JPH07292517A - Viscose rayon yarn - Google Patents

Abstract

(57) [Abstract] [Purpose] The heavy feel of conventional viscose rayon is eliminated, it is soft and warm, you can obtain the desired gloss, and it is excellent in dimensional stability against hot water, and it has excellent process wear. It is intended to provide a viscose rayon filament yarn having excellent morphological stability of a package without problems. A yarn made of viscose rayon containing hollow fine particles having a porosity of 20 to 60% and a specific gravity of 1.45 or less, wherein the side surface of the viscose rayon has a size of 2 μm.
A viscose rayon yarn having an average of 5 or more craters below and ridges 3 μm or less in size per 100 square μm in total.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a viscose rayon yarn which is lightweight, has a calm luster, and is soft and warm, and has improved dimensional stability against hot water and a package form. The present invention relates to a viscose rayon filament yarn that is excellent in stability and has no problem of process abrasion.

[0002]

2. Description of the Related Art Conventionally, viscose rayon has an excellent gloss,
It has been used for various clothing such as linings because it has moisture absorbing / releasing property and drape property, but it has been attempted to use viscose rayon especially for outerwear due to the recent variety of fashion. And, depending on the application, it is required to have a viscose rayon that has the characteristic luster that is suppressed, good moisture absorption and desorption is disliked as a cold feel, and good drapeability is also a little heavy. Therefore, there is a demand for a new rayon that has never existed before.

In an attempt to make the gloss of viscose rayon mild, 1 μm each is applied over the entire circumference of the fiber surface.
A viscose rayon having at least one minute streak on each side is proposed in Japanese Patent Laid-Open No. 2-191709.

As a method for reducing the weight of rayon, a carbonate is added to viscose to foam it into a hollow rayon (Japanese Patent Publication No. 26-939 and Japanese Patent Publication No. 28).
No. 1914, Japanese Patent Publication No. 28-2815, Japanese Patent Publication No. 31-1615, Japanese Patent Publication No. 31-9668, Japanese Patent Publication No. 34-8957), and small-sized air bubbles are uniformly dispersed in viscose. A method of spinning by using a spinning nozzle having a special shape is proposed (for example, JP-A-52-85511). ing.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the technique described in Japanese Patent Publication No. 9, it is possible to improve gloss suppression to some extent, but as a method for forming such minute streaks on the fiber surface, a normal pot-type spinning method cannot be adopted, and a special device is used. However, since it is necessary to adopt specific manufacturing conditions and to control the size and the number of streaks freely, as a result, there is a problem that the gloss cannot be made as desired. Furthermore, in such a method,
It has been impossible to reduce the weight of viscose rayon and impart softness to the obtained yarn.

Further, when hollow rayon is manufactured by the above-mentioned conventional method, although a hollow structure is formed for some time, it means that the hollow portion of the fiber is crushable and easily hollow until the final product such as clothes is reached. Had the problem of not being able to find. With such a technique, the gloss of the fiber cannot be made mild, and it is impossible to impart soft warmth.

The object of the present invention is to eliminate the heavy feeling of conventional viscose rayon, to provide a soft and warm feeling, to obtain a desired gloss, and to obtain a novel viscose having excellent dimensional stability against hot water. It is to provide course rayon yarn. Furthermore, the morphological stability of the package is excellent,
It also provides a viscose rayon filament yarn free from process wear problems.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present invention have diligently studied how a spinning dope should be, and as a result, spinning is carried out by adding specific hollow fine particles to viscose dope. Then, it was found that not only the weight of the fiber can be reduced, but also the obtained yarn can be soft and warm.

That is, the present invention has a porosity of 20 to 60%.
Of the viscose rayon containing the hollow fine particles of 1.45 or less in specific gravity, the craters having a size of 2 μm or less and the ridges having a size of 3 μm or less are added to the side surface of the viscose rayon. The viscose rayon yarn has an average number of 5 or more per 100 square μm.

In the present invention, it is essential that the hollow fine particles are added to the viscose rayon, and the hollow portions of the fine particles in the fiber are substantially voids. The hollow fine particles have a porosity of 20 to 60%,
The void is not crushed from the fiberization to the final product, and is not particularly limited as long as it is relatively stable to alkali and acid, but substantially spherical particles from the viewpoint that the void is difficult to crush. Is preferred. Further, if the hardness of the fine particles is high, the fine particles exposed on the fiber surface may cause a problem of process abrasion. Therefore, it is preferable to use organic polymer fine particles. Further, the polymer may be a thermoplastic polymer or a polymer stable to heat.

The porosity in the present invention is a percentage of the apparent volume of voids with respect to the apparent volume of hollow fine particles containing voids. This measurement can be determined from the outer diameter of the particles and the diameter of the void by taking an enlarged photograph of the cross section of the fine particles.

When the porosity of the hollow fine particles is less than 20%, weight reduction cannot be sufficiently achieved, and the effect of imparting warmth may not be sufficient, and the production of such fine particles is difficult, so that they are not preferably used. On the other hand, the porosity is 60
If it exceeds%, the shell constituting the fine particles becomes thin, so that the voids are likely to be crushed and it is difficult to contribute to weight reduction. Therefore, the lower limit of the porosity of the hollow fine particles used in the present invention is preferably 30%, and the upper limit thereof is preferably 55%.

The fine particles are added to the viscose rayon so that the specific gravity of the viscose rayon can finally be 1.45 or less, preferably 1.4 or less.
It may be selected according to the specific gravity of the fine particles and the porosity thereof.
And, in the present invention, it is possible to achieve a weight reduction of 10% or more as compared with a normal rayon yarn. Here, the weight reduction rate is represented by the formula of (cross-section fineness / weight fineness × 100) -100, and the weight fineness indicates g weight fineness per 9000 m (true weight fineness), and the cross-sectional fineness is
From the cross-sectional area (S ′) of the yarn to which the hollow fine particles are added to the cross-sectional area (S) of the predetermined weight fineness (D) of the yarn obtained using viscose to which the hollow fine particles are not added, Is a fineness (D ': apparent weight fineness) obtained by performing a proportional calculation on. D ′ = D × (S ′ / S) In the present invention, it is preferable to use hollow fine particles having a dry density of 0.6 g / cc or less in order to effectively reduce the weight. Here, the dry density is measured under the conditions of 20 ° C. and 60% RH. Further, the lower limit of the specific gravity of the viscose rayon yarn of the present invention is preferably 1.3 or more in consideration of the deterioration of the fiber physical properties.

The average size of the hollow fine particles is preferably 0.1 μm to 2 μm. If the particle size is too small, the fine particles are likely to cause secondary aggregation, and it is difficult to uniformly disperse the particles in the fiber, and the spinning stability is likely to be impaired. Furthermore, it may be difficult to form desired craters or ridges on the fiber surface, and it may be difficult to impart sufficient softness and warmth to the yarn. On the other hand, if the particle size is too large, yarn breakage or the like is likely to occur and spinning stability tends to be poor, and the physical properties of the fiber are significantly deteriorated, which is not practical. Therefore, the more preferable lower limit value of the average particle diameter of the hollow fine particles is 0.2 μm, and the further preferable upper limit value thereof is 1.6 μm.

The hollow fine particles used in the present invention are:
It can be produced by various methods. For example, as proposed in JP-A-56-32513, volatile polymer particles composed of an alkali-soluble core part and a shell part covering it are volatile. It is impregnated with alkali to swell and expand the core to form a hollow structure.
As described in JP-A-62510, a method for producing hollow fine particles by polymerizing a monomer mixture having a solubility parameter different by 0.1 or more in the presence of predetermined polymer fine particles, Also, JP-A-62-127
As described in Japanese Patent No. 336, a polymer containing a solvent is utilized by polymerizing a monomer mixture in the presence of a non-polymerizable solvent, whereby the solvent is phase-separated into polymer fine particles. A method of forming hollow particles by forming coalescing particles and then distilling off the solvent is known.

These fine particles are commercially available from various companies. For example, hollow fine particles of styrene-acrylic copolymer are preferable, and such fine particles are Rhopaque HP-91, OP-62, OP of Rohm and Haas. -8
4 or the like can be used.

The present invention is characterized by the fact that the weight reduction of viscose rayon containing such hollow fine particles is achieved, and at the same time, a special structure is formed on the side surface of the fiber. That is, on the side surface of the viscose rayon, it is important that there are a total of 5 or more craters having a size of 2 μm or less and ridges having a size of 3 μm or less per 100 square μm on average.

