JPH11181627A - Polyester conjugated staple fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester conjugated staple fiber excellent in spinning properties, opacity and heat shielding properties. SOLUTION: This conjugated staple fiber comprises two or more kinds of polyesters different in content of a white pigment and has 1-5 denier fineness of single fiber. In this case, the content of the white pigment is >=1.5 wt.% and <=10.0 wt.% in the polyester containing the maximum amount thereof and that of the white pigment is <=0.5 wt.% in the polyester containing the minimum amount thereof. The two or more kinds of polyesters are regulated so that the polyester containing the maximum amount of the white pigment accounts for 25-75% of the fiber cross-sectional area and the polyester containing the minimum amount of the white pigment accounts for >=80% of the fiber surface area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester conjugate short fiber having excellent spinnability, opacity and heat shielding properties.

[0002]

2. Description of the Related Art Polyester is a transparent polymer by nature, and there is a drawback that clothes and nonwoven fabrics using fibers made of only the polymer are transparent.

[0003] Therefore, as a general industrial technique, a white pigment is blended with polyester in order to adjust the transmittance of light and heat to form a fiber. If you want enough light and heat shielding, and especially if you want a distinct whiteness for clothing,
It is industrially performed to contain a large amount of a white pigment. In this case, sufficient opacity, heat shielding property, and whiteness can be obtained. Per production cost increases, and since there are many white pigments on the fiber surface, when spinning staple fibers containing a large amount of white pigment, due to changes in the friction characteristics in the spinning process, Various troubles such as falling off and winding are liable to occur, causing a serious problem of poor process passing. That is, spinnability is reduced, and cost increases due to loss of production opportunities.

Japanese Patent Publication No. Sho 63-17926 discloses that a long fiber contains a large amount of titanium oxide in the core portion of a fiber having a core-sheath structure in order to achieve both the opacity of the fiber and the reduction of friction in the spinning process. It is proposed to reduce the titanium oxide content of the sheath portion, but even if it is attempted to apply the method described therein to short fibers as it is,
When producing a polyester short fiber, a special crimping method must be adopted from the poor buckling seen in the case of a large white content in the step of imparting crimp, which is indispensable in the production of polyester short fibers. Did not.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester conjugate short fiber which can solve the above problem of spinnability while maintaining sufficient opacity and heat shielding properties.

[0006]

The present invention has the following structure to solve the above-mentioned problems. That is, in the case of a conjugate fiber having a single fiber fineness of 1 to 5 deniers composed of two or more polyesters having different white pigment contents, the polyester containing the largest amount of white pigment has the white pigment content. In the polyester having an amount of 1.5% by weight or more and 10.0% by weight or less and containing the least amount of white pigment, the content of the white pigment is 0.5% by weight or less and A polyester conjugate short fiber characterized in that the polyester containing a large amount accounts for 25% to 75% of the fiber cross-sectional area, and the polyester containing the least white pigment occupies 80% or more of the fiber surface area. .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The main component of the polyester used in the present invention is one prepared from terephthalic acid or an ester-forming derivative thereof and polyalkylene glycol, preferably polyethylene terephthalate. When producing fibers, it is usually 0.4 to 0.7. In addition, an organic substance such as an antistatic agent, a heat-resistance imparting agent, or a dye may be added to the polyester, as required, in addition to the white pigment described below.

In the present invention, at least two kinds of polyesters having different white pigment contents are used. As the white pigment, for example, titanium oxide, zinc white, aluminum oxide, zirconium oxide, magnesium oxide, calcium oxide, and the like are used. Titanium oxide is most preferably used in terms of cost, light, and heat shielding performance. Also,
The white pigments contained in two or more kinds of polyesters may be the same kind or different.

In the polyester composite staple fiber of the present invention, in the polyester having the highest white pigment content, the white pigment content should be 1.5% by weight or more and 10% by weight in order to impart sufficient light and heat shielding properties. % Or less, preferably 2.
It is required to be 0% by weight or more and 8.0% by weight or less, and the area ratio of the polyester to the fiber cross section should be 25% or more and 75% or less, preferably 35% or more and 70% or less. If the proportion of the polyester having the largest white pigment content in the cross section of the fiber is less than 25%, sufficient light / heat shielding properties cannot be obtained. Unlike in the case of long fibers, short fibers in which single fibers are twisted into a spun yarn can impart sufficient heat and light shielding properties to the obtained woven fabric with a smaller cross-sectional occupancy.

