JPH08246245A - Core-sheath conjugate short fiber for nonwoven fabric - Google Patents

Abstract

PURPOSE: To obtain the subject short fiber capable of improving the shrinkage characteristics and dyeability of a nonwoven fabric made of the fiber, enabling the increase of productivity in processing of the nonwoven fabric and useful for a nonwoven fabric for a core cloth, etc., by using a copolymer polyester as the core component and nylon 6 as the sheath component and specifying the weight ratio of the core part to the sheath part. CONSTITUTION: This core-sheath conjugate short fiber for producing a nonwoven fabric is obtained by using a copolymer polyester, in which >=90mol% recurring units are polyester units, as a core component and nylon 6 as a sheath component and specifying the weight ratio of the core part/the sheath part at (10-60)/(90-40). The obtained short fiber is excellent in vividness after dying and also in passage through a carding engine, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to short fibers for non-woven fabric,
More specifically, the present invention relates to a core-sheath composite staple fiber for a non-woven fabric, which is made of polyester and nylon for the purpose of improving the shrinkage property and the dyeability of the non-woven fabric, and at the same time, improving the productivity when processing the non-woven fabric.

[0002]

2. Description of the Related Art Natural fibers, chemical fibers and synthetic fibers are often used for non-woven fabrics, and particularly nylon short fibers are often used for interlining fabrics. The reason why nylon short fibers are often used in interlining nonwoven fabrics is that nylon short fibers have a soft texture. However, a nonwoven fabric made of short nylon fibers has a drawback that the dimensional change due to heat and the dimensional change due to tension are large, and several proposals have been made in the past for improvement thereof.

For example, Japanese Unexamined Patent Publication (Kokai) No. 62-288276 proposes a non-woven fabric adhesive interlining material using short fibers in which the core component is polyester and the sheath component is nylon. It is thought that this proposal improved the heat shrinkage property,
Since the nylon used as the sheath component is contaminated because the dye used for dyeing the polyester as the core component is a disperse dye, the interface between the two components, which has a low affinity when the core component is simply polyethylene terephthalate, peels off. However, there was a defect that the sharpness was insufficient. Further, Japanese Patent Laid-Open No. 2-2
Japanese Patent No. 10024 proposes a method of improving the spinnability by specifying the melt viscosity of a nylon-polyester composite yarn. Although this proposal can improve the spinnability, it cannot solve the defects of nylon contamination and interfacial separation of the two components as described above.

[0004]

It is considered that the above-mentioned proposal has maintained the soft texture of nylon and improved the dimensional stability considerably, but it is still insufficient, and the sharpness of the nonwoven fabric after dyeing is not sufficient. The problem of insufficient improvement has not been resolved. The present invention is a proposal for solving the above-mentioned problems.

[0005]

The object of the present invention is to provide a core-sheath composite fiber having a core / sheath composite ratio of 10 to 60/90 to 40 in weight ratio, wherein the core component is 10 mol% or less. This is achieved by a core-sheath composite short fiber for a non-woven fabric, which is characterized in that a copolymerized copolyester which is copolymerized and a sheath component is made of nylon 6.

The core component of the present invention is required to be a copolymerized polyester copolymerized in an amount of 10 mol% or less. The copolyester of the present invention is not particularly limited as long as it is a copolyester such as polyethylene terephthalate copolyester and polybutylene terephthalate copolyester, but it has a high melting point and a repeating unit because of its excellent physical properties. 90% by mole or more of the polyester must be polyester. Particularly, it is preferable that 90 mol% or more of the repeating unit of the polyester is ethylene terephthalate. As the copolymerization component of the copolyester, a component capable of forming a dyeing seat of an ionic dye is preferable, and examples thereof include a sulfonic acid metal salt and isophthalic acid. A sulfonic acid metal salt having excellent affinity with nylon, particularly 5-sodium sulfoisophthalic acid is preferable. Copolymerization rate is ionic,
In particular, it should be possible to achieve a deep color with a cationic dye.
From the standpoint of preventing peeling of the interface with nylon, 1.5 mol% or more is preferable, and from the standpoint of achieving dyeing under normal pressure, its copolymerization rate is particularly preferably 4.5 mol% or more. On the other hand, if the copolymerization rate is too high, the dyeing property reaches saturation, the melting point drop becomes large, and the physical properties deteriorate, so the copolymerization rate is required to be 10 mol% or less, and 6 mol% or less. Preferably there is.

The intrinsic viscosity [η] of the copolyester is preferably in the range of 0.30 to 0.55. The intrinsic viscosity has a great influence on the melt viscosity of the polymer and the strength of the raw cotton, which will be described later, and also on the soft hand.
When it is lower than 0.30, the melt viscosity becomes low and the spinnability is lowered, and at the same time the strength is lowered. On the other hand, when it is higher than 0.55, the balance of melt viscosity with nylon as a sheath component is likely to be lost, and in order to maintain a soft texture, the intrinsic viscosity [η] is preferably 0.30 to 0.55, More preferably, it is 0.34 to 0.50.

Nylon 6 which has a soft texture and a unique sliminess is required as the sheath component which has a great influence on the texture of the non-woven fabric. Nylon 6 may be copolymerized within a low ratio range, but it is preferable that 95 mol% or more is nylon 6. Further, nylon 6 as a sheath component may contain titanium dioxide in an amount of 0.1% by weight or more in order to impart a unique mineral texture.

In the core-sheath composite short fibers of the present invention, the relative relationship between the melt viscosity of the core component copolymer polyester and the sheath component nylon 6 is very important. The core-sheath composite fiber of the present invention can achieve the object of the present invention with either a concentric core sheath or an eccentric core sheath, but it is preferably substantially concentric circles. The reason for this is that in the case of the eccentric core-sheath composite, when the fiber is heat-treated, the fiber becomes curved and the card passability is deteriorated, or when the fiber is spun, it is kneaded directly under the spinneret. When the kneeling occurs, the fiber is cut, and the unstretched portion is mixed into the raw cotton, and the unevenness of the thickness of the fiber becomes apparent, which deteriorates the quality of the raw cotton. From this, it is particularly preferable that the core-sheath composite staple fibers of the present invention are concentric circles. In order to control the composite form of the core-sheath, the ratio of the melt viscosity of the sheath component to the core component is preferably in the range of 0.3 or more and 4.0 or less. If it goes out of this range, the above-mentioned control becomes difficult,
It is not preferable because the unevenness of the thickness in the fiber length direction and the decrease in the tensile strength, which occur just below the die, become apparent and it becomes difficult to produce a high-speed card and a uniform nonwoven fabric. A more preferable melt viscosity ratio is 0.4 or more and less than 2.5, and particularly preferably 0.4 or more and less than 1.5.

It is preferable that the melting point of nylon 6 as the sheath component is 15 ° C. or more lower than the melting point of the copolymerized polyester as the core component. There is a method of fixing the structure of the non-woven fabric used for the interlining, such as a point seal, by fusing fine dots. In this method, it is necessary that the sheath component is fused, but at the same time, the core component is not fused and it is necessary that the nonwoven fabric structure is firmly formed and held. For that purpose, the melting point of the core component that does not melt at the point seal processing temperature is required. That is, in order to suppress the decrease in the strength of the nonwoven fabric, the melting point of the sheath component is 15
It is preferable that the temperature is lower than ℃. If the melting point of the sheath component is too low, fusion will occur due to daily heating of an iron or the like when used as an interlining material, so the melting point of the sheath component is preferably 210 ° C or higher.

The core-sheath composite short fibers of the present invention preferably have a dry heat shrinkage at 180 ° C. of 10% or less. If the dry heat shrinkage ratio of the core-sheath composite short fibers exceeds 10%, the shrinkage ratio of the nonwoven fabric becomes large and the dimensional stability decreases, which is not preferable. From the viewpoint of dimensional stability, the more preferable dry heat shrinkage is 5%
The ratio is particularly preferably 3.5% or less. It is more preferably 2.0% or less.

The strength of raw cotton is preferably 2.5 g / d or more, particularly preferably 3.5 g / d or more, in order to support a card requiring high speed. Further, in order to support high speed cards, it is important to have a specified crimp characteristic, particularly a specified crimp rate. When the crimping rate is less than 8%, the entanglement of the web becomes insufficient and the web is easily broken, and the preferable crimping rate is 8% or more. On the contrary, when the crimping rate is too high, the web having high uniformity is obtained. Since it is difficult to form, it is preferably 20% or less.

The core-sheath composite single fiber for nonwoven fabric of the present invention can be manufactured, for example, as follows. 5 as core component
-4.5 mol% of sodium sulfoisophthalic acid component
A composite ratio of polyethylene terephthalate having an intrinsic viscosity of 0.35 copolymerized with nylon 6 having a relative viscosity of 2.3 as a sheath component and 0.35% by weight of titanium dioxide (core / core)
(Sheath) 30% by weight / 70% by weight, and the sheath component is uniformly arranged around the core component by a known method, and the composite spinning is performed using a spinneret in which the cross-sectional shape of the fiber is concentric. The spinning may be carried out by winding it as an undrawn yarn or pre-oriented yarn (POY) and drawing it in another step.
A high-speed spinning at about 0 m / min may be used to obtain a drawn yarn in one step. In the case of undrawn yarn or POY, the composite fiber is drawn by wet heat. Then, buckling crimps are applied with a stuffer box. Then heat treatment in a relaxed state,
Then, the obtained fiber is cut into a predetermined length to obtain a core-sheath composite staple fiber for a non-woven fabric.

[0014]

The present invention will be described in more detail with reference to the following examples.
The physical properties in the examples were determined by the following measurements. Intrinsic viscosity: Orthochlorphenol is used as the solvent, and 2
Intrinsic viscosity [η] measured at 5 ° C.

Melting point: Perkin Elmer DSC
The temperature of the melting peak measured with -4 at a temperature rising rate of 16 ° C / min.

Melt viscosity: Toyo Seiki Co., Ltd. CAPILO
Using GRAPH, at spinning temperature, shear rate 1216se
It was measured under the condition of c ^-1 .

Dry heat shrinkage: Dry heat was measured at 180 ° C. under no load.

Tensile strength: Tensilon manufactured by Orientec Co., Ltd. was used for measurement with a sample length of 20 mm and a pulling speed of 20 mm / min.

Crimping rate: Measured according to JIS 1015-7-12. However, initial load 2 mg / d, predetermined load
It was set to 150 mg / d.

Card passability: The uniformity of the web coming out of the card and the state of web breakage were observed.

Nonwoven fabric shrinkage: Dry heat of the obtained nonwoven fabric 18
Vertical shrinkage at 0 ° C. under no tension.

Non-woven fabric softness: 10 people touch the non-woven fabric,
The point where the softness was excellent was set to 10 points and the point where it was considered to be coarse and hard was set to 0 point, and the average value was calculated and displayed as a score.

Nonwoven fabric sharpness: A dye dyed with a basic dye, malachite green, and then dyed with an acid dye was visually evaluated.

Examples 1 to 5 and Comparative Examples 1 to 2 Nylon 6 having the properties shown in Table 1 was used as the sheath component, and the core component was a polyethylene whose copolymerization composition, copolymerization ratio, etc. as shown in Table 1 were changed. Terephthalate was used. The spinning temperature was 280 ° C. and the single fiber fineness was 1.
The discharge rate is determined to be 2 denier and 1500 m /
The core-sheath composite spinning of substantially concentric circles was performed under the conditions of min and Table 1. Then the resulting undrawn yarn is drawn in a liquid bath,
It was drawn tow. Buckling crimp was applied to the tow by a stuffer box, and the tow was cut into 51 mm to obtain short fibers. After manufacturing the obtained non-woven fabric consisting of 100% short fibers, point-sealing was performed using an embossing roller. The measurement results are shown in Table 1.

[0025]

[Table 1] In Example 1, the card passing property was good, and the non-woven fabric characteristic values sufficiently satisfied the purpose. In Example 2, as a result of using the core component in which the copolymerization rate of 5-sodium sulfoisophthalate (SSI) was reduced, the sharpness after dyeing the nonwoven fabric was slightly poor. In Example 3, as a result of increasing the SSI copolymerization rate, the card passing property and the nonwoven fabric property were good except that the nonwoven fabric shrinkage property was slightly large. Example 4 is SS
As a result of newly copolymerizing the isophthalate component by the amount that the I copolymerization rate was reduced, it was good except that the sharpness was slightly poor. Example 5 was carried out in the same manner as in Example 1 except that the SSI copolymerization rate was further increased and the melt viscosity was increased. As a result, the nonwoven fabric discharged from the card was slightly inferior in uniformity but was a satisfactory nonwoven fabric. On the other hand, Comparative Example 1 and Comparative Example 2 were carried out in the same manner as in Example 1 except that polyethylene terephthalate which was not copolymerized was used. The sharpness was poor and it could not be used as a high-grade interlining.

Examples 6 to 7 and Comparative Example 3 Examples 6 and 7 have composite ratios of 50/50 and 10 /, respectively.
The same procedure as in Example 1 was performed except that the number was changed to 90. In Example 6, the texture of the non-woven fabric was slightly rough and the sharpness was slightly insufficient, but the purpose was satisfied. In Example 7, the non-woven fabric characteristics were satisfactory, and the card passing property was also good. Comparative Example 3 was a single component fiber of nylon 6 only, and the nonwoven fabric shrinkage rate was high at 5.0%, which was not satisfactory.

[0027]

[Table 2] Examples 8-12, Comparative Examples 4-5 The copolymerization composition / copolymerization rate and melt viscosity of polyethylene terephthalate were changed. Example 8 was performed in the same manner as in Example 1 except that the SSI copolymerization rate and the melt viscosity were changed as shown in Table 3. It was satisfactory except that the web uniformity from the card was slightly poor. Example 9 is Example 1 except that the melt viscosity of the polyester is significantly reduced.
It carried out similarly to. The non-woven fabric properties were good except that the card passing property was slightly poor. In Example 10, the melt viscosity of polyester and the melt viscosity of nylon 6 were changed as shown in Table 3. It was good except that the card passing property was slightly poor. In Example 11, the copolymerization composition and the copolymerization rate were changed as shown in Table 3. The non-woven fabric was rather coarse and hard, probably because of high shrinkage. In Example 12, the copolymerization composition and the copolymerization rate were changed as shown in Table 3. Part of the non-woven fabric was fused during point seal processing. On the other hand, in Comparative Example 4, the copolymerization rate of polyester was increased to 11.5 mol%, and as a result, web breakage occurred and the nonwoven fabric could not be obtained. In Comparative Example 5, the texture was coarse and hard as a result of using the single component fiber of only polyester.

[0028]

[Table 3]

[0029]

The nonwoven fabric comprising the core-sheath composite short fibers of the present invention has good dimensional stability due to heat, has the same softness as 100% nylon, and has excellent sharpness after dyeing. The non-woven fabric processability represented by the card passing property is also very good.

Claims (8)

[Claims] 1. The core / sheath composite ratio is 10 to 10 by weight.
A core-sheath composite short fiber for a non-woven fabric, wherein the core-sheath composite fiber is 60/90 to 40 and a core component is copolymerized with 10 mol% or less and a sheath component is nylon 6. 2. The intrinsic viscosity of the copolyester is 0.3.
It is in the range of 0 to 0.55. The core-sheath composite staple fiber for nonwoven fabric according to claim 1, which is characterized in that. 3. A copolymerized polyester having a sulfonic acid metal salt as a copolymerized component, and the copolymerization ratio of the copolymerized component is 1.5 to 6.0 mol%. The composite short fiber for a non-woven fabric according to claim 1 or claim 2. 4. The non-woven fabric according to claim 1, wherein the ratio of the melt viscosity of the copolyester to the melt viscosity of nylon 6 is 0.3 to 4.0. Core-sheath composite short fibers for use. 5. The non-woven fabric core according to claim 1, wherein the sheath component nylon 6 has a melting point of 15 ° C. or more lower than the melting point of the core component copolymerized polyester. Sheath composite staple fiber. 6. The core-sheath composite staple fiber for a non-woven fabric according to claim 1, which has a dry heat shrinkage at 180 ° C. of 10% or less. 7. The composite core-sheath short fiber for a non-woven fabric according to claim 1, wherein the raw cotton strength is 2.5 g / d or more. 8. The composite core-sheath short fiber for a non-woven fabric according to any one of claims 1 to 7, which has a crimping rate of 8% or more.