AU2003204527A1 - Improved web - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION Invention Title: IMPROVED WEB The following statement is a full description of this invention, including the best method of performing it known to me: IMPROVED WEB This invention relates to an improved web for providing a warm, useable and readily washable covering. It is particularly aimed at an improved blanket, mat or covering having a substantial percentage of natural fibres. However it is not limited to such use and can include materials for clothing or the like.

Natural fibres have been found to provide a substantial warming cooling and general insulation properties generally due to the amorphous fibrous structure having a plurality of air bubbles caught therein. In contrast synthetic fibres by their construction and then mechanical inclusion in garments, mats rugs or the like results in a regimented tight fabric structure that only with specialised treatment provides substantial insulation properties.

Therefore natural fibres have received a substantial resurgence in recent years although the fashion and weather does affect its seasonal use. However natural fibres such as wool often do not wash easily without undertaking a change of structure. The natural grease, lanolin or other surface coating materials provides an initial resistance to detrimental washing. However often the woollen fibre will knot, curl or otherwise deform quite readily rendering the product ill-shaped and not aesthetically pleasing as well as decreasing the insulation properties.

Many ways of rendering wool shrink resistant are known. These typically involve subjecting the wool to an oxidative treatment alone or, more commonly nowadays, followed by a polymer treatment.

The oxidative treatment of garments using permonosulphuric acid proceeds at a much slower rate than when a chlorinating agent is used. Often the slowness of reaction is linked to a poorer result, and this is still the case even when great care has been taken to remove oil and other contaminants, prior to the shrink resist treatment, by performing multiple scouring operations on the wool using detergent.

The level of shrink resistance which can be attained using oxidative treatments of the above-mentioned kinds alone is, generally speaking, not sufficient to meet the exacting modem standards set for shrink resist performance. It is common practice with chlorinebased oxidative treatment processes, which do not in themselves generate the full shrink resistance for adequate wash performance, to apply a polymer to the wool to generate a further shrink resist effect capable of meeting the standard. Few polymers are known which will adhere satisfactorily to wool that has been treated with permonosulphuric acid alone, and result in wool which fully meets the requirements for machine washability.

This is particularly true with regard to treatments on wool top and worsted spun yam or garments. Only those processes where the application ofpermonosulphuric acid is accompanied by chlorination in the form of hypochlorite or dichloroisocyanurate) are usually able to reach an acceptable standard of shrink resistance.

In order to produce wool with a machine washable (or "SuperwashTM") standard of shrink resist performance, by the continuous processing of wool tops, it has therefore been necessary to subject the wool to an oxidative treatment involving the use of chlorine. In recent years, however, increasing concern has been expressed about the generation of chlorinated residues during SuperwashTM treatments and their damaging effects on the environment.

According to the process described in US Patent No. 5,755,827 to Bamford et al there is provided a method for the treatment of wool so as to impart shrink resistance and which comprises treating the wool simultaneously with permonosulphuric acid, or a salt thereof, one or more scouring or wetting agents and one or more fibre swelling or dispersing agents.

However the applicant believes it is important to move away from the chemical treatment which always has its residues, treatment wastes' and costs.

It is therefore an object of the invention to provide an improved covering which makes use of natural fibres such as wool and overcomes or at least ameliorates the problems of the prior art while still providing an enhanced washable and shrink resistant material.

In accordance with the invention there is provided a method of forming an improved web including the steps of: a) carding a first fibrous material b) carding a second fibrous material including low melt synthetic fibrous material c) crosslapping the webs of the two carded material in layers d) building up the thickness to a wad e) passing the wad through an oven to bond the low melt synthetic fibrous material to and or around the natural fibre material wherein the natural fibre is substantially held in position by the bonded synthetic material to provide a washable web that is substantially resistant to shrinkage.

It can be seen that the invention provides a web material which stops shrinkage or the material falling apart because the method of mixing and distributing the low melt there is an even distribution and not clumping or coagulating. Therefore the benefits of wool or other natural fibre is used while overcoming some shortfalls of wool and other natural fibres.

The natural fibre can be wool and preferably the first or second material is at least wool. The fibre thickness of the wool can be substantially in the range of 5 to 20 denier and more particularly substantially in the range of 5 to 8 denier.

