DE1560653B1 - Process for producing a bonded fiber fleece - Google Patents

Description

The invention relates to a method for producing a bonded nonwoven fabric by production a fiber structure containing a binder and bonding by activation of the binder.

A method of this type is known from French patent 1306 205. Here is first an unbonded nonwoven fabric made from crimped or crimpable fibers, wherein in the Fiber structure a binder in the form of a powder or in the form of fibrils is incorporated. Of the The fiber structure is heated to activate the binder. When using crimpable fibers At the same time, the fibers will crimp.

The disadvantage of this process is that when the binder is activated, it splits into small The beads contract, causing the product to lose its suppleness and softness.

From British patent specification 640 411 it is also known to use nonwovens made of cellulose fibers produce, which are partly composed of cyanoethylated cellulose. These fibers are there-. manufactured by treating cellulose fibers with acrylonitrile, whereby the fibers have their fiber structure maintained. The cyanoethylated cellulose can by various means, such as. B. Solvent, sticky be made. When binding such a fiber fleece, however, pressure must be applied to the to combine cyanoethylated cellulose fibers. This makes it a pretty tough product that is suitable for towels and other cleaning cloths.

The present invention is now based on the object of providing a method of the type described at the outset Type of creating which provides a soft and pliable product in which the binder evenly distributed and does not interfere with the softness and drapability of the product.

The object is achieved according to the invention in that, in a method, the method described at the outset At least 5 percent by weight of crimpable composite fibers are added to the fiber structure, which have an eccentric component arrangement with at least one disposed on the outer surface Component consists of an activatable binder, and that treats the fiber structure is used to develop the curl and activate the binder component.

Because the binder is present along a fiber to which it adheres well, the surface tension can be reduced Do not pull this binder together into a spherical shape, as in the case of the one described at the beginning The process does, but the binder remains uniform and in a fine layer on the Fiber distributed. The crimping that takes place during activation in the method according to the invention causes the threads, on the surface of which there is softened adhesive, to be pulled tightly together so that they connect at their crossing points. So it's not a sizable exterior here Pressure needed to connect the fibers at their crossing points. These two characteristics confer the product has an unusual softness and drapeability.

In the method according to the invention, such heterofilaments are used which consist of at least two eccentric arranged components are constructed, with a Koiüponente arranged on the outer surface consists of a binder which can be activated under such conditions as the other Do not influence the component or components.

The expression "activation" is to be understood as any process that involves the binding agent component makes it sticky. For convenience, only the term "fibers" is used here, but is pointed out that this expression should also be understood to mean "threads". "■>

The two components occupy certain zones in the cross-section of a fiber. The components can e.g. B. have a side-by-side relationship, or a component can be full and eccentric be surrounded by the other component, the component forming the shell from the Binder consists. The heterofibers can also have a non-circular shape, such as z. B. three-lobed, cross-section have, wherein one or two lobes are formed by the binder component.

Suitable components for the production of the heterofibers can be in all groups of synthetic fiber-forming materials can be found. Because of their cheapness, easy processing and excellent quality Properties are the condensation polymers, such as. B. polyamides and polyesters for use very suitable in the present process. Other hetero fibers that can be used are z. B. those based on polyesteramides, polysulfonamides, polyolefins, polyurethanes or any Combination of these polymers are based, with the only major limitation therein insists that the components of the heterofiber are sufficiently compatible to prevent undesired fiberization to prevent.

Examples of suitable hetero fibers are as follows Table listed:

Binder component Polyhexamethylene adipamide Poly-iomega-aminoundecylic acid) Polyhexamethylene adipamide Polyhexamethylene adipamide / poly-epsilon-caprolactam mixed polymer (different proportions of the two components) Polyethylene terephthalate Poly (omega-aminoundecylic acid) Polyethylene terephthalate A mixed polymer (different parts by weight) made of polyethylene terephthalate and polypropylene terephthalate Polyethylene Polypropylene Polyhexamethylene adipamide A suitable polyurethane Polyethylene terephthalate A polyether / polyurethane mixed polymer

There are several methods of making fibrous webs of a suitable thickness.

Staple fiber webs can be produced, for example, on a carding machine, with one web is obtained in which the staple fibers are oriented predominantly in one direction. There can be several such Sheets are laid one on top of the other to give the sheet sufficient thickness and uniformity admit.

When building such a track, alternating layers can also be placed crosswise on top of one another will. Isotropic staple fiber webs can be z. B. by depositing staple fibers by means of air a base. The pad preferably consists of a net, with the other side suction is applied. For short fibers such as B. those with a length of 1.2 cm or less, a wet deposition technique such as that used in the papermaking industry can also be used is common.

Tracks with endless hetero threads can be made by having a number of threads a conveyor belt sets which moves forward more slowly than the feed speed of the threads. Here, the threads are deposited on the conveyor belt in a tangled manner.

The crimp and the activation of the binder component can be achieved by the most varied Treatments are made. For example, the unbonded fiber fleece can be subjected to a heat treatment undergo, whereby a wide variety of heating media can be used, such as z. B. water vapor, air or certain liquids, which compared to those present in the web Fibers are largely inert.

Examples of heterofibers that can be curled and activated by heat are shown in US Pat given in the following table:

Binder component

Hot air

Polyhexamethylene adipamide
Polyhexamethylene adipamide poly (omega-aminoundecylic acid)
Polyhexamethylene adipamide / polyepsilon-caprolactam

220 to 240 ⁰ C 220 to 240 ⁰ C

The crimping and activation of the fibers can also be achieved by treating them with a chemical Bath done. So one can use heterofibers in which one component is made of polyhexamethylene adipamide and the other component of an 80:20 copolymer of polyhexamethylene adipamide / poly-epsilon-caprolactam activate and curl by dipping in nitric acid.

It is not absolutely necessary that the activation and the crimp be done at the same time will.

The titer of these fibers and their length are not critical. To achieve a corresponding tensile strength it is preferred to use fibers which are at least about 1.2 cm in length Have length, although shorter fibers are also suitable in certain cases. From a handling point of view of the fiber web in standard textile machines it is sometimes convenient to use fibers that are shorter than 8 inches.

It is expedient to use fibers which have a titer within the range from 1 to 16 den / Own thread. On the other hand, fibers with a titer down to 0.1 den / thread can also be used with fibers of a larger denier, e.g. 5 to 8 denier / thread, can be used. Fibers that have a higher titer, for example greater than 20 den / thread, result in a product with an excellent Strength and durability, but they tend to be tough to the touch.

It is only necessary that the fiber web and the products obtained from it contain 5% heterofibers, although it is preferred that the heterofibers be present in an amount of 20% or more are. Other fibers that are inert or substantially inert to the curl activation treatment are inert can be used in admixture with the heterofibers. Depending on the desired Properties of the product to be manufactured, the percentage of heterofibers, which are present in the fibrous web and the product made from it, can be varied widely. Products, which consist entirely of hetero fibers, or have those in which such fibers predominate greater strength and resistance to tearing, abrasion and fraying. Products of this Nature are useful in many different applications, where light, flexible, elastic and soft structure is applied, such as B. for insulation, garment inserts, bodice padding, Sleeping bags, pads and molds for clothing and hats. In web form, they are also available as Carpet underlay and useful in smooth or shaped form for filtering purposes. These products in web form have many uses in the manufacture of laminated structures, e.g. B. of insulating or cushioning materials, where they act as the core between two continuous layers of film, Cloth and the like can be used.

The presence in an amount of other fibers evenly distributed throughout the fibrous web of up to 95 percent by weight, for example 50 to 80 percent by weight, based on the fiber weight in the web, results in more flexible products, which in many cases have aesthetic qualities, such as e.g. B. drapability, good grip and softness. Such products can be manufactured so that they serve a wide variety of uses for nonwoven materials. they are especially for many household purposes including blankets, bedspreads, draperies, linings, Padding and the like and for use in clothing including suits, Ties and linings suitable.

Cotton, silk, wool, flax, casein, kapok, mineral fibers, including asbestos and rock wool, Glass fibers, rayon, synthetic polymer fibers (e.g. polyamide and polyethylene terephthalate fibers) and the like are examples of such fibers which can be incorporated into the nonwoven fabric.

The nonwoven composite fiber article products of this invention can optionally contain any

knew textile finishing treatment, such as B. brushing, roughening, shearing and embossing, are subjected.

The invention is explained in more detail with reference to the drawing. It shows

F i g. 1 in perspective a device which for the production of a web-shaped, bonded fiber fleece according to the invention in a continuous Procedure suitable and

F i g. 2 shows a schematic representation of a product produced according to the invention.

F i g. 1 of the drawing shows the production of a web material from a fiber web of continuous filaments, by feeding such threads 11 onto a wire mesh conveyor belt with the aid of two corrugated surfaces having feed rollers 12 14 are directed. The speed at which the threads are deposited onto the conveyor belt 14 is greater than the speed of the belt, whereby the threads are deposited in the fiber web 13 in an arbitrary form as shown in FIG. 2 can be seen.

The fiber web 13, after being deposited on the belt 14, is passed through an oven 15 in which the The fiber web is curled and bonded by heating to a suitable temperature. Press roller 16 lightly the received web material and transport it to a take-off point at 17.

The process according to the invention will now be explained in more detail in the following examples. The tensile strength the product is identified on a 14.7 cm long and 4.9 cm wide strip using a tensile tester with jaws 5 cm apart. The tensile strength was at 60% relative humidity and a stretch rate of 5 cm / min (i.e. 100%).

30th

35

example 1

This example explains the production of a bonded fleece, which consisted of 100% heterofibers. A quantity of 38.1 cm long staple fibers with a linear density of 12 denier made from drawn, crimpable polyhexamethylene adipamide / poly (omega-aminoundecylic acid) heterofilaments (nylon 66/11) in which the two components were in equal amounts by weight and in having a side-by-side relationship and having a slight spiral curl caused by the drawing process was carded into a 2.5 cm thick web having a density of 0.005 g / cm ³ using a carding machine. This web was then heated for 3 minutes in an oven at a temperature of 230 to 240 ° C, with an initial pressure of 0.04 g / cm ² , giving the product a soft surface.

Initially, the fibers curled in a helical fashion and the web contracted (approximately 15% shrinkage in terms of area). The curl that had formed in the fibers now had had an opposite sense and was much denser. This reversal and compaction of the crimp caused the fibers to tangle and mechanical connection.

As the fibers reached the oven temperature, where they were essentially completely curled, the lower melting component of the heterofibers, ie the poly (omega-aminoundecylic acid), which melts at a temperature of around 165 ° C, became sticky, whereby the fibers became sticky . The resulting sheet had an average density of 0.035 g / cm ³ , excellent elasticity; after being deformed under pressure, it returned to its original shape. The web had a textile-like feel, was extremely porous, highly flexible and had very good resistance to abrasion and tearing.

The various properties of the web were then determined from it using a test piece and are shown in the following table:

In this and in the other tables given in this specification, the porosity is measured as a percentage of the total volume of the product which is empty. - ^ - represents the ratio of tensile strength in g / g / cm to density in g / cm ³ .

density
²⁰ g / cm ³ weight
each length
unit
g / cm Tear
strain
% Tear
strength
kg / g / cm porosity
% _s_
D. 0.035 0.091 66 130 96.8 3710

Under the microscope it could be seen that the polyamide fibers at the points where they pass through the Poly (omega - aminoundecylic acid) component crossed or touched, combined with one another were, the latter component forming a small drop at such points, however along the entire length of the fiber in contact with the polyhexamethylene adipamide component remained. In addition, the spaces between the fibers were completely devoid of anything Binding material.

The soft elastic structure obtained could be used as a floor covering. The material was easy to emboss, whereby by pressing the surface with a patterned heated embossing plate a sharp and permanent pattern was obtained.

Example 2

An amount of the staple fibers from Example 1 was mixed in a weight ratio of 60:40 with an amount of a non-activatable, upset-crimped polyhexamethylene adipamide staple fiber of 38.1 mm length and a denier of 6 den / thread. A portion of this mixture was carded into a loose sheet 1.3 cm thick using a carding machine. It had an average density of 0.02 g / cm ³ . The web was heated for 4 minutes in an oven at a temperature of 220 to 232 ° C, with an initial pressure of 0.05 g / cm ² , giving the product a soft surface. While the fibers reached the oven temperature and the hetero threads were largely crimped completely, the lower melting component of the hetero thread, i.e. poly (omega-aminoundecylic acid), became sticky and caused the hetero fibers to stick together where they came into contact with one another or with non-activatable fibers found. As a result of the heat treatment, the sheet shrunk about 25% in area, obtaining a sheet which had an average density of 0.03 g / cm ³ and a more open structure than those in the previous example using 100% hetero threads was obtained. The open nature of the

Web, which had a porosity of approximately 92%, was demonstrated by placing the web between the eye and a light source was held. It was very translucent. Objects were through this clearly visible, which indicated that there were many undestroyed paths through the thickness of the web. if if she was kept under a stream of water, the stream only became when passing through the railway easily distracted.

The web had fabric-like softness and drapability better than that of Example 1. Its soft, flexible, drapable, and wrinkle-resistant nature made them suitable for use Very suitable as an intermediate lining.

Various properties were then determined using a test piece of the web. details the measurements and properties are given in the following table:

density

g, crtr

0.025

weight
per unit of length

Elongation at break

0.090

Tear resistance

kg / g, cm

porosity

97.8

S_ D.

3280

Example 3

A nonwoven carded web similar to that of Example 2, but composed of 20 percent by weight heterofibers and 80 percent by weight of the non-activatable, upset-crimped polyhexamethylene adipamide fibers, was allowed to shrink freely, in all directions, while in hot air at a temperature of 230 to 240 ⁰ C for a time of 3 ¹ Z ₂ minutes was heated. The areal shrinkage was approximately 12% and the resulting web had an average density of 0.020 g / cm ³ . Various properties of the web were then determined using a test piece 6 cm long and 2 cm wide. The results are given in the following table:

density

according to

0.019

weight
per unit of length

8 cm

Elongation at break

0.031

Tear resistance

kg / g / cm

porosity
%

98.3

45

S_ D.

3683

The track had a very open structure and was extremely flexible. It could be wrinkled and folded and then worked out flat in the original state. In appearance she was a conventional one Very similar to wool blanket textile. It was very plump and light, and it had good thermal insulation properties. Once moistened, it dried quickly and was easy to apply evenly with just one dye to be colored. The web was then made into a duvet, which was excellent Had wear properties.

B ei s ρ i e 1 4

A quantity of staple fibers 57 mm long and having a denier of 6 denier was made from fully drawn, crimpable polyhexamethylene adipamide / poly (omega-aminoundecylic acid) heterofilaments (nylon 66/11) in which the two components were present in equal parts by weight . The fibers were then carded using a carding machine and then crossed in a conventional manner to give a loose sheet approximately 38.1 mm thick. This web was then divided into two 22.86 cm long and 17.14 cm wide webs, each having a weight of nearly 136 g / m ² and an average density of 0.005 g / cm ³ . The panels were then placed on each side of a light woven fabric. The sandwich structure was then lightly needled on a simple needle loom to improve dimensional stability and tensile strength. After harvesting, the structure was heated for 4 ¹ Z ₂ minutes in an oven to a temperature of 230 to 240 ° C, under an initial pressure of 0.03 g / cm ^2, which was caused by a mica plate, of the surface To soften fabric. During this heating period, the web gradually shrank, losing 22% of its area and activating the poly (omegaaminoundecylic acid) component of the heterofilaments. The web obtained had a smooth, even-armed surface and resisted fraying and was fairly tear-resistant.

Various properties of the web were then determined. The results are in the following Table specified:

density
according to ³ weight
each length
unit
g, cm Tear
strain
% Tear
strength
kg, g / cm porosity
% S_
D. 0.055 0.108 30th 220 95.2 4000

The results show that the dimensional stability and tensile strength of the web are improved by incorporation a light fabric and improved by needling. The web had excellent elasticity, was evenly porous and very suitable for upholstery and upholstery material.

Example 5

This example illustrates the manufacture of a nonwoven composite fiber article in sheet form from a wet-laid web.

An uncrimped tow of drawn 12 denier heterofilaments in which polyhexamethylene adipamide was one component and an 80:20 random copolymer of polyhexamethylene adipamide / poly-epsilon-caprolactam was the other component (nylon 66/66/6) was converted into 6.35 mm long staple fibers cut. 10 g of these staple fibers were dispersed by vigorous agitation over a period of 10 minutes in 3 liters of water containing a small amount of a dispersing agent. The resulting uniform suspension was ^{filtered through a 51.6 cm 2} wire mesh to produce a uniform cohesive web. After drying, the web was placed in an air oven and ^{heated to a temperature of 226 to 236 ° C. for 3 1} ₂ minutes under gentle pressure (0.06 g / cm ² ), the pressure being generated by a mica plate to create a to bring about a smooth surface of the resulting product. During the heating treatment, the fibers of the were curled

109551/411

Web, the web shrunk, and the fibers in contact with each other coalesced as Result of the activation of the binder component. This sheet had excellent elasticity and good flexibility.

density
g / cm ³ weight
each length
unit
g / cm Tear
strain
% Tear
strength
kg / g / cm porosity
% .S.
D. 0.032 0.055 35 112 97.2 2036

Claims (3)

Patent claims: 1. A method for producing a bonded nonwoven fabric by producing a binder containing fiber structure and binding 10 by activating the binder, thereby characterized in that the fiber structure comprises at least 5 percent by weight of crimpable composite fibers which have an eccentric component arrangement, at least one being arranged on the outer surface Component consists of an activatable binder, and that the fiber structure is treated, to develop the curl and activate the binder component. 2. The method according to claim 1, characterized in that the crimping and the activation is made by heating. 3. The method according to claim 1, characterized in that the crimping and activation made by treatment with a swelling or solvent for the binder component will. 1 sheet of drawings