JP2011069010A - Latently crimped fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester conjugate fiber not manifesting latent crimps in a raw staple-producing process, and manifesting the latent crimping ability having excellent elasticity and bulkiness in a secondary finishing at a comparatively low temperature. <P>SOLUTION: The conjugate fiber in a side-by-side type comprises a polyester-based resin A and a polyester-based resin B, regulated so that the weight ratio of the polyester-based resin A to the polyester-based resin B may be within the range of from 40:60 to 60:40, and the polyester-based resin B may contain 10-30 mol% of isophthalic acid and 2-10 mol% of diethylene glycol. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a composite fiber having a high potential for crimp formation during heat treatment, or a high crimp produced thereby, and a fiber assembly constituted thereby.

  Since composite fibers having latent crimping ability can impart good bulkiness and stretch recovery to fabrics such as woven and knitted fabrics and nonwoven fabrics, several proposals have been made in the past. For example, by compound spinning of two polyesters with different shrinkage properties, such as polyesters copolymerized with normal polyester and isophthalic acid having isophthalic acid or sulfonate groups, latent crimps are developed during heat treatment, and elasticity is improved. It is known that the fiber which has can be obtained (for example, refer patent document 1). However, high temperature treatment was necessary to develop crimp in the above-described composite fiber. For this reason, there is a possibility that the raw cotton may be thermally deteriorated or stuck between fibers, resulting in a decrease in texture.

  On the other hand, as a means for solving these problems, several proposals have been made on composite fibers that develop crimps at low temperatures (see, for example, Patent Documents 2 to 3). However, in the case of these composite fibers, since polyester having a difference in intrinsic viscosity and melt viscosity is used, the oblique direction of the fibers discharged from the nozzle during spinning becomes large, and it becomes difficult to perform melt spinning continuously. Not only that, but the raw cotton drying process after the stretching process may cause crimping, which may cause a problem in handling properties.

  From such a problem, as a demand for raw cotton having latent crimping ability, latent crimp is not expressed in the raw cotton manufacturing process, for example, latent crimp is expressed at a relatively low temperature during secondary processing after the web manufacturing process. There is a need for fiber.

JP 2005-029644 A JP-A-9-228218 Japanese Patent Laid-Open No. 3-019916

  An object of the present invention is to provide a polyester-based composite fiber that does not express latent crimps in the raw cotton production process and that is relatively low-temperature during secondary processing, and has excellent stretchability or bulkiness and exhibits latent crimping ability. It is for the purpose.

  As a result of intensive studies to solve the above problems, the present inventors have made a so-called side-by-side type composite fiber obtained by combining and spinning a specific two kinds of polyesters in a side-by-side type. It has been found that a composite fiber that does not develop latent crimps and that develops latent crimps can be obtained by applying heat treatment during secondary processing.

  That is, the present invention is a side-by-side type composite fiber comprising a polyester resin A and a polyester resin B, and the weight ratio of the polyester resin A to the polyester resin B is in the range of 40:60 to 60:40. And the polyester resin B is a composite fiber characterized in that it contains 10 to 30 mol% of isophthalic acid and 2 to 10 mol% of diethylene glycol. Preferably, the melting point of the polyester resin B is 180 to 250 ° C. It is said composite fiber characterized by the above.

  Furthermore, in the present invention, the number of crimps that preferably develops during dry heat treatment at 110 ° C. is 20 or more and 80 or less per 25 mm fiber length, and the crimp rate that develops during dry heat treatment at 110 ° C. is 20% or more and 50 %, And more preferably, the area shrinkage rate is less than 50% when dry-heat treated at 90 ° C. for 1 minute, and dried at 110 ° C. for 1 minute. The composite fiber is characterized in that the area shrinkage rate when heat-treated is 70% or more.

  And this invention is a fiber assembly comprised from said composite fiber.

  According to the present invention, there is provided a polyester-based composite fiber that does not express latent crimping in the raw cotton production process and that exhibits a latent crimping ability that is relatively low temperature during secondary processing and has excellent stretchability or bulkiness. Therefore, there is an advantage that a stable nonwoven fabric can be obtained at low cost without causing thermal degradation of the raw cotton due to heat treatment at high temperature. Moreover, since there is no expression of latent crimps in the production process, stable production can be performed.

Hereinafter, the present invention will be described in detail. The composite fiber used in the present invention refers to a so-called side-by-side type composite fiber obtained by performing composite spinning by combining two specific types of polyester in a side-by-side type.
The composite fiber of the present invention can be produced by performing melt composite spinning using the polyester-based resin A and the polyester-based resin B, and performing a stretching treatment, a heat treatment or the like as necessary. Various conditions such as spinning temperature, take-up speed, stretching temperature, stretching ratio, heat treatment temperature and the like can be appropriately selected and set according to the raw cotton properties such as target fineness and shrinkage rate. For example, the polyester resin A and the polyester resin B are melted by separate extruders, the melts are introduced into a spinning device having a composite spinning pack, and are spun by joining and compounding in a side-by-side type in the spinning pack. Thus, a side-by-side type composite fiber can be produced. In this case, each polymer is usually melted at 300 ° C. or lower, and a spinning temperature in the range of 250 to 300 ° C. is employed. As for the post-spinning process, after spinning, if necessary, the fiber may be stretched. Considering the strength and elongation characteristics of the resulting fiber, the stretching temperature is 50 to 90 ° C., and the stretching ratio is 2 to 5 times. It is desirable to stretch.

  The polyester-based resin A which is one component of the composite fiber in the present invention is a general polyethylene terephthalate resin, and preferably contains 47 mol% or more of terephthalic acid residues and ethylene glycol residues, respectively. As long as it is satisfied, a small amount of a dicarboxylic acid component and an oxycarboxylic acid component may be included as copolymerized units as the third component. In this case, examples of other dicarboxylic acid components include aromatic dicarboxylic acids such as diphenyldicarboxylic acid and naphthalenedicarboxylic acid or ester-forming derivatives thereof; dimethyl 5-sodium sulfoisophthalate, bis (sodium sulfoisophthalate) ( Metal sulfonate group-containing aromatic carboxylic acid derivatives such as 2-hydroxyethyl); aliphatic dicarboxylic acids such as oxalic acid, adipic acid, sebacic acid, dodecanedioic acid or ester-forming derivatives thereof. Examples of the oxycarboxylic acid component include p-oxybenzoic acid, p-β-oxyethoxybenzoic acid, or ester-forming derivatives thereof.

  The other component, polyester-based resin B, is a modified polyethylene terephthalate resin in which 10 to 30 mol% of isophthalic acid (hereinafter referred to as IPA) and 2 to 10 mol% of diethylene glycol are copolymerized. As long as it contains 20-40 mol% of acid and 40-49 mol% of ethylene glycol and satisfies the effects of the invention, it may have copolymer units similar to the third component of polyester resin A.

  When the IPA copolymerized in the polyester resin B is less than 10 mol%, the difference in thermal shrinkage with the polyester resin A is reduced, so that the crimp developability during heat treatment is inferior, and the crimp developed during 110 ° C. dry heat treatment. The physical properties of 20 or more and 80 or less per 25 mm fiber length cannot be secured. On the other hand, if the IPA exceeds 30 mol%, the oblique direction when discharged from the spinneret increases, and not only the spinning process properties deteriorate, but also the crimp development during heat treatment becomes stronger. Crimps appear, adversely affecting subsequent processes, and the melting point due to IPA modification is excessively lowered, causing sticking between fibers during heat treatment, resulting in poor texture. Therefore, in order to satisfy the effects of the present invention, the IPA copolymerized in the polyester resin B needs to be 10 to 30 mol%, preferably 12 to 25 mol%, and preferably 15 to 20 mol%. It is more preferable.

On the other hand, diethylene glycol is produced as a by-product during the polymerization of polyester, and is usually present in the polyester at around 1%. However, in order to reduce heat resistance and light resistance, it is present in a large amount in the polyester. It is not preferable. However, in order to ensure the physical properties of the present invention, it is necessary to contain 2 to 10 mol% of diethylene glycol in the polyester resin B. The straight chain part composed of diethylene glycol is amorphous, but since it is oriented along the fiber direction by stretching, the polyester modified with diethylene glycol is relaxed by heating to a temperature above the glass transition point (Tg). Causes heat shrinkage. Therefore, in the raw cotton production process, latent crimps are not expressed, and in order to develop the latent crimping ability at a relatively low temperature during secondary processing, it is necessary that the polyester resin B contains 2 mol% or more of diethylene glycol. It is. When diethylene glycol is less than 2 mol%, the weight ratio of IPA is increased, but the IPA molecule is weakly oriented even after stretching treatment, so shrinkage due to orientation relaxation during heat treatment is reduced, and the shrinkage performance of raw cotton is reduced. descend. Therefore, it is necessary to contain 2 mol% or more of diethylene glycol.
On the other hand, when the diethylene glycol content exceeds 10 mol%, the melt viscosity is lowered, and not only the spinning condition is deteriorated due to the oblique direction at the time of discharge of the die, but also the thermal deterioration progresses and the spinning condition is also deteriorated. . Furthermore, since the light resistance and heat resistance of the obtained raw cotton also deteriorate, it is not preferable. Therefore, in order to satisfy the effect of the present invention, the diethylene glycol content in the polyester resin B needs to be 2 to 10 mol%, preferably 2 to 8 mol%, and 3 to 7 mol%. More preferred.

The composite fiber of the present invention requires that the composite ratio (weight ratio) of the polyester resin A and the polyester resin B is polyester resin A: polyester resin B = 40: 60 to 60:40, 45 : 55-55: 45 is preferable.
When the weight ratio of the polyester-based resin B exceeds 60%, there is a problem that bending when discharged from the spinneret increases, and the discharged polymer adheres to the base and leads to yarn breakage. On the other hand, when the weight ratio of the polyester-based resin B is less than 40%, the oblique direction opposite to the previous oblique direction occurs, and similarly to the previous case, the discharged polymer adheres to the base and leads to a yarn breakage. is there. Furthermore, when the weight ratio of the polyester resin B is less than 40%, the difference in heat shrinkage stress between the polyester resin A and the polyester resin B is small, and therefore the number of crimps that develops during the dry heat treatment at 110 ° C. is 25 mm in fiber length. The physical properties of 20 or more and 80 or less cannot be secured.

The intrinsic viscosity [η] of the polyester resin used in the present invention is preferably 0.4 to 1.0 dl / g, more preferably 0.5 to 0.8 dl / g, and still more preferably 0.6 to 0. 0.7 dl / g. An intrinsic viscosity [η] of less than 0.4 is not preferable because the molecular weight of the polymer is too low and it becomes difficult to develop strength. In addition, when the intrinsic viscosity [η] is 1.0 dl / g or more, flow spots of the molten polymer easily occur in the spinneret and the spinnability becomes unstable, which is not preferable.
The intrinsic viscosity [η] is an intrinsic viscosity (dl / g) measured with a mixed solvent of tetrachloroethane: phenol = 1: 1 (weight ratio) at 30 ° C. using an Ubbelohde viscometer.

The fiber obtained by the present invention is a side-by-side type composite fiber comprising a polyester resin A and a polyester resin B, and the polyester resin B is a modified polyester containing IPA 10-30 mol% and diethylene glycol 2-10 mol%. Therefore, the melting point of the polyester resin B is lower than the melting point of the polyester resin A. However, in order to satisfy the present invention, the melting point of the polyester resin B is preferably 180 to 250 ° C., more preferably 190. It is -240 degreeC, More preferably, it is 200-230 degreeC. When the melting point of the polyester resin B is less than 180 ° C., the nonwoven fabric produced using the obtained raw cotton is subjected to heat treatment to develop latent crimps, causing sticking between the fibers, resulting in poor texture. Therefore, it is not preferable. On the other hand, when the melting point of the polyester resin B exceeds 250 ° C., the target crimp of the present invention does not appear.
The melting point was obtained from a differential thermal analysis curve when the temperature was increased to 300 ° C. at a temperature increase rate of 10 ° C./min in a nitrogen atmosphere using Thermo Plus TG8120 manufactured by Rigaku Corporation.

