DE1075028B - trf Fran cesco Malaguzzi, Milan (Italy) j mixed yarn - Google Patents

Description

Blended Yarn The invention relates to blended yarns made of at least two different types of staple fiber.

The processing of fully synthetic fibers in combination with others Fibers into yarns by the worsted and carded yarn spinning process is known. However, mixed yarns of polypropylene fibers and other fibers were not known. It has now been found that when processing polypropylene fibers, fibers with others Fibers mixed yarns are obtained which have surprisingly good tensile strengths and elongation values exhibit.

The mixed yarns according to the invention contain at least 20% staple fibers made of highly crystalline polypropylene with a high molecular weight. The other staple fiber material or the other staple fiber materials are selected depending on the intended use of the yarn, and natural or synthetic fibers can be used for this. In the case of textile fabrics containing polypropylene fibers, such as woven, knitted, knitted goods, etc., can. the different types of fibers within> the yarn itself are mixed with one another, or a yarn consisting exclusively of highly crystalline polypropylene can be processed together with a different type of yarn to form a sheet.

It is known to use fibers from various materials such as wool, cotton, regenerated cellulose, polyamides, acrylic or polyvinyl chloride, to each other mix in order to lower the cost price, the aesthetic and the functional To improve the properties of the product or certain textile operations, such as carding, Spinning, weaving or finishing. When spinning in a mixture with other fibers, the polypropylene gives the yarns its excellent mechanical properties and chemical resistance, its heat insulation ability, its lightness. Moreover polypropylene fibers can be processed very well in the spinning mill.

The same methods are used to produce the mixtures, as they are used for other fibers. Sometimes it is enough to use a small amount of polypropylene fiber and the other staple fibers to be mixed therewith simultaneously in a feed hopper from which they enter an opener with a rotating arm that holds the two of them Fiber types open and mix. The weight ratio of the fibers fed must always correspond to what is to be achieved in the finished structure. The one in this Wise mixed fibers are normally processed further.

In most cases, however, it is preferred to place the fibers after the Mixing "sandwich" method, which is done as follows: A first layer made of polypropylene fibers is deposited, on which a layer, for example made of wool fibers, another layer of polypropylene fibers and another layer of wool fibers, etc. is applied until a thick layer structure consisting of alternating layers of polypropylene fibers and fibers mixed with them. The fibers are now peeled off from one side surface of this layer structure and on to the other Homogenization led into the opener. In this case too, of course, the number will be of the layers and the weight of the individual layers through the desired mixing ratio certainly.

The fibers to be mixed are expediently chosen so that they approximately equal in length and fineness, so as to allow the two to be intimately mixed To facilitate fiber types, as long fibers are known to be more in the interior of the yarn along the axis, while short fibers are more on the periphery of the yarn wont to be. The same applies to mixtures of thick and thin fibers the thin fibers more on the inside, the thick fibers on the other hand more on the outside of the yarn.

Furthermore, since the polypropylene fibers are "clean", make sure that that the fibers to be mixed with it, especially if it is deals with natural fibers, knocked and washed beforehand in the required manner, earbonized or otherwise pre-treated. At the The fibers should be mixed and opened with a suitable size with a lubricating effect and antistatic properties to facilitate subsequent operations, such as carding, stretching, combing, dissecting and spinning.

That. Carding is mainly used to separate the individual fibers in order to align them parallel, to remove knots and to convert the pile into an even pile. Compared to treating natural or artificial fibers without the addition of polypropylene, costs can be saved, since the card can be overloaded without any disadvantage. For example, while a maximum production rate of 15 kg / hour is achieved with 100 % wool, a production rate of 25 kg / hour can be achieved under the same conditions with a mixture of 50 % wool and 50% polypropylene. Of course, these numbers correspond to the middle yarn counts, since with very fine yarns the speed of carving has to be reduced and thus the production is lowered. in any case - but, if all other conditions remain the same, there is a very considerable increase in productivity when processing a batch which contains a high proportion of polypropylene. The grains according to the invention are suitable for spinning both according to the carded yarn system and according to the worsted yarn system.

In general, the shorter polypropylene fibers are preferred according to the carded yarn system, long polypropylene fibers on the other hand according to the worsted yarn system processed.

When processing according to the worsted yarn system, the pile of fibers leaving the Krernpel is stretched into a tape and wound onto bobbins. A certain number of these stretch ribbons are tickled once or several times on the needle bar stretchers in order to further refine the stretch ribbon, to make it more uniform and to align the fiber axis parallel to the ribbon axis. The stretch slivers then get into the combing machine, which removes the shorter fibers, i. H. those that do not reach a predetermined length are eliminated. The tops of the tops emerging from the combing machine are further refined and doubled and arrive on the fine spindle bench, where they are drawn into roving and slightly rotated. The roving is elfaktor on the ring spinning machine or on the south, plugged-where it is spun into fine or finished yarn.

When processing according to the carded yarn system, this becomes the first Clutter leaving pile on a rotating drum to form a thick one Clad fur. This fur is placed on a second card in which it is in turn is processed into a fiber pile. This pile comes under the formation of a cotton wool-like Ribbon of uniform thickness and predetermined weight moving in a sinusoidal manner Conveyor belts. The carding belt is fed into a third carding machine and again processed into a pile. The pile leaving the third clutter goes directly on the pile divider and is divided into strips with the help of movable belts, which are wound up on roving rollers. The roving rollers are placed on ring or self-actuator spinning machines spun into yarn. The operations described are familiar to the person skilled in the art and do not belong to the invention. In all of these operations the behavior of mixtures containing polypropylene fibers is very good.

It should be pointed out that with wool in the carded yarn spinning process, at most yarns with a metric yarn count of Nni = 20 'can be obtained. while with a mixture of 50 % wool and 50 % polypropylene it is possible to achieve a yarn count of Nm = 35 ' . This means that the use of polypropylene significantly increases the spinnability limit.

It should also be noted that the spinning speed of mixtures of 50 % wool and 50 % polypropylene can be increased up to 25 m / minute, while that of 100 11 / o wool can be at most 15 m / minute. The addition of polypropylene thus increases the spinning speed and thereby lowers manufacturing costs.

Finally, the mechanical resistance properties of mixed polypropylene yarns are very interesting during weaving operations.

During these operations the gaxne are put under considerable strain subjected, -only as a result of the normal yarn tension and also as a result of the additional Tension that arises when opening the compartment and as a result of the friction that arises, if the yarns rub against each other when opening or closing the compartment or if they slide over the exit rollers, strands, cross rods and comb teeth.

These combined stresses cause frequent stoppages on the looms, as the tension can cause the yarn to break, while the friction leads to wear of the yarn surface, so. that thread breaks can enter.

With the yarns according to the invention, thread breaks occur only very rarely especially if the warp yarns have been given a size beforehand.

During the weaving of carded yarns of 100 1 / o wool a worker can supervise two looms maximum, he can easily oversee four looms in weaving with carded yarns of 50 11 / o wool and 50 1 / o polypropylene. In other words, the labor costs for weaving are cut in half with blends that contain a sufficient proportion of propylene fibers.

These numerous advantages in the production are further advantages of the finished product, d. that is, the polypropylene fibers considerably improve the properties of the other fibers, particularly those of natural fibers. This is explained in more detail on the basis of the following examples.

Finally, it should be mentioned that it is sometimes advantageous to manufacture yarns from 100 % polypropylene (which thus have the highest possible strength properties) and to use these together with other yarns to obtain fabrics with particular mechanical and aesthetic properties.

Example 1 Using the carded yarn process and using a carded yarn ring spinning machine, a mixed yarn is produced from polypropylene staple fibers and wool in a ratio of 50:50 . The yarn obtained, which has a fineness of Nm = 30 ' , has the following properties: Tensile strength .......... 1.5 g / den (a corresponding 10011 / o wool yarn has tensile strength of 0.5 g / den) Elongation at break ..... 17.3% The four-fold twisted yarn is processed into a seven-strand atlas on a normal wool loom. The fabric is then finished for the production of suits and women's coats.

The finished fabric has the following properties: Burst strength Burst height ......... 11.5 mm Burst pressure ........ 21 kg / CM2 (Burst pressure for a appropriate fabric made of 1001/0 wool 8 kg / CM2) Abrasion resistance (determined after the Regulation No. 2637 of the Italian Am- tes for unification (UNI) Reason of weight decrease after 1000 Revolutions below a load of 5 kg) .............. 1.3% (with a corresponding appropriate tissue 100% wool 8.86%) Example 2 In the same way as in Example 1 , a mixed yarn is produced from 20 parts of polypropylene and 80 parts of polyvinyl chloride. The yarn has the following properties: Tensile strength ......... 1.28 g / den (for 100% polyvinyl chloride 0.4 g / den) Elongation .............. 16.6% Example 3 A mixed yarn of viscose rayon and polypropylene 50:50 with a metric yarn count of Nni = 30 'is produced, which has the following properties: Tensile strength .......... 1.8 g / den (a corresponding 100% Vis- Kosereyon owns one Tensile strength of 1 g / den) Elongation ................ 14% This yarn is processed into a crepe fabric that is suitable for making suits. In the bursting strength test, this fabric shows a bursting height of 10.8 mm and a bursting pressure of 14 kg / cm2. The comparison test for a corresponding fabric made of 100 % viscose rayon (artificial silk) resulted in a burst pressure of only 6.5 kg / cm2.

Claims (2)

PATENT CLAIMS-. 1. Mixed yarn of at least two different types of staple fiber, characterized by a content of at least 20% staple fibers made of highly crystalline polypropylene with a high molecular weight. 2. A method for spinning yarn according to claim 1, characterized in that the mixed yarns are spun in a manner known per se according to the worsted or carded yarn spinning process. 3. Textile planar structures, characterized in that they are wholly or partially made from a mixed yarn according to claim 1 . Documents considered: Franz Fourn #, Synthet. Fibers, Stuttgart, 1953, pp. 48 and 49. When the application was announced, a priority document was laid out.