Here, the following equation holds for the relationship between cotton count and fineness.

Cotton count = 5314.88 / fineness Therefore, when a 40th spun yarn is manufactured from short fibers having a single fineness of 1.5 denier, about 90 single fibers occupy the cross section of the spun yarn. become. Therefore, a spun yarn in which a large number of short fibers having a proportion of 25% or more and 75% or less in the cross-section of the polyester having the highest white content than the long fibers is twisted is a short yarn from the simple polyester having the highest white content. It is no different from a spun yarn obtained from fibers.
On the other hand, when the proportion of the polyester having the largest content of white pigment in the cross section of the fiber is more than 75%, the white pigment is contained in an amount of 1.5% by weight or more in the crimping step which is a feature of the short fiber spinning step. When crimping is performed on a single polyester fiber, poor buckling occurs, and a special crimping method is required, which leads to an increase in cost and cannot be adopted.

Furthermore, when the area ratio of the polyester having the largest amount of white pigment on the fiber surface exceeds 20%, the spinnability is remarkably deteriorated.

In the polyester having the largest amount of white pigment, if the content of the white pigment exceeds 10% by weight,
Since the light and heat shielding performance reaches saturation, not only is it disadvantageous in terms of cost, but also clogging of the filter medium due to the large amount of white pigment occurs, and stable spinning cannot be performed.
If the content is less than 1.5% by weight, sufficient light and heat shielding performance cannot be obtained.

On the other hand, the white pigment content of the polyester having the smallest white pigment content must be 0.5% by weight or less in order to improve spinnability.

In the fiber of the present invention, the single fiber fineness is
If it is greater than 5 denier, it will give a rough feeling to clothing, etc. If it is less than 1 denier, it is difficult to produce an industrially stable composite spinning, and special spinning of short fibers is required. It is not versatile because it requires sophisticated spinning technology and machinery.

The fiber cross-section composite structure shown in FIGS. 1 (a) to 1 (d) relates to the present invention. FIG. 1 (a), (d)
Is a composite fiber having a substantially concentric core and sheath, and FIG.
(B) is a substantially radial composite fiber, and FIG.
(C) is a substantially concentric core-sheath hollow composite fiber. In short fibers having a fiber cross-section composite structure as shown in FIGS. 1 (a) to 1 (d), the polyester having the largest amount of white pigment accounts for 25% to 75% of the fiber cross section, and has the highest white pigment content. Less polyester 80% of fiber surface area
The spinning ability that is aimed at by making the above composite structure,
Opaque and heat shielding properties can be obtained.

The fiber aggregate made of the fiber of the present invention, so-called raw cotton, is used as a spun yarn. The spun yarn is used as a woven or knitted fabric, or needle punched into a non-woven fabric to be used as a fabric. Such fabrics are usually used for clothing and vehicle interiors, but are suitable for fields where light shielding is strongly desired, such as thin shirts and linings that require softness and drapability. Preferred uses include various types of clothing such as sportswear and underwear. In such a fabric, the fiber of the present invention is used for 50 times.
By being present in an amount of at least 60% by weight, preferably at least 60% by weight, more preferably at least 65% by weight, and even more preferably at least 70% by weight, the opacity and heat shielding properties of the fabric can be made particularly excellent. .

[0019]

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

The evaluation method employed in this embodiment is as follows.

[Spinnability] The weight dropped per unit length in the drawing step and the roving step (metal part and comb part) in the spinning step of the short fiber and the low per unit length in the drawing step. The number of times the wire was wound around was determined based on the criteria shown in Table 1.

[0022]

[Table 1] Here, HK means a passage length of 764 m (840 yards).

[Light shielding property] Using an automatic goniophotometer GP-1 (manufactured by Murakami Color Research Laboratory Co., Ltd.), the light from the light source was installed under the following conditions so that the woven fabric sample was blocked. Then, the intensity (%) of light passing through the sample was measured.