Here, as shown in the photograph of FIG. 1, the crater is observed as a depression on the side surface of the fiber, and is a substantially circular shape or a substantial shape formed as a drop mark when the hollow fine particles fall off the side surface of the fiber. It refers to an oval shape or a hollow that is partially buried in the fiber side surface and a hollow formed in the fiber axis direction due to partial separation of viscose rayon, and the size of the crater is 2
It is important to be less than μm. The size referred to here means the diameter of the crater when it is circular, and the minor diameter when it is elliptical or oval. For other shapes, the diameter of the circumscribed circle drawn from that shape is used.
If the size of the crater exceeds 2 μm, inconvenience such as fibril formation tends to occur from that portion, and conversely if it is too small, the effect of improving gloss cannot be sufficiently achieved. Therefore, it is preferably 1.5 μm or less and 0.2 μm or more. It is desirable to use a crater of the size.

On the other hand, the ridge means a structure formed by hollow fine particles partially embedded in the side surface of the fiber, and it is important that the size is 3 μm or less. The protrusions exceeding 3 μm are likely to fall off, and conversely, if they are too small, the effect of improving the gloss cannot be sufficiently achieved.

In the present invention, craters and ridges which do not correspond to the above size may be present, but on the side surface of the viscose rayon of the present invention, a total of 100 craters and ridges of the above size are present. It is necessary that there be an average of 5 or more per square μm. The number can be determined, for example, by observing the side surface of the enlarged fiber with an electron microscope. Where the average value is
It is an average of the results obtained by observing at least 10 side surfaces. When there are less than 5 yarns on average, the softness and warmth of the yarn cannot be sufficiently satisfied. Also, in terms of suppressing gloss, sufficient effect cannot be achieved. Further, by increasing the amount of the hollow fine particles added, the number of such structures per unit area can be increased, but if the amount is too large, the effect on the softness and gloss will reach a ceiling, and the physical properties of the fiber will deteriorate significantly.

Further, the viscose rayon yarn of the present invention has a unique uneven shape formed on the fiber side surface as described above, and has a high static friction coefficient (fiber-fiber) of about 0.32 or more. Therefore, the stability of the winding form is superior to the conventional rayon yarn package, while the static friction coefficient (fiber-metal) is about 0.28 or less, which is lower than that of the additive-free yarn (about 0.32). Therefore, for example, it has an excellent feature that there is little problem of pin wear during false twisting (boundary lubrication). Further, since the coefficient of dynamic friction (fiber-metal) is about 0.33 or less, which is lower than that of the additive-free yarn (about 0.5), there is almost no problem of wear in the working process at a normal working speed. It is a thing. Despite the unevenness formed on the side surface of the fiber, there is almost no problem of abrasion, which means that a fiber to which a large amount of fine particles such as matting material is added generally has a problem of process abrasion. It is unpredictable from conventional wisdom.

In the present invention, the craters and ridges present on the side surface of the fiber achieve various useful effects of imparting softness and warmth to the yarn and stabilizing the winding form of the package. And for that reason, the total of craters and ridges is 100 square μm.
The average number is preferably 9 or more and 100 or less, and particularly preferably 9 or more and 60 or less.

Further, in the present invention, a large number of hollow fine particles are present inside the fiber, and a tensile force acts in the fiber axis direction in the fiberizing process, so that the fine particles and the fiber matrix are partially interfacially separated. Voids (voids) are formed around the fine particles in the fiber axis direction. Since the voids formed at this time are present in the fiber, the yarn of the present invention has a synergistic weight-reducing effect of further weight reduction.

Although the reason why the yarn of the present invention exhibits softness and warmth is not clear, when the viscose rayon exists as an aggregate like multifilament, the ridges on the side surface of each fiber are the same as those of the single fiber. Prevent surface contact,
It is speculated that the soft feel and warmth of the yarn are achieved by increasing the space between the fibers. In particular,
As for the softness of the yarn of the present invention, the viscose rayon yarn having a special side structure has a Young's modulus lower by 10% or more than the Young's modulus of normal viscose rayon (strength at 5% elongation). What is done is also synergistic.

Further, in the present invention, the weight reduction rate is 1
By adding a large amount of hollow fine particles so as to exceed 0%, the boiling water shrinkage of the obtained yarn can be reduced to 1/2 or less as compared with the yarn without addition, for example, 1% for cake yarn. Below, especially below 0.6%, 4% in continuous spinning
The following is a great feature in that the content can be made particularly 3% or less and the dimensional stability against hot water is improved.

