JPH07118979A - Conjugate spun yarn and its production - Google Patents

Abstract

PURPOSE:To provide a conjugate spun yarn causing minimized single fiber breakage and fluff breakage in the fiber-forming process without deteriorating the excellent tensile strength of a rigid carbon fiber or glass fiber and exhibiting extremely excellent squeezing resistance and to provide a process for the production of the yarn. CONSTITUTION:This conjugate spun yarn is produced by spirally winding a continuous yarn around the outer circumference of a non-twisted short fiber bundle containing carbon fiber and/or glass fiber. It can be produced by cutting fibers containing carbon fiber and/or glass fiber by stretch-breaking method to obtain a sliver, drafting the sliver to a fleece having a desired thickness, separately unwinding a continuous yarn from a package attached to a hollow spindle by rotating the package, spirally winding the continuous yarn around the outer circumference of the fleece and finally taking off the product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite spun yarn and a method for producing the same. More specifically, the present invention relates to a composite spun yarn excellent in resistance to squeeze in which a continuous yarn is wound around the outer periphery of a non-twisted short fiber bundle of carbon fiber or other fiber having high rigidity.

[0002]

2. Description of the Related Art Conventionally, carbon fibers and glass fibers which are rigid and vulnerable to shear stress caused by twisting have been developed mainly by continuous filament yarns or chopped fibers. It is known that carbon fiber or glass fiber tow, sub tow, or continuous filament yarn is cut into sliver, then the sliver is drafted into a fleece, and twists are inserted into the fleece to form a spun yarn. .

[0003]

However, on the spreading surface of continuous filament yarn of carbon fiber or glass fiber, filament winding, unidirectional prepreg or sheet molding compound (SM) based on woven fabric is used.
C), cross prepreg, etc. can be seen, but since they are often developed as a composite base material of a relatively thin material, they cannot be used when the total fiber fineness of the raw material is large.

Further, a mat made of wet paper is mainly used for development as a chopped fiber, and it is used as an electrode base material for a fuel cell, etc., but it has little industrial significance because of a small production lot.

Further, in the case where a spun yarn is obtained by inserting an actual twist, the raw material fiber has an excellent performance in tensile strength, but is extremely vulnerable to a shearing external force. From this point of view, the spun yarn has an extremely low strength utilization factor of the material, and when used as a fabric or a composite substrate, various problems occur. Furthermore, as a problem in the spinning process, short fibers are frequently damaged or cut due to twisting or rubbing by a traveler, and dust scattering is remarkable, resulting in yarn breakage,
Process troubles such as mixing of fly dust occur. In addition, a large torque is generated by twisting, and there is a problem that a single yarn cannot be used in the weaving and weaving process, and thus it is inevitable that the double yarn processing (various threads) processing is performed.

[0006] In order to process the twin yarn, it is necessary to make the spinning number of the spun single yarn thin, and the spinnability is further deteriorated and the cost becomes high. Not only will it cause short fiber breaks and fluff breaks, but it will also create a vicious cycle in which the cost of twisting yarn will be added. When spun yarn with a lot of fluff on the yarn surface is supplied to the weaving and weaving process, in addition to yarn breakage due to unwinding failure and poor resistance to squeeze, fluff breakage, falling off, and scattering frequently occur, resulting in poor workability. There is a problem of being dismissed.

The object of the present invention is not to impair the excellent tensile strength of rigid carbon fibers and glass fibers, to minimize single yarn breakage and fluff breakage during yarn formation, and to achieve extremely excellent anti-squeeze performance. It is an object to provide a composite spun yarn having the same and a manufacturing method thereof.

[0008]

The present invention has the following constitution in order to solve the above-mentioned problems of the prior art.

That is, a continuous spun yarn is formed by winding a continuous filament around the outer peripheral portion of a non-twisted short fiber bundle containing carbon fibers and / or glass fibers.

Fibers containing carbon fibers and / or glass fibers are cut by a sawing method to form a sliver, then the sliver is drafted to form a fleece having a desired thickness, and then mounted on a hollow spindle. The method for producing a composite spun yarn is characterized in that the continuous filamentous material is unwound around the outer periphery of the fleece while being rotated by a package in which the continuous filamentary material is wound, and then wound.

The present invention will be described in more detail below.

The untwisted short fiber bundle in the present invention means a sliver itself obtained by cutting a tow, sub tow or filament yarn of carbon fiber, glass fiber or a mixture of these fibers, or the sliver. A fleece obtained by drafting to a desired thickness. Further, the untwisted short fiber bundle of the present invention may be one containing carbon fiber, glass fiber or a mixed fiber thereof, as other mixed fiber polyester, synthetic fiber such as polyamide, semi-synthetic fiber, It may contain natural fibers.