Angle between light source and light receiver: 180 ° Neutral filter: ND-1 used Scale: 100% when there is no sample (air). [Heat Shielding Property] A white light bulb of a photographic reflex lamp 300W was used as an energy source under the air of 20 ° C. and 65% RH. A temperature sensor (thermocouple) was installed below the woven fabric sample, and the reflex lamp was turned on from above the sample by 25 cm, and the sample surface temperature after 15 minutes was measured.

[Intrinsic Viscosity of Polyester] This is a value obtained by dissolving a dried polymer sample in an orthochlorophenol solvent and measuring it at 25 ° C. with an Ostwald viscometer.

Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.64 was used as a polyester, and a white pigment containing 0.40% by weight of titanium oxide with respect to the polymer was used as a sheath portion. Viscosity 0.
65 polyethylene terephthalate containing 2.2% by weight of titanium oxide as a white pigment is used as a core, and the discharge amount of the core and the sheath is set at a volume ratio of 70 to 30, and the spinning speed is 1000 m / m. min. To obtain an undrawn yarn. Then, after stretching is performed at a natural stretching ratio in a 90 ° C. bath solution, it is passed through a stuffer box to impart crimp necessary for spinning short fibers, and subjected to a relaxation heat treatment at 90 ° C. with a cutter. A core-sheath composite short fiber as shown in FIG. 1A having a fiber length of 38 mm and a short fiber fineness of 1.5 denier was obtained.

Using the obtained short fibers, a spun yarn of 40 cotton count is obtained through a normal spinning process such as roving and spinning, and is subjected to a normal weaving process such as winding, gluing and warping to obtain a plain woven fabric. I got Table 2 shows the spinnability of the short fibers and the light shielding and heat shielding properties of the obtained woven fabric.

Example 2 A core / sheath composite short fiber was obtained in the same manner as in Example 1 except that the content of titanium oxide in the core polyester was changed to 6.5% by weight. A woven fabric was obtained from the obtained short fibers in the same manner as in Example 1. Table 2 shows the spinnability of the short fibers and the light shielding and heat shielding properties of the obtained woven fabric.
Shown in

Example 3 Polyethylene terephthalate having an intrinsic viscosity of 0.64 was used as the polyester, and titanium oxide was contained as a white pigment in an amount of 0.05% by weight based on the polymer. A 0.65% polyethylene terephthalate containing 3.0% by weight of titanium oxide as a white pigment is used as a dividing wall, and the spinning speed is 1200 m at a volume ratio of 25 to 75 at the dividing portion and the dividing wall. / Min. To obtain an undrawn yarn. Then, after stretching was performed at a natural stretching ratio in a bath solution of 90 ° C., it was passed through a stuffer box in order to impart crimp necessary for spinning of short fibers, and then heated at 90 ° C.
The heat treatment was carried out to obtain a radial composite short fiber having a denier of 2 deniers as shown in FIG. 1 (b).

The proportion of titanium oxide containing 3.0% by weight on the fiber surface was 15%. A woven fabric was obtained from the obtained short fibers in the same manner as in Example 1. Table 2 shows the spinnability of the short fibers and the light shielding and heat shielding properties of the obtained woven fabric.

(Example 4) Polyethylene terephthalate having an intrinsic viscosity of 0.54 was used as the polyester, and a titanium oxide containing 8.0% by weight of the polymer as a white pigment was used as the core portion. Viscosity 0.
55 of polyethylene terephthalate containing 0.45% by weight of titanium oxide as a white pigment was used as a sheath portion, and the discharge amount of the core portion and the sheath portion was set at a spinning speed of 1200 m / min. To obtain an undrawn yarn. Then, after stretching is performed at a natural stretching ratio in a 90 ° C. bath solution, it is passed through a stuffer box to impart crimp necessary for spinning short fibers, and subjected to a relaxation heat treatment at 90 ° C. with a cutter. A hollow core-sheath composite short fiber as shown in FIG. 1C having a fiber length of 51 mm and a single fiber fineness of 3 denier was obtained. A woven fabric was obtained from the obtained short fibers in the same manner as in Example 1. Table 2 shows the spinnability of the short fibers and the light shielding and heat shielding properties of the obtained woven fabric.

Example 5 Polybutylene terephthalate was used as a polyester, and titanium oxide was contained as a white pigment in an amount of 0.05% by weight based on the weight of the polymer. The innermost portion is made of polyethylene terephthalate containing 9.7% by weight of titanium oxide as a white pigment, polyethylene terephthalate having an intrinsic viscosity of 0.64 as polyester, and aluminum oxide as a white pigment. An intermediate layer containing 0.30% by weight of the polymer was used.

The discharge rate of the innermost part, the intermediate layer and the sheath part is set at a spinning speed of 900 m / min. To obtain an undrawn yarn. Then, after stretching is performed at a natural stretching ratio in a 90 ° C. bath solution, it is passed through a stuffer box to impart crimp necessary for spinning short fibers, and subjected to a relaxation heat treatment at 90 ° C. with a cutter. A concentric layered conjugate short fiber as shown in FIG. 1D having a fiber length of 76 mm and a single fiber fineness of 3 denier was obtained. A woven fabric was obtained from the obtained short fibers in the same manner as in Example 1. Table 2 shows the spinnability of the short fibers and the light shielding and heat shielding properties of the obtained woven fabric.

Comparative Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.64 was used as a polyester, and a single component containing titanium oxide as a white pigment containing 0.36% by weight of the polymer was spun. A drawn yarn was obtained. Then, after stretching at a natural stretching ratio in a bath solution of 95 ° C., it is passed through a stuffer box to give crimps necessary for spinning of short fibers, and subjected to a relaxation heat treatment at 120 ° C. with a cutter. A short fiber having a round section as shown in FIG. 3 having a fiber length of 38 mm and a single fiber fineness of 1.5 denier was obtained.

A woven fabric was obtained from the obtained short fibers in the same manner as in Example 1. Table 2 shows the spinnability of the short fibers and the light shielding and heat shielding properties of the obtained woven fabric.

(Comparative Example 2) Polyethylene terephthalate having an intrinsic viscosity of 0.65 was used as the polyester, and titanium oxide was contained as a white pigment in an amount of 8.0% by weight based on the polymer. 0.
Using polyethylene terephthalate No. 64 and 0.40% by weight of titanium oxide as a white pigment as a dividing wall, a spinning speed of 1200 m / at a volume ratio of 30 to 70 at a volume ratio of 30 to 70 was used. min. To obtain an undrawn yarn. Then, after stretching was performed at a natural stretching ratio in a bath solution of 90 ° C., it was passed through a stuffer box in order to impart crimp necessary for spinning of short fibers, and then heated at 90 ° C.
The fibers were adjusted to a fiber length of 38 mm using a cutter to obtain radial composite short fibers having a single fiber fineness of 2 denier as shown in FIG. 2A.

The proportion of the fiber surface containing 8.0% by weight of titanium oxide occupied 85% of the fiber surface. A woven fabric was obtained from the obtained short fibers in the same manner as in Example 1. Table 2 shows the spinnability of the short fibers and the light shielding and heat shielding properties of the obtained woven fabric.

(Comparative Example 3) Polyethylene terephthalate having an intrinsic viscosity of 0.64 was used as a polyester and titanium oxide was contained as a white pigment in an amount of 8.0% by weight with respect to the polymer. 0.6
5 and polyethylene oxide containing 0.45% by weight of titanium oxide as a white pigment.
/ Min. To obtain an undrawn yarn. afterwards,
After stretching at a natural stretching ratio in a 90 ° C. bath,
Staffer to give crimp necessary for spinning short fiber
The fiber was passed through a box and subjected to a relaxation heat treatment at 90 ° C., and the fiber length was adjusted to 51 mm with a cutter to obtain a side-by-side type composite short fiber having a single fiber fineness of 2 denier as shown in FIG. 2B.

The proportion of the fiber containing 8.0% by weight of titanium oxide occupying the fiber surface was 50%. A woven fabric was obtained from the obtained short fibers in the same manner as in Example 1. Table 2 shows the spinnability of the short fibers and the light shielding and heat shielding properties of the obtained woven fabric.

