JPH09228222A - Fiber laminate comprising fiber having latent crimping ability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fiber laminate capable of providing a nonwoven fabric having stretchability and urethane-like cushoning property and comprising a conjugate fiber having latent crimping ability. SOLUTION: This fiber laminate contains a conjugate fiber obtained by eccentrically joining polyethylene terephthalate or a polyester consisting essentially of polyethylene terephthalate with a polyethylene terephthalate-based copolymer ester obtained by copolymerizing isophthalic acid(IPA) with an ethylene oxide adduct (BAEO) of bisphenol A in a copolymer mol fraction satisfying the formula (I) IPA <=4.5 or BAEO<=1.5 and the formula (II) 5<=IPA+BAEO<=10 and having latent crimp ability capable of developing >=50/25 mm spiral crimp by 170 deg.C free shrinkage heat treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber laminate which imparts stretchability and urethane-like cushioning properties to a nonwoven fabric by appropriate heat treatment.

[0002]

2. Description of the Related Art Heretofore, there has been known a technique in which short fibers having a latent crimping ability are laminated and heated to develop crimps to obtain a stretchable nonwoven fabric. (For example, JP-A-59-1
No. 68159, Japanese Patent Laid-Open No. 3-269147) In Japanese Patent Laid-Open No. 4-100961, a composite fiber of ethylene terephthalate unit-based copolyester and polyethylene terephthalate in which a structural unit having a metal sulfonate group is copolymerized. And 50 / 25m
A polyester cotton wool having a urethane-like texture in which fibers having a spiral crimp of m or more are point-joined with binder fibers is disclosed.

However, in the case of a composite fiber of polyethylene terephthalate and a copolymerized polyester mainly composed of ethylene terephthalate units obtained by copolymerizing a constitutional unit having a metal sulfonate group, which has a latent crimping ability,
The fiber is pulled in the carding process for making the fiber laminate, and at this point the coil spring-like three-dimensional spiral crimp is developed to some extent, making it difficult for the fiber to be completely opened. It was easy to form a so-called nep where the fibers were entangled in the fiber laminate or when the heat treatment was performed to make the nonwoven fabric. When this nep is formed, there are problems that the stretchability of the non-woven fabric is hindered and the soft feel of urethane-like is impaired when it is used as a cushioning material.

Further, in JP-A-7-54216, ordinary polyester, isophthalic acid and bisphenol A are disclosed.
There is known a fiber having a latent crimping ability, which is composited with a polyethylene terephthalate-based copolyester obtained by copolymerizing a specific amount of the ethylene oxide adduct. However, in the case of such a combination, the degree of manifestation of latent crimps is greatly different due to a slight difference in the temperature of the heat treatment for manifesting latent crimps, and there is a problem in the stability of quality during the production of nonwoven fabrics. there were.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to satisfactorily card even when a fiber having a latent crimping ability is used, and it is possible to obtain a good-quality non-woven fabric with less nep. At the same time, it is an object of the present invention to provide a fiber laminate in which the change in the area shrinkage ratio due to the difference in the temperature of the heat treatment for manifesting the latent crimp is small to some extent and a stable nonwoven fabric product can be obtained.

[0006]

The present invention achieves the above object, and its gist is as follows. That is, polyethylene terephthalate or polyester mainly containing this, isophthalic acid and bisphenol A
A terephthalate-based copolyester obtained by copolymerizing the ethylene oxide adduct of bisphenol A
The copolymerization mole fraction of the ethylene oxide adduct of (1) satisfies the following formulas (1) and (2), and at the same time, has a latent crimping ability capable of expressing 50/25 mm or more spiral crimps by free shrinkage heat treatment at 170 ° C. A fiber laminate comprising fibers having a latent crimping ability, which is characterized by containing 60% by weight or more of fibers. IPA ≦ 4.5 or BAEO ≦ 1.5 (1) 5 ≦ IPA + BAEO ≦ 10 (2) (where IPA: mol% of isophthalic acid relative to the number of moles of repeating units of copolymerized polyester, BAEO: repeating units of copolymerized polyester (Mole% of ethylene oxide adduct unit of bisphenol A relative to the number of moles) In addition to the card web obtained through the carding step, the fiber laminate referred to in the present invention includes needle punch and hydroentanglement treatment for card web. Non-woven fabric that has been mechanically entangled, or heat-bonding treatment such as heat calendering, heat embossing, and thermal through at a temperature that does not cause latent crimps to appear, including heat-fusible binder fibers. Non-woven fabrics and laminated structures formed by laminating and integrating these non-woven fabrics.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. In order to obtain a polyester fiber having a latent crimping ability used for the fiber laminate of the present invention, it is necessary to make an appropriate combination of the kind and the degree of polymerization of two kinds of polyester components which are eccentrically joined. In the above, a polyester mainly composed of polyethylene terephthalate is combined with a polyethylene terephthalate-based copolyester obtained by copolymerizing a specific amount of isophthalic acid and an ethylene oxide adduct of bisphenol A. Examples of the eccentrically joined composite form include a side-by-side type in which two types of components are arranged in parallel along the longitudinal direction of the yarn, and an eccentric core-sheath type in which the core portion is eccentric.

The fiber used in the present invention is a polyethylene terephthalate-based copolyester which is one of its constituents, wherein the mol% of isophthalic acid is 4.5 mol% or less relative to the number of moles of the repeating unit, or the copolyester repeat Bisphenol A per unit number of moles
Ethylene oxide adduct (hereinafter abbreviated as BAEO. The bisphenol A ethylene oxide adduct is preferably 2 to 20 mol% of ethylene oxide added to 1 mol of bisphenol A).
Is 1.5 mol% or less, and at the same time, the total of isophthalic acid and BAEO must be 5 mol% or more and 10 mol% or less. The relative viscosity of the copolyester (measured at a concentration of 0.5 d / dl and a temperature of 20 ° C. using an equivalent weight mixture of phenol and ethane tetrachloride as a solvent) is
Those of 1.35 to 1.50 are suitable.

When the mol% of isophthalic acid exceeds 4.5 mol% and the mol% of BAEO units exceeds 1.5 mol%, the temperature of the heat treatment for revealing the latent crimp may be small. The degree of actualization of latent crimps varies greatly depending on the difference in the above, and there is a problem in the stability of quality during the production of nonwoven fabrics, which is unsuitable. That is, the degree of contraction of the non-woven fabric is different due to the different degree of latent crimp manifestation, and uneven density of the non-woven fabric is generated, which is not preferable.

The total of isophthalic acid and BAEO is 5
If it is less than mol%, the degree of latent crimp manifestation is small, and the nonwoven fabric obtained by exposing the latent crimp by heat treatment of the fiber laminate may provide sufficient stretchability and urethane-like cushioning property. It is not suitable because it cannot be done. When the total amount of isophthalic acid and BAEO exceeds 10 mol%, the degree of latent crimp manifestation varies greatly even if the temperature of the heat treatment for manifesting the latent crimp is slightly different, and the fiber laminate is heat treated. It is unsuitable because it causes a problem in quality stability when producing a nonwoven fabric. That is, it is not preferable because the degree of contraction of the non-woven fabric becomes different due to the different degree of latent crimp manifestation, or uneven density of the non-woven fabric occurs.

On the other hand, polyethylene terephthalate alone is preferably used as the polyester which is another constituent of the composite fiber, but isophthalic acid, adipic acid, sebacic acid, 1,4-
It may contain a small amount (about 10 mol% or less) of a copolymerization component such as butanediol, 1,6-hexanediol, diethylene glycol and polyethylene glycol.
The relative viscosity of polyester is 1.35 to 1.40.
Is appropriate.

The fibers having a latent crimping capacity of the present invention are 170
It is necessary to have a latent crimping ability capable of developing a three-dimensional spiral crimp of 50 pieces / 25 mm or more by free shrinkage heat treatment at ℃. If this value is less than 50/25 mm, a nonwoven fabric having sufficient stretchability and urethane-like cushioning properties cannot be obtained even if the fiber laminate is heat-treated, which is unsuitable. The upper limit of the number of spiral crimps is not particularly limited, but it is 15 in consideration of the texture of the nonwoven fabric.
The number is preferably 0/25 mm or less.