  The single fiber length of the fiber of the present invention is not particularly limited, but is preferably in the range of 10 mm to 150 mm. When the fiber length deviates from these ranges, for example, when the carding process is performed, the processability is deteriorated, and a defect in product processing may occur. The fiber length is more preferably in the range of 20 to 100 mm from the viewpoint of improving the card passing property at the time of product processing and the formation of the nonwoven fabric.

Although the composite fiber of the present invention is characterized by having latent crimpability, it is desirable that the composite fiber itself is preliminarily used as a crimped yarn from the viewpoint of improving the card passing property during product processing. More specifically, the number of mechanical crimps per fiber length of 25 mm is preferably 5-30, more preferably in the range of 5-30%, and even more preferably mechanical crimps per fiber length of 25 mm. The number is 10 to 25 and the crimp rate is in the range of 10 to 25%. If the crimping rate is less than 5%, the fibers fall off during the carding process, making it difficult to pass through the process. On the other hand, if the crimping rate exceeds 30%, winding around the cylinder occurs during the carding process, and not only carding becomes difficult, but also nep is generated, which is not preferable.
As a method for imparting mechanical crimp, a general stuffing box method, a heating gear method, or the like is employed.

The conjugate fiber of the present invention is a conjugate fiber having latent crimping ability that develops a spiral crimp by performing heat treatment regardless of whether it is dry heat or wet heat. Spiral crimp refers to a crimp having a three-dimensional spiral structure.
Specifically, the number of crimps developed during a dry heat treatment at 110 ° C. is preferably 20 or more and 80 or less, more preferably 30 or more and 60 or less per 25 mm fiber length.
If the number of crimps is less than 20, good bulkiness and stretch recovery cannot be imparted to the resulting woven or knitted fabric or nonwoven fabric, and it is difficult to obtain a fabric having sufficient performance. Become.
Further, when the number exceeds 80, the entanglement between the fibers becomes too strong, the texture becomes hard, and a good fabric cannot be obtained.

  Furthermore, it is preferable that the crimp rate developed at the time of the dry heat treatment at 110 ° C. is 20% or more. When the crimp rate is less than 20%, the resulting woven or knitted fabric or nonwoven fabric does not have good stretch recovery properties, which is not preferable. On the other hand, if the crimp rate is too high, the fabric feels too hard, so it is necessary to be 50% or less, and more preferably 40% or less.

Since the conjugate fiber of the present invention has a latent crimping ability that develops a spiral crimp by heat treatment, the web produced using the conjugate fiber of the present invention is characterized by shrinkage during the heat treatment. Shrinkage during heat treatment can be expressed by area shrinkage. The area shrinkage ratio during dry heat treatment of a web prepared using the conjugate fiber of the present invention is preferably less than 50% in the case of 90 ° C. treatment for 1 minute and 70% or more in the case of 110 ° C. treatment for 1 minute. .
In addition, the area shrinkage rate in this invention calculates the area (A1) by creating a web with a basis weight of 100 g / cm ² and 20 cm × 20 cm using a miniature card, measuring the length in the vertical direction × the horizontal direction in advance. . Next, the measured sample is subjected to a dry heat treatment at a predetermined temperature for 1 minute, and the area (A2) is calculated. The area shrinkage rate is calculated from the following formula.
Area shrinkage rate (%) = [(A1-A2) / A1] × 100

  An area shrinkage rate of 50% or more when treated at 90 ° C. for 1 minute indicates that crimp performance is exhibited in the raw cotton production process, and area shrinkage when treated at 110 ° C. for 1 minute. A rate of less than 70% indicates that the latent crimping ability is low, and it is impossible to obtain a raw cotton excellent in stretchability or bulkiness. Therefore, a polyester composite fiber that expresses the latent crimping ability, which is the effect of the present invention, does not express latent crimping in the raw cotton production process, is relatively low temperature during secondary processing, and has excellent stretchability or bulkiness. In order to provide, it is preferable that the area shrinkage rate at 90 ° C. for 1 minute is less than 50%, more preferably less than 30%, and the area shrinkage rate at 110 ° C. for 1 minute. Is preferably 70% or more, more preferably 80% or more.

Furthermore, the composite fiber of the present invention preferably has a dry heat shrinkage at 120 ° C. of 30% or less, more preferably 20% or less. A dry heat shrinkage of 30% or more is not preferable because the dimensional stability during the production of the nonwoven fabric is deteriorated.
In the present invention, the dry heat shrinkage rate is obtained by cutting the composite fiber to about 50 cm and tying both ends so that the knot interval is 35 cm using a drooping device having appropriate performance. The weight is measured using a direct balance, an initial load of 50 mg per denier is added, and the yarn length between the knots is measured (L1). Next, the initial load is removed, and heat treatment is performed at 120 ° C. for 15 minutes in a hot air dryer. After allowing to cool, a load of 50 mg per denier is added again and the yarn length between the knots is measured (L2). The dry heat shrinkage is calculated and calculated by the following formula.
Dry heat shrinkage (%) = [(L1-L2) / L1] × 100

  The single fiber fineness of the fiber of the present invention is not particularly limited, but is preferably 0.5 to 10 dtex, and 1.0 to 5.0 dtex is more preferable in order to express a good texture and stretchability more remarkably. preferable. When the single fiber fineness is less than 0.5 dtex, there is a problem that winding around the cylinder occurs during the carding process, and carding becomes difficult. In addition, when the single fiber fineness exceeds 10 dtex, the diameter of the spiral crimp generated during the heat treatment becomes large, so the number of crimps during the 110 ° C. dry heat treatment that is the object of the present invention reaches the target number of crimps. This is not preferable.

  In the composite fiber of the present invention, the cross-sectional shape of the fiber is not limited to a round cross section as long as the effects of the present invention are not impaired, but a flat cross section, a polygonal cross section, a multileaf cross section, a U-shaped cross section, a Y-shaped cross section, and the like. These can have a modified cross section, a hollow cross section, or the like.

  In the conjugate fiber of the present invention, the polyester resin A and the polyester resin B may include inorganic fine particles, fragrance, antibacterial agent, flame retardant, deodorant, dye / pigment, matting agent, antistatic agent (as required). 1 type of arbitrary additives, such as an antistatic agent), antioxidant, and a light stabilizer, or may contain 2 or more types.

  In addition, the fiber assembly composed of the conjugate fiber of the present invention includes, for example, a woven fabric, a knitted fabric, a dry nonwoven fabric or a wet nonwoven fabric, and the production method includes, for example, a card method, an airlaid method, or a papermaking method. The one obtained in Further, it may be produced by blending with other fiber aggregates at an arbitrary ratio according to the purpose of use and production method, and other fiber aggregates are synthetic fibers other than the present invention, wool, cotton, hemp , Which consists of natural fibers such as silk. In addition to this, for example, by utilizing the fact that the fiber surface is melted in a wet or water-containing state, it is assembled with other fibers in a steam atmosphere, or is aggregated with other fibers under hot hot water. Or a fiber assembly obtained by molding in the above-mentioned atmosphere.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these at all.

<Terephthalic acid content mol%>
^The measurement was performed using a ¹ H-NMR spectrometer (500 MHz manufactured by JEOL).
<IPA content mol%>
The sample was sandwiched between glass slides and heated to 275 ° C. to form a thin film sample, and the IPA content was determined using a SYSTEM2000FT-IR manufactured by PerkinElmer.
<Ethylene glycol content mol%>
The sample was dissolved in a 10% hydrazine / butanol solvent, and measurement was performed using a gas chromatograph GC-8A type manufactured by SHIMADZU and a CR-6A chromatopack.
<Diethylene glycol content mol%>
The sample was dissolved in a 10% hydrazine / butanol solvent, and measurement was performed using a gas chromatograph GC-8A type manufactured by SHIMADZU and a CR-6A chromatopack.

<Area shrinkage%>
Using a miniature card, a web having a basis weight of 100 g / cm ² and 20 cm × 20 cm is created, the length in the vertical direction × the horizontal direction is measured in advance, and the area (A1) is calculated. Next, the measured sample is subjected to a dry heat treatment at a predetermined temperature for 1 minute, and the area (A2) is calculated. The area shrinkage rate was calculated from the following formula.
Area shrinkage rate (%) = [(A1-A2) / A1] × 100

<Dry heat shrinkage%>
Cut the composite fiber to about 50 cm, and use a drooping device with appropriate performance to tie both ends so that the knot spacing is 35 cm. The weight is measured using a direct balance, an initial load of 50 mg per denier is added, and the yarn length between the knots is measured (L1). Next, the initial load is removed, and heat treatment is performed at 120 ° C. for 15 minutes in a hot air dryer. After allowing to cool, a load of 50 mg per denier is added again and the yarn length between the knots is measured (L2).
The dry heat shrinkage rate was calculated by the following formula.
Dry heat shrinkage (%) = [(L1-L2) / L1] × 100

<Number of crimps>
The evaluation was made according to JIS L1015 “Testing method for chemical fiber staples (8.12.1)”.
<Crimping rate%>
Evaluation was made according to JIS L1015 “Testing method for chemical fiber staples (8.12.2)”.

[Example 1]
(1) Polyester resin A containing 50 mol% terephthalic acid, 49.2 mol% ethylene glycol, and 0.8 mol% diethylene glycol, 30 mol% terephthalic acid, 20 mol% IPA, and 46.8 mol% ethylene glycol Polyester resin B containing 3.2 mol% of diethylene glycol was spun at 295 ° C. using a composite melt spinning apparatus, spinning temperature of 295 ° C., composite ratio (A / B) = 50/50 (weight ratio), single hole It spun | joined and spun in the side by side type | mold with the discharge amount of 0.4 g / min. The spun yarn was cooled and solidified, and then wound on a bobbin via a take-up roller.
(2) Next, this crimped yarn was heat-drawn at a drawing temperature of 90 ° C. at a draw ratio of 3 times, and after applying an oil agent in an oil agent bath, a mechanical crimping treatment was performed. The mechanical crimping treatment was performed using a crimping device such as a normal stuffer type crimping device. Subsequent to the crimping treatment, the fibers were dried with hot air at 80 ° C. and then cut to 51 mm to obtain short fibers having a single yarn fineness of 1.7 dtex and a crimp number of 12/25 mm. Both spinnability and stretchability were good. The results are shown in Table 1.
(3) Next, the 120 ° C. dry heat shrinkage rate, the crimp number rate after 110 ° C. dry heat treatment, and the area shrinkage rate after web creation of the fiber obtained in (2) above were measured. The results are shown in Table 2.

[Example 2]
(1) Polyester resin A containing 50 mol% terephthalic acid, 49.2 mol% ethylene glycol, and 0.8 mol% diethylene glycol, 40 mol% terephthalic acid, 10 mol% IPA, and 47.6 mol% ethylene glycol Polyester resin B containing 2.4 mol% of diethylene glycol was spun at 295 ° C. using a composite melt spinning apparatus, spinning temperature of 295 ° C., composite ratio (A / B) = 50/50 (weight ratio), single hole It spun | joined and spun in the side by side type | mold with the discharge amount of 0.4 g / min. The spun yarn was cooled and solidified, and then wound on a bobbin via a take-up roller.
(2) Next, this crimped yarn was heat-drawn at a drawing temperature of 90 ° C. at a draw ratio of 3 times, and after applying an oil agent in an oil agent bath, a mechanical crimping treatment was performed. Subsequent to the mechanical crimping treatment, the fiber was dried with hot air at 80 ° C. and then cut to 51 mm to obtain a short fiber having a single yarn fineness of 1.7 dtex and a crimp number of 12/25 mm. Both spinnability and stretchability were good. The results are shown in Table 1.
(3) Next, the 120 ° C. dry heat shrinkage rate, the crimp number rate after 110 ° C. dry heat treatment, and the area shrinkage rate after web creation of the fiber obtained in (2) above were measured. The results are shown in Table 2.