Furthermore, the viscose rayon yarn of the present invention is also characteristic in terms of whiteness and glossiness, whereas the ordinary rayon bright yarn has a whiteness of around 75 and a semi-dull yarn of around 85. The yarn of the present invention has a mild whiteness of about 76 to 80. Regarding the glossiness, ordinary rayon bright yarns have 6 to
On the other hand, the yarn of the present invention exhibits a glossiness close to that of a semi-dal yarn. These values are the values for the cake yarn, but the same tendency is observed in the continuous spun yarn, whereas the whiteness of the conventional bright continuous spun yarn is around 60, and the semi-dal yarn is around 75. 65-
It exhibits a whiteness of about 70.

Next, a method for manufacturing the yarn of the present invention will be described. The viscose used in the present invention may have a conventionally known composition. The hollow fine particles can be added in a predetermined amount at any time before spinning the viscose dope from the spinneret, but in order to make the dispersion of the hollow fine particles uniform, it is preferable to add the fine particles in a powder state. The fine particles are preferably added in the form of a slurry in which they are dispersed in a dispersion medium. The viscosity of the dope after adding the slurry is preferably about 30 to 50 poise at 20 ° C. from the viewpoint of spinnability.

The dispersion medium is preferably an aqueous solution, and may contain a surfactant or the like so that the fine particles are uniformly and stably present in the slurry. The viscosity of the slurry is preferably equal to or lower than that of the viscose to be added, from the viewpoint of uniform kneading property. When a slurry having a viscosity higher than that of viscose is used, it is difficult to uniformly disperse the slurry, spinning stability is deteriorated, and physical properties of the obtained fiber are increased. In order to obtain a suitable viscosity, the slurry concentration depends on the type of the dispersion medium used and the like, but the slurry concentration is 10 to 50% by weight in terms of fine particle solid content, and particularly 20
It is preferably about 35% by weight.

The spinning stock solution thus prepared can be spun into a conventionally known coagulation bath from a spinning nozzle and can be made into fibers according to a conventional method, and any spinning method of a pot type spinning method and a continuous spinning method can be used. It can also be applied to methods. The shape of the nozzle at this time may be circular or may be a nozzle for a modified cross section such as a dog bone. When nozzle clogging occurs, it is preferable to make the cross section of the nozzle elliptical or oval because stable spinning can be performed. The technique of the present invention can also be applied to the manufacture of soufu.

The viscose rayon yarn of the present invention thus obtained has a filament denier of from 30 to 30.
The filament structure can be selected from 600 denier and 10 to 100 filaments according to the purpose. Moreover, the preferable single fiber fineness is 1.5 to 30.
It is denier. Further, the yarn may be used alone or in combination with other materials such as polyester to give various yarn forms. In the present invention, such a yarn can be woven or knitted by a known method, and a lightweight, soft, warm rayon woven or knitted fabric that could never be achieved by conventional rayon can be obtained. It is possible to develop a wide range of rayon applications from innerwear to outerwear.

[0031]

EXAMPLES The present invention will be described below with reference to specific examples.
The present invention is not limited to these. Also,
Specific gravity, whiteness, glossiness, and friction coefficient are values obtained by the following methods.

Measuring method of specific gravity: The yarn sample is hung on the hook of the balance, and its weight is W. Then, the weight when the yarn sample is completely immersed in the beaker containing benzene placed on the table is W '. When the specific gravity of benzene at the temperature at the time of measurement is d, the specific gravity of the sample yarn is expressed by d × W / (W−W ′).

Whiteness: JIS L 1013 7.20
It is represented by the reflectance measured by the whiteness (D method).

Glossiness: A thread is wound around the panel a predetermined number of times. The reflectance in the yarn direction and the reflectance in the direction perpendicular to the yarn are measured by the same method as the above-mentioned method of measuring whiteness. It is expressed by the reflectance obtained by subtracting the reflectance Rb in the perpendicular direction from the reflectance Ra in the yarn direction. The larger the difference, the greater the glossiness.

Friction coefficient: The initial load is 6 according to the radar method.
20 mg / dr, dynamic friction coefficient measurement rotation speed is 720 times /
The static friction coefficient measurement load speed was 50 mg / sec, and the twisting bobbin winding load for fiber-fiber measurement was 20 g.

Example 1 Styrene having a porosity of 50% and a dry density of 0.55 g / cm ↑ 3 was added to viscose (cellulose 8%, alkali 6%) prepared by a conventional method using a high-speed stirrer at 980 rpm. -Aqueous slurry of hollow fine particles made of acrylic copolymer and having an average particle size of 1 μm (Rhopaque HP91: manufactured by Rohm and Haas Co., hollow fine particle dispersion concentration; about 30 w
(t%) was mixed and left for 24 hours for defoaming. At this time, the addition of hollow fine particles to viscose was 1
It is 2.5 wt%.

Next, using this hollow fine particle-containing viscose, a coagulation regeneration bath (H ↓ 2SO ↓ 4: 155 g / l, ZnSO ↓) was formed from a spinneret having a hole shape of 0.07 mm × 40 holes.
4:22 g / l, Na ↓ 2SO ↓ 4: 250 g / l, bath temperature 60 ° C.) at a discharge rate of 13 cc / min, and spinning, scouring, by a conventionally known continuous spinning method at a spinning speed of 150 m / min. The dried viscose rayon yarn was manufactured.
The wound yarn package maintained a very stable morphology.

The obtained yarn has a weight fineness of 85.0 denier and a cross-sectional fineness of 95.2 denier, and the weight reduction rate expressed by (cross-sectional fineness / weight fineness × 100) -100 is 1.
It was 2%. The specific gravity of the yarn is 1.44, the dry strength is 1.45 g / d, and the Young's modulus (strength at 5% elongation) is 0.98.
g / d (Young's modulus decrease rate relative to additive-free 15%),
The boiling water shrinkage rate is 2.3%, and the static friction coefficient μs (thread-thread) is 0.
32, dynamic friction coefficient μd (thread-thread) 0.26, static friction coefficient μs (thread-metal) 0.27, dynamic friction coefficient μd (thread-thread)
(Metal) was 0.32, and the reflectance (whiteness) at 480 nm was about 76. In addition, the difference (glossiness) between the reflectance in the longitudinal direction and the reflectance in the lateral direction measured by winding the thread around the panel is 1.3.
And showed a calm luster.

The fiber side surface of this yarn was magnified 7500 times with an electron microscope to observe craters and ridges. As a result, oval craters and ridges were observed along the fiber axis direction on the side surface, with a minor axis of 0.5 μm and a major axis of 1.8.
There were an average of 2 μm craters per 100 square μm and an average of 11 ridges having a size of about 1.5 μm per 100 square μm, and a total of 13 averages per 100 square μm.

The yarn obtained here is used for warp and weft,
When a back satin was made and a panel test was conducted by 10 people, it was evaluated that all were soft and warm. In addition, I was able to feel a considerably lighter weight than the conventional rayon fabric.

Example 2 Example 1 was repeated except that the spinning method was a centrifugal pot type (spinning speed: 115 m / min), the addition rate of hollow fine particles was 11.8 wt%, and the discharge rate was 14.3 cc / min. A viscose rayon yarn was obtained in the same manner as above, and various measurements and observations of the fiber side surface were performed.

As a result, the package in which the cake is wound on the corn maintains an extremely stable form, and the obtained yarn has a weight fineness of 125.1 denier and a cross-sectional fineness of 1
It was 45.5 denier and the weight reduction rate was 16%.
The specific gravity of the yarn is 1.45, the dry strength is 1.41 g / d,
Young's modulus (strength at 5% elongation) 0.70 g / d (Young's modulus decrease rate 18% with respect to additive-free), boiling water shrinkage rate 0.5
%, Static friction coefficient μs (thread-thread) is 0.32, dynamic friction coefficient μd (thread-thread) is 0.26, static friction coefficient μs (thread-metal) is 0.27, dynamic friction coefficient μd (thread-metal) is 0.3
1, and the reflectance (whiteness) at 480 nm was about 75. The difference (glossiness) between the reflectance in the longitudinal direction and the reflectance in the lateral direction, which was measured by winding the yarn around the panel, was 1.3, showing a calm gloss.

The fiber side surface of this yarn was magnified 7500 times with an electron microscope, and craters and ridges were observed. As a result, oval craters and ridges were observed along the fiber axis direction on the side surface, with a minor axis of about 0.5 μm and a major axis of 1.
The average number of craters of 8 μm was 1 per 100 μm 2. In addition, there are 10 ridges with a size of about 1.5 μm.
There was an average of 8 observations per 0 square μm, and a total of 9 observations per 100 square μm.

