JPS636661B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention uses a multifilament thermoplastic synthetic fiber, which is a spun-like mixture of single yarns cut at random lengths in the longitudinal direction and uncut single yarns, and has bulkiness and elasticity with rich air content. The present invention relates to a method for producing a fluffy crimped yarn with excellent properties. Conventionally, many methods have been proposed for producing spun yarn-like yarn using multifilaments of thermoplastic synthetic fibers. In other words, methods of cutting filaments by scraping with a knife or grindstone, using high-pressure fluid, etc., and drafting or fluid treatment of multi-filaments in which high elongation filaments and low elongation filaments or high strength filaments and low strength filaments are mixed. Typical examples include methods. Each of these conventional techniques has some drawbacks; for example, in the method of cutting the filament by abrasive means using a knife or a grindstone, all the filaments of the yarn are subject to cutting, resulting in yarn breakage due to shedding. It is possible that the cut single yarn may have come loose and fallen. Therefore, as a means to prevent this, it is necessary to add a considerable number of twists in advance or to entangle or fuse the filaments together. The yarn obtained in this way is easily affected by the degree of twisting, entangling, or fusing in the preliminary process, and when made into a woven or knitted product, it is prone to pilling or a rough texture, resulting in poor dimensional stability. It also tends to decrease. Furthermore, in the method of cutting only one filament of a yarn containing a mixture of filaments of different elongation and strength by drafting or high-pressure fluid treatment, it is necessary to make the difference in the absolute values of the different elongation and strength considerably large. If the difference in absolute values is small, it will be extremely difficult to uniformly cut one filament, and the equipment and conditions for cutting the filament will also require high precision. Furthermore, the length of the cut single filaments of the obtained yarn tends to be longer than the fluff length of the spun yarn, and the yarn has poor air-containing properties, so that it cannot escape from the range of long fiber-like. Also, JP-A-53-6657 and JP-A-51-
Publication No. 147648, etc., proposes a method in which weak points are formed randomly using a single-component supplied yarn, and then a fluid treatment is performed to cut the weak points to generate fuzz. . However, in these methods, since the supplied yarn is a single component, all of the filaments constituting the yarn are cut at some part, and there are no uncut filaments. Therefore, in order to maintain the strength of the yarn at a level that can be used in practical use, there is a drawback that the amount of fluff and the length of fluff are limited. It is easy for threads to come loose, fall off, and break.
For this reason, there is a drawback that the operability of the production process of the fluffy crimped yarn becomes unstable. The present invention improves upon the drawbacks of the prior art. That is, the present invention subjects yarns made of two types of thermoplastic synthetic fiber multifilaments with different single yarn finenesses and heat shrinkage rates to false twist and crimp processing,
The gist is a method for producing a fluffy crimped yarn, which is characterized in that only multifilaments with a fine single filament fineness and a high heat shrinkage rate are cut by twisting or high-pressure fluid injection treatment. be. The present invention will be explained in detail below. First, in the present invention, two types of thermoplastic synthetic fiber multifilaments with different single filament fineness and heat shrinkage rate are used. One type is multifilament A, which has a thin single filament fineness and high heat shrinkage rate, and the other As one type of multifilament B, which has a thicker single yarn fineness and a lower heat shrinkage rate than the multifilament A, is used. Examples of thermoplastic synthetic fibers include polyester, polyamide, and polyacrylonitrile. In particular, the single filament fineness Da of the multifilament A and the single filament fineness Db of the other multifilament B are 0.1≦Da/Db≦
Satisfies the relationship 0.8, and furthermore, the thermal contraction coefficient Sa of multifilament A and multifilament B
In order to obtain the desired effect of the present invention, it is desirable that the thermal shrinkage rate Sb of Sb satisfies the relationship of 1.1≦Sa/Sb≦5.5. Further, when the multifilaments A and B are subjected to the false twisting process, it is preferable that the multifilaments A and B are supplied to the twisting area in the form of mixed fiber yarns. Normal processing conditions are applied to the false twisting process. Multifilaments A and B supplied to the twisting region of the false twisting process are subjected to thermal action, twisting, and tensile action. At this time, since multifilament A has a higher shrinkage rate than multifilament B, it naturally causes torsional stress and It will be subjected to a large amount of tensile stress, etc. Therefore, multifilament A has a thin single fiber fineness, and its strength is significantly reduced. In the false twisted yarn thus obtained, two types of multifilaments with large differences in strength are mixed together to form a false twisted crimp, and then the yarn is twisted or entangled by high-pressure fluid jet treatment. Only the multifilaments A in the false twisted yarn are randomly cut. In this way, the cut single yarns and uncut single yarns are uniformly mixed together, the cut single yarns become fuzz with short, random lengths similar to spun yarn, and the cut single yarns and uncut single yarns become fluffy in the form of a false-twisted crimp. A crimped yarn having a shape is obtained. This crimped yarn is highly air-containing, has a shape and texture similar to that of spun yarn, and also has the characteristics of a filament yarn. The fabric also has soft fuzz on its surface. It is a soft, span-like product. In the present invention, as mentioned above, a multifilament with a thin single filament fineness and a high heat shrinkage rate was used as the supplied yarn, and a filament with a thick single filament fineness and a low heat shrinkage rate were used, so the former was cut. The fluffed multifilament and the latter become the uncut multifilament, and since the strength of the yarn can be maintained with the uncut multifilament, the composition ratio, fluff amount, or fluff length of the cutting multifilament can be adopted over a wide range. Furthermore, the conjugation with uncut multifilaments prevents the occurrence of yarn breakage due to the shedding of cut fluffed multifilaments, so there is less looseness and shedding of fluff, which improves the production process of fluffy crimped yarns. It has the advantage of stable operability and the ability to diversify and speed up operations. Furthermore, a relaxation treatment may be performed as necessary after the false twisting and crimp processing, and by performing the relaxation heat treatment, the crimpability and torqueability of the yarn can be changed appropriately, and the performance and texture can be improved. You can get a wide range of products on the market. Example 1 Polyester synthetic fiber multifilament (A-1) 50D/36f and (B-1) shown in Table 1
A mixed yarn of 100D/48f consisting of 50D/12f was false twisted under the conditions shown in Table 2.

【table】

[Table] The false twisted yarn obtained under the above conditions was twisted under the conditions shown in Table 3.

[Table] The yarn obtained under the above conditions has countless fine single filament fluffs on the yarn surface, and becomes a fluffy crimped yarn with appropriate swelling and elasticity. When made into a woven fabric, the fuzz of the cut single yarns stood out uniformly on the surface of the fabric, resulting in a product with a soft, spun-like texture. Example 2 Polyester synthetic fiber multifilament (A-2) 50D/36f and (B-2) shown in Table 4
A mixed yarn of 75D/48f consisting of 25D/12f was false twisted under the conditions shown in Table 5.

【table】

[Table] The false twisted yarn obtained under the above conditions was subjected to a series of twisting and heat treatment under the conditions shown in Table 6 below.

[Table] When the fluffy crimped yarn obtained under the above conditions was knitted, a spun-like product with a soft surface, bulkiness and firm waist, and countless single yarn fluffs of appropriate length and shortness was obtained. Obtained.

Claims (1)

[Claims] 1. Single yarn fineness and heat shrinkage rate are different. 2.
By applying false twisting and crimping to yarns made of multifilament thermoplastic synthetic fibers, and then subjecting them to twisting or high-pressure fluid injection treatment, only multifilaments with fine single filament fineness and high heat shrinkage are produced. A method for producing a fuzzy crimped yarn, which comprises cutting the yarn. 2 The two types of multifilaments are multifilaments A and B, and the single fiber fineness of A and B is
The single yarn fineness Db satisfies 0.1≦Da/Db≦0.8, and the heat shrinkage rate Sa of A and the heat shrinkage rate Sb of B are 1.1≦Sa/Sb
The method for producing a fuzzy crimped yarn according to claim 1, which satisfies ≦5.5.