Next, the continuous filaments wound around the outer peripheral portion of the untwisted short fiber bundle are not particularly limited, but so-called synthetic fibers or semi-fibers represented by polyethylene terephthalate, polyamide and the like. A filament yarn made of synthetic fiber can be preferably applied. Furthermore, spun yarn, multifilament yarn or monofilament yarn drawn yarn, semi-drawn yarn or undrawn yarn may be used as the continuous filamentous material, and the presence or absence of crimping and the fiber cross-sectional shape are not limited.

In the present invention, the Young's modulus of the continuous yarn is preferably smaller than the smallest Young's modulus of the carbon fibers or glass fibers constituting the untwisted short fiber bundle. This is because it is possible to prevent the short fiber bundle-like material from having a wavy shape when the continuous yarn is wound. Young's modulus means initial tensile resistance.

The untwisted short fiber bundle of the present invention will be described in more detail. Regarding the fiber length characteristics of the short fibers constituting this bundle, those obtained by cutting by the Ken cutting method are yarn quality,
It is preferable to use short fibers having irregular fiber lengths because they are excellent in yarn quality. The average fiber length is 30 mm
The above is preferable. A more preferable range of average fiber length is 7
It is 6 to 2000 mm. If the average fiber length is less than 30 mm, it is not preferable because it causes deterioration of the yarn streaks due to draft spots, and if it exceeds 2000 mm, it is difficult to control the floating fibers in the draft region and tend to cause yarn unevenness, which is not preferable.

Further, the total denier of the constituent fibers of the above short fiber bundle is preferably 20 denier or more from the standpoint of thread quality and operation.

In the present invention, the untwisted short fiber bundle (fleece) is wound into a continuous filament at a feed rate of + 5.0% to -5.0% to form a thread. Underfeed is preferable. This makes it possible to improve the fiber orientation degree, which was difficult because it is a rigid untwisted material, by winding with a continuous yarn, and also contributes greatly to the process stability and the improvement of adhesion between fibers, Not only the uniformity of the composite yarn, but also the yarn strength is greatly improved.

The feed rate of the fleece of the present invention is calculated by the following equation.

Feed rate [%] = 100 × (V _F −V _D ) / V _D where V _F : front roller surface speed [m / min] V _D : separate roller surface speed [m / min] In addition, the underfeed is a case where the feed rate is negative (minus), that is, a case where the take-up speed is faster than the surface speed of the front roller. The term "overfeed" means that the feed rate is positive (plus), that is, the take-up speed is slower than the surface speed of the front roller.

Next, the winding coefficient K of the continuous filament material is T = K
In x (Nm) ^1/2 , the range of K = 25 to 500 is preferable. However, T: the number of windings of the continuous yarn (T / m),
Nm: represents the metric count of the composite spun yarn of the present invention.

If K is less than 25, problems such as spinnability and yarn strength tend to occur. On the other hand, when it exceeds 500, the number of revolutions of the package in which the continuous filaments are wound is rate-determining and the productivity is remarkably lowered. Also, the torque is increased and the handling, the process passability or the quality of the fabric
It is not preferable because the quality tends to deteriorate.

A description will be given below with reference to the drawings.

FIG. 1 is an enlarged schematic view showing an example of the composite spun yarn of the present invention. FIG. 1 shows a state in which one continuous filament 2 is spirally wound around the outer periphery of a non-twisted short fiber bundle F having rigidity. Clearly shows that they have no wavy shape and that they have very few fluff K.

FIG. 2 is an enlarged schematic view showing another example of the composite spun yarn of the present invention. The difference from FIG. 1 is that two continuous filaments 2 are wound in different directions. The yarn shape does not take a wavy shape, and the fact that the fluff K is extremely small is almost the same as in FIG.

FIG. 3 is an enlarged schematic view showing a spun yarn in which a conventional twist is inserted. It can be seen that the appearance frequency of fluff K is extremely high.

FIG. 4 is a process schematic view showing an example of the method for producing the composite spun yarn of the present invention. Rigid carbon fiber, glass fiber, or a sliver containing a mixture of these 1
Is supplied to the back roller 3, and then sent to the front roller 5 via the apron roller 4. At this time, the back roller 3
A desired draft is provided between the front roller 4 and the front roller 4 to obtain the fleece F. Next, the continuous filament yarn 2 is set on a hollow spindle P for mounting a wound package 6, the continuous filament 2 is unwound while the package 6 is rotated, and the filament is wound around the outer periphery of the fleece F to form a yarn, which is then collected. The composite spun yarn of the present invention is taken up by the roller 7. Here, the front roller 5 and the take-up roller 7
It is preferable to underfeed during the period.

