sheets of flexible material, eg fabric sheets, require to be assembled together in a stack. Where it is not important to prevent an individual sheet in the stack from being spaced from its neighbours over some of its area, a stack can be secured by edge clamps. However, where this is important, the sheets need to be secured together at least at intervals over their area. This can be achieved by use of adhesive provided either as coatings on the sheets or as free-standing sheets placed between the sheets and activated by heat. This method, however, significantly reduces the flexibility of the stack. Accordingly, where a stack is required in which the individual sheets must remain in close proximity with their neighbours over their area, the usual solution is to criss-cross the stack with lines of stitching.Thus, for example, anti-ballistic jackets are marketed which comprise a stack of a plurality of sheets, eg 28, of woven fabric made of aramid fibre. These sheets are secured by lines of stitching running in two perpendicular directions and passing through the stack. The stitching keeps the sheets together over their area (which is necessary for their anti-ballistic function) and the stack is flexible (necessary for comfort) but the stitching is hard to do through so many sheets and is labour-intensive.
It is an object of the present invention to provide an improved method of securing a plurality of sheets of flexible material together in a stack, the method keeping the sheets together over their area and producing a flexible stack.
The invention provides a method of securing together a plurality of sheets of flexible material to form a stack, the method comprising stacking said sheets and a plurality of nets made of thermoplastic material so that the nets are positioned between adjacent sheets, and applying heat and pressure to the stack so that the thermoplastic material of the nets melts and adheres to said sheets.
In a method according to the invention, the sheets are held together at intervals over their area by the thermoplastic material which acts as an adhesive, the thermoplastic material can be positioned in criss-cross lines so that flexibility is retained, and stitching is avoided.
Preferably, said sheets are sheets of fabric, eg woven fabric, which may be made of aramid fibres.
The flexibility of the stack is enhanced if the nets are aligned with one another, ie junctions of the nets are on straight lines passing through the stack normally of the sheets and the nets.
The nets may be made by the methods described in US 2919467 in which molten thermoplastic material is extruded through slots in two contra-rotating circular dies. When the slots are separated, strands are formed and, when the slots are in register, junctions are formed. The tubular net so formed is expanded and then slit to form the net.
Such nets are commercially available for use as fencing etc. The extruded net is, preferably, stretched in such a way that the net comprises lumps of the thermoplastic material held in their relative positions in the net by strands of the thermoplastic material. The lumps may have a diameter of 1 to 2mm and the strands may be about 0.4mm in thickness. These lumps soften, in a method according to the invention, and act to "spot weld" the sheets together.
The net can be of any form but a rectilinear, eg square, net provides the nearest equivalent to lines of stitching.
The net is, preferably, made of a relatively low melting point thermoplastic material such as polypropylene, polyethylene, nylon (eg nylon 12), or ethylene vinyl acetate.
Preferably, in a method according to the invention, said pressure is maintained after heating has terminated in order to enable the thermoplastic material to solidify while the pressure is maintained.
The invention also provides an anti-ballistic garment comprising a plurality of sheets of woven aramid fibres, the sheets being secured together in a stack by nets of thermoplastic material positioned between adjacent sheets in the stack and adhered thereto.
There now follows a detailed description, to be read with reference to the accompanying drawing, of an illustrative method of securing together a plurality of sheets of flexible material to form a stack.
The drawing is a diagrammatic perspective view of a portion of an anti-ballistic garment made by the illustrative method, with parts broken away to show the construction.
The drawing shows a portion of an anti-ballistic garment 10 which comprises a plurality of sheets 12 of woven aramid fibre. In this case, there are 28 of the sheets 12 but only 7 are shown in the drawing. The sheets 12 are positioned one-above-the-other in a stack. The sheets 12 are secured together by thermoplastic material which is in the form of nets 14 which are positioned in the stack in between the sheets 12. There is a net 14 in between each pair of adjacent sheets 12, ie there are 27 nets 14. The nets 14 are aligned directly one above the other in the stack.
Each net 14 is made of polypropylene and has the form of a rectilinear mesh having a distance of 15mm between intersection points (in both perpendicular directions).
The net 14 is formed with a lump 16 of polypropylene at each intersection point, the lumps 16 being held in position relative to one another by thin strands 18 of the polypropylene. The lumps 16 have a diameter of about lmm and the strands 18 have a thickness of about 0.4mm.
The sheets 12 are held together by the nets 14 having softened and adhered to the sheets 12. Thus, the sheets 12 are "spot welded" together by the lumps 16 and are also secured together by line "welds" along the strands 18.
Accordingly, the sheets 12 are secured together across their areas and the stack is flexible because the nets 14 do not significantly reduce the flexibility of the stack.
The garment 10 is manufactured by the illustrative method. In the illustrative method, the sheets 12 of flexible material are secured together to form the stack of the garment 10. The illustrative method comprises stacking said sheets 12 and said nets 14 so that the nets are positioned between adjacent sheets. Next, the stack is positioned between the platens of a press and the platens are heated while the stack is compressed. This applies heat and pressure to the stack so that the thermoplastic material of the nets 14 melts and adheres to said sheets 12. The pressure is maintained after heating is terminated so that the sheets 12 do not pull apart before the thermoplastic material solidifies.

Claims (11)

1 A method of securing together a plurality of sheets of flexible material to form a stack, the method comprising stacking said sheets and a plurality of nets made of thermoplastic material so that the nets are positioned between adjacent sheets, and applying heat and pressure to the stack so that the thermoplastic material of the nets melts and adheres to said sheets.
2 A method according to Claim 1, wherein said sheets are sheets of fabric.
3 A method according to Claim 2, wherein the fabric is made of aramid fibres.
4 A method according to any one of Claims 1 to 3, wherein the nets are aligned with one another.
5 A method according to any one of Claims 1 to 4, wherein each net comprises lumps of the thermoplastic material held in their relative positions in the net by strands of the thermoplastic material.
6 A method according to any one of Claims 1 to 5, wherein each net is of rectilinear form.
7 A method according to any one of Claims 1 to 6, wherein the thermoplastic material is selected from polypropylene, polyethylene, nylon, or ethylene vinyl acetate.
8 A method according to any one of Claims 1 to 7, wherein said pressure is maintained after heating has terminated.
9 A method of securing together a plurality of sheets of flexible material to form a stack substantially as hereinbefore described with reference to the accompanying drawing.
10 An anti-ballistic garment comprising a plurality of sheets of woven aramid fibres, the sheets being secured together in a stack by nets of thermoplastic material positioned between adjacent sheets in the stack and adhered thereto.
11 An anti-ballistic garment according to claim 10 made by a method according to any one of claims 1 to 9.
GB9525873A 1995-12-16 1995-12-16 Anti-ballistic garment Expired - Fee Related GB2308094B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9525873A GB2308094B (en) 1995-12-16 1995-12-16 Anti-ballistic garment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9525873A GB2308094B (en) 1995-12-16 1995-12-16 Anti-ballistic garment

Publications (3)

Publication Number Publication Date
GB9525873D0 GB9525873D0 (en) 1996-02-21
GB2308094A true GB2308094A (en) 1997-06-18
GB2308094B GB2308094B (en) 1999-07-28

Family

ID=10785632

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9525873A Expired - Fee Related GB2308094B (en) 1995-12-16 1995-12-16 Anti-ballistic garment

Country Status (1)

Country Link
GB (1) GB2308094B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10011701A1 (en) * 2000-03-10 2001-09-27 Verseidag Indutex Gmbh Flexible laminate
WO2004008059A1 (en) 2002-07-16 2004-01-22 Hänsel Textil GmbH Ballistic protective textile
WO2006124995A2 (en) * 2005-05-18 2006-11-23 Composix Co. Ballistic laminate structure

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1209523A (en) * 1967-01-23 1970-10-21 Hercules Inc Improvements in or relating to nonwoven fabrics
EP0049014A2 (en) * 1980-09-25 1982-04-07 LASAR S.p.A. Improved high impact resistant nonmetallic shield
GB2133345A (en) * 1983-01-11 1984-07-25 Procter & Gamble Strong laminate

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1209523A (en) * 1967-01-23 1970-10-21 Hercules Inc Improvements in or relating to nonwoven fabrics
EP0049014A2 (en) * 1980-09-25 1982-04-07 LASAR S.p.A. Improved high impact resistant nonmetallic shield
GB2133345A (en) * 1983-01-11 1984-07-25 Procter & Gamble Strong laminate

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10011701A1 (en) * 2000-03-10 2001-09-27 Verseidag Indutex Gmbh Flexible laminate
WO2004008059A1 (en) 2002-07-16 2004-01-22 Hänsel Textil GmbH Ballistic protective textile
WO2004007190A1 (en) * 2002-07-16 2004-01-22 Hänsel Textil GmbH Geotextile
WO2006124995A2 (en) * 2005-05-18 2006-11-23 Composix Co. Ballistic laminate structure
WO2006124995A3 (en) * 2005-05-18 2007-07-12 Composix Co Ballistic laminate structure

Also Published As

Publication number Publication date
GB2308094B (en) 1999-07-28
GB9525873D0 (en) 1996-02-21

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Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20011216