(Comparative Example 4) Polyethylene terephthalate having an intrinsic viscosity of 0.60 was used as a polyester, and a single component containing 5.36% by weight of a titanium oxide as a white pigment with respect to the polymer was spun and unpolished. A drawn yarn was obtained. Then, after performing stretching at a natural stretching ratio in a bath liquid of 95 ° C., crimping is applied by a special method in order to impart crimp necessary for spinning short fibers, and then subjected to a relaxation heat treatment at 120 ° C. -The fiber length is adjusted to 38 mm and the single fiber fineness is 1.5 denier.
As shown in FIG.

A woven fabric was obtained from the obtained short fibers in the same manner as in Example 1. Table 2 shows the spinnability of the short fibers and the light shielding and heat shielding properties of the obtained woven fabric.

(Comparative Example 5) Polyethylene terephthalate having an intrinsic viscosity of 0.54 was used as the polyester, and 5.5% by weight of titanium oxide was contained in the polymer as a white pigment. 0.55
3 layers containing 0.45% by weight of titanium oxide as a white pigment using polyethylene terephthalate as described above, and the spinning speed was 1000 m / m at a volume ratio of 60 to 40 and a spinning rate of 60 m
in. To obtain an undrawn yarn. Then 90
After stretching at a natural stretching ratio in a bath solution at a temperature of 100 ° C., it is passed through a stuffer box to give crimps necessary for spinning of short fibers, subjected to a relaxation heat treatment at 90 ° C., and subjected to a 51 mm fiber with a cutter. Fig. 2 of single fiber fineness 2 denier aligned to length
A composite short fiber as shown in (c) was obtained.

The proportion of titanium oxide containing 6.5% by weight on the fiber surface was 35%. A woven fabric was obtained from the obtained short fibers in the same manner as in Example 1. Table 2 shows the spinnability of the short fibers and the light shielding and heat shielding properties of the obtained woven fabric.

[0044]

[Table 2]

[0045]

According to the present invention, falling off during the spinning process,
Opacity without spinning failure due to frictional abnormalities such as wrapping,
Polyester staple fibers having excellent heat shielding properties can be provided.

The use of a polyester containing a small amount of white material is advantageous in terms of cost.

The woven fabric obtained by using the fiber of the present invention has not only opacity and heat shielding property but also excellent drapability, flexibility and a soft texture. Also, at the time of dyeing,
A matte or milky color tone such as that seen in polyester fibers using a large amount of white pigment is rarely obtained, and a clear color can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of four types ((a) to (d)) of fiber cross sections showing a fiber composite structure that can be employed in the present invention.

FIG. 2 is a schematic view of three types of fibers ((a) to (c)) showing a fiber composite structure of a short fiber obtained in a comparative example.

FIG. 3 is a schematic view of a fiber cross section of a short fiber obtained in a comparative example.

[Explanation of symbols]

 1. 1. Polyester with the highest white pigment content 2. Polyester with the lowest white pigment content Polyesters other than 1 and 2

Claims (5)

[Claims] 1. A conjugate fiber composed of two or more polyesters having different white pigment contents and having a single-fiber fineness of 1 to 5 denier, wherein the polyester containing the largest amount of white pigment is white. The pigment content is 1.5% by weight or more 1
0.0% by weight or less, in the polyester containing the least white pigment, the content of the white pigment is 0.5% by weight or less, and the polyester containing the most white pigment, A polyester conjugate short fiber, wherein the polyester occupying 25% to 75% of the fiber cross-sectional area and containing the least white pigment occupies 80% or more of the fiber surface area. 2. The polyester composite staple fiber according to claim 1, wherein the polyesters having different contents of the white pigment are two types and are substantially concentric core-sheath conjugate fibers. 3. The polyester conjugate short fiber according to claim 1, wherein the polyesters having different contents of the white pigment are two kinds, and are substantially radial conjugate fibers. 4. The polyester composite staple fiber according to claim 1, wherein said polyester having two different white pigment contents is a substantially concentric core-sheath hollow composite fiber. 5. The polyester conjugate short fiber according to claim 1, wherein said white pigment is titanium oxide.