The yarn obtained here is used for warp and weft,
When tricotine was prepared and a panel test was conducted by 10 people, it was evaluated that all were soft and warm. In addition, I was able to feel a considerably lighter weight than the conventional rayon fabric.

Example 3 A spinning pot method was adopted, and the addition rate of hollow fine particles was 2
2.5 wt%, discharge amount 16.3 cc / min, filament count 50 filaments
A viscose rayon yarn was obtained in the same manner as in Example 1, and various measurements and observation of the fiber side surface were performed.

As a result, the package in which the cake was wound on the corn maintained an extremely stable form, and the obtained yarn had a weight fineness of 230.3 denier and a cross-sectional fineness of 2
It was 90.3 denier and the weight reduction ratio was 26%.
Also, the specific gravity of the yarn obtained is 1.39,
Dry strength 1.11 g / d, Young's modulus (strength at 5% elongation)
0.60 g / d (Young's modulus decrease rate 3 with no additive)
0%), boiling water shrinkage 0.1%, static friction coefficient μs (thread-
(Thread) 0.35, dynamic friction coefficient μd (thread-thread) 0.3
The coefficient of static friction μs (thread-metal) was 0.23, the coefficient of dynamic friction μd (thread-metal) was 0.29, and the reflectance (whiteness) at 480 nm was about 79. Further, the difference (glossiness) between the reflectance in the longitudinal direction and the reflectance in the lateral direction measured by winding the yarn around the panel was 0.8, showing a calm gloss.

The fiber side surface of this yarn was magnified 7500 times with an electron microscope and craters and ridges were observed. As a result, oval craters and ridges were observed along the fiber axis direction on the side surface, with a minor axis of about 0.5 μm and a major axis of 1.
An average of 7 craters of 8 μm per 100 square μm,
In addition, a ridge with a size of about 1.5 μm is 100 square μ.
An average of 28 per m was observed, and an average of 35 per 100 square μm was present.

A sweater was knitted using the yarn obtained here, and a panel test of the texture by 10 people was conducted.
Everyone rated it soft and warm. Also, I was able to feel the lightness that cannot be imagined from the conventional rayon knitting.

Example 4 As hollow fine particles, the porosity was 26% and the dry density was 0.85 g.
/ Cm ↑ 3, styrene-acrylic copolymer fine particles having an average particle diameter of 0.55 μm (Rhopaque OP84: manufactured by Rohm and Haas Co., Ltd.) were used, the addition ratio to cellulose was 20 wt%, and the discharge amount was 15. 1cc / min, except that the filament count is 40 filaments,
A viscose rayon yarn was obtained in the same manner as in Example 2, and various measurements and fiber side surfaces were observed.

As a result, the package in which the cake was wound on the corn maintained an extremely stable form, and the obtained yarn had a weight fineness of 130.9 denier and a cross-section fineness of 1
It was 45.3 denier, and the weight reduction rate was 11%.
In addition, the specific gravity of the yarn is 1.45,
Dry strength 1.33 g / d, Young's modulus (strength at 5% elongation)
0.66 g / d (Young's modulus decrease rate 7 with no additive)
8%), boiling water shrinkage 0.2%, static friction coefficient μs (thread-
(Thread) is 0.34, dynamic friction coefficient μd (thread-thread) is 0.2
4, the coefficient of static friction μs (thread-metal) was 0.25, the coefficient of dynamic friction μd (thread-metal) was 0.29, and the reflectance (whiteness) at 480 nm was about 78. The difference (glossiness) between the reflectance in the longitudinal direction and the reflectance in the lateral direction, which was measured by winding the yarn around the panel, was 1.8, showing a calm gloss.

The fiber side surface of this yarn was magnified 7500 times with an electron microscope, and craters and ridges were observed. As a result, the minor axis is 0.8 along the fiber axis direction on the side surface.
An average of 13 oval craters having a diameter of 1.2 μm and a diameter of 1.2 μm were observed per 100 square μm. In addition, 42 ridges having a size of about 0.6 μm were observed on average per 100 square μm, and there were 55 ridges in total.