The heat shrinkage characteristic of the fiber having latent crimping ability according to the present invention is 70 g prepared with 100% of this fiber.
Area shrinkage (S ₂₀₀ (%)) of the needle punched nonwoven fabric of 100 m ² / m ² when heat-treated at 200 ° C. for 1 minute,
Similarly, when the needle-punched nonwoven fabric of 70 g / m ² made of 100% of this fiber was heat-treated at 140 ° C. for 1 minute, the difference from the area shrinkage ratio (S ₁₄₀ (%)) of the nonwoven fabric (S ₂₀₀ −
S ₁₄₀ ) is preferably in the range of 25% or more and 55% or less. If the value of S ₂₀₀ -S ₁₄₀ are less than 25%,
It is not preferable because the latent crimp is less likely to be manifested, and the nonwoven fabric tends to be unable to have sufficient stretchability and urethane-like cushioning properties even if the fiber laminate is heat-treated. On the other hand, the value of (S ₂₀₀ -S ₁₄₀ ) is 55%
When the temperature exceeds the above value, the degree of latent crimp manifestation varies significantly even with a slight difference in the temperature of heat treatment for manifesting latent crimps, and the stability of quality when heat-treating a fiber laminate and producing nonwoven fabrics is improved. It is not preferable because it tends to cause problems.

The value of (S _200- S ₁₄₀ ) is 25% or more 55
In order to control the content to be in the range of not more than%, the mole% of isophthalic acid and BAEO with respect to the number of moles of the repeating unit in the copolyester which is one of the constituent components of the fiber having the latent crimping ability may be controlled within an appropriate range. .

A needle-punched non-woven fabric of 70 g / m ² made of 100% of fibers having a latent crimping capacity is used for 175
The area shrinkage of the non-woven fabric when heat-treated at ℃ for 1 minute is S
₁₇₅ (%), (S _200- S ₁₇₅ ) / (S _175-
It is preferable that the value of S ₁₄₀ ) is 1 or less because a nonwoven fabric having latent crimps can be stably produced at a relatively low temperature. In order to obtain a fiber having such a latent crimping ability, the heat setting conditions for drawing the fiber may be optimized, and the heat setting temperature is preferably in the range of 110 ° C or higher and 170 ° C or lower.

If the temperature of the heat setting for drawing the fiber is too high, the area shrinkage ratio of the fiber laminate may change rapidly near the heat treatment temperature for revealing the latent crimp.
In this case, the value of (S ₂₀₀ -S ₁₇₅ ) / (S ₁₇₅ -S ₁₄₀ ) becomes 1 or more, which may cause a problem in quality stability during production of the nonwoven fabric, which is not preferable.

The composite fiber in the present invention can be manufactured by a method generally following the conventional technique. That is, first, spinning is performed using a general-purpose composite melt spinning device. During spinning, stabilizers, fluorescent agents, pigments, etc. may be present together. The cross-sectional shape of the fiber may be a circular cross-section, a flat shape, a hexalobal shape, a triangular cross-section or the like, or a hollow cross-section.

The spun fiber is drawn or heat-treated continuously or in a separate step, if necessary, but the degree of latent crimpability of the fiber can be controlled by adjusting the drawing conditions.

The fiber is applied with an oil agent, mechanically crimped with a crimper or the like, aligned to tens of thousands to millions of denier, and cut into a predetermined length with a cutter such as an EC cutter or a gurgle cutter. Cutting length is 30 to 102 mm
It is a degree.

The fiber laminate of the present invention contains 60% by weight or more of fibers having a latent crimping capacity based on the whole fiber laminate. 6
When the content is less than 0% by weight, a nonwoven fabric having the elasticity and cushioning property like urethane, which is the object of the present invention, cannot be obtained. In addition to the fibers having the latent crimping ability used in the present invention, in consideration of the required characteristics depending on the application, ordinary polyester fibers, heat-fusible binder fibers, and cotton, hemp, and other natural fibers are mixed. Good.

The fiber laminate of the present invention can be obtained by carding the raw cotton consisting of the above-mentioned fibers having latent crimping ability alone or, if necessary, mixing other fibers.

The heat treatment for causing the fiber laminate of the present invention to exhibit spiral crimping and to impart elasticity and cushioning property of urethane-like may be appropriately carried out within the range of 100 to 230 ° C. For example, when it is used as a stretchable non-woven fabric for a base fabric of a patch, a relatively thin non-woven fabric that has been needle punched or hydroentangled with a basis weight of about 80 to 150 g / m ² and a relatively low temperature of 120 to 160 ° C. To process. When used as a non-woven fabric for cushion materials (so-called solid cotton), a non-woven fabric with a thick basis weight of about 500 to 1500 g / m ² may be treated at a relatively high temperature of 150 to 200 ° C. Further, in these cases, a non-woven fabric having a high tensile strength and a high peel strength can be obtained by using a heat-fusible binder fiber (for example, Melty <4080> manufactured by Unitika Ltd.). In the case of a fiber laminate containing a heat-fusible binder fiber, a heat-bonding treatment may be performed at a relatively low temperature in advance, and then a heat treatment may be performed at a higher temperature to develop spiral crimps. And heat treatment for developing spiral crimps may be performed at the same time.

[0023]

[Function] The conventional polyester fiber having the latent crimping ability that eccentrically joins two components is stretched a little in the carding process and the three-dimensional spiral crimping is apparent due to the difference in the shrinkage degree of both components. And becomes a cause of so-called nep in the fiber laminate, and only a low-quality non-woven fabric can be obtained. Further, the degree of latent crimp manifestation varies greatly even with a slight difference in the temperature of heat treatment for manifesting latent crimps, which causes a problem in quality stability during production of nonwoven fabrics. That is, the degree of contraction of the non-woven fabric is different and the density unevenness of the non-woven fabric is caused due to the different degree of latent crimp manifestation.

On the other hand, although the reason for the polyester fiber having the latent crimping ability of the present invention is not clear, a slight degree of stretching during carding does not cause spiral crimping due to the degree of shrinkage of both components. There is a very good spiral crimp expression performance starting from heat treatment at about 230 ° C. Therefore, if a heat treatment is performed after the carding process, a nonwoven fabric having sufficient elasticity and urethane-like cushioning properties can be obtained. Further, even if the temperature of the heat treatment for manifesting the latent crimps is slightly different, the degree of manifestation of the latent crimps is not significantly different, and the quality stability during production of the nonwoven fabric is good.

[0025]

Next, the present invention will be described specifically with reference to examples. In addition, the measuring method of a characteristic value is as follows. (1) Fineness: Measured by the method of JIS L-1015 7 ・ 5 ・ 1A. (2) Strength and elongation: Measured by the method of JIS L-1015 7.7. (3) Latent crimping ability: After heat-treating the fiber at 170 ° C. for 5 minutes in a freely shrinkable state, JIS L-1015
The number of crimps was measured by the method of 7.12.1. (4) Heat shrinkage property: 1 for a card web (70 g / m ² ).
After performing needle punching with a needle density of 92 needles / cm ² ,
The sample was cut into a size of 30 cm × 30 cm and heat-treated at a predetermined temperature for 1 minute. The sample area S after this heat treatment was measured, and the area shrinkage rate S _T was calculated by the following equation. (Where T: heat treatment temperature (° C))

Example 1 Polyethylene terephthalate-based copolyester having a relative viscosity of 1.45 obtained by copolymerizing 6 mol% of polyethylene terephthalate having a relative viscosity of 1.38 and 1 mol% of an ethylene oxide 2 mol adduct of bisphenol A with isophthalic acid. After drying the two types of chips under reduced pressure using an ordinary composite melt spinning device, the two components are compounded side by side (weight ratio 1: 1), spinning temperature 285 ° C, total discharge Composite melt spinning was performed at an amount of 230 g / min. After cooling the spun yarn, it was taken up at a take-up speed of 1000 m / min to obtain an undrawn yarn. Converging the obtained yarn,
It was made into a tow of 100,000 denier, stretched at a draw ratio of 3.4, stretched at a stretch temperature of 75 ° C., heat-treated with a heat drum at 150 ° C., mechanically crimped with a crimper and cut into 51 mm. The obtained fiber has a single yarn fineness of 2.4 denier (d),
Strength 4.8 g / d, Elongation 36%, Number of mechanical crimps / 2
5 mm, heat shrinkage characteristics S ₂₀₀ = 63%, S ₁₇₅ = 47
%, S ₁₄₀ = 13%, and the latent crimping capacity was 60 pieces / 25 mm. 80% of this fiber is a heat-fusible binder fiber (manufactured by Unitika Ltd., <4080> 2d × 51 m).
m) 20% was mixed and carded under the same conditions as 2d class ordinary polyester fibers. As with normal polyester fibers, no nep 120
A fiber laminate (web) of g / m ² was obtained. After needle-punching this web, it was subjected to free heat treatment in a 170 ° C. hot oven for 5 minutes, resulting in a non-woven fabric with good stretchability.

Example 2 Example 1 is the same as Example 1 except that 4 mol% of isophthalic acid and 2 mol% of an ethylene oxide adduct of bisphenol A are copolymerized with a relative viscosity of 1.46. It carried out similarly to. The obtained fiber has a single yarn fineness of 2.4 denier (d) and a strength of 4.6 g.
/ D, elongation 35%, number of mechanical crimps / 25 mm, heat shrinkage characteristics S ₂₀₀ = 55%, S ₁₇₅ = 41%, S ₁₄₀ = 9
%, Latent crimping capacity was 58 pieces / 25 mm. In addition, the obtained non-woven fabric had good stretchability.

Example 3 In Example 1, a copolymerized polyester having a relative viscosity of 1.46 obtained by copolymerizing 2.5 mol% of isophthalic acid and 5 mol% of an ethylene oxide adduct of bisphenol A was used. Heat drum heat set temperature to 120
It carried out like Example 1 except having set it as (degreeC). The obtained fiber has a single yarn fineness of 2.4 denier (d) and a strength of 4.2.
g / d, elongation 36%, mechanical crimp number 9/25 mm, heat shrinkage characteristics S ₂₀₀ = 60%, S ₁₇₅ = 46%, S ₁₄₀ = 1
6%, latent crimping capacity was 61 pieces / 25 mm.
In addition, the obtained non-woven fabric had good stretchability.

Example 4 In Example 1, a copolymerized polyester having a relative viscosity of 1.46 obtained by copolymerizing 8 mol% of isophthalic acid and 1.5 mol% of an ethylene oxide adduct of bisphenol A was used. Heat drum heat set temperature to 120
It carried out like Example 1 except having set it as (degreeC). The obtained fiber has a single yarn fineness of 2.4 denier (d) and a strength of 4.0.
g / d, elongation 35%, number of mechanical crimps / 25 mm, heat shrinkage characteristics S ₂₀₀ = 62%, S ₁₇₅ = 52%, S ₁₄₀ = 1
8%, latent crimping capacity was 68 pieces / 25 mm.
In addition, the obtained non-woven fabric had good stretchability.

Comparative Example 1 Example 3 was repeated except that as the copolyester, a copolyester having a relative viscosity of 1.46 obtained by copolymerizing 7 mol% of isophthalic acid and 4 mol% of an ethylene oxide adduct of bisphenol A was used. It carried out similarly to. The obtained fiber has a single yarn fineness of 2.4 denier (d) and a strength of 4.3 g.
/ D, elongation 33%, number of mechanical crimps / 25 mm, heat shrinkage characteristics S ₂₀₀ = 73%, S ₁₇₅ = 41%, S ₁₄₀ = 16
%, Latent crimping capacity was 67 pieces / 25 mm. Further, the obtained nonwoven fabric had a good stretchability, but the difference in the area shrinkage ratio of the nonwoven fabric due to the difference in the heat treatment temperature was large, and it was unsuitable for industrial stable production.

Comparative Example 2 Example 2 was repeated except that as the copolyester, a polyester having a relative viscosity of 1.46, which was obtained by copolymerizing 10 mol% of isophthalic acid and 1.5 mol% of an ethylene oxide adduct of bisphenol A, was used. It carried out like Example 3. The obtained fiber has a single yarn fineness of 2.4 denier (d), a strength of 4.1 g / d, an elongation of 33% and a mechanical crimp number of 9 pieces / 25 m.
m, heat shrinkage characteristics S ₂₀₀ = 78%, S ₁₇₅ = 40%, S
₁₄₀ = 9%, latent crimping capacity was 87 pieces / 25 mm. Further, the obtained nonwoven fabric had a good stretchability, but the difference in the area shrinkage ratio of the nonwoven fabric due to the difference in the heat treatment temperature was large, and it was unsuitable for industrial stable production.

Comparative Example 3 Example 1 was repeated except that as the copolyester, a copolymer having a relative viscosity of 1.46 obtained by copolymerizing 3 mol% of isophthalic acid and 9 mol% of an ethylene oxide adduct of bisphenol A was used. It carried out similarly to. The obtained fiber has a single yarn fineness of 2.4 denier (d) and a strength of 4.2 g.
/ D, elongation 31%, mechanical crimp number 9/25 mm, heat shrinkage characteristics S ₂₀₀ = 73%, S ₁₇₅ = 47%, S ₁₄₀ = 14
%, Latent crimping capacity was 79 pieces / 25 mm. Further, the obtained nonwoven fabric had a good stretchability, but the difference in the area shrinkage ratio of the nonwoven fabric due to the difference in the heat treatment temperature was large, and it was unsuitable for industrial stable production.

Comparative Example 4 In Example 1, as a copolymerized polyester, 2 mol% each of isophthalic acid and 2 mol of an ethylene oxide adduct of bisphenol A were copolymerized to give a relative viscosity of 1.3.
The same procedure as in Example 1 was carried out except that No. 3 was used. The obtained fiber has 10 mechanical crimps / 25 mm, heat shrinkage characteristics of S ₂₀₀ = 34%, S ₁₇₅ = 23%, S ₁₄₀ =
5%, latent crimping capacity was 34 pieces / 25 mm.
The web had few neps and was good in quality, but the nonwoven fabric after the heat treatment did not exhibit the spiral crimp and the stretchability was hardly recognized.

Comparative Example 5 In Example 1, 5 mol% of 5-sulfoisophthalic acid was copolymerized as the copolyester, and the relative viscosity was 1.28.
Was carried out in the same manner as in Example 1 except that the total discharge amount was 200 g and the draw ratio was 2.9 times. The resulting fiber has a mechanical crimp number of 11/25 mm and a latent crimp capacity of 6
8 pieces / 25 mm. When this was carded, the web had many neps and the stretchability of the nonwoven fabric was lower than that of Example 1.

Example 5 Nep-free webs carded with 100% of fibers having latent crimping ability obtained in Example 1 were laminated with a cross wrapper to obtain a laminated web having a basis weight of 1200 g / m ² . This laminated web was heat-treated at 190 ° C. for 2 minutes with a suction band type continuous heat treatment machine while controlling the thickness to 5 cm. The obtained cotton wool was a soft material similar in texture to urethane foam.

[0036]

EFFECTS OF THE INVENTION According to the present invention, there is provided a high-quality fiber laminate comprising a composite fiber having latent crimping ability and having a small number of neps. And, even if the temperature of the heat treatment for manifesting the latent crimps is slightly different, the degree of manifestation of the latent crimps does not differ greatly. It is possible to stably obtain a non-woven fabric having a certain amount.

Claims (2)

[Claims] 1. A composite fiber comprising polyethylene terephthalate or a polyester mainly comprising polyethylene terephthalate and a polyethylene terephthalate copolymer polyester obtained by copolymerizing an ethylene oxide adduct of isophthalic acid and bisphenol A, which are eccentrically joined together. When the copolymerization mole fraction of the ethylene oxide adduct of bisphenol A satisfies the following formulas (1) and (2), at the same time, the latent crimping ability to develop 50/25 mm or more spiral crimps by the free shrinkage heat treatment at 170 ° C. Having 60% by weight of fiber
A fiber laminate comprising fibers having latent crimping ability, characterized by containing the above. IPA ≦ 4.5 or BAEO ≦ 1.5 (1) 5 ≦ IPA + BAEO ≦ 10 (2) (In the above formula, IPA: mol% of isophthalic acid based on the number of moles of repeating units of the copolyester, BAE
O: mol% of ethylene oxide adduct unit of bisphenol A relative to the number of moles of the repeating unit of the copolyester) 2. The fiber laminate comprising fibers having latent crimping ability according to claim 1, wherein the heat shrinkage property of the fiber having latent crimping ability satisfies the following formula (3). 25 ≦ S ₂₀₀ −S ₁₄₀ ≦ 55 (3) (In the above formula, S ₂₀₀ : Fiber 10 having latent crimping ability.
Area shrinkage (%) of a 70 g / m ² needle-punched nonwoven fabric prepared at 0% when heat-treated at 200 ° C. for 1 minute, S ₁₄₀ : 70 g / m prepared at 100% fiber having a latent crimping capacity ² Needle punched nonwoven fabric 140
Area shrinkage (%) of non-woven fabric when heat-treated at ℃ for 1 minute)