DE2352847A1 - Stretchable artificial leather - made from chain weaves bonded together with thermoplastic - Google Patents

Abstract

Stretchable artificial leather, based on a chain weave in two layers bonded together with a polymer and with cloth stitch in one layer, has stockinet and fringed stitch in the second layer. The material has good stretch and resistance to stitch tear. The chain weave is made on usual machines, pref. of continuous mono- or multi-filament polyamide or polyester fabrics. The polymer bonding layer is e.g. plasticised PVC and the two other layers are bonded together by coating, dipping, or hot rollers, the polymer being foamed if desired.

Description

GERMAN GOLD AND SILVER SCHEIDEANSTALT FORMERLY ROESSLER Frankfurt a.M., Veissfrauenstrasse 9

Synthetic leather web, with warp knitted as a carrier material

With the introduction of endless synthetic threads, mainly based on of polyamide or polyester, the warp knitting technique has one experience strong upswing »

While textile articles were initially produced, for example shirts and underwear fabrics, curtains and outerwear fabrics, Velours, etc., have also used warp knitted fabrics as a carrier material for production in recent years of plastic coatings, especially on a PVC and PU basis Entrance found. They mostly have other stretchable carrier materials such as cotton and rayon knitted fabrics replaced and surpassed in many properties. This is mainly because it succeeds with one essential lower use of endless synthetic fiber threads in practically all properties a much heavier knitted fabric (mostly weft knitted fabrics) made of cotton and / or viscose viscose. In the course of the production of increasingly cheaper articles for the bag-making sector, but also for automotive interiors as upholstery fabric and sky fabric and also for other applications is what the coating industry strives for to use synthetic knitted fabrics that are as light as possible and yet to achieve the technical properties required for the application.

From the large number of bindings available in the warp knitting technique, mainly the following two laying combinations have been used because of their low weight;

1. Two-rail goods with cloth laying in the laying rail 1 and Fra'nselposition in the guide rail 2 ("blocked mesh"), with both equal and opposite offset

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find use because of the similarity of properties can.

2, two-rail goods with cloth laying in the laying rail 1 and Tricot laying in the guide rail 2 (Charmeuse), whereby because of the instability of the same-layer variant, especially the opposite one Displacement is used. Also the exchange of the laying in the laying rail, i.e. jersey in rail 1 and Cloth in rail 2 - has very, similar properties as an opposing product.

Practically all other laying combinations are either in their properties too unstable so that they can be coated or not suitable for bonding with plastic layers, or si.e are by long floating legends, for example Trikot / Velvet, Fringe / Sarnt, Fringe / Satin etc., because of the higher Consumption of thread significantly heavier and then surpass the conventional carrier knitted or woven fabric based on natural fibers in the properties by far, but they are out no longer or no longer sufficiently superior for economic reasons.

Of the two most commonly used knitted weaves mentioned above, goods based on threads are used in the field between 20 and 100 dtex continuous yarn and mainly manufactured on knitting machines with pitches from Io to 30, preferably IS and 28, needles per inch.

A closer look at the artificial leather produced from cloth / tricot or tricot / cloth-binding knitted fabric has now revealed itself shown that they have significantly lower manufacturing costs with a corresponding weight saving compared to knitted cotton the synthetic leather on cotton and / or viscose wool supports in almost all properties that they achieve but one in the tear strength in the longitudinal direction

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Show direction dependence, depending on how the tear direction for machine direction is set.

If you tear "into the mesh", that is, in the direction from the bottom of the mesh to the top of the mesh, you will find remarkably high ones Verte, each depending on the thread thickness and the embedding in the plastic layer of the artificial leather.

But if you tear in the other direction, that is, from the mesh head towards the bottom of the mesh, one finds values of the tear strength, which are usually only about half of the values in the other direction, often even below.

The low value of the tear strength in the longitudinal direction against the mesh head is caused by the Meshes caused by the attempt to tear further in the manner of a zipper, even with very good embedding and adhesion of the The back of the knitted fabric comes into or on the plastic layer hardly a thread bundling, but it has to - about the Forward tear - only a single thread will be torn, whereupon the next stitch without breaking one Thread can be pulled apart.

When using the cloth fringe, the tear strength is was slightly less than when laying the tricot cloth in the favorable longitudinal direction, but there is no evidence of this There is a noticeable difference between the two possibilities for longitudinal tearing, namely in the direction of the mesh head or on the foot of the mesh, so that in this way overall a satisfactory tear resistance is achieved with this laying Value in relation to the knitted fabric used and its other data can be found.

With this laying, however, the warp knitted fabric is - conditional by the straight line and only a short thread path descriptive

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So severely limited in the elongation in the longitudinal direction such that the finished product at approximately the same properties fo otherwise only about 50 of the achievable with cotton and rayon knitted fabric elongations has - Franselegung. As a result, processing is often made very difficult in cases where elongation in the longitudinal direction is necessary, in some cases even made impossible, because the stretching of the cloth-fringe weave practically comes into the areas that you would with a fabric could achieve, so that the elasticity and suppleness advantage of the coated knitted fabric comes in omission.

In summary, it must be said that the two basic types of warp knitting technology that offer themselves in terms of weight and economy, namely the laying of tricot-cloth or cloth-tricot (charmeuse) and the laying of cloth-fringe ("blocked mesh")., cannot be used as a substitute for more expensive knitted fabrics made of cotton or viscose because either the required static elongation is not achieved with cloth-fringe laying or the tear strength in the longitudinal direction is insufficient with tricot-cloth laying.

Surprisingly, it has now become a very stretchable synthetic leather sheet found with a light warp knitted fabric as a carrier material that has all the desired favorable properties, in particular with regard to the amount of elongation and tear strength owns.

The stretchable synthetic leather web or blanks or sections thereof based on a citrus-like warp knitted fabric connected to a plastic layer, which has cloth mesh in the guide rail 1, is characterized in that the warp knitted fabric has tricot and fringe stitches in the guide rail 2. The tricot and fringe stitches are preferably arranged in a regularly recurring order.

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Bs can also be particularly useful when two on top of each other the following tricot stitches, possibly only interrupted by fringe stitches, run in the same direction.

In the warp knit of the artificial leather sheet, in the guide rail 2 but also two tricot stitches in a row in the same way Run before reversing direction so that the tricot meshes to the cloth meshes are partly aligned and partly opposed * The thread changes when forming the jersey marriage, i.e. twice in the same direction into the left or right adjacent row of needles, so that a thread tricot stitches within three rows of needles forms, forming one stitch at each transition on each row of needles.

The warp knitted fabric used according to the invention in the synthetic leather web always has, in the laying formed by a laying bar, a cloth binding (cloth laying) or a laying with a longer thread path than cloth binding, for example a velvet or satin binding, _{or the like}

The binding pattern can be chosen so that that of the laying rail 2 laying formed is always opposite to that of the laying rail 1; or it can also be chosen to be within of the report, opposing and equal arrangements occur ^

The tricot and fringe stitches in the laying rail 2 are preferably in regularly recurring order _9, for example in the numerical ratio 1: 1, 1: 2, 1: 3 (2s 6), 2: 2, 2: 1, 3: 1, (6 : 2.) Etc., arranged o

Depending on the frequency of the tricot mesh, the stretch is the Goods can be variably adjusted, and elongation values can be achieved effortlessly, as is the case with the end articles with a much heavier one Knitted fabrics made of cotton or rayon are also available ο

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Surprisingly, the tear propagation resistance of the artificial leather exceeds that of an artificial leather with a knitted fabric made of a pure cloth-fringe combination as a carrier (order of magnitude 15-25 %). and, moreover, shows no differences in the two directions of tearing in the longitudinal direction, so that not only the disadvantageous zipper effect of the tricot-cloth lay-up is avoided, but the addition of the tricot stitches to the fringe-lay-up can even improve its tear strength values.

In parallel to the increase in the tear strength values, to the same extent an increase in the puncture tear resistance on.

As is well known, the cloth-tricot-bound warp knitted fabric shows at the Processing a number of difficulties; it reacts sensitively to the machine train by constricting in width, shows The side edges tend to curl, and it is often not at all, or only The connection with the plastic sheet is possible with great effort Can be achieved over the full length and width »In contrast to this, the cloth-fringe warp-knitted fabric process quite easily. In terms of processing properties, it is usually even more favorable than cotton and cotton Rayon knitted fabrics. Surprisingly, all show according to the invention When using warp knitted fabrics, the processing behavior is similar to that of the cloth-fringed warp-knitted fabric. This favorable behavior is shown even by patterns that have more tricot than fringe stitches in the guide rail 2, so formally more of the cloth-tricot laying with poor processing properties resemble.

In addition, the stretchability in the transverse direction can also be improved compared to the cloth fringe arrangement or, by choosing the appropriate fixing conditions with constant stretching in the transverse direction, an even greater stretch in the longitudinal direction can be achieved, i.e. the knitted fabrics used according to the invention have opposite the tucb.-f _r ~ ANSE cohesive product a greater overall expansion reserve.

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It must be noted here that all information on the comparison of the elongations of the various knitted bonds is based on the assumption the same fixation conditions and the same fixation jump have been made.

It is clear that a certain "redistribution" of the elongation values between the longitudinal and transverse directions can be achieved by deviating fixing conditions can be carried out as long as the ratio between the raw effective area and the area remains the same after fixing. If you have the Area consciously reduced by fixing - and thereby that Increased weight of the knitted fabric - you can also achieve slightly increased elongation values with cloth-fringe binding, of course with lower profitability.

The achieved according to the invention by the change in effect Increases in elongation are of a significantly different order of magnitude and are achieved while maintaining the .Fixierbedingungen ,, so that an increase in weight is practically not accepted must become. It is clear that a similar improving effect in elongation and tear strength is also achieved, if in the second laying rail - or also in the first, if the cloth is used in the second rail too a combination of fringed stitches with cloth stitches or of fringed stitches with tricot and cloth stitches for same technical effect can be used, however the use of longer floating threads between the meshes results in heavier goods and is therefore economical Reasons are usually limited by themselves.

An arrangement which is particularly advantageous in terms of the optical structure is the even alternation of tricot and fringe stitches in the warp knitted fabric, with one or two or more stitches of the same type can follow one another.

The low elongation of

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Artificial leather with warp-knitted fabric-fringe is used by the artificial leather according to the invention depending on the distribution and arrangement the fringe and / or tricot mesh in the guide rail 2 by 50 Exceeded to $ 100 and thus achieved effortless processing.

The new plastic-coated warp knitted fabrics are used in all areas where stretchable synthetic leather are required, for example in the bag maker, clothing, Automotive, furniture and shoe industries, in all cases in which synthetic leather based on cotton has already been used or cellular woolen knitted fabrics based on synthetic endless knitted fabrics, based on nonwovens or Raschel knitted fabrics have been.

The warp knitted fabric or the warp knitted fabric is made on the usual Warp knitting machines (also called chain chairs) manufactured. The warp knitted fabric is preferably made of endless mono or multifilament man-made fiber threads. The synthetic fiber knitted fabric can have two or more continuous thread types, thread sizes, number of fibrils, Contain titer and / or directions of rotation of possibly different chemical composition. Preferably, threads made of polyamide or polyester are used, but other man-made fibers such as those made of rayon can also be used or polyacrylonitrile can be used. The warp knitted fabric can be roughened on one side.

The plastic layer consists of a pliable and stretchable one adjusted layer based on, for example, plasticizer-containing Polyvinyl chloride, other common vinyl chloride copolymers or polyurethanes that have been adjusted to be flexible and elastic, optionally also polyamides, polyolefins or other customary coating materials, the coating of the Warp knitted fabric with plastic or the connection of the warp knitted fabric with the plastic layer can be done in the usual way.

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be taken, for example using a deletion process, Dip process, by roller coating (melt roller process) , by gluing or laminating. The plastic layer can be foamed or foamed in layers and also be trimmed in the usual way. This includes, for example, printing, embossing, flocking, Dusting, grid painting, spray painting and / or perforation »The plastic layer can be flame retardant or antistatic and pigmented in the usual way for artificial leather. , ·

example 1

A foam PVC sheet provided with a sealing lacquer and weighing about 600 g / m ² plastic based on plasticized polyvinyl chloride divided into about 250 g / m ² top layer and 350 g / m ² foam layer is made by means of 80 g / m ² Laminating paste based on soft PVC with an addition of isocyanates to achieve sufficient adhesion through reaction with the fiber raw material polyamide combined with a warp knitted fabric with the following setting: "'

6,6-polyamide yarn, 78 dtex, with ^ h single capillaries; Knitting machine needle density 18 needles per inch; Laying of the guide rail 1: cloth binding; Laying of guide rail 2 (opposite to the laying of guide rail 1); alternating two mesh fringe and two mesh tricot; Numbering of the laying: Laying rail 1 (L 1): 1 0/2 3/1 0/2 3; Guide rail 2 (L 2) ι 0 l / l O / l 2/1 0 (symbols used in warp knitting); Number of stitches: about 12 stitches per centimeter in the longitudinal direction and about 8 wales per centimeter in the transverse direction; Weight of the warp-knitted part of the synthetic leather sheet: approx. 65 g / m ² . The synthetic leather sheet is still embossed in the usual way.

The onward travel and elongation properties obtained with the finished synthetic leather web are given in a table below

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indicated, namely of the synthetic leather sheets in comparison with synthetic leather sheets produced by means of cloth-fringe-binding and by means of cloth-tricot-binding warp knitted goods.
(For example 1, sample l).

Example 2

Compared to Example 1, all parameters, all starting materials and the production are the same, only the layout is in the guide rail 2 changed to: alternating a mesh fringe, two mesh tricot, one mesh fringe, two mesh tricot, but direction reversal to the first two tricot stitches. the The numbering for L 2 is: 1 2/2 1/2 3/2 l / l 2/1 0.

(Pattern 2).

Example 3

Compared to Example 1, all parameters are all starting materials and manufacturing method the same. Only the laying in the laying rail 2 has been changed, namely in: alternating two mesh fringes, six mesh jersey. The numbering for L 2 is: 1 0/0 1/1 2/1 0/1 2/1 0/1 2/1 0.

(Pattern 3). '

The comparative artificial leathers "a" and "b" are the same and made from the same materials as the types of artificial leather according to the examples.

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Comparison table with regard to tear strength (measured in accordance with DIN 53 356) and static Elongation (measured based on DIN 53 36o)

In the table, the ranges of the measured values are given, which indicate the spread of series measurements mark.

Binding of the warp knitted fabric

L 1: cloth Ll: cloth example example example L 2: fringe L 2: jersey 1 2,

away

Ca) CJl

Tear strength according to DIN 53 356 in Kp

Longitudinal direction against the mesh head

Longitudinal direction against

Mesh foot

Transverse direction

2.1-2.5

2.2-2.6 2.6-2.9

1.4 - 1.7

2.9-3.2

2.9-3.3

2.5 - 2.8 2.4 - 2.7 2.3 - 2.7 2.7 - 3.1 2.6 - 3.0 2.5 - ■ 2.9 2.6-2.9 2.6-2.9 2.7-3.1

static strain in $
at 5 kp / 5 cm 8th - XX) 15th - 20th 13 - 17th 14th - 18th 15th - 18th K) Strip width according to 24 - 11 ' 45 - 55 32 - 36 38 - 42 35 - 40 • co 30 minutes of exercise 28 K) Longitudinal direction 847 Transverse direction

x) "Zipper effect" xx) Too little longitudinal stretch for good processability

As the values in the table show, the static elongations in the longitudinal and transverse directions in the types of artificial leather according to examples 1, 2 and 3 according to the invention are considerably higher than the elongation values of the comparative artificial leather "a", above all by more than 60 $> improved longitudinal elongation is a significant processing advantage. In the case of the tear strength in the longitudinal direction with the incision directed towards the mesh head, not only is the insufficient value that occurs with the comparative artificial leather "b" avoided (i.e. no easy opening of the stitches in the manner of a zipper with only seldom tearing of threads), but also the Tear strength values compared to the comparative artificial leather "a" increased more or less significantly in practically every direction.

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Claims (3)

Claims 1.) Extensible synthetic leather sheet or cuts based on it a double rail connected to a plastic layer Warp knitted fabric, which has 1 cloth mesh in the guide rail, characterized in that the warp knitted fabric in the Laying rail has 2 tricot and fringe stitches. 2. artificial leather sheet according to claim 1, "characterized in that the tricot and fringe patches regularly recurring Order are arranged. 3. Synthetic leather sheet according to Claims 1 and 2, characterized in that that two consecutive tricot stitches, possibly only interrupted by fringe stitches, run in the same direction. H. Synthetic leather web or blanks from it, based on a double-bar warp knitted fabric connected to a plastic layer, which has a sheet mesh in the guide rail 1 and / or a longer thread path than a sheet mesh, characterized in that in the warp knitted fabric in the guide rail 2, two tricot tabs run one behind the other in the same direction, before the direction is reversed, so that the tricot meshes are arranged partly in the same way and partly in opposition to the cloth meshes. PL / Gt-Pr October 19, 1973 50 98 18/113 5