A belt B for rotating the package 6 is also shown in FIG.

[0028]

In order to form a non-twisted short fiber bundle, no twisting force is applied to the fibers forming the short fiber bundle. Therefore, the tensile strength can sufficiently exert the performance of the fibers constituting the short fiber bundle, and since the short fiber bundle is tightly wound by the continuous yarn, the untwisted short fiber bundle is formed. The product takes the closest packing, so that the frictional force acting between the fibers can be utilized to the maximum extent, which contributes to the improvement of the yarn tensile strength.

Further, since it is wound with a continuous yarn,
The short fiber end that constitutes the untwisted short fiber bundle is stably wrapped. Therefore, not only the number of fluffs becomes extremely small at the yarn stage, but also the seam resistance is dramatically improved.
Therefore, fluffing and dust scattering are remarkably improved also in the process passability.

Furthermore, since the composite spun yarn of the present invention has linearity without taking a wavy form, the quality and quality of the fabric are extremely excellent.

[0031]

The present invention will be described in more detail with reference to the following examples.

[Example 1] PAN-based carbon fiber T700
S-12K-90 (Young's modulus: 1478 g / d ,, specific gravity 1.76 g / cm ^3, Toray Co., Ltd.) to align eight pull the Ken switching opponent's Ken opener, the average fiber length of 162mm Got a sliver. The thickness of the sliver is 4.056 g / m
Met.

Next, the sliver was fed to a three-wire type drafting device to obtain a fleece which was a non-twisted short fiber bundle component in the composite yarn. The fleece with a thickness of 0.198 g / m (Nm =
5.05) was delivered at 25 m / min, and then polyester filament yarn (40 denier-24 filaments, Young's modulus 124 g as a continuous yarn to the fleece.
/ D, specific gravity 1.38 g / cm ³ , bright yarn) packaged with 5000 r.p.m. p. m. Was unwound and wound while being rotated to obtain a composite spun yarn (Nm = 4.95). The winding coefficient K of the continuous yarn at this time was 89.
9 (T = 200 T / m).

The underfeed rate between the front roller and the take-up roller was 0.3%.

The resulting composite spun yarn was a yarn having a uniform linear streak having linearity without taking a wavy form. The strength of this yarn was 8.6 g / d (when the tensile speed was 0.5 m / min and the test length was 0.5 m in a Shopper type tensile tester). This strength level is a spun yarn (thickness: 0.099 g / m, lower twist number: 250) spun for actual comparison and twisted.
T / m) was 1.83 times the level of the twinned product (upper twist number: 175 T / m).

The composite spun yarn obtained in this example was subjected to a 16G circular knitting machine to prepare a knitted fabric, which resulted in a knitted fabric. Moreover, fluffing was extremely small when passing through the process, and therefore the generation of dust was extremely small.

On the other hand, in the case of the above-mentioned actual twisted yarn for comparison, the yarn was broken at the time of knocking over and a lot of perforated defects were generated. Also in the process passability, a large amount of surface drop occurs due to yarn breakage due to poor unwindability and fluff breakage,
Dust scattering became remarkable.

Further, the composite spun yarn of the present invention is made to have a length of 12.5.
A plain woven fabric of 25/25 mm and 12.5 / 25 mm horizontal was manufactured. The basis weight was 200 g / m ² . The obtained woven fabric was finished into a high-quality fabric having a smooth surface. In addition, stable and high productivity was obtained in both the training process and the weaving process without dropping off the cotton wool.

On the other hand, the actual twisted yarn for comparison often suffered from yarn breakage and fluff breakage during the training process, and stable training performance was not obtained. Next, in the weaving process, a large number of fluffs were seen due to the squeeze on the reed, and the yarn separating property at the opening was also poor. Therefore, the obtained woven fabric was a fabric with a large amount of fly dust and poor surface quality.

[Example 2] PAN-based carbon fiber T300-
30 pieces of 3K-40B (manufactured by Toray Industries, Inc.) were subjected to a desizing treatment, while 4 pieces of glass roving having a fiber diameter of 17 μm and 550 tex (Young's modulus 302 g / d) were also subjected to a desizing treatment. Prepare each of them and arrange them in a sheet shape and supply them to a sawing machine, about 50% carbon fiber,
A sliver of 2.843 g / m of about 50% glass fiber was obtained.

Next, the same spinning machine as in Example 1 was set to obtain 0.099 g / m fleece (Nm = 10.1). A 17-denier-3 filament nylon yarn (Young's modulus 41 g / d) was used as the continuous yarn of the fleece, and the number of revolutions of the package in which the nylon yarn was wound was 6500 rpm. p. m. As composite spun yarn (Nm = 9.8
85) was spun at 30 m / min. The underfeed rate was 0.2%. The winding coefficient K of the continuous yarn at this time was 68.9 (T = 216.7 T / m).

The composite spun yarn obtained in this example is a continuous filament that is strongly wound, so that it has very few fluff breaks during spinning, is a yarn with almost no fluff, and is extremely smooth with linearity. It became a thread.

0.0495 g / m spun out for comparison
The strength of the spun single yarn having a thickness of 400 T / m in the lower twist was 1.42 times that of the yarn obtained by processing the double yarn (280 T / m in the upper twist). Further, during the processing of spun single yarns and twin yarns for comparison, remarkable scattering of fluff, dropout and yarn breakage occurred frequently, and the operating state was extremely poor.

[0044]

EFFECTS OF THE INVENTION Since the yarn forming method of winding untwisted short fibers in continuous filaments is adopted, almost all the cotton wool is spun during spinning even though the filaments are rigid and have no entanglement in the first place. There is no occurrence, and since it is non-twisted, it is a composite spun yarn that is firmly integrated without impairing the characteristics of the raw material fibers in the fiber axis direction.

When the Young's modulus of the continuous filamentous material is smaller than the Young's modulus of the fibers constituting the untwisted short fiber bundle, the yarn side surface shape is not wavy and is a smooth and linear yarn. Becomes Regarding this point, it should be supplemented that making an underfeed fleece also contributes.
As a result, even when it is made into a cloth, it does not have a snake-like spot that causes a wavy thread and causes no roughness.

In addition to being able to exert the above-mentioned excellent effects, in the era when the total fineness of the carbon fibers described in the present invention becomes very thick, for example, these are made into fine products with high quality and high efficiency. Being able to make a composite spun yarn is a versatile material, so its industrial implications are extremely high, and it is a significant cost reduction compared to a woven fabric made of expensive fine carbon fiber filament yarn. Becomes

When it is used as various composite materials, it exhibits excellent effects such as improvement of adhesion with matrix resin, improvement of substrate strength, and further improvement of reliability.

[Brief description of drawings]

FIG. 1 is an enlarged schematic view showing an example of a composite spun yarn of the present invention.

FIG. 2 is an enlarged schematic view showing another example of the composite spun yarn of the present invention.

FIG. 3 is an enlarged schematic view showing a spun yarn into which a conventional twist is inserted.

FIG. 4 is a process schematic diagram showing an example of a method for producing a composite spun yarn of the present invention.

[Explanation of symbols]

 1: Sliver 2: Continuous filament 3: Back roller 4: Apron roller 5: Front roller 6: Package in which continuous filament is wound 7: Take-up roller 8: Composite spun yarn of the present invention 9: Composite spun yarn of the present invention Winded package K: Fluff B: Package drive belt S: Hollow spindle F: Untwisted short fiber bundle (present invention) F ′: Twisted short fiber bundle (conventional)

[Procedure amendment]

[Submission date] October 28, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 4

[Correction method] Change

[Correction content]

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Claims (7)

[Claims] 1. A composite spun yarn in which a continuous filament is wound around an outer peripheral portion of a non-twisted short fiber bundle containing carbon fibers and / or glass fibers. 2. The composite spinning according to claim 1, wherein the Young's modulus of the continuous yarn is smaller than the smallest Young's modulus of the carbon fibers or glass fibers constituting the short fiber bundle. yarn. 3. The composite spun yarn according to claim 1 or 2, wherein the short fiber bundle is composed of short fibers having different fiber lengths. 4. The composite spun yarn according to claim 1, 2 or 3, wherein the single fiber fineness of the short fiber bundle is 20 denier or more. 5. A fiber containing carbon fiber and / or glass fiber is cut by a sawing method to form a sliver, and then the sliver is drafted to form a fleece having a desired thickness, and then mounted on a hollow spindle. A method for producing a composite spun yarn, characterized in that the continuous filamentous material is unwound and wound around the outer periphery of the fleece while rotating a package in which the continuous filamentous material is wound, and is then taken up. 6. The composite spun yarn according to claim 5, wherein when the continuous yarn is wound on the fleece, the fleece is fed at a feed rate of + 5.0% to −5.0%. Manufacturing method. 7. The winding coefficient K of the continuous yarn in the following formula is 25 to 500, wherein
A method for producing the composite spun yarn according to 1. T = K × (Nm) ^1/2 where T: number of windings of continuous yarn (T / m) Nm: metric number of composite spun yarn