A sweater was knitted using the yarn obtained here, and a panel test of the texture by 10 people was carried out.
Everyone rated it soft and warm. Also, I was able to feel the lightness that cannot be imagined from the conventional rayon knitting.

Comparative Example 1 A viscose rayon yarn was produced in the same manner as in Example 2 except that hollow fine particles were not added and the discharge rate was 17.0 cc / min.

As a result, the package in which the cake was wound on the cone was more likely to lose its package form than the yarn package of the present invention. The obtained yarn had a weight fineness of 145.1 denier. Also, the specific gravity of the yarn obtained was 1.49, and the dry strength was 1.83 g /
d, Young's modulus (strength at 5% elongation) 0.85 g / d, boiling water shrinkage 2.3%, static friction coefficient μs (thread-thread) is 0.3.
1, the coefficient of dynamic friction μd (thread-thread) is 0.25, the coefficient of static friction μs (thread-metal) is 0.32, the coefficient of dynamic friction μd (thread-metal) is 0.49, and the reflectance of 480 nm (whiteness )
Was about 75. Further, the difference (reflectance) between the reflectance in the longitudinal direction and the reflectance in the lateral direction measured by winding the yarn around the panel was 6.5, and the gloss was strong.

Further, the fiber side surface of this yarn was magnified 7500 times with an electron microscope and the side surface was observed, but no craters and ridges were observed.

Comparative Example 2 Hollow fine particles having a porosity of 12% and a dry density of 0.95 g
/ Cm ↑ 3, styrene-acrylic copolymer fine particles having an average particle size of 0.55 μm are used, the addition rate to cellulose is 20 wt%, the discharge rate is 15.8 cc / min, and the filament count is 40 filaments. Except for the above, a viscose rayon yarn was obtained in the same manner as in Example 2, and various measurements and observation of the fiber side surface were performed.

As a result, the package in which the cake was wound on the corn maintained an extremely stable form, and the obtained yarn had a weight fineness of 136.1 denier and a cross-sectional fineness of 1
It was 45.2 denier, and the weight reduction rate was 7%. Further, the specific gravity of the yarn obtained was 1.47, which did not achieve the target of the present invention. Also, the dry strength is 1.3
1 g / d, Young's modulus (strength at 5% elongation) 0.65 g / d
(Young's modulus decrease rate to additive-free 76%), boiling water shrinkage 0.2%, static friction coefficient μs (thread-thread) is 0.35,
Dynamic friction coefficient μd (thread-thread) is 0.25, static friction coefficient μs
(Thread-metal) is 0.24, dynamic friction coefficient μd (thread-metal)
Was 0.28, and the reflectance (whiteness) at 480 nm was about 78. The difference (glossiness) between the reflectance in the longitudinal direction and the reflectance in the lateral direction, which was measured by winding the yarn around the panel, was 1.8.

Further, the fiber side surface of this yarn was magnified 7500 times with an electron microscope, and craters and ridges were observed. As a result, the minor axis is 0.8 along the fiber axis direction on the side surface.
An average of 10 craters having an elliptical shape with a diameter of 1.2 μm and a diameter of 1.2 μm was observed per 100 square μm. Further, an average of 48 ridges having a size of about 0.6 μm were observed per 100 square μm, and a total of 58 ridges were present.

A sweater was knitted using the yarn obtained here, and a panel test of the texture by 10 people was conducted.
Two people rated it soft and warm, while others rated it
It was evaluated that the difference from the conventional rayon knitted fabric was not clear and that the lightness of the product of the present invention was not felt.

[Brief description of drawings]

FIG. 1 is a photograph showing the shape of a fiber obtained by enlarging the fiber side surface of a viscose rayon yarn of the present invention with an electron microscope.

[Explanation of symbols]

 1: Crater 2: Uplift

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Osamu Takemura, 12-13 Umeda, Kita-ku, Osaka City, Kuraray Co., Ltd. (72) Junji Ohkita, 7471 Tamajima Otoshima, Kurashiki City, Kuraray Co., Ltd.

Claims (1)

[Claims] 1. A yarn comprising viscose rayon containing hollow fine particles having a porosity of 20 to 60% and having a specific gravity of 1.45 or less, the size of which is 2 on a side surface of the viscose rayon.
A viscose rayon yarn having an average of 5 or more craters having a size of 3 μm or less and protrusions having a size of 3 μm or less per 100 square μm.