JP2005299002A - Polyester conjugate staple fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide latent crimpable polyester conjugate staple fibers capable of giving not only high elasticity but also soft touch, and improved in texture, when forming a woven or a knitted fabric therefrom and to provide a nonwoven fabric comprising the latent crimpable conjugate staple fibers, excellent in elasticity, dimensional stability, and softness. <P>SOLUTION: This polyester conjugate staple fibers is joined together eccentrically a polyester (A) comprising a trimethylene terephthalate unit as an essential repeating unit and a polyester (B) having different crimping properties from the polyester (A), and the cojugate staple fiber has ≥75% of crimp modulus of elasticity, and ≥50/25 mm of crimp expression under no load at 180°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a latent crimpable polyester composite short fiber, and a nonwoven fabric excellent in stretchability and softness containing the latent crimpable polyester composite fiber.

  Polyester fibers are excellent in mechanical properties, thermal stability, washability, etc., and are therefore used in a very wide range of fields such as clothing and industrial materials.

  Among them, fibers that are rich in elasticity and elasticity are required for garments, particularly woven and knitted fabrics and non-woven fabrics for sports clothing, etc., because of demands for functionality and fit.

In order to solve these problems, conventionally, as a method for imparting stretchability, a polyester composite fiber having latent crimping ability has been proposed. For example, a composite fiber using a copolymerized polyester having a copolymerization rate of 7 mol% or more and 15 mol% or less with isophthalic acid (see, for example, Patent Document 1), or a polymer having different heat shrinkability is used as a side-by-side or eccentric core sheath A method (for example, see Patent Document 2) has been proposed in which a latent crimpable composite fiber composited with a structure is used. However, a composite fiber of polyethylene terephthalate with a polyester obtained by copolymerizing only one component of isophthalic acid or a polyethylene terephthalate copolymer polyester copolymerized with 5-sodium sulfoisophthalic acid has insufficient elastic recovery after stretching. However, these composite fibers need to be heat-treated at a high temperature in order to impart excellent stretchability, and have a problem that the texture of the resulting nonwoven fabric becomes hard.
Japanese Patent Laid-Open No. 3-161519 Japanese Patent Publication No. 3-10737

  An object of the present invention is to solve the above-mentioned problems, and when it is made into a woven or knitted fabric, not only is it very rich in elasticity but also a soft touch can be obtained and the texture can be improved. An object of the present invention is to provide a latent crimpable polyester composite short fiber, and to provide a nonwoven fabric excellent in extensibility, dimensional stability and softness containing the latent crimpable polyester composite short fiber.

The present invention adopts the following configuration in order to solve the above problems. That is,
(1) A composite short fiber in which a polyester (A) whose main repeating unit is a trimethylene terephthalate unit and a polyester (B) having a different shrinkage property from the polyester (A) are eccentrically joined, A polyester composite short fiber having an elastic modulus of 75% or more and a crimp expression number of 50 co / 25 mm or more during heat treatment under no load at 180 ° C.

  (2) The polyester composite short fiber as described in (1) above, wherein the polyester (B) is mainly composed of a copolymer polyester mainly composed of ethylene terephthalate units.

  (3) Polyester (B) is 5 to 13 mol% isophthalic acid as a copolymerization component and 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane and / or bis [4- (2-hydroxyethoxy). The polyester composite short fiber according to (1) or (2) above, which is a polyester mainly composed of ethylene terephthalate units copolymerized with 2 to 7 mol% of phenyl] sulfone.

  (4) A nonwoven fabric containing at least 50% by weight of the polyester composite short fiber according to any one of claims 1 to 3, wherein the elongation rate is 70% or more, the elongation recovery rate is 65% or more, and the dimensional change rate Is a nonwoven fabric characterized by being 10% or less.

  According to the present invention, a nonwoven fabric excellent in extensibility, dimensional stability, and softness can be provided, which eliminates the drawbacks of latent crimpable polyester composite short fibers and contains the latent crimpable polyester composite short fibers.