[Example 3]
(1) Polyester resin A containing 50 mol% terephthalic acid, 49.2 mol% ethylene glycol, and 0.8 mol% diethylene glycol, 30 mol% terephthalic acid, 20 mol% IPA, and 46.8 mol ethylene glycol % Polyester resin B containing 3.2 mol% of diethylene glycol residue was spun at 295 ° C. using a compound melt spinning apparatus with a round cross-section die, compound ratio (A / B) = 56/44 (weight ratio) Then, spun by bonding to a side-by-side mold at a single hole discharge rate of 0.4 g / min. The spun yarn was cooled and solidified, and then wound on a bobbin via a take-up roller.
(2) Next, this crimped yarn was heat-drawn at a drawing temperature of 90 ° C. at a draw ratio of 3 times, and after applying an oil agent in an oil agent bath, a mechanical crimping treatment was performed. The mechanical crimping treatment was performed using a crimping device such as a normal stuffer type crimping device. Subsequent to the crimping treatment, the fibers were dried with hot air at 80 ° C. and then cut to 51 mm to obtain short fibers having a single yarn fineness of 1.7 dtex and a crimp number of 12/25 mm. Both spinnability and stretchability were good. The results are shown in Table 1.
(3) Next, the 120 ° C. dry heat shrinkage rate, the crimp number rate after 110 ° C. dry heat treatment, and the area shrinkage rate after web creation of the fiber obtained in (2) above were measured. The results are shown in Table 2.

[Example 4]
(1) Polyester resin A containing 50 mol% terephthalic acid, 49.2 mol% ethylene glycol, and 0.8 mol% diethylene glycol, 30 mol% terephthalic acid, 20 mol% IPA, and 46.8 mol ethylene glycol % Polyester resin B containing 3.2% by mole of diethylene glycol is prepared by using a composite melt spinning apparatus with a round cross-section die at a spinning temperature of 295 ° C., a composite ratio (A / B) = 45/55 (weight ratio), It spun | joined and spun in the side-by-side type | mold with the hole discharge amount of 0.4 g / min. The spun yarn was cooled and solidified, and then wound on a bobbin via a take-up roller.
(2) Next, this crimped yarn was heat-drawn at a drawing temperature of 90 ° C. at a draw ratio of 3 times, and after applying an oil agent in an oil agent bath, a mechanical crimping treatment was performed. The mechanical crimping treatment was performed using a crimping device such as a normal stuffer type crimping device. Subsequent to the crimping treatment, the fibers were dried with hot air at 80 ° C. and then cut to 51 mm to obtain short fibers having a single yarn fineness of 1.7 dtex and a crimp number of 12/25 mm. Both spinnability and stretchability were good. The results are shown in Table 1.
(3) Next, the 120 ° C. dry heat shrinkage rate, the crimp number rate after 110 ° C. dry heat treatment, and the area shrinkage rate after web creation of the fiber obtained in (2) above were measured. The results are shown in Table 2.

[Comparative Example 1]
Polyester resin A containing 50 mol% terephthalic acid, 49.2 mol% ethylene glycol, and 0.8 mol% diethylene glycol, 30 mol% terephthalic acid, 20 mol% IPA, 46.8 mol% ethylene glycol, diethylene glycol Polyester resin B containing 3.2 mol% of the resin with a round cross-section die using a composite melt spinning apparatus, spinning temperature of 295 ° C., composite ratio (A / B) = 35/65 (weight ratio), single hole discharge amount When spinning as a side-by-side type at 0.4 g / min, the increase in the weight ratio of the polyester-based resin B causes severe kneeing (diagonal discharge) when releasing the die, leading to thread breakage, making it impossible to cut Met.

[Comparative Example 2]
(1) Polyester resin A containing 50 mol% terephthalic acid, 49.2 mol% ethylene glycol, and 0.8 mol% diethylene glycol, 16 mol% terephthalic acid, 34 mol% IPA, and 42.5 mol ethylene glycol % Polyester resin B containing 7.5 mol% of diethylene glycol is prepared by using a composite melt spinning apparatus with a round cross-section die at a spinning temperature of 295 ° C., a composite ratio (A / B) = 50/50 (weight ratio), It spun | joined and spun in the side-by-side type | mold with the hole discharge amount of 0.4 g / min. The spun yarn was cooled and solidified, and then wound on a bobbin via a take-up roller.
(2) Next, this crimped yarn was heat-drawn at a drawing temperature of 90 ° C. at a draw ratio of 3 times, and after applying an oil agent in an oil agent bath, a mechanical crimping treatment was performed. Subsequent to the mechanical crimping treatment, the fibers were dried with hot air at 80 ° C., and latent crimps were developed in the drying process.
(3) Table 2 shows the physical properties of the fiber obtained in (2) above after various heat treatments. When the 120 ° C. dry heat shrinkage was measured, the copolymerization ratio of IPA was too large and agglutination occurred between the fibers, so that the measured value could not be obtained. Similarly, the crimp number ratio after the dry heat treatment at 110 ° C. did not reach the measurement result because the crimp expression performance was too strong.

[Comparative Example 3]
(1) Polyester resin A containing 50 mol% terephthalic acid, 49.2 mol% ethylene glycol, and 0.8 mol% diethylene glycol, 30 mol% terephthalic acid, 20 mol% IPA, and 38 mol% ethylene glycol, Polyester resin B containing 12 mol% of diethylene glycol is spun at 295 ° C., compound ratio (A / B) = 50/50 (weight ratio), single-hole discharge rate 0 with a round cross-section die using a compound melt spinning apparatus. It spun | joined and spun to the side-by-side type | mold at 0.4 g / min. The spun yarn was cooled and solidified, and then wound on a bobbin via a take-up roller.
(2) Next, this crimped yarn was heat-drawn at a drawing temperature of 90 ° C. at a draw ratio of 3 times, and after applying an oil agent in an oil agent bath, a mechanical crimping treatment was performed. Subsequent to the mechanical crimping treatment, the fibers were dried with hot air at 80 ° C., and latent crimps were developed in the drying process.
(3) Table 2 shows the physical properties of the fiber obtained in (2) above after various heat treatments. When the 120 degreeC dry heat shrinkage rate was measured, since there was too much diethylene glycol, it became a highly shrinkable fiber.

[Comparative Example 4]
(1) Polyester resin A containing 50 mol% terephthalic acid, 49.2 mol% ethylene glycol, and 0.8 mol% diethylene glycol, 42 mol% terephthalic acid, 8 mol% IPA, and 48.1 mol ethylene glycol % Polyester resin B containing 1.9 mol% of diethylene glycol was prepared by using a composite melt spinning apparatus with a round cross-section die at a spinning temperature of 295 ° C., a composite ratio (A / B) = 50/50 (weight ratio), It spun | joined and spun in the side-by-side type | mold with the hole discharge amount of 0.4 g / min. The spun yarn was cooled and solidified, and then wound on a bobbin via a take-up roller.
(2) Next, the drawn yarn was hot drawn at a drawing temperature of 90 ° C. at a draw ratio of 3 times, and was cut to 51 mm after imparting mechanical crimping to obtain a single yarn fineness of 1.7 dtex, a number of crimps of 12 / 25 mm short fibers were obtained.
(3) Table 2 shows the physical properties of the fiber obtained in (2) above after various heat treatments. Since the copolymerization ratio of IPA was small, it became a low shrinkage raw cotton.

[Comparative Example 5]
(1) Polyester resin A containing 50 mol% terephthalic acid, 49.2 mol% ethylene glycol, and 0.8 mