WO2001089823A1

WO2001089823A1 - Pliable sheet material and processes of manufacture thereof

Info

Publication number: WO2001089823A1
Application number: PCT/NZ2001/000093
Authority: WO
Inventors: Murray Leslie Cruickshank; Kingsley Stanhope Gordon; Marinus Eduardus Johnnus Kulik; Philip Louis Dunn; Warwick Bosson; Roger Frank Harrison
Original assignee: Murray Leslie Cruickshank; Kingsley Stanhope Gordon; Marinus Eduardus Johnnus Kulik; Philip Louis Dunn; Warwick Bosson; Roger Frank Harrison
Priority date: 2000-05-24
Filing date: 2001-05-18
Publication date: 2001-11-29
Also published as: AU2001260841A1

Abstract

A procedure for producing a pliable sheet material of paper shreds adhesively interrelated between outer paper liners. Such a material has use as covers, containers and barriers. The procedure involves a cascade transfer of the shreds on to an advancing underlying paper ply during which time adhesive is preferably sprayed on the shreds. Preferably the even spread of shred on to the underlying paper web is enhanced by a kinetic levelling of shred accumulation on a feeder conveyor to cascade the shred on to the underlying web.

Description

Bagging device for cuts of meat

TECHNICAL FIELD

The present invention relates to a pliable sheet material, processes for producing such materials and to related means and apparatus.

New Zealand Patent Specification 270410 (Stevens) discloses a mulch or seed mat which relies upon a mat like matrix of shredded paper and a binder.

New Zealand Patent Specification 270410 discloses one mode of manufacture where shredded paper is deposited onto a continuous belt after and/or prior to a binder being applied to the shredded paper. A complete alternative process disclosed involves a batch type process involving the pressing of the shredded paper using a flat platen.

As an option the provision of a thin paper such as tissue paper on one or both sides of the mulch mat of the pressed and bound shredded paper is discussed.

The full content of the aforementioned New Zealand Patent Specification 270410 is here included by way of reference.

BACKGROUND ART

The present invention relates to a material likewise formed using shredded paper but having characteristics different from the embodiments disclosed in the aforementioned New Zealand Patent Specification 270410. The present invention also relates to methods of forming mulch or seed mats as previously defined. The present invention also relates to sheets of a pliable sheet material (whether spooled, rolled, sheeted or otherwise) which will have application in diverse uses. Uses will include pliable covers, containers and barriers, eg; factory floor covers, bags, landfill covers, heat barriers, pots and covers thereof, packaging, liners, etc. Other uses are as carriers to carrier materials (eg; seeds, fertilisers, pesticides, chemicals, fire retardants, crystals, etc).

DISCLOSURE OF THE INVENTION

In a first aspect the present invention consists in a process for producing a pliable sheet material of a kind having a first outer layer, a second outer layer, and interposed between said outer layers, a three dimensional matrix of paper shreds, each shred being adhesively fixed to one or more of the following

(a) said first outer layer

(b) said second outer layer, and

(c) at least one other said shred, said process comprising or including advancing as a web (hereafter "underlying web") the material of said first outer layer, cascading as a curtain onto said underlying web said shreds of paper, applying at least some adhesive to the cascading shreds, and advancing as a web the material of said second outer layer to overlay the accumulated shreds of paper on said underlying web thereby to form a composite web.

As used herein the term "cascading as a curtain" covers any cascade that decends even if interfered within its fall. Likewise the term "cascading the shreds".

Preferably there is an additional step of causing and/or allowing the adhesive set of the composite web after compaction thereof.

Preferably said shreds prior to cascading as a curtain have been spread as a mat of substantially dry shreds onto a roller or conveyor (hereafter "sirred supply conveyor") from which they will be allowed to cascade.

Preferably said spreading on said shred supply conveyor is across at least most of the web width of said underlying web.

Preferably the shred supply conveyor is moving in a direction opposite to the underlying web.

Preferably said shred supply conveyor has the paper shreds disposed thereon evenly there across.

Preferably said shreds are less than 80 mm in length.

Preferably said shreds have a length of less than 50 mm in length.

Preferably said shreds have shreds have a dimension of about 6 mm by about 48 mm.

Preferably said first outer layer is a kraft paper. Preferably said second outer layer is a kraft paper. Preferably at least one of the kraft papers is greater than 15 gsm. Preferably at least one of the kraft papers is from 20 to 250 gsm. Preferably at least one of said kraft papers is about 40 gsm. Preferably said first and second outer layers are each provided from a roll of such paper, the lateral extent or width of each roll being substantially the same.

Preferably at least one of said outer layers has been or is perforated prior to forming part of said composite web.

Preferably the resultant pliable sheet material is from 0.5 to 20 mm thick.

Preferably adhesive is applied to the shred at any one or more of the following instances (a) prior to the cascading, (b) during the cascading, (c) after the cascading.

Preferably adhesive is applied at least during the cascading.

Preferably adhesive is applied both during the cascading and after the cascading.

Preferably adhesive is applied to the cascading shreds of paper from both sides of the curtain as the shreds cascade.

Preferably shreds of paper are deposited on the shred supply conveyor and excess quantities thereof in the mat are spread or trimmed from the mat reliant upon at least one rotating member having sufficient speed to kinetically remove excess shreds from underlying shreds reliant upon the inertia of the underlying shreds.

Preferably shreds of paper are deposited on the shred supply conveyor from a reservoir thereof and kinetic evemng means moves excess shred to at least one side of the shred supply conveyor from whence it is recycled for subsequent presentation on to the shred supply conveyor.

Optionally said slired supply conveyor is moving at a higher speed than said underlying web.

Optionally said slired supply conveyor is travelling at a speed the same as or less than the speed of the underlying web. Most preferably is a speed about the same.

Preferably said adhesive is a water based adhesive system sufficiently dilute to achieve a reduction of the memory of the shred (ie; to reduce spring back of the shred) and/or to allow gravity distribution of the adhesive after spray and/or other application prior to compaction.

Preferably the viscosity of the water based adhesive system is such as to ensure a degree of flow around both prior to and during precure compaction.

Preferably said adhesive is PVA or a starch based adhesive. Other suitable adhesives may be two pot adhesives (eg; formaldehyde based, cellulose, epoxy, etc.).

Optionally said adhesive, shreds or liner(s) may have inclusions e.g. fertiliser, biocides, colourings, reflectants, etc. Preferably said shreds to be cascaded pass under shred disrupting rotating means which contacts at least some of the shreds as they leave or are about to leave as an accumulation of shreds from the shred supply surface, said shred disrupting means ensuring that during the cascading of the shreds more separation thereof than just prior to encountering said shred disrupting rotating means.

Preferably the shreds have been subjected to an air entrainment procedure having a capability of increasing separation of shreds prior to their being fed for the cascading step.

A process of any one of the preceding claims wherein the adhesive is cured in a heated zone (eg; air heated zone) from whence the product is fed to a take up roll (optionally via further rollers).

In another aspect the invention is a process for preparing a three dimensional matrix of shredded paper between outer liners, which process comprises or includes spreading the shreds of paper on to a shred supply conveyor, advancing as an underlying web one of said outer paper liners, cascading shreds from said slired supply conveyor onto the underlying web, spraying at least the shreds with liquid adhesive as they cascade and/or accumulate on to the underlying web, overlaying the accumulated shreds with an overlaying web of the other liner, and causing and/or allowing the adhesive set of the composite web after pressing as the composite web advances.

Preferably the outer liners includes at least one paper liner.

Preferably at least one of the liners is perforate.

In still a further aspect the invention is a process for preparing a pliable sheet like material having a matrix of paper shreds disposed between outer paper layers, which process comprises or includes advancing as an underlying web one of said outer paper liners, supplying shreds of paper on to a shred supply conveyor at a rate beyond that required for the product from a source of such shreds, spreading the shreds across the shred supply conveyor to a shred mat height appropriate for the product (having regard to relativities of speed between a shred supply conveyor and the underlying web) while (optionally) recycling excess shreds to the source of such shreds, cascading the shreds from said shred supply conveyor on to the advancing underlying web so as to provide an even spread thereon, spraying at least the shreds as they cascade with a liquid adhesive, overlaying the at least in part adhesive coated shreds with an overlaying web of the other paper liner, compacting the composite web of the underlying web, the shreds and the overlying liner, and causing and/or allowing the adhesive set to provide adhesive affixing within the product of each shred to at least one of (a) the first liner, (b) the second liner, and (c) at least one other shred.

Preferably the shreds largely individualised are spread on the shred supply conveyor in excess of requirements of the underlying web (in excess having regard to the relative speeds of the underlying web and the shred supply conveyor) and the spreading across the supply conveyor to the desired height occurs under the action of at least one rotating member having a rotational axis in a plane parallel to a corresponding planar region of the slired supply conveyor, yet angled therefrom, so as to throw back excess slireds on to other shreds of the shred supply conveyor, or the shred supply conveyor itself, until such time as there is a movement of the excess shreds over at least one edge of the shred supply conveyor for immediate or subsequent recycling.

Preferably the surface speed of each said at least one rotating member is such that, taking into account the advance speed of the shred supply conveyor, there is sufficient relativity of speed whereby there is a kinetic separation of the excess shreds reliant upon the inertia and staying put of the shreds forming the mat to proceed to cascading.

Preferably the cascading results from shred leaving the shred supply conveyor under the action of a shred accelerating roller the undersurface of which moves in the same direction as the shred supply conveyor, the effect of the shred accelerating roller being to loosen the shreds being cascaded.

Preferably the surface speed of the shred acceleration roller is about three times that of the shred supply conveyor.

Preferably said at least one rotating member is a pair of rotary brushes or the equivalent, each set to rotate with their lower surface moving against the shred supply conveyor direction a speed relating ("the relative speed") to the shred supply conveyor of at least 2 metres/minute. Preferably the relative speed of each is at least 2.5 metres/minute with that brush closer to the cascade of shreds rotating faster and closer to the shred supply conveyor.

In yet a further aspect the invention is a method of ensuring a substantially predetermined mass spread of paper shreds on a moving web of sheet material, said method comprising or including

(I) providing a spread mass of said shreds on a delivery conveyor to the web or on the moving web itself, said mass being in excess of that needed for the predetermined mass spread,

(II) ensuring (simultaneous with such provision (I) and/or after (I)) the spread mass is reduced in thickness without any or any substantial compaction thereof reliant on a sufficient kinetic throwing off of the excess shreds whereby the inertia of the lower shreds maintains at least substantially their positioning and level, and

(III) (a) if the shreds are on a said delivery conveyor, transferring such spread mass that remains on to a separate moving web to provide said predetermined mass spread (which may differ from the levelled mass spread being transferred), or (b) if the levelling has been of shreds on the moving web itself, simply allowing its moving advancement. Preferably step (I) is onto a delivery conveyor and a transfer step (III)(a) occurs by means of a cascading.

In another aspect the present invention is a method of providing a pliable sheet material product comprising or including a first outer layer of kraft paper, a second outer layer of kraft paper and a three dimensional matrix of paper shreds there between, such slireds being adhesively and randomly fixed to at least two of (a) said outer layer, (b) said second outer layer, and (c) at least one other said shred, said method comprising or including shredding paper to provide said matrix, feeding the shreds provided by such shredding substantially as individual shreds across a shred supply conveyor, advancing under said shred supply conveyor (whether in the same direction or otherwise) an underlying web of the material to provide said first outer layer, cascading as a curtain the shreds from said shred supply conveyor onto said underlying web, prior to, during and/or subsequent to such cascading applying an adhesive at least to some of said shreds, advancing as a web a material to provide said second outer layer over top of the at least partly adhesive coated shreds on said underlying web, advancing the composite web of said two webs and said shreds therebetween through rollers to apply a compacting pressure thereto, advancing the thus compacted composite web through an adhesive curing zone at and/or in which the adhesive is at least substantially cured, and thereafter harvesting the output from such curing zone.

Preferably the product has the shreds accounting for from 0.5 to 10 mm of the thickness the harvested composite web.

Preferably the shreds account for about 1 mm of the thickness.

In still another aspect the invention is a pliable sheet material (whether spooled, rolled, sheeted or otherwise), said material comprising or including a first outer layer, a second outer layer, and interposed between said outer layers, a three dimensional matrix of paper shreds each less than 80 mm in length, with substantially little, if any, of one said outer layers (other than, optionally, one or both peripheral regions) being in direct contact with and/or directly adhered to the other layer, and wherein shreds in said three dimensional matrix are each adhesively fixed by a flexible set adhesive to one or more of the following (a) said first outer layer, (b) said second outer layer, and (c) at least one other said shred.

Preferably each outer layer is of kraft paper.

Preferably at least one of said outer layers is perforate.

Preferably said material has a thicl ness of from 20 to 250 gsm.

Preferably at least one of said outer layers is a kraft paper of about 40 gsm.

Preferably the material is less than equal to 2mm thick.

In another aspect the present invention is a pliable sheet material made by a process of the present invention or which has been made by a process which includes a process of the present invention. In another aspect the present invention consists in apparatus for performing a method of the present invention said apparatus comprising or including means to supply an underlying web, means to supply an overlaying web, a shred supply or delivery conveyor to have a discharge zone over the underlying web, means to supply and spread shreds to a desired level across the shred supply or delivery conveyor, means to spray adhesive on to the shreds of the shred supply or delivery conveyor as they cascade on to the underlying web, means to compact the feed of the overlaying outer liner on the shreds having had adhesive applied thereto on said underlying web, and means to cause and or allow the cure of the composite web thus far produced without allowing substantial de-compaction thereof, and means to harvest the output composite.

As used herein the term "shred" refers to the individual discrete lengths of shredded paper to be derived from the shredding of sheet or strip paper. Such discrete lengths preferably are not the almost continuous slireds disclosed in NZ 270410 but are of a cut length that better enables a randomised disposition thereof with respect to other such shreds, ie; preferably without reliance on bunching, crimping, twisting, etc. required for the shredded material of NZ 270410 to ensure a spread of the material. Preferably said shreds are less than 15 times their width in length (eg; 5 to 10 times). Preferably said shreds are less than 80 mm in length and preferably they have a length of less than 50 mm in length. For example, a preferred shred has a dimension of about 6 mm by about 48 mm.

As used herein "composite" or "composite web", where the usage allows, refers to both outer layers and the interposed matrix of pressable or pressed shreds.

As used herein "shred supply conveyor" or "delivery conveyor" or "shred delivery conveyor" includes multiples thereof or instead means one or more equivalents thereto, eg; a large rotating drum. Likewise all references to rotating members, rollers, brushes, etc. include equivalents thereto.

Preferably said underlying web is advanced in a taut condition (whether supported slidingly or otherwise from below or not) at the zone of deposition of the elongate members thereon. Preferably shreds are "randomised" and/or"separated" and/or "individualised" by one or both of

(a) air entrainment, and/or

(b) some process of spinner distribution onto a feeder conveyor.

DETAILED DESCRIPTION OF THE INVENTION

Preferred forms of the present invention will now be described with reference to the accompanying drawings in which;

Figure 1 shows a diagram of a sheet of pliable material such as might be sheeted from a composite web in accordance with the present invention, the overlaying layer of preferably kraft paper having been uplifted to show the nature of the three dimensional matrix of paper shreds on the underlying web or sheet,

Figure 2 is a depiction of the three dimensional matrix as it exists in the final product with an outer layer removed,

Figure 3 shows a simplified flow diagram in accordance with the present invention,

Figure 4 is a diagrammatic side elevational view of a preferred form of performing the process of the present invention (for convenience part of the system having been shown above the remainder of the system when in fact, preferably, a flexible air entrainment conduit allows any convenient placement of that part to provide the shredded paper),

Figure 5 is a view "AA" of the arrangement shown in Figure 4,

Figure 6 is a similar view to that of Figure 3 showing some enhancements beyond the procedure of Figure 3, namely, the use of a vibrating hopper from which the temporarily stored shredded material is auger dispensed onto a spinner for spreading onto the conveyor from whence it is transversely spread by reliance upon the inertia of the shred and the affect of the kinetic brush, the collection of overflow shred from one side of the upper conveyor, the use of a preferably higher speed over roller or brush at the cascade formation, and the use of top sheet perforation to assist in heating/drying etc.,

Figure 7 in a matter similar to that of Figure 4 is a diagram of apparatus for performing the procedure of Figure 6,

Figure 8 is a simplified plan view of a spinner with respect to the arrowed direction of advancement of the conveyor showing two kinetic rotary brushes to provide the spreading of the shred from the zone indicated by the asterisk fully across the transverse web of the conveyor as it advances to the top roller at the point of cascading, Figure 9 is a similar view to that of Figure 8 but showing in more detail in plan the apparatus of Figure 7, there being shown air entrainment in feeds of both initial shred supplies into a hopper as well as side offtake of excess shred from the upper conveyor under the transverse movement affects of the angled brashes,

Figure 10 in the manner of Figure 3 and Figure 6 shows a variant of the process to include in place of the vibration compaction/auger dispensing/centrifugal spreading onto the upper conveyor a collection and pin conveyor spreading utilising apparatus such as that which is used to uplift wool from bins in wool classing or the like applications,

Figure 11 is a similar view to that of Figures 4 and 7 but this time of apparatus capable of performing the collection and pins conveyor spreading function referred to in step 10,

Figure 12 is a simplified plan view in the manner of Figure 8 but of the apparatus of Figure 11 which picks up the material from a bin hopper or the like (shown at least in part in Figure 11), and

Figure 13 shows how, if desired, cascading can involve multiple curtains, Figure 13 showing a first cascade being spread by counter rotating rollers as a split curtain (but curtains nonetheless) onto the underlying web, the "S" indicating possible multiple spray stream option.

In the preferred form of the present invention paper is accumulated by appropriate apparatus (not shown) and then fed by conveyor 1 into a shredder 2. The paper feed conveyor 1 preferably has an ability to metre the feed of sheet paper into the shredder 2 so as to ensure a desired consistent feed of paper shred into the system.

To achieve this ideally an accumulator is provided with papers of a known kind, (ie; thickness) and thereafter the surface area of the off feed papers from such piles are etred to ensure a constant throughput of the desired mass of cellulosic fibres. Whilst a thicker sheet from which shreds are derived may provide more cellulosic material, there is not necessarily a linear relationship between paper shred thickness and the bulk of the three dimensional matrix to be provided.

The arrangement shown in Figure 4 is one whereby shredder 2 has the effect preferably of providing shreds of a desired size such as, for example, 6 mm x about 38 mm.

From the shredder 2 preferably an air blower 3 entrains the shred 4 in a flexible ribbed conduit 5 and then provides the shred as a feed through to a spinner 6. The spinner 6 as can be seen in Figure 5 includes veins 7 adapted to take the off centre dumping of shred, ie; down chute and outlet 8 on to the feed conveyor 9 which moves in the arrowed direction shown in Figures 4 and 5.

The off centred dumping of the shred at 8 on to the spinner 6 is such as to ensure an even distribution of the shred across the lateral extent of the feed roller 9 as shown in Figure 5.

A feed from a roll 10 of an outer layer material, (eg; 40 gsm kraft paper) provides an underlying web on to which the shred from the feed conveyor 9 can cascade as a curtain at 11. This cascading of the shred after it has been randomised and individualised (ie; de- clumped) by virtue of its passage through the blower 3, the conduiting 5 and on to the spinner 6 then better enables sprays 12 to fully or substantially fully coat the individual shreds as they fall on to the underlying web 13.

This underlying web 13 is preferably advanced in tension under the action of, for example, one pair of pinch rollers 14.

Preferably the underlying web is not carried on a conveyor that runs at the same speed as the underlying web. Indeed, preferably there is no such underlying conveyor whatsoever.

Preferably it is the tensile strength and tautness of the material forming the underlying web that itself acts as a conveyor and thus ultimately part of the structure of the sheet material being made. Accordingly, since it is the underlying web that pulls through the system, preferably where there is any disparity in tensile strength between the upper and lower layers, preferably the tensile strength of the lower layer is greater.

Whilst in the preferred form both webs are preferably of kraft paper this need not necessarily be so, ie; it would be possible for the overlying layer to be of a low tensile strength paper or other material. For example, tissue paper may be a possible material for an overlying layer where that is an appropriate layer for the desired end usage.

The relevant advancement speeds of the underlying web 13 and the feed conveyor 9 is such that the feed conveyor 9 optionally moves at a faster speed of advancement thereby accumulating material to a greater depth than that at which the shred is spread on the conveyor 9 by the spinner 6.

It is therefore a desired feature of the present invention to provide within any such process for the feeding of the shred from a spreading thereof to a lower accumulated height of the shred on to the underlying web at such a rate to achieve a greater accumulation height with a corresponding spread evenness.

A roll 15 preferably provides a feed of an overlying web 16 which is to be said second outer layer and this is compacted down onto the shred/underlying web by the roller sequence shown prior to entering an air oven or adhesive curing zone 17.

It is to be seen that as from the first roller pair depicted, ie; 18, the underlying web 13, the accumulated shred 19 and the overlying web 16, whilst the preferred adhesive (PNA and/or a starch like adhesive) has yet to cure, can be compacted and pass as a composite web onwardly through an air oven 17, through compacting idling rollers 22, through a cooling zone 23, through to drive rollers 20 and from thence on to a take up spool, roll or the like 21. The preferred curing zone therefore includes the oven 17 and the cooling zone 23.

Where the adhesive system is a PNA (eg; Emulsion PC804-MC of Edson Chemical, Division of Mercator Technologies Ltd of Auckland, New Zealand) the curing conditions are air drying and/or contact drying in the range of ambient to 70 °C.

Preferably such an adhesive is sprayed at about 27% w/w solids in an aqueous emulsion.

Suitable nozzles for spraying include Unijet Flat Spray nozzles above 30 micron orifice sizes, eg; 41 or 46 microns.

Preferably the speed of advancement of the underlying web 13, the overlying web 16 and the composite web downstream of the rollers 18 is at, for example, about 5 metres per minute.

Preferably a relationship exists between the driving rollers 14 and 20 such that no damage is done to the composite web nor is there any over-pulling beyond the tensile limits of either web 13 or 16.

Preferably in preferred forms of the present invention each web material is a Iσaft paper and preferably of a sufficient thickness, for example, about 40 gsm for the purpose.

Persons skilled in the art will appreciate how, if desired, the accumulation at 19 may allow for the insertion of other materials whether embodied in the adhesive being sprayed at 12 or otherwise.

Persons will additionally appreciate how, if desired, one or other of the webs (whether before becoming part of the composite web or otherwise) can be perforated or otherwise treated (eg; pre-laminated, precoated, etc.) for any appropriate purpose. Persons also will appreciate how a running wheel can be provided on one or more of the webs 13, 16 and the composite web so as to ensure, as a sensor, some control of the speed of rotation of one or both of the roller pairs 14 and 20. Such tension wheels are well known in the art.

The outcome of the process as shown in Figures 4 and 5, and as shown as a flow diagram by reference to Figure 3, is to provide a three dimensional matrix of shredded paper. The shreds are as depicted in Figure 2. Such shreds 22 provide a thickness of from 0.5 mm to 100 mm (preferably 0.5 mm to 10 mm, eg; about 1 mm) in their compacted state between the outer liner sheets 23 and 24.

The serially sheet covered embodiment or the uncovered embodiment may likewise be manufactured.

In more preferred forms of the present invention apparatus either as depicted and/or described by reference to process steps in conjunction with Figures 6 through 9 or Figures 10 through 12 are utilised.

In Figure 7 a hopper 24 of a vibrating kind receives the air entrained shred from the conduit 25, that is then auger fed by the auger 26 down onto the spinner 27 that then drops the shred material 28 upstream (with respect to the locus of advancement of the upper belt region 29 of the upper conveyor in the advancement direction to the left with respect to Figure 7 or as shown by way of arrows in Figures 8 and 9.

The substantially horizontally extending rollers or brushes (preferably brashes) 30 provide a first level with the first brash and a reduced level with the second brash such that shred 28 is moved to the right with respect to the arrowed conveyor advancement shown by the arrows in Figure 8.

The windage caused by the brushes 30 which rotate with their lower tangential extremity moving backwardly against the direction or advancement is such as to allow a more or less surgical uplift of shred that has been layered beyond the desired level so that it spreads transversely across the conveyor 29 to then be drawn in to the air entrainment arrangement 32 from whence the excess shred is passed back into the vibrating hopper 24.

By way of example each of the rollers 30 could be angled as shown in Figure 9. Preferred angles with respect to travel is in the range of from 30 to 60 ° . A number of such brushes or their equivalent (eg; dimpled rollers, etc.) can be used. Each would have sparse bristles of, for example, polypropylene and the first to be encountered roller could be rotated at a tangential speed backwards against the conveyor induced movement of the shred consistent with the 400mm diameter roller being rotated at a tangential speed from 1.5 to 5 metres/a minute. A preferred speed is of the order of about 2.6 metres/a minute. That preferably identical roller brash nearer the cascade preferably rotates at a higher speed but is adapted to provide a finer "cut" of excess material down to the desired level. There the tangential speed is preferably of the order of 3 to 8 metres/a minute against the conveyor direction, more preferably 3.5 to 7 and most preferably about 5.4 metres/a minute.

Irrespective of the configuration of the rotary brashes, rollers or the equivalent that might be utilised, what is desired is with one or several such angled rotary means to provide a kinetic cutting of the level reliant upon the inertia of the shred below and the kinetic impact effects that shows higher shred rearwardly on the conveyor.

A final adjustment of the shred as it cascades arises from the use of a brash or roller (preferably a profiled roller) 31 that rotates in the direction arrowed in Figure 7 so as to provide a final loosening of the shred for the cascade spraying procedure therebelow. Preferably that roller or brush with its lower edge advancing in the same direction as the shred supporting underlying conveyor is preferably at a surface speed approximately three times that of the underlying conveyor.

Figure 7 also shows a pair of pinch rollers 33, the upper one of which preferably is provided with pins to provide a perforation of the top web sheet thereby to assist drying, heating etc in the air oven etc.

A different embodiment to that of the preceding figures is described with reference to Figures 10 to 12 but there there is a simple substitution with a pin like uplifting conveyor 34 for much of the hopper auger spinner apparatus previously described.

Such a conveyor 34 could be one of any of several kinds frequently used in the wool classing facilities prevalent here in New Zealand. Such a conveyor would operate at appropriate speed and with such projections as are most desirable for the nature of the shred being used and preferably uplifts from a bin or other recipient of the supplied slired (including any recycled shred) at an angle of, for example, about 70° to the horizontal with such an arrangement preferably there is still (with a view to control of shred volume) a disposition of the shred on one side of the locus of the cascade producing roller so that the angled brushes and/or rollers can have a spreading and levelling effect, preferably also in conjunction with an over roller feature as previously described at the point of cascading. Such material of any of the three preferred embodiments can be used for any of the purposes referred to in the aforementioned patent specification plus a multitude of other uses.

Uses which fall within the scope of the present invention include the use of such pliable sheet material (whether as a roll or individual sheets) for the purpose of, for example, covering tip waste in a rabbish dump, providing a disposable floor covering (eg; as might be used in a factory on a hard surface, eg; concrete), as a mulch, as a seed mat, etc, as a floor or cage cover for collecting pet waste, etc.

The material may also be further treated by one or both fabrication procedures and/or mould or other shaping procedures to make, for example, seed trays, planting pots. etc.

The material of the present invention has advantages over corrugated board structures which are not pliable equally in all directions meaning it is more easily laid out over and to follow a contoured surface.

Claims

CLAIMS:

1. A process for producing a pliable sheet material of a kind having a first outer layer, a second outer layer, and interposed between said outer layers, a three dimensional matrix of paper shreds, each shred being adhesively fixed to one or more of the following

(a) said first outer layer

(b) said second outer layer, and

(c) at least one other said shred, said process comprising or including advancing as a web (hereafter "underlying web") the material of said first outer layer, cascading as a curtain or curtains onto said underlying web said slireds of paper, applying at least some adhesive to the cascading shreds, and advancing as a web the material of said second outer layer to overlay the accumulated shreds of paper on said underlying web thereby to form a composite web.

2. A process of claim 1 wherein there is an additional step of causing and/or allowing the adhesive set of the composite web after compaction thereof.

3. A process of claim 1 or 2 wherein said shreds prior to cascading as a curtain have been spread as a mat of substantially dry shreds onto a roller or conveyor (hereafter "shred supply conveyor") from which they will be allowed to cascade.

4. A process as claimed in claim 3 wherein said spreading on said shred supply conveyor is across at least most of the web width of said underlying web.

5. A process of claim 3 or 4 wherein the shred supply conveyor is moving in a direction opposite to the underlying web.

6. A process of claim 4 or 5 wherein said shred supply conveyor has the paper shreds disposed thereon evenly there across.

7. A process of any one of the preceding claims wherein said shreds are less than 80 mm in length.

8. A process of claim 9 wherein said shreds have a length of less than 50 mm in length.

9. A process of claim 8 wherein said shreds have shreds have a dimension of about 6 mm by about 48 mm.

10. A process of any one of the preceding claims where said first outer layer is a kraft paper.

11. A process of any one of the preceding claims wherein said second outer layer is a kraft paper.

12. A process of claim 10 and 11 wherein said first and second outer layers are each provided from a roll of such paper, the lateral extent or width of each roll being substantially the same.

13. A process of claim 12 wherein at least one of the kraft papers is greater than 15 gsm.

14. A process of claim 13 wherein at least one of the kraft papers is from 20 to 250 gsm.

15. A process of claim 14 wherein at least one of said kraft papers is about 40 gsm.

16. A process of any one of the preceding claims wherein at least one of said outer layer has been or is perforated prior to forming part of said composite web.

17. A process of any one of the preceding claims wherein the resultant pliable sheet material is from 0.5 to 20 m thick.

18. A process as claimed in any one of the preceding claims wherein adhesive is applied to the shred at any one or more of the following instances (a) prior to the cascading, (b) during the cascading, (c) after the cascading.

19. A process as claimed in claim 18 wherein adhesive is applied at least during the cascading.

20. A process as claimed in claim 19 wherein adhesive is applied both during the cascading and after the cascading.

21. A process as claimed in any one of the preceding claims wherein adhesive is applied to the cascading shreds of paper from both sides of the curtain as the shreds cascade.

22. A process as claimed in any one of the preceding claims wherein shreds of paper are deposited on the shred supply conveyor and excess quantities thereof in the mat are spread or trimmed from the mat reliant upon at least one rotating member having sufficient speed to kinetically remove excess shred from underlying shreds reliant upon the inertia of the underlying shreds.

23. A process as claimed in any one of the preceding claims wherein shreds of paper are deposited on the shred supply conveyor from a reservoir thereof and kinetic evening means moves excess shred to at least one side of the shred supply conveyor from whence it is recycled for subsequent presentation on to the shred supply conveyor.

24. A process as claimed in any one of the preceding claims wherein said shred supply conveyor is moving at a higher speed than said underlying web.

25. A process as claimed in any one of claims 1 to 23 wherein said shred supply conveyor is travelling at a speed substantially the same as or less than the speed of the underlying web.

26. A process as claimed in any one of the preceding claims wherein said adhesive is a water based adhesive system sufficiently dilute to achieve a reduction of the memory of the shred (ie; to reduce spring back of the shred) and/or to allow gravity distribution of the adhesive after application prior to compaction.

27. A process as claimed in claim 26 wherein the viscosity of the water based adhesive system is such as to ensure a degree of flow around both prior to and during compaction.

28. A process of claim 3 wherein said shred to be cascaded passes under shred disrupting rotating means which contacts at least some of the shreds as they leave or are about to leave as an accumulation of shreds from the shred supply surface, said shred disrupting means ensuring that during the cascading of the shreds more separation thereof than just prior to encountering said shred disrupting rotating means.

29. A process of any one of the preceding claims wherein the shreds have been subjected to an air entrainment procedure having a capability of increasing separation of shreds prior to their being fed for the cascading step.

30. A process of any one of the preceding claims wherein the adhesive is cured in a heated zone from whence the product is fed to a take up roll.

31. A process for preparing a three dimensional matrix of shredded paper between outer liners, which process comprises or includes spreading the shreds of paper on to a shred supply conveyor, advancing as an underlying web one of said outer paper liners, cascading shreds from said shred supply conveyor onto the underlying web, spraying at least the shreds with liquid adhesive as they cascade and/or accumulate on to the underlying web, overlaying the accumulated shreds with an overlaying web of the other liner, and causing and/or allowing the adhesive set of the composite web after pressing as the composite web advances.

32. A process of claim 31 wherein the outer liners includes at least one paper liner.

33. A process of claim 30 or 31 wherein at least one of the liners is perforate.

34. A process for preparing a pliable sheet like material having a matrix of paper shreds disposed between outer paper layers, which process comprises or includes advancing as an underlying web one of said outer paper liners, supplying shreds of paper on to a shred supply conveyor at a rate beyond that required for the product from a source of such shreds, spreading the shreds across the shred supply conveyor to a shred mat height appropriate for the product (having regard to relativities of speed between a shred supply conveyor and the underlying web) while (optionally) recycling excess shreds to the source of such shreds, cascading the shreds from said shred supply conveyor on to the advancing underlying web so as to provide an even spread thereon, spraying at least the shreds as they cascade with a liquid adhesive, overlaying the at least in part adhesive coated shreds with an overlaying web of the other paper liner, compacting the composite web of the underlying web, the shreds and the overlying liner, and causing and/or allowing the adhesive set to provide adhesive affixing within the product of each shred to at least one of (a) the first liner, (b) the second liner, and (c) at least one other shred.

35. A process of claim 34 wherein the shreds largely individualised are spread on the shred supply conveyor in excess of requirements of the underlying web (in excess having regard to the relative speeds of the underlying web and the shred supply conveyor) and the spreading across the supply conveyor to the desired height occurs under the action of at least one rotating member having a rotational axis in a plane parallel to a corresponding planar region of the shred supply conveyor, yet angled therefrom, so as to throw back excess shreds on to other shreds of the shred supply conveyor, or the shred supply conveyor itself, until such time as there is a movement of the excess slireds over at least one edge of the shred supply conveyor for immediate or subsequent recycling.

36. A process as claimed in claim 34 wherein the surface speed of each said at least one rotating member is such that, taking into account the advance speed of the shred supply conveyor, there is sufficient relativity of speed whereby there is a kinetic separation of the excess shreds reliant upon the inertia and staying put of the shreds forming the mat to proceed to cascading.

37. A process of any one of claims 34 to 35 wherein the cascading results from shred leaving the shred supply conveyor under the action of a shred accelerating roller the undersurface of which moves in the same direction as the shred supply conveyor, the effect of the shred accelerating roller being to loosen the shreds being cascaded.

38. A process of claim 37 wherein the surface speed of the shred acceleration roller is about three times that of the shred supply conveyor.

39. A process of any one of claims 34 to 38 wherein said at least one rotating member is a plurality of rotary brashes or the equivalent, each set to rotate with their lower surface moving against the shred supply conveyor direction a speed relating ("the relative speed") to the shred supply conveyor of at least 2 metres/minute.

40. A process of claim 39 wherein the relative speed of each is at least 2.5 metres/minute with that brash closer to the cascade of shreds rotating faster and closer to the shred supply conveyor.

41. A method of ensuring a substantially predetermined mass spread of paper shreds on a moving web of sheet material, said method comprising or including

(II) ensuring (simultaneous with such provision (I) and/or after (I)) the spread mass is reduced in thiclαiess without any or any substantial compaction thereof reliant on a sufficient kinetic throwing off of the excess shreds whereby the inertia of the lower slireds maintains at least substantially their positioning and level, and

(III) (a) if the shreds are on a said delivery conveyor, transferring such spread mass that remains on to a separate moving web to provide said predetermined mass spread (which may differ from the levelled mass spread being transferred), or (b) if the levelling has been of shreds on the moving web itself, simply allowing its moving advancement.

42. A method of claim 41 wherein step (I) is onto a delivery conveyor and a transfer step (III)(a) occurs by means of a cascading.

43. A method of providing a pliable sheet material product comprising or including a first outer layer of kraft paper, a second outer layer of kraft paper and a three dimensional matrix of paper shreds there between, such shreds being adhesively and randomly fixed to at least two of (a) said outer layer, (b) said second outer layer, and (c) at least one other said shred, said method comprising or including sliredding paper to provide said matrix, feeding the shreds provided by such shredding substantially as individual shreds across a shred supply conveyor, advancing under said shred supply conveyor (whether in the same direction or otherwise) an underlying web of the material to provide said first outer layer, cascading as a curtain the shreds from said shred supply conveyor onto said underlying web, prior to, during and/or subsequent to such cascading applying an adhesive at least to some of said shreds, advancing as a web a material to provide said second outer layer over top of the at least partly adhesive coated shreds on said underlying web, advancing the composite web of said two webs and said shreds therebetween through rollers to apply a compacting pressure thereto, advancing the thus compacted composite web through an adhesive curing zone at and/or in which the adhesive is at least substantially cured, and thereafter harvesting the output from such curing zone.

44. A method of claim 43 wherein the product has the shreds accounting for from 0.5 to 10 mm of the thickness the harvested composite web.

45. A method of claim 44 wherein the shreds account for about 1 mm of the thickness.

46. A pliable sheet material (whether spooled, rolled, sheeted or otherwise), said material comprising or including a first outer layer, a second outer layer, and interposed between said outer layers, a three dimensional matrix of paper shreds each less than 80 mm in length, with substantially little, if any, of one said outer layers (other than, optionally, one or both peripheral regions) being in direct contact with and/or directly adhered to the other layer, and wherein shreds in said three dimensional matrix are each adhesively fixed by a flexible set adhesive to one or more of the following (a) said first outer layer, (b) said second outer layer, and (c) at least one other said shred.

47. A material of claim 46 wherein each outer layer is of kraft paper.

48. A material of claim 46 or 47 wherein at least one of said outer layers is perforate.

49. A material of any one of claims 46 to 48 wherein said material has a thickness of from 20 to 250 gsm.

50. A material of any one of claims 46 to 49 wherein at least one of said outer layers is a kraft paper of about 40 gsm.

51. A material of any one of claims 46 to 50 that is less than equal to 2mm thick.

52. A pliable sheet material made by a process as claimed in any one of claims 1 to 45 or which has been made by a process which includes a process of any one of claims 1 to 45.

53. Apparatus for performing a method of any one of claims 1 to 45, said apparatus comprising or including means to supply an underlying web, means to supply an overlaying web, a shred supply or delivery conveyor to have a discharge zone over the underlying web, means to supply and spread shreds to a desired level across the shred supply or delivery conveyor, means to spray adhesive on to the shreds of the shred supply or delivery conveyor as they cascade on to the underlying web, means to compact the feed of the overlaying outer liner on the slireds having had adhesive applied thereto on said underlying web, and means to cause and/or allow the cure of the composite web thus far produced without allowing substantial de-compaction thereof, and means to harvest the output composite