  The fiber which has the outstanding characteristic of this invention contributes to the performance improvement of base fabrics, such as non-woven fabric for sports and medical use, especially skin patch. In addition, taking advantage of this characteristic, a woven or knitted fabric is not only very rich in stretchability, but also has a soft touch and can improve the texture.

  Hereinafter, the present invention will be described in more detail.

  In the present invention, the polyester (A) constituting one component of the composite fiber is a polyester whose main repeating unit is a trimethylene terephthalate unit. Here, the polyester whose main repeating unit is a trimethylene terephthalate unit (hereinafter referred to as polytrimethylene terephthalate; abbreviated as PTT) is a polyester obtained by using terephthalic acid as the main acidic component and 1,3-propanediol as the main glycol component. It is. However, it may contain a copolymer component capable of forming an ester bond at a ratio of 20 mol%, more preferably 10 mol% or less.

  Examples of the copolymerizable component include dicarboxylic acids such as isophthalic acid, succinic acid, and cyclohexadicarboxylic acid, and diols such as ethylene glycol, diethylene glycol, butanediol, neopentyl glycol, and polyethylene glycol. It is not limited to these. Preferably, it is made of 100% PTT from the viewpoint of manifesting the stretch back property of PTT when it is formed into a fiber. In addition, if necessary, titanium dioxide as a matting agent, silica or alumina fine particles as a lubricant, hindered phenol derivatives as antioxidants, coloring pigments, stabilizers, fluorescent agents, antibacterial agents, deodorants, reinforcing agents Etc. may be added.

  By disposing PTT as the polyester (A) in the present invention, the rigidity (Young's modulus) of the composite fiber is smaller than that of polyethylene terephthalate (hereinafter abbreviated as PET), so that the softness becomes excellent, and the nonwoven fabric, When formed into a woven or knitted fabric, it is possible to obtain a fabric with a good texture. Moreover, the nonwoven fabric, textile fabric, and knitted fabric which have the outstanding stretching property can be obtained by making a heat-shrinkage characteristic and the crimp expression ability appropriate.

  In the present invention, the polyester (B) constituting the other component of the composite fiber is different from the polyester (A) in terms of shrinkage characteristics. Here, the polymer having different shrinkage characteristics refers to a polymer having a difference in shrinkage when heat is applied. For example, a polyester having a composition different from that of the polyester (A) is used, or a component having a different main repeating unit. A copolymerized product can be used. For reasons such as suppression of changes in physical properties of PTT over time and improvement in yarn production, it is preferable that the main repeating unit is a copolymer polyester mainly composed of ethylene terephthalate units. As long as the effect of the present invention is not impaired, terephthalic acid is 50 mol% or more, more preferably 60 mol% or more, and still more preferably 70 mol% or more of the total acid content, and the rest is used as a copolymerization component. Aromatic dicarboxylic acid components such as isophthalic acid and 5-sodiumsulfoisophthalic acid, aliphatic dicarboxylic acids such as sebacic acid and adipic acid, diol components such as 1,4-butanediol and polyethylene glycol, and aromatic diol components such as BAEO In order to develop a spiral crimp having a high crimp holding power when heat treatment is performed, preferably 5 to 13 mol% of isophthalic acid and 2,2-bis [ 4- (2-hydroxyethoxy) phenyl] propane and / or bis [4- (2-hydroxyethoxy) phenyl] sulfone 2-7 It is preferable to use a polyester of ethylene terephthalate units mainly obtained by copolymerizing and Le%.

  The fiber of the present invention is a composite fiber in which polyester (A) and polyester (B) are eccentrically bonded, and is a latent crimped raw cotton that develops spiral crimps by relaxation heat treatment. Eccentric bonding refers to a side-by-side type or an eccentric core-sheath type, and the form is not particularly limited as long as the two components are bonded.

  In addition, the cross-sectional shape of the composite fiber may be circular, triangular, H-shaped, T-shaped, flat, or hollow.

  The composite ratio (weight ratio) of the polyester (A) and the polyester (B) in the composite fiber of the present invention is preferably 25/75 to 75/25. If it is out of this range, the yarn will bend greatly when discharged from the die in the spinning process, resulting in poor spinning and inferior latent crimp expression. More preferably, it is 40 / 60-60 / 40 from the surface of the extensibility when it becomes soft nature and a nonwoven fabric.

  The fineness of the composite fiber of the present invention is preferably in the range of 0.5 dtex to 30 dtex. If it is less than 0.5 dtex, the yarn forming property is poor or the card passing property is poor, which is not preferable because the nonwoven fabric is poor. Moreover, when it exceeds 30 dtex, when it is set as a nonwoven fabric, sufficient crimp expression is not obtained and it becomes a nonwoven fabric with poor flexibility. 1 dtex to 10 dtex are more preferable in terms of card passing property and use of mixed cotton with other materials.

  It is important that the crimp elastic modulus of the composite fiber of the present invention is 75% or more. In addition, the crimped elasticity modulus here shows what is measured by the method of JIS-L1015 (1999) -8-12-3. If the crimp elastic modulus is less than 75%, the crimp holding force is low, so that the crimp is stretched in a process where stress is applied to the fiber, such as the carding process and the needle punching process, and sufficient crimping is achieved. The performance is not obtained or the spiral shape is not exhibited, and when the nonwoven fabric is formed during the relaxation heat treatment, the stretchability is inferior. In applications that require high extensibility, such as cataplasms, it is more preferably 85% or more, and the higher the crimp elastic modulus, the more preferable it is.

  In the conjugate fiber of the present invention, the intrinsic viscosity of polyester (A) and polyester (B) is 0.7 to 1.5 for polyester (A) and 0.45 for polyester (B) from the viewpoint of smooth melt spinning. It is preferable that the difference between the intrinsic viscosities of the two polymers is 0.10 or more from the viewpoint of sufficient crimp expression and high crimp elastic modulus. Preferably it is 0.20 or more. Further, from the viewpoint of not impairing the spinnability, the intrinsic viscosity difference between the two polymers is preferably 0.70 or less.

  Furthermore, in order to obtain a woven fabric, knitted fabric or nonwoven fabric having stretchability and stretch recovery properties, the composite fiber of the present invention has a crimp expression number of 50 co / 25 mm or more during heat treatment under no load at 180 ° C. . If the number of crimps expressed is less than 50/25 mm, the stretchability is remarkably lowered and the stretch recovery property is low. There is no particular upper limit for the number of crimps to be expressed, but it is preferably 90 co / 25 mm or less from the viewpoint of particularly improving the texture when made into a nonwoven fabric.

  It is important that the nonwoven fabric of the present invention contains 60% by weight or more of the above-described composite short fiber of the present invention, and it is preferable that the nonwoven fabric be composed of 100% of the composite fiber. If the composite short fiber is less than 60% by weight, the nonwoven fabric excellent in stretchability as the object of the present invention cannot be obtained.

  The conjugate fiber of the present invention is obtained, for example, as follows.

  Polyester (A) and polyester (B) are melted and compound-spun using an ordinary spinning machine. Then, after stretching at an appropriate magnification, crimping is performed with a stuffing box type crimper, and then a relaxation heat treatment is performed at an appropriate temperature to make crimp expression latent. Next, after applying the oil agent, the fiber can be cut to a predetermined length to obtain the short fiber of the present invention.

  Further, other than the fibers of the present invention, ordinary polyester fibers, heat-bonding fibers, natural fibers such as cotton, wool, hemp and the like can be blended as appropriate within a range not exceeding 40% by weight.

  The nonwoven fabric of the present invention requires a web obtained by applying a short fiber made of the above-described conjugate fiber of the present invention alone or mixed with a normal polyester fiber or heat-sealing fiber as necessary, over a card. Depending on the condition, after performing needle punching or hydroentanglement, heat treatment is performed in a free state, and the latent crimps are manifested at a temperature at which the latent crimps of the composite fiber can be manifested, thereby causing entanglement between the fibers. It is possible to obtain a nonwoven fabric that is excellent in crimping, stretch recovery and dimensional stability.

  The elongation percentage of the nonwoven fabric of the present invention is preferably 70% or more. If the elongation rate is less than 70%, it cannot be applied to applications that require stretchability. The elongation rate is preferably as high as possible, and more preferably as close to 100%.

  Moreover, it is preferable that the elongation recovery rate of the nonwoven fabric of this invention is 65% or more, and a dimensional change rate is 10% or less. If the stretch recovery rate is less than 65%, the stretchability changes when used for products that repeatedly require stretchability, and cannot be developed for long-term use. When the dimensional change rate is in a range exceeding 10%, in applications such as a poultice, the elasticity and the adhesion to the skin are inferior due to the shape change. The elongation recovery rate is preferably as high as possible, and more preferably as close to 100%. Further, the dimensional change rate is preferably as low as possible and more preferably as close to 0%.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these specific examples.
(1) Intrinsic viscosity [η]
It calculated from the solution viscosity measured at 25 degreeC in the o-chlorophenol solution.
(2) Fineness Fineness was measured by the method shown in JIS L-1015 (1999) -8-5-1.
(3) Number of crimps The number of crimps (crests / 25 mm) was measured by the method shown in JIS L-1015 (1999) -8-12-1.
(4) Crimp elastic modulus: Shown by the crimp elastic modulus (%) measured by the method shown in JIS L-1015 (1999) -8-12-3.
(5) Texture (softness)
The touch feeling (texture; softness) when touched by 10 panelists is ranked as very good (10 points), good (8 points), normal (5 points), and bad (0 points). When the average score exceeds 8 points, the texture as the nonwoven fabric is very good (◎), 7 points to 8 points is good (◯), 4 points to less than 7 points is normal (△), 4 Less than points were evaluated as bad (x).
(6) Elongation rate About a nonwoven fabric test piece (5 cm x about 60 cm length), one end of the test piece is fixed with an upper clamp using a tensile tester, and an initial load of 30 g is applied to the other end. Then mark 50 cm intervals and gently apply a load of 240 g. The length between the marks after being left for 1 minute is measured, the elongation percentage (%) is calculated by the following formula, and the average value of 10 times (up to one decimal place) is expressed.

Elongation rate (%) = {(L1-L0) / L0} × 100
here,
L0: Length between original marks 50cm
L1: Length (cm) between marks after applying a load of 240 g and leaving for 1 minute
(7) Elongation recovery rate Using the same test piece as for the above elongation rate measurement, test using a low-speed extension type tensile tester with a self-recording device so that the distance between the grips is 50 cm under an initial load of 30 g. A piece was mounted and a pulling rate of 100% of the gripping interval per minute was determined. The test piece is stretched to 80% of the elongation at a load of 240 g, the elongation recovery rate (%) at a constant load of 240 g is determined by the following formula, and each is represented by an average value of 10 times.

Elongation recovery rate (%) = {(L10−L11) / L10} × 100
here,
L10: Elongation at 80% of elongation at a load of 240 g (cm) obtained at a 100% tensile speed at a grip interval per minute
L11: Residual elongation after repeated loading 5 times (cm)
(8) Dimensional change rate For a nonwoven fabric test piece (5 cm × about 60 cm length), one end of the test piece is fixed with an upper clamp using a tensile tester, and an initial load of 30 g is applied to the other end. Then mark 50 cm intervals. Next, the length is extended by 25% (12.5 cm) of the original length at a constant speed, and returned to the original length at a constant speed in the same manner as at the time of extension. Next, the length between the marks when the test piece was stretched until the load required when the test piece was stretched 25% first was measured, and the dimensional change rate was calculated by the following formula, and the average of 10 times Expressed by value.

Dimensional change rate (%) = {(L110−L100) / L100} × 100
here,
L100: Length between original marks (50cm)
L110: A length (12.5 cm) of 25% of the original length is extended at a constant speed, and returned to the original length at a constant speed in the same manner as at the time of extension. Next, the length between the marks (cm) when the test piece was stretched until it became a load required when the test piece was stretched 25% first.
(9) Number of crimps expressed at 180 ° C .:
In accordance with the method of JIS L-1015 (1999) -8-12-1, after heat-treating one obtained fiber in a heat-shrinkable state at 180 ° C. for 3 minutes in a state where it can freely shrink. Measured.

Example 1
PTT having an intrinsic viscosity [η] of 1.3 as the polyester (A), ethylene terephthalate as the main component as the polyester (B), 7.1 mol% of isophthalic acid (hereinafter IPA), 2,2-bis [4- ( 2-hydroxyethoxy) phenyl] propane (hereinafter referred to as BHPP) 4.4 mol% polyester was discharged from a round cross-section die hole at a spinning temperature of 280 ° C. at a spinning temperature of 280 ° C. using a composite melt spinning device, and discharged. Winding was performed at an amount of 310 g / min and a speed of 1200 m / min to obtain a side-by-side undrawn yarn. The obtained yarn is converged to 130,000 dtex, drawn in a bath having a draw ratio of 3.0 times and a drawing temperature of 85 ° C., subjected to tension heat treatment at a temperature of 140 ° C., and mechanical crimped by an indentation crimper. Then, an oil agent was applied to the fiber by a spray method so as to be 0.3% by weight with respect to the fiber, and then cut to obtain a short fiber having 13 crimps / 25 mm of crimps.

Next, the short fibers are opened with an opener, a web having a basis weight of 120 g / cm ² is prepared using a card machine, needle punching is performed to entangle the fibers, and then in an oven at 160 ° C. Was subjected to free shrink heat treatment for 2 minutes to obtain a nonwoven fabric.

Example 2
Example PTT having intrinsic viscosity [η] of 1.3 as polyester (A), and polyester obtained by copolymerizing ethylene terephthalate as a main component and IPA 6.0 mol% and BHPP 5.4 mol% as polyester (B) 1 and the same manufacturing method, the fiber and the nonwoven fabric were obtained.

Comparative Examples 1-3
Each polyester (A) is a polyester having an intrinsic viscosity [η] of 0.65 consisting essentially of ethylene terephthalate, and terephthalic acid is the main carboxylic acid component as polyester (B), and 9.1 mol% of IPA is copolymerized. Polymer (Comparative Example 1), polymer obtained by copolymerization of 5.1 mol% of 5-sodium isophthalic acid (Comparative Example 2), IPA 3.4 mol% and 5-sodium isophthalic acid (abbreviated as 5-SIPA in Table 1) 2.4 mol % And a non-woven fabric were obtained in the same manner as in Example 1 except for using three types of polymers (Comparative Example 3).

  Table 1 shows various characteristics of the composite short fibers and nonwoven fabrics obtained in Examples 1 and 2 and Comparative Examples 1 to 3. As is clear from Table 1, in the polyester-based composite fibers obtained in Examples 1 and 2, those having excellent nonwoven fabric stretchability and flexibility are obtained. For example, when used in a patch or the like, to the skin. The adhesion was good. On the other hand, in Comparative Examples 1 to 3, the stretchability was poor, the recovery after stretching was poor, the dimensional stability and the texture were poor, and the flexibility was poor.

Claims (4)

A composite short fiber in which a polyester (A) whose main repeating unit is a trimethylene terephthalate unit and a polyester (B) having a different shrinkage property from the polyester (A) are eccentrically bonded, and having a crimped elastic modulus A polyester composite short fiber characterized by having a crimp appearance number of not less than 50% / 25 mm at 75% or more and heat treatment under no load at 180 ° C. 2. The polyester composite short fiber according to claim 1, wherein the polyester (B) is composed of a copolyester mainly composed of ethylene terephthalate units. Polyester (B) has 5 to 13 mol% of isophthalic acid as a copolymerization component and 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane and / or bis [4- (2-hydroxyethoxy) phenyl] sulfone. 3. The polyester composite short fiber according to claim 1, wherein the polyester composite short fiber is a polyester mainly composed of ethylene terephthalate units copolymerized with 2 to 7 mol%. A nonwoven fabric containing 50% by weight or more of the polyester composite short fiber according to any one of claims 1 to 3, wherein the elongation rate is 70% or more, the elongation recovery rate is 65% or more, and the dimensional change rate is 10%. A non-woven fabric characterized by: