IL29021A - Non-woven fabrics and their manufacture - Google Patents

Description

oniuji umu -ηιπΐ"Ί ·Π PATENT ATTORNEYS · □ ' 01 D 3 'Dili) DR. REINHOLD COHN QQQH j..0¾ l^ ^-D -≥J , Π □ TJ I Π J · · Ί ■ Ί 1 DR. MICHAEL COHN Z ^ ' |Π 3 1 N D ' D Π ISRAEL 5HACHTER B.Sc. "103111 Ί N T HI · c' 27506 PATENTS AND DESIGNS ORDINANCE SPECIFICATION Improvements in non-woven fabrics and their manufacture on FIBRELOCK FABRICS MHITBS, a Bri sh Company, of Springfield Mills Farsley, Pudsey Yorkshire, England do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement :— This invention relates to non-woven fabrics and their methods of manufacture and has for an object to provide an improved fabric and process which is applicable to a wide variety of kinds of fabric, whether made by the needle-loom process or by tufting.

It is a further object of the invention to provide a process which is equally applicable to natural and man-made fibres or to mixtures thereof.

Another object of the invention is to provide a process for the manufacture of fabrics having a wide range of utility from light wearing apparel cloths to heavy blankets, simulated furs, and wall or floor coverings.

In this specification, the following terms have the meanings stated :- Shrinkage - dimensional changes in individual retractile fibres induced by either relaxation, under treatment such as wetting or heat, of tensile stresses imposed on the fibres in the normal course of manufacturing operations, or by structural changes as a result of chemical action; felting - the process of matting or closing together of adjacent fibres or filaments in a fabric, or densification of a mass of fibres; milling - the operation of subjecting a fabric to alternate compression and relaxation, usually in. a repetitive cycle, under either acid or alkaline conditions and frequently accompanied by another physical treatment such as wetting' heating, friction etc; ■ retraction - shortening of the effective or mean axial lengths of fibres or filaments, for example by crimping or . curling; . ' . - tentering - the stretching and drying of a fabric in which the fabric is passed through a heated machine, the fabric being held by clips or pins on a travelling frame which can be varied in width as required. simple substrate - a normally flat, relatively thin, foundation layer or carrier material which may be a reticulated fabric such as scrim or a warp-knitted fabric, or may be a paper or like web, and which has sufficient mechanical strength and dimensional stability to withstand the disruptive forces exerted thereon by successive stages of the process; base fibres - fibres of up to 30 microns diameter or 7 denier and capable of densification by shrinkage, felting, retraction, or compaction under appropriate treatment and incorporated, or intended for incorporation, into the simple substrate to form a composite prepared substrate; Primary' ibres - fibres, other than base fibres, whose specific purpose is to constitute the body of the fabric and which determine, its nature, character, handle,, value and appearance* Primary fibres may or may not themselves be.shrin- kable or subject to felting or retraction or compaction. The^ term will, for convenience, be used in this specification to define both staple fibres as used in a needling process, and spun yarn as used in a tufting process.

Non-woven materials have hitherto suffered from certain disadvantages in comparison with their conventional woven counterparts - for example, in respect of strength and sti*uc- tural stability, or of "handle", drape, or appearance. In addition, they have frequently been incapable of withstanding finishing processes such as scouring, dyeing in the piece, or -multiple raising and cutting for the purpose of improving their appearance and feel, because the fibres are' not sufficiently Attempts to overcome this defect by the use of adhesives, such as rubber latex, have not always been successful because of odour or of their unsuitability for washing or dry-cleaning, and because such use invariably impairs other desirable properties, such as softness or flexibility, or the general appearance of the finished product.

The advantages, on the manufacturing side, of non-woven fabrics compared with their conventional woven counterparts reside mainly in their greatly superior speed of manufacture -due to the abolition of spinning and weaving and associated procedures - and to their cheapness.

In seeking to produce a non-woven fabric (either needled or tufted) which is designed to take the place of a comparable woven fabric, attention must be given to all of the characteristics which the conventional woven fabric provides. Among these may be listed:- (a) Structural stability and strength; (b) Dimensional stability and freedom from distortion; ' ' (c) Wear; (d) Warmth and insulating properties; (e) Relative- eight ; (f) Draping qualities and flexibility; (g) Relative bulk; (h) Handle and touch; (i) Appearance and quality of finish;. ' (j) Price. t An object of the present invention is to provide a fabric or material embodying the manufacturing advantages of non-woven fabrics, such as needle-loom fabrics and tufted fabrics as hither to known, with one or more of the superior properties of compar and dimensional stability.

The solution offered by the present invention is the provision of an inherent bond or anchor (i.e. without the use of adhesives or other additives) of the required strength in the body of the fabric which physically grips and binds together the different elements in the construction of the fabric so that it retains a built-in structural strength. The individual fibres are firmly anchored so that the layers of fibre cannot easily be separated from the basic substrate, and the anchoring bond1 itself is so designed that it provides improved dimensional stability and greater freedom from distortion in handling. These factors, taken together, give the desirable, quality of "wear" and, at the same time, enhance the fabric in respect of the characteristics and properties listed -under (d) to (j) above.

Basically, the present invention consists in needling through a simple .substrate at least a first layer of fine staple fibres of substantially equal small diameter - preferably not. exceeding 30 microns or 7 denier. An additional layer or- layers of the same fine fibre, may then be needled through the substrate, preferably from alternate sides, and the thus needled two-part semi-finished product may, if desired, be finished as described below to constitute the final fabric. Alternatively, it may be used as a composite substrate for further needling or tufting, the fine fibres "then forming base, fibres for locking the subsequently needled or tufted primary fibres. The attainmen 'of substantial uniformity of fibre diameter throughout the mass of each layer is of prime importance for a successful result of the process.

After needling as required, the product is compacted by crushing - preferably under moist conditions, as in a wool combination of these steps, -or by any other finishing process capable of densifying the material and locking all the fibres together and to the substrate in a homogeneous, tight and intimate bond.

The result ' is a fabric in which the layers of fibre and substrate cannot readily be separated by peeling, or pulling the fibres apart from opposite sides.

Preferably, however, the small diameter fibres are used as a means for anchoring primary fibres into the substrate.

These may be longer, thicker, or of a different material, or a combination of any of these properties, according to the characteristics required in the finished fabric, and are needled or. tufted through the already needled composite substrate before compaction.

The number of passes through a needling or tufting machine for each layer of fibres can be varied as desired and in the light of tests, but usually one or two passes, for each layer will be sufficient.

Preferably - also, where primary fibres are needled through a composite substrate, a single layer of base fibres only is needled through the substrate, and the first layer of primary fibres is needled or tufted from the same side' as that from which the base fibres were needled. Thereafter, any further layers of primary fibres are needled or tufted from alternate sides, and one or more such layers of primary fibres may joe applied according to the weight of each layer of the primary fibre and the required characteristics of the finished fabric.

Where scrim is used for the simple substrate, it preferably has a mesh size in the range 12 to 50 warp threads and weft threads per inch.

The scrim chosen for the basic simple substrate of a convenient material, whether natural or man-made in origin, or a mixture of "both. Similarly, the fine "base fibres and the-primary fibres may also be of any preferred nature, whether protein, cellulose, synthetic, melt-spun or of any other nature.

When all the fibres, including the spun yam in a tufted fabric, required in the finished fabric have been needled through or tufted into the substrate, the latter will have contracted - at least in width - by between 5Ϋ<> and 8$ (or even more), depending upon the weight of fibre and the degree of needling or tufting. This phenomenon is observed in the dry state of the partly finished fabric and is due to the progressive crimping or cockling of the nominally flat substrate by successive needling or tufting operations.

If now the partly finished fabric is subjected to a stretching operation, as in a conventional tentering machine, to restore its original dimensions - or at least its original width the action of stretching and flattening the scrim serves also to QQinpact the tangled fibres more tightly into interlocking engagement both with the substrate and with each other.

The action of needling the first layer of primary fibres through the composite substrate also increases the interlock between the base fibres and the substrate, as well as producing, at the same time, interlocking between the fine base fibres and the primary fibres .

The invention is most advantageously realised, in the case of fabrics consisting of primary fibres needled through a composite substrate, as defined above, when the fine denier base fibres are needled through the simple substrate on one side only, and the first layer of primary fibres is needled through the resultant composite substrate on the same side, thus in effect providing a second needling operation for the fine denier the simple substrate from both sides if desired.

Since the wearing properties of a fabric produced in accordance with the present invention depend, inter alia, on the tightness of the bond holding the primary fibres into the composite substrate, it is prima facie advantageous to use a relatively coarse grade of needle in a needle loom in order to ensure the maximum degree. of pick-up of the fibres. However, there is a fairly strict limit of coarseness of needle for any one' fabric, and this becomes apparent when permanent needle marks are left in that fabric. Over a representative range of fabrics, and compositions of fibre, it has been found that the . present invention requires that the needles be within a narrow range of grades. Preferably, only Grades 3 , 34 and 36 (English standard) are used, or any combination of two or more of these grades in the same needle board. Grade 36 needles would be used for more critical or sensitive fabrics, although it is to be understood that needles outside this range of grades may in fact be usable where special effects are required.

Experience has shown, however, that needles finer than Grade 36 do not pick up or interweave sufficient numbers of fibres during a needling stage of the process to provide the necessary structural stability of the fabric either to withstand the rigorous compacting finishing and raising steps or the stresses of normal usage of the fabric. Similarly, needles coarser than Grade132 have been found unacceptable because of permanent marking of the fabric which results from their use. However, if such marks are required acceptable for purposes of special effect, then a fabric according to the present invention can be manufactured with the use of such coarse needles. For all normal commercial fabrics such as cloths for wearing apparel, furnishing and blankets, the needles must be within Furthermore, in view of the principle of intimate and repeated interlocking between fibres and substrate, and between individual fibres themselves, successive needling operations normally serve to increase stability of the finished fabric, especially if these operations are carried out on opposite sides of the substrate alternately - except for the case noted above of the first needling of the first layer of primary fibres,, which is most beneficially carried out from the same side as the needling of the fine base fibres through the substrate.

A very satisfactory fabric according to the present invention has at lea.st one of its principal components - substrate and the fibres carried thereby - wholly or preponderantly of a melt-spun man-made substance having a relatively low softening temperature to ensure flexibility of the fibre. Polypropylene is especially suitable in this respect. "Where three components -substrate, base fibres, and primary fibres - are used, the base fibres may provide the melt-spun man-made constituent of the finished fabric. Clearly, however, more than one of the three principal components may conform to this requirement.

Highly satisfactory results have been achieved by the process thus far described using a variety of different types of scrim and fibre. However, ' it will be apparent that if at least one of the components - such as the primary fibres - is of a. nature to contract or contort or otherwise shrink when subjected .to a particular treatment such as friction, wetting or external heating, or each or all of them, the use of such a component in the process according to the present invention, supplemented by the subjecting of the partly finished fabric to the treatment concerned, significantly promotes a further increase in strength of the . finished fabric. For example, if the fine base fibres are of wool, the wet processing of the needled fabric under suitable alkaline or acid conditions will cause the base fibres to shrink and swell and thus further to increase the frictional component of the bond betvreon the various components of the fabric. Similarly, where a melt-spun fibre is used, subjection of the partly finished needled or tufted fabric to friction or to an ambient temperature in or near softening range will tend to cause the fibres to increase their tenacity of bonding, and thus to cling more firmly to their adjacent fibres or scrim.

In order to improve the bond between the various components of a fabric as fcitherto described, it is preferred to compact or compress the needled fabric prior to tentering and this can advantageously be carried out by first wetting the fabric - as with soap and water, detergent solution, or acid liquor (depending on the nature of the fibres) and then beating, rolling, or squeezing the fabric both to remove excess moisture and to densify the mass of fibres in the fabric* A convenient form of machine, which is already commercially available, for carrying out this process is a conventional milling machine as used in the wool textile industry and in which the needled or tufted fabric is wetted and passed first through a roller gate and milling rollers, then through a stationary throat, this operation preferably being repeated one or more times with successive and progressive reduction of the pass between the gate rollers, or of the cross section of the throat, or of the pressure on the milling rollers, or of any combination of these factors. After sufficient passes through the milling machine or other compacting device the fabric is then stretched or tentered in the conventional manner. collars. The invention described in that specification is characterised by the steps of laying an unfolded fleece upon the backing fabric, anchoring said fleece to said fabric solely by needling some of its fibres through the latter so that their free ends project from the back thereof, and subjecting the assembly to a condensing process whereby the said projecting fibres are at least partially felted together.

It is to be observed, that the process described in Specification 990689 uses only a single layer of fleoce which is needled into the backing. ¾or does the specification indicate the denier of the fibres which are to be used for the fleece, and presumably this is of no great moment for the purpose of a felt.

According to the present invention however base fibres not exceeding 30 microns or 7 denier are first needled to a substrate, and this is followed by needling primary fibres through the composite substrate. Furthermore, whilst the specification 99Q689 describes a condensing process, this is not the equivalent of the wet compaction followed by stretching which produces the locking of the fibres necessary to produce a stable fabric as disclosed in the present invention.

The specification of British Patent No, 928871 describes a paper-makers felt comprising a ba3e fabric woven from yarns at least sosae of which contain sufficient fullable fibre material to render said fabric capable of substantial fulling, and a nap consistin of one or more continuous layers of non-woven fibre secured to at least one side of said base fabric by needling whilst said base fabric is capable of substantial fulling and being further secured to the said base fabric by fulling of said base fabric with said non-woven fibres needled thereto to promote felting and shrinkage of said base fabric. This is only relevant in as much as it discloses ■ is no par icular limit on the siae of the first layers of fibres, which i<?ould correspond to the base fibres of the present invention and there is nothing in Specification 928871 which corresponds to the wet compacting followed by stretching of the present invention. The invention described in 928871 might be satisfactory for the production of a paper-makers felt, but it could not produce a fabric of the required dimensional stability and drape which is the object of the present invention.

The accompanying drawings illustrate the essential features of the invention as followsί Figure 1 "is a wholly diagrammatic representation of the cross-section of a composite substrate consisting of a scrim ·' with a layer of wool noil needled thereinto; Figure 2 is a similar representation of the composite substrate of Figure 1 after having primary fibres needled thereinto; Figure 3 is a similar representation of the fabric after compaction of the intermediate product represented by Figure 2; Figure 4 illustrates schematically, and for the purpose ' of visual identification in the subsequent figures, a cross- section of a simple substrate before needling; Figure 5 shows, in more pictorial but still stylised • form, fine base fibres of small micron diameter needled through the simple substrate of Figure 4 to form a composite substrate; Figure 6 illustrates the result of needling through the composite substrate of Figure 4 coarser primary fibres, and Figure 7 illustrates the finished fabric of Figure β after compacting.

Referring first to Figure 1, a scrim 10, preferably of · cotton. or nylon, and preferably having from 12 to 30 weft threads and 12 to 30 warp threads per inch, has base fibres 11 of fine wool or fine wool noil needled through it at the rate of about 2 - 4 ounces per square yard (oz. per sq. yd.). Fine wool or fine wool noil is chosen in this example because its fibres are of small diamete (designated in the Yorkshire wool trade as 60' s and upwards) and possess marked characteristics of felting and shrinkage during a wet compacting process. The fibres are further selected with a view to ensuring the maximum uniformity to diameter throughout the layer to be needled so as to provide the maximum uniformity of bond throughout the fabric. The needling is carried out in such a way as to ensure .

After the substrate has thus been prepared, it is passed through either a needle loom or a tufting machine which needles or tufts through the prepared substrate the required primary fibres 12 which, in the .case of tufting, ill be spun. yarn, as shown in Figure 2. -These can be of any suitable material whether animal, vegetable or man-made according to the nature of the fabric to be produced. In a specific case in which the finished prqduct is to be a blanket, man- i made primary fibres 12 of isubstantially equal small diameter are needled through from one side of the prepared substrate at the rate of from 2 to 7 oz. per sq. yd. The resultant product is then passed through a second needling stage in which the same amount of the .primary fibres is needled through from the other side.

During both these latter needling stages care is taken to ensure that as many of the fibres 12 as possible are pushed into and through the prepared substrate 10, 11 so that the mass of random-orientated base and primary fibres is so interlocked and interconvoluted that individual fibres 12 are intimately bound into the prepared substrate by mechanical action. At the same time the quality of the needling process must be controlled and, if deemed necessary, re-needling may be adopted, so that the fabric as a whole is sufficiently well compacted mechanically to be able to withstand the. initial stage of a limited wet pro-cessing operation.

The care and control referred to above involve the customary aspects of supervision of the operation of a needle loom to ensure that base and primary fibres project approximately equally on both sides of the simple substrate; that the fabric is kept suitably tight during the needling process, and that the speed of the needle^ loom is not so high that it breaks normal in the making of conventional needled fabrics such as felts.

In a process according to the present invention, however one further item of supervision is of particular importance, viz: the grade of the needles in the needle bed. As already noted, since the prime object of each needling operation is to obtain the maximum interconvolution of the fibres and their interlock with the simple substrate, the achievement of optimum' pick-up of the fibres is essential without leaving permanent needle marks in the fabric. This considerably narrows the permissible range of grades, and the optimum limits of this range have been found to be Grade 32 to Grade 36. As the coarseness of the needle increases, so does its capacity to pick up and interweave the fibres. Similarly, with increasing fineness, the ability to pick up fibres decreases, and the tightness of the bond between the fibres themselves and between the fibres and the substrate falls below the acceptable minimum to ensure that the fabric will survive the mechanical stress which the compacting, finishing and raising stages of the process impose. .

Having needled the primary fibres through the prepared substrate as described above, the partially completed fabric is. wetted and then su jected to a gentle milling process under suitable alkaline or acid conditions. After a few minutes the wool base fibres 11 of the prepared substrate have felted or otherwise compacted sufficiently, as indicated at 13 in figure 3, to firmly grip the primary. fibres 12 which have been needled into and. through the substrate and the milling process can be made more vigorous. Milling is continued until the desired texture and degree of flexibility has been achieved at which stage the constituents of the fabric are sufficiently firmly bonded to be quite capable of undergoing a conventional dyeing according. to the requirements of the finished product; ■ After washing off and stretching and tentering to the , appropriate width, the fabric is raised and finished and results' in a blanket which is structurally and dimensionally stable, and satisfactorily meets the requirements of the characteristics (a) to ( ) as listed above.

In Figure 4, the original scrim is represented as a pair of parallel dotted lines 14 signifying warp and weft threads. In Figure 5, fine base fibres 15 of small diameter have been needled once only from one side of the scrim and are reasonably firmly interlocked with the scrim 14 - at least sufficiently to enable' the material to pass through the next -step without disintegrating or being seriously damaged. The scrim 14, however, is hardly affected so far as concerns its length and width.

Figure 6 shows the fabric after all the primary fibres 16 have been suitably needled thereinto. The scrim 14 is now considerably cockled or crimped.

Figure 7 shows the densification of the components of the fabric simultaneously with the flattening of the simple substrate 14 due to compaction under moist conditions, stretchin . and tentering. The restoration. of the scrim to its original width and flatness (see Figure 4) is also to be noted. This restoration further increases the tightness of the bonding of the fibres 1 and 16 in the fabric .

The manufacture of tufted fabrics by the process according to the present invention is substantially similar to 'that described above for needled fabrics. The substrate is chosen and prepared both as to texture and fibre content for its suitability in the light both of the tufting process itself and the characteristics required of the finished material. If the composite substrate of Figure 1 consists of a nylon scrim 10 through has heen found that in' order to improve the anchorage of the tufts on the one hand and the drape and fullness of the finished tufted fabric on the other hand,' it is desirable to increase the quantity of wool base fibre 11 over the value mentioned above for a needled fabric. For the purpose of pro-' viding acceptable mechanical anchorage of the tufts the rate of application of the fine wool or fine wool noil to the scrim should preferably be about 3 - 5 oz. per sq. yd.- The actual quantity used in any given case can be increased further depending upon such other considerations as the bulk and flexibility required in the final tufted fabric.

After preparing the composite substrate as previously described, it is fed to a tufting machine for the application of the tufting yarn. The resultant tufted fabric is then subjected to wetting and milling as described above for a needled fabric. Thereafter it can be passed through, the necessary drying and dyeing and finishing processes.

Whether the finished fabric is of the needled or tufted type, the material of the substrate is chosen primarily for its suitability in terms of weight,, strength and density of weave, having regard to the required (Characteristics of the finished material. Within the limitations imposed by these required -characteristics also, the material of the primary fibres including the tufting yam can be chosen at will. ¾ius they may be natural fibres such as cotton, wool, flax, hair or the like. Alternatively, they may be of any of the man-made fibres.

Where base fibres are first needled through a scrim to form the composite substrate, the base fibres can also be either natural or man-made but must be of sufficiently small diameter to compact under an appropriate treatment which may be either physical, mechanical or chemical, or a combination of any or man-made fibre field, any fibre which exhibits properties similar to the natural protein or cellulosic fibres can be used, or fibres such as those of the polyvinyl chloride or Q polypropylene groups which can be caused to retract under friction or heat. Other possible fibres for use in making a composite substrate can be chosen for their ability to retract, felt or compact under chemical treatment by exposure to appropriate liquors or atmospheres.

As regards the primary fibres, any type can be used without restriction other than the conditions imposed by the requirements to be met by the finished fabric. Thus, cloths can be made- from cashmere, camel hair, alpaca, llama, mohair, wool, cotton, linen, jute or any of the known range of man-made fibres . Certain of the latter - notably polypropylene -are notoriously difficult to use in the manufacture of cloth by traditional methods. The method according to the present invention, however, greatly facilitates the use of these difficult fibres. lifflilaply, ¾§ ffli hgd QQTd g th§ ¾&¥§_¾= tion imposes no significant restriction on the weight or texture of the fabric prepared thereby. Heavy coating fabrics from 20 oz. to 3 oz. per linear yard can be manufactured in accordance with the present .invention, as also can medium-weight fabrics in the range of from 12 oz. to 20 oz. per yard and light-weight fabrics in the region, for example, of 10 oz. to 12 oz. per yard - assuming a conventional width in eacli case of 54 to 6 inches. These latter can, for example, readily be made by needling the chosen primary fibre through one side only of the prepared substrate.

Compaction of a fabric according to the present invention is preferably effected, as noted above, by passing a milling machine. This treatment is repeated several times while the pass between the guide rollers is progressively reduced to exert increasing compression on the fabric. Alternatively, or in addition, the cloth speed is increased. At the same time the fabric is moistened, normally by means of soapy water, or water to which a detergent or appropriate amount of acid has been added, which acts as a lubricant for the fabric in its passage through the throat. The total number of passes through the machine and the degree of compression exerted will depend on the characteristics of the required finished fabric and of the materials used.

Whereas it is conventional to pass woollen or regenerated casein fibre fabrics through a milling or fulling machine in order to densify them and give them a "woolly" surface texture, other fabrics such as cotton, silk, linen, and man-made fibres generally have not been subjected to a milling or .fulling process because their surface structures and other pl^sical characteristics do not respond in the above manner to this method of treatment. It has now, however, surprisingly been discovered that a non-woven fabric according to the present invention does respond to this treatment in a significant but quite different way which causes the primary fibres to become tightly bonded to the substrate. Normally, depending on the length of the piece undergoing this treatment, the necessary bonding of the primary fibres in the substrate is achieved in a time of 'between 20 and 50 minutes.

The weight of needled or tufted fibres per square yard of substrate can vary between relatively wide limits depending on the required weight of the finished fabric. For blanket cloths, rugs, ladies' and men's coatings and other clothing generally, the weight of primary fibre needled or tufted through will · ormally vary between 2 oz./sq.yd./side and 74" oz./sq.yd./ side, with a normal range of 3 - 44" oz./sq.yd./side. The upper., limit of 74" oz./sq.yd./side results in a fabric of approximately 24 oz./yd of about 60-inch width assuming that the substrate is needled on both sides.

Although the material of the simple substrate is not critical in the production of a fabric according to the present invention, it has been observed that where it is of a melt-spun type, such as nylon, the qualities and characteristics of the finished product are much enhanced as compared with similar fabrics produced on a cotton or other cellulosic scrim or warp knitted substrate.

Practical experiments have shown that the friction engendered by repeated passage of a length of needled or tufted fabric according to the present invention through a restricted throat such, as that of a conventional milling machine (or by such other treatment as results in similar conditions of compression and friction) produces an increasingly firm anchorage of the needled or tufted fibres in the substrate accompanied by compaction of the fabric. If this process is repeated too often, or too vigorously, however, some fabrics begin to stiffen, and subse- . quent raising becomes more difficult. Normally, depending on the length of the piece of fabric being treated, the milling process will continue for between 20 minutes and 50 minutes.

The observed reduction in bulk of the fabric is apparently due to the increasing compaction and interconvolution of t e needled or tufted fibres among themselves and with respect to the strands of the simple substrate, since it is accompanied by increasing resistance of the fabric to damage by the pulling out of individual fibres.

It has also been observed that the progressive closing milling machine while the fabric is bein ^treated therein until they exert a significant squeezing' .action on the fabric . produces a better result more quickly than by maintaining the size of the gap or pass constant. Only a relatively light pressure need be exerted on the fabric by the driving or milling rollers themselves. Moreover, the moisture content of the fabric is reduced by repeated passes throug the throat of the milling machine, and this is accompanied by an increasing rate of compaction of the fabric.

The continuing cycle of friction, compression, pounding by the drive rollers, and squeezing by the. oller gate and the throat of the millboards induces a locking condition in the components of the fabric, although the fabric rarely feels more than hand-warm as it emerges from the throat . Some man-made fibres also shrink under this treatment - polypropylene being one example - and this aids the compaction of the fabric. This property of such fibres also renders them suitable for needling through the simple substrate as part of a composite substrate through which other fibres, including those of a cellulosic nature such as viscose and cellulose acetate, and the natural fibres of vegetable' or animal origin, can subsequently be needled. Such other fibres then become locked in the composite substrate so that a mixed fabric results having similar powerful anchorage of the fibres in the body of the fabric as is achieved by the comparable shrinkage and compaction of wool base fibres. ✓ Preliminary trial runs ,of fabrics having given fibre, properties and characteristics will determine the optimum degree of milling to produce the desired finished product.

Excessive milling is revealed by a surface hardening' of the fabric which impairs the effectiveness of. a subsequent raising Man-made melt-spun fibres which are thermopla.stic are particularly suitable for processing in accordance with the present invention, and if they also possess the property of linear retraction at temperatures within their softening ranges or under conditions of friction they are more effective. They include polypropylene, polyethylene derivatives, polyvinyl chlorides and acetates, polyamides, polyacrylonitriles, and various modified acrylic materials.. Fibres having a lower softening temperature are best used as components of the substrate for locking other fibres with higher softening temperatures, or cellulosic fibres, or fibres of animal or vegetable origin, where the finished fabric is intended for use in personal clothing fabrics, blankets, rugs and the like.

One particularly successful fabric, and its method of manufacture, according to the present invention comprises a composite substrate consisting of nylon or cotton scrim through which are needled polypropylene base fibres. Through this composite substrate constituent are then needled fibres of a poly-acrylonitrile material such' as that known as "Courtelle". This fabric is then partially milled by repetitive passage through a conventional milling machine in the manner described above and is then subjected to a tentering and stretching process, followed by a raising process which produces a luxurious pile. The finished fabric is dense, soft, very flexible, and dimen-sionally highly stable, and the primary fibres cannot readily be pulled out of the substrate, and only with great 'difficulty can the material be mechanically broken down into its various constituents.

Another successful fabric consists of a nylon scrim having base fibres of fine wool or fine wool noil needled thereinto to form a composite substrate. Through this substrate a conventional cotton or wool fabric.

A further successful fabric according to the present invention consists of a nylon scrim having a blend of 5 denier polypropylene extruded fibre and fine wool or fine wool noil as the base fibre needled thereinto. Through this composite substrate an acrylic yarn is tufted and the β resultant fabric is milled as described above. The finished fabric is soft and pliable, yet has"body", and the tufts cannot readily be pulled out nor can the fabric be mechanically broken down into its constituent parts without much difficulty.

It is clear from the foregoing that the action of a 1 conventional milling machine on a fabric according to the present invention is of a different kind from the well-known milling or fulling action on woollen fabrics, and produces an entirely unexpected result in the locking of the primary fibres in the substrate. Furthermore, there is evidence that prolonged subjection of a material according to the present invention to a "milling" treatment eaa have detrimental effects, causing a general stiffening and ultimately a surface hardening. In some cases, of course, a stiffened material may be of advantage -for example, where it is required to be used as a trim or soundproofing material for a vehicle, or for temporary window ' display or like decorative purposes. Normally, however, the process will be discontinued before such stiffening becomes apparent in order to ensure the necessary flexibility and' "drap of the material.

In a typical process according to the present invention, where compaction is achieved in a milling machine, cloth speeds through the throat of between.150 and 250 yards/minute are normal. „ 1007° Acrylic fibre Blanket on Cotton Scrim.

Simple substrate: cotton scrim of 18 warp threads x 18 weft threads per inch, 74 in. wide and the yarn in each case is spun to a count ., of 12's (English cotton count).

Base Fibre: 3 oz. per sq. yd. "Acrilan" (manufactured by Chemstrand Ltd.) needled through one side only of the scrim.

Primary Fibre: a blend of three "Acrilan" fibres, the three constituents in the blend being as follows (proportions by weight):-. . . ' : ' · ■ - 5 Denier - 33 8 Denier - 33 ^ Denier - 33 3 3 OZ. per square yard needled through each side of the prepared substrate.

R©∞nee&le& on each @ide to tighten the eonetraction of the fabric.

A.65-yard piece was subsequently milled as described hereinbefore in /2 gallons of hot water and 1 lb. soap, washed off., dyed, stretched and tentered, and raised.

The above blanket has been formally approved by the manufacturers of "Acrilan". fibre under their "1-year Wear-dated" Scheme. ' 100 Acrylic fibre Ladies' Coating - 13-14 oz. per' yd.56in.wide . Simple substrate: cotton scrim of 18 warp threads x 18 weft threads per inch, 60in. wide, and the yarn in each case is spun to a count of 12's (English cotton count).

Base Fibre; 3 Denier "Acrilan" - 3 oz. per sq.yd. needled throug the cotton scrim, one side only.

Primary Fibre; 8 Denier "Acrilan" - 3 oz. per square yard needled through each side.

Re-needled on each side to tighten the construction.

A 65-yard piece was subsequently milled as described hereinbefore in 4τ gallons of hot water and 1 lb. soap, washed off, dyed, stretched and tentered, and raised.

This cloth has also been formally approved by the manufacturers of "Acrilan" fibre.

Duffle Coating (or Donkey Jacket Gloth). ¾ool and Wool Waste.

Simple substrate; cotton scrim of 18 warp threads x 18 weft threads per inch and the yarn in each case is spun to a count of 12's (English cotton count).

Base Fibre; 2 oz. per sq. yd. each side fine wool noil needled through the scrim.

Primary Fibre; 6'^ oz. per square yard wool waste needled through each side of the prepared base.

Re-needled on each side to give added firmness.

A 65-yard piece was subsequently milled as described hereinbefore in gallons of hot water and 1 lb. soap, washed off, dyed, stretched and tentered, and raised.

Alpaca/Wool Apparel Cloth.

Simple substrate; a nylon scrim of a construction on 18 : 18, . 12' s 12's (English cotton count).. .

Base Fibre; fine' wool noil of not less than 64' s quality, needled through the scrim at Primary Fibre; Fine white Alpaca Fleece, needled through the composite substrate at 4½ ozs. per sq. yd. each side. ¾ Re-needled on both sides to tighten the fabric. Subsequently milled and processed as described hereinbefore with 1 lb. soap dissolved in 6½ gallons hot water.

Stretched, tentered, raised and finished.

The above Example is typical of all fabrics using a protein hair fibre, e .g. cashmere, camel hair, llama, mohair.

. P.V.C. Fibre Apparel Cloth.

Simple substrate: a nylon scrim as in Example 4.

Base Fibre; 3 Denier "Movil T", needled through the scrim at 3 ozs. per sq. yd., one side only.

Primary Fibre: 6 Denier "Movil T", needled through the composite substrate at 3r ozs. per sq. yd. each side.

Re-needled on both sides to tighten the fabric. Subsequently milled and processed as described hereinbefore with 1 lb. soap dissolved in 4 gallons of hot water.

Stretched, tentered, raised one side only, and finished.

The fabric produced is a light-weight cloth suitable for children's dressing gowns. The fabric is fire-proof. 6. Virgin Wool Blanket.

Simple substrate; a worsted scrim woven from single 16's (English Worsted Count) yam at 16 warp threads and 16 weft threads. The yarn is steamed and the finished scrim sized.

■ ■ Base Fibre: fine wool noil of not less than 64 's quality, needled through the scrim at ½ ozs. per sq.. ■ yd. one side only.

. Primary Fibre:- a Crossbred New Zealand 2¼" - 3" Slipe Wool, "..-.·· _ made shrinkproof;. needled through the compo- ■· site substrate at 3i ozs. per sq. yd. each side .

Re-needled on both sides to tighten the fabric. Subsequently lightly milled and processed as hereinbefore described with 1 lb. soap and 5 gallons of hot water.

Stretched, tentered', raised both sides and finished.

The fabric produced, is an all wool blanket.

All the foregoing fabrics can be produced more quickly and with less labour than their conventionally manufactured equivalents, and have been accepted by the respective branches of the Textile Trade for commercial use. 29021/2 ^

Claims (1)

1. CLAIMS 1, The method of manufacturing a non-woven fabric comprising the steps of needling a layer of base fibres, as hereinbefore defined, not exceeding 30 microns or 7 denier through a simple substrate, as hereinbefore defined, to form a composite substrate? needling primary fibres, as hereinbefore defined, or tufting primary yarn through the composite substrate; wetting the resultant fabric and compacting it xfhile wet, and finally stretching or tentering the compacted fabric, or both, to restore the substrate to its original width and flatness, 2, The method of manufacturing a non-woven fabric wherein a simple substrate such as a scrim is selected for its resistance to shrinkage by wetting, and a first layer of fine base fibres not exceeding 50 microns or 7 denier is needled into the simple substrate to form a composite substrate; a subsequent layer of primary fibres is needled into the composite substrate, or a yam is tufted thereinto, to irm the required fabric; the fabric is wetted and subjected to a compaction process while wet; and finally any reduction in width of the simple substrate due to deformation, as by crinkling or cockling during a needling or a tufting process, is removed by stretching or tentering the compacted fabric, or both* 3* In the manufacture of a non-woven fabric* the steps of selecting a simple substrate, such as a scrim, made of material which is resistant to shrinkage by wetting; needling into the simple substrate at least one layer of fine gauge base fibres not exceeding 30 microns or 7 denier to form a composite substrate; thereafter either needling at least one layer o^ primary fibres into the composite substrate or tufting a yarn thereinto to form the required fabric; wetting the fabric and subjecting it while 2902l/2¾ 27 - wet to a compaction process; and finally stretching or tentering the fabric until the simple substrate is restored to its original flat dimensions. 4· The method of manufacturing a non-woven fabric by wetting, compacting while wet and then stretching a prepared fabric vrhich comprises a simple substrate reduced in width by corrugation and a layer of base fibres which do not exceed 30 microns or 7 denier needled into the substrate with primary fibres needled or spun yarn tufted into the composite substrate, the stretching being such as to restore the substrate to a substantially flattened formation, 5» The method according to Claim 1, xfherein tho substrate is made of a material not liable to shrinkage during subsequent stages of manufacture of the fabric. 6. The method according to any one of Claims 1 to 5» wherein needling is continued until approximately 5Q?J of the base fibres are forced through the substrate, 7. The method according to any one of Claims 1 to 6 wherein each needling step is performed by needles whose size is between &rad© 32 and ©rade 36 (English standard). 8. The method according to any one of Claims 1 to 7 wherein the compaction process includes milling. 9· The method according to any preceding claim wherein at least 2 oz. per sq. yd, of fine wool or fine wool noil base fibres are needled through the simple substrate to form a composite substrate through which primary fibres are needled. 10. The method according to any one of Claims 1 to 9 wherein at least 3 oz, per sq. yd. of fine trool or fine wool noil base fibres are needled through the simple substrate to form a composite substrate, and primary fibres in the form of spun yarn - 28 - 11# The method according to any one of Claims 1 to 10 wherein the baee fibres are needled through the simple substrate f om ©ne side only to form a composite substrate through which primary fibres are subsequently needled, the first layer of primary fibres being needled from the same side of the substrate as the base fibres o ' 12. ihe method according to Claim 11 wherein successive layers of primary fibres are needled through the composite substrate from alternate sides. 13. The method according to any preceding claim wherein at least one component of the finished fabric is a melt-spun, man-made thermo-plastic substance and the compaction process includes exposure of the fabric to an ambient temperature not exceeding the softening range of the thermoplastic substance. 14. The method according to any preceding claim wherein the fibres needled through the substrate are or include polypropylene. 15. The method according to any preceding claim wherein the primar fibres are of a melt-spun man-made thermoplastic substance and the compaction process includes exposure of the fabric to friction. 16. The method according to any preceding claim wherein the weight of primary fibres needled or tufted into the substrate is between 2 and 7" οζ· ©r sq. yd. per side. 17. The method according to any preceding claim wherein the simple substrate is a scrim having between 12 and 30 wef threads and warp threads per inch. 18. The method according to Claim 17 wherein the scrim is of nylon. 19. A non- oven fabric when made by the method according - 29 - 20* file method of making a non-woven fabric substantially as hereinbefore described. 21, A non-woven fabric substantially as hereinbefore described with reference to the accompanying drawings. For the Applicants DR. MOLD 00ΗΙΪ AHD PARSHBRS IS.CB