Composite Nonwoven Fabric

Abstract

A composite nonwoven fabric composed of a plurality of superimposed nonwoven fibrous textile layers. This fabric includes spaced-apart rows of chain-loops of threads consisting of the same type of fibers as the respective outer layer; these threads serving for reinforcing the respective outer layer. The fabric also includes a plurality of spaced needling connections passing through the fabric layers, securing the same to each other so as to form a coherent composite nonwoven fabric.

Description

The object of the invention is a multilayer nonwoven fabric from at least two fibrous layers and the method of making it.

There are known multilayer nonwoven fabrics consisting of a single ground fabric, made by weaving, knitting, stitch-bonding a web with binding thread, bonding a fibrous web, or of a plastic sheet covered from one or both the sides by webs, which are connected with the ground fabric by needling.

The production, processing and use of the known multilayer nonwoven fabrics exhibit certain disadvantages. The said ground fabrics are rather costly. During needling, the structure of the fabric is interfered with, resulting in reduced mechanical properties of the product. Further, the layers are often imperfectly bound with the ground fabric, particularly if the number of needle punches is low, and they may consequently separate.

The fibers on the surface of the known fabrics are for some end-uses insufficiently anchored and they easily shed, especially if the fabrics are subsequently raised.

The woven ground fabric tends to unravel at the cut line during making up.

If the knitted fabric is used for the ground fabric, the handling during the production is more difficult because of the high extensibility and selvedge rolling.

In stitch-bonded fabrics, the binding warp gets damaged by needling.

The material used in the layers-- plastic sheets, woven fabrics, webs, knitted fabrics, binding warps-- being nonhomogeneous, mechanical properties of the product cannot be improved by subsequent and uniform shrinking.

Nonwoven fabrics comprising at least two layers connected by needling have already been disclosed. The application of such fabrics is very limited because of the reduced strength. They are therefore used mainly for interlinings. Substantially higher strength is exhibited by nonwoven fabrics consisting of three web layers, the middle layer being reinforced by loops made from the fibers of the same layer, all the layers being interconnected by needling. By raising both the outer layers of the fabric, a blanket is obtained.

It is a disadvantage of nonwoven fabrics of this type that the cohesion of the surface texture of outer layers is insufficient so that the fibers easily shed or are pulled out. For some end-uses, if for example the outer layer is subsequently raised or if the outer layer is the fabric face, such loose structure of the outer layer is unsatisfactory.

The above disadvantages are eliminated by the multilayer nonwoven fabric according to the invention characterized by the fact that of all the layers interconnected by needling, at least a single outer layer is reinforced by stitch-bonding, with loops formed from fibers of the same outer layer.

In multilayer nonwoven fabrics according to the invention, it is of special advantage if the side of the outer layer provided with the loops is positioned inside the fabric.

Multilayer nonwoven fabrics according to the invention, with higher cohesion, density and better usage properties, can further be obtained by strengthening the layer bonding by heat or chemical shrinking.

Very fine gradation of cohesion, density and usage properties of the multilayer nonwoven fabric according to the invention can be obtained by incorporating 5 to 100 percent of shrinkable fibers in at least a single layer.

For a number of end-uses, such as for domestic textiles, it is of advantage to raise at least one of the outer layers of the multilayer fabric according to the invention.

For some special uses, such as for outerwear or for shoe tops, it is of particular advantage to incorporate in at least a single layer, of the fabric according to the invention, differently shrunk fibers.

Multilayer nonwoven fabrics are made according to the invention on a needle punching machine by needling from one or both sides, thus connecting at least two fibrous layers, one of them having been reinforced by loops made from the fibers of the same layer by stitch-bonding on a stitch-bonding machine.

After connecting the layers by needling, the multilayer nonwoven fabric, made by the method according to the invention, is with advantage shrunk by heat or by chemical means.

In the production of some multilayer nonwoven fabrics according to the invention, e.g. for domestic textiles, it was found useful to raise the multilayer fabric after needling and/or shrinking, on a raising machine, on one or both the fabric sides.

Fibrous bodies from a single or more webs, reinforced by stitch-bonding loops made from the same fibers, are known e.g. as arabeva. Multilayer nonwoven fabrics according to the invention can be made from various combinations of such fabrics, e.g. arabeva with loose-fiber webs, or a number of such fabrics, e.g. arabeva without further layers of loose-fiber webs.

A great scope has also been found for blankets made from fabrics according to the invention, consisting e.g. of two arabeva fabrics, connected by needling, with the face sides with the loops in juxtaposition, the back sides being raised forming the pile surface of the blanket.

Fabrics according to the invention can be successfully used for backing artificial leather. Such backing comprises e.g. two arabeva fabrics sandwiching a loose web, made of a blend of collagen and synthetic fibers, the three layers being interconnected by needling from both the sides and subsequently shrunk to get the required volume density. In the same way blankets can be made, from layers of appropriate fiber blend, by needling and raising on both the fabric sides.

A similar fabric, consisting of a single arabeva fabric only and of a single layer of loose-fiber web, connected by needling from one or both the sides, represents excellent backing for flooring in its unshrunk state, after raising on both the sides it can be used for blankets, and after shrinking it can substitute classical felts for clothing and industrial outlets.

The fabric according to the invention can also be used for apparel fabrics of astrakhan appearance. It is made from an arabeva fabric, containing high-shrink fibers, by needling with a fibrous web of unshrinkable fibers, whereupon the whole fabric is shrunk.

In all the said cases, the fibers of all the layers are well bonded due to the fact that in the arabeva fabric, as compared with other fabric types, the fibers are arranged more loosely and the number of loose fiber ends is greater. The fibers can thus be better interlaced by needling with fibers of other layers, and the fibers of the ground fabric are not damaged by needling.

If the arabeva fabric forms the surface of such multilayer nonwoven fabric, with the face side with loops inside the multilayer fabric, the anchorage of surface fibers is very good because besides needling, the majority of fiber ends are bound in the stitch-bonding loops and do not consequently shed even in subsequent raising.

The multilayer fabric according to the invention consists of fibers only and it can therefore be either uniformly and perfectly shrunk, or differential shrinkage in the various layers can be obtained by using fibers of different shrinkage, as required.

By shrinking the shrinkable part of the fibers, high fabric density is attained, the fibers are firmly anchored and the layers are firmly connected, as required for the exacting end-uses.

The method of producing fabrics according to the present invention is described in detail in the following examples.

EXAMPLE 1

A sandwich is made of two arabeva fabrics from a blend of 75 percent PVC fibers, 4 den, 60 mm., black color, and 25 percent of rayon fibers, 3.5 den, 60 mm., white color, 35 courses per 10 cm. and 40 wales per 10 cm., weighing 120 g./sq.m., and a fibrous web which is placed between the two fabrics. The web is made of the same fibrous web and its real weight is 80 g./sq.m.

The sandwich is needled on a needle punching machine with one head operating downwards and the other head upwards. The machine is set out with felting needles of the type 15.times.18.times.36.times.3 RB NKU. The layers of the three-tier sandwich are reinforced by two passes through the needling machine at 240 needle punches per sq. cm. The sandwich is further shrunk by steam in two passes over a steaming table at 98 .degree. C. This brings about surface shrinkage of about 60 percent. The fabric is finally steam-blown. The product is used for shoe tops and its weight is 800 g./sq.m.

EXAMPLE 2

Two arabeva fabrics of about 170 g./sq.m., 35 courses per 10 cm., 40 wales per 10 cm., made from pure acrylic fibers, 6 den, 80 mm. are positioned facing each other with their face sides with loops and connected by needling. The process and the machine are the same as in example 1. After needling the two-layer fabric is raised on both sides. It is used for blankets.

EXAMPLE 3

A fabric which can be used as felt, e.g. for collar lining, decorative and industrial uses, is made from a layer of arabeva fabric from a blend of 15 percent of highly shrinkable copolyester fibers, 2.75 den, undyed, and of 85 percent of rayon fibers, 3 den, 60 mm., black-dyed, of 100 g./sq.m., 40 courses per 10 cm., 40 wales per 10 cm. A fibrous web, made of pure rayon fibers, 3.5 den, 60 mm., black-dyed, is laid on the face side (with loops) of the arabeva fabric. The web is first needled into the arabeva ground, followed by four to six passages through a needle punching machine for needling alternately from back and face side, yielding 200 to 300 needle punches per sq. cm. The fabric is then preshrunk on the steaming device of a rotary press and it is then pressed on the same press at 150.degree. C. contact temperature and 3-ton pressure. The area shrinkage is 23 percent.

EXAMPLE 4

Fabric for plastic leather backing with smooth surface. Two arabeva fabrics and a web of collagen fibers are used. Both the arabeva fabrics are of the same constitution, containing 70 percent rayon fibers, 3.5 den, 60 mm. and 30 percent highly shrinkage polypropylene fibers, 3 den, 90 mm. Weight 90 g./sq.m., 35 courses per 10 cm., 45 wales per 10 cm. The web incorporates 70 percent collagen fibers and 30 percent high-shrink polypropylene fibers, 3 den, 40 mm., weight 200 g./sq.m. The arabeva fabrics cover the collagen web from both sides in such a way that their face sides, with the loops, face the web. The three layers are then connected by needling from both sides by the felting needles of a need570000000000000000000000000000000000000000000000000000000000000000