The first or second material can include polyester fibre. The polyester fibre can be regenerative fibre from recycled sources.

The low melt fibre can be about 5% to 20% ofthe first or second fibrous material.

The web can be formed of about 50% each of first and second fibrous material.

The invention also provides a web material formed from a mixture of layered fibrous materials including low melt polyester bonding the material together. The web material can be formed of layers of fibrous material comprising at least 25% wool and held together by 5 to 20% of low melt fibre.

The invention also provides a web material formed according to a method as detailed above.

In order that the invention might be more readily understood an embodiment will be described by way of illustration only with reference to the drawings wherein: Figure 1 is a schematic flow diagram of a method for producing an improved web in accordance with the invention; Figure 2 is a diagrammatic illustration of a crosslapper able to be used in the preferred method of Figure 1 for the invention for producing the improved web; Figure 3 is a diagrammatic illustration of the interlayering of two layers by the crosslapper in accordance with the method of the invention of Figure 1.

Referring to the drawings and particularly Figure 1 there is shown a method of producing an improved web including providing a first fibrous material fed via a hopper or other means into a carding station 110, such devices being well known and not requiring further explanation. The method also requires'carding of a second fibrous material via a hopper or other means into a carding station 111. At least a portion of the first or second fibrous material is a natural material and the first or second material includes a portion of low melt synthetic fibrous material.

The two carded fibrous materials are fed along a moving conveyer which transports the carded webs 15, 16 from carding stations 110, 111 to a crosslapper 115 which can be as shown in Figure 2. The crosslapping forms a layered web having fibres at various angles to machine direction and builds up the thickness to a wad 41.

The wad 41 is fed into an oven 125 to bond the low melt synthetic fibrous material to and or around the natural fibre material then passes through rollers 130 and mounted on a roll 140 for later use as required. In this way the natural fibre is substantially held in position by the bonded synthetic material to provide a washable web that is substantially resistant to shrinkage.

The system of the invention forming an improved web including the steps of carding a first natural fibre material and carding a second low melt synthetic fibrous material.

Crosslapping of the webs of the two carded material in layers occurs at the crosslapper 115 so as to build up the thickness to a wad.

The carded web can preferably pass through a needling station to form a needled web which can be passed through calender station (not shown). The wad passes through an oven 125 to bond the low melt synthetic fibrous material to and or around the natural fibre material wherein the natural fibre is substantially held in position by the bonded synthetic material to provide a washable web that is substantially resistant to shrinkage.

The wad can be passed through another set of calender rollers, which can be used to emboss a pattern, fuse the surfaces, and impart other qualities to the article. The wad can pass through a second needling station to perforate the wad for decorative or other purposes, after which the wad is slit and wound onto take-up roll.

The crosslapper represented in Figure 2 is of a familiar general design and is used herein for purposes of illustrating this invention. In that crosslapper 115, first and second carded material 15, 16 is fed from either side by first group of rollers and belts 19, 20, 21, 22 and second lower level of rollers belts 26, 27, 28 29 with third grouping of rollers 35, 36, 38 ,38. The arrangement of the rollers and particularly the reciprocal lateral motion of rollers 28, 29, 37 and 38 provide a layering of carded material into wad 40. Fibrous material feed means can be a belt, as shown, or it can be the delivery end of a carding machine or an interface with any other preparation device. The feed means can be one end of the transporting belt which has merely been positioned to receive fibrous material from some outside source for the crosslapping operation.

Fixed feed rollers 21, 22, 26, 27 are located in close proximity so that there can be a successful transfer of fibrous material from the feed means to the transporting belt.

Transporting belt is passed around reciprocating belt carriage means and between those reciprocating belt carriage means, the transporting belt is passed around a pair of fixed rollers. Reciprocating belt carriage means includes roller which carries the fibrous material 15, 16 in a reciprocating manner at the upper end of the crosslapper and roller which serves as a loop control for the upper end of transporting belt.

As shown by Figure 3 the crosslapper 115 process provides a layering of the carded material 15, 16. This results in alternate two layers of each material.

The features of the various aspects of the invention will be better understood in reference to the following: EXAMPLE 1 An improved web is formed by a method which includes the steps of: a) carding a first fibrous material which includes over 50% woollen fibre evenly mixed with polyester fibre of about 50 to 65 millimetre and 6 to 7 denier; b) carding a second fibrous material of 80 or more polyester fibre of about 50 to 65 millimetre and 6 to 7 denier and evenly mixed with up to 20% low melt polyester but preferably 10% of about 50 millimetre and 4 denier c) crosslapping the webs of the two carded material in layers with the layers alternating but a plurality of carded woollen fibres can be included before the alternate carded low melt polyester is used.

d) building up the thickness to a wad of required thickness; and e) passing the wad through an oven at a temperature sufficient to melt the low melt polyester but not the polyester or wool to bond the low melt polyester to and or around the natural fibre material so that in this way the natural fibre being wool in this case is substantially held in position by the bonded synthetic material being polyester to provide a washable web that is substantially resistant to shrinkage.

Due to the crosslapping process the layers are formed in an interfolded S shape such that there are two layers of one carded material with two layers of the other carded material.

The process of the invention provides a web material which stops shrinkage or the material falling apart because the method of mixing and distributing the low melt there is an even distribution and not clumping or coagulating.

Clearly in a final product produced by the method of the invention the benefits of wool or other natural fibre is used while overcoming some shortfalls of wool and other natural fibres. For example the spread of the material is substantially maintained and shrinkage is minimised or eliminated. Further the bleeding of material through an outside cover is substantially reduced or eliminated. In particular loose fibres in woollen products can through their microscopic shape work their way through loosely woven material. It is often necessary to use a very close knitted outer layer such as japara to prevent such bleeding of fibres through the outer covering. However the web produced by the processes of this invention holds the fibres and substantially overcomes such problem thereby allowing looser woven outer layers to be used.

Another substantial advantage occurs in the post production of web material by quilting or the like. Since the process provides a material which has a spatial integrity it is not necessary to have feed machinery feeding the web in the quilting process. Shrinkage and stretch is substantially controlled and allows ready automatic feed into the quilting machinery.

It should be understood that the above description is of a preferred embodiment and not limiting of the invention. Clearly persons skilled in the art will understand variations to the invention without any inventive input and such are included within the scope of the invention as defined broadly in the following claims. For example other material can be included to provide their benefit such as super absorbent gel linear fibres which act to absorb moisture.

NOVALUX MANUFACTURING PTY LTD BY THEIR PATENT ATTORNEYS PIPERS PATENT AND TRADE MARK ATTORNEYS 4 June 2003

Claims (14)

1. A method of forming an improved web including the steps of: a) carding a first fibrous material b) carding a second fibrous material wherein at least a porion of the first or second fibrous material is a natural material and said first or second material includes a portion of low melt synthetic fibrous material c) crosslapping the webs of the two carded material in layers d) building up the thickness to a wad e) passing the wad through an oven to bond the low melt synthetic fibrous material to and or around the natural fibre material wherein the natural fibre is substantially held in position by the bonded synthetic material to provide a washable web that is substantially resistant to shrinkage.

2. A method of forming an improved web according to claim 1 wherein the natural fibre is wool.

3. A method of forming an improved web according to claim lor 2 wherein the first or second material is at least 50% wool.

4. A method of forming an improved web according to claim 3 wherein the fibre thickness of the wool is substantially in the range of 5 to 20 denier.

A method of forming an improved web according to claim 4 wherein the fibre thickness of the wool is substantially in the range of 5 to 8 denier.

6. A method of forming an improved web according to any one of the preceding claims wherein the first or second material includes polyester fibre.

7. A method of forming an improved web according to claim 6 wherein at least part of the polyester fibre is regenerative fibre from recycled sources.

8. A method of forming an improved web according to any one of the preceding claims wherein the low melt fibre is about 5% to 20% of the first or second fibrous material.

9. A method of forming an improved web according to any one of the preceding claims wherein the web is formed of about 50% each of first and second fibrous material.

A web material formed from a mixture of layered fibrous materials including low melt polyester bonding the fibrous materials together.

11. A web material formed of layers of fibrous material comprising at least wool and held together by of low melt fibre substantially in the range of 5 to

12. A web material formed according to a method of any one of claims 1 to 9.

13. A method of forming an improved web substantially as hereinbefore described with reference to the example and the drawings.

14. A web material substantially as hereinbefore described with reference to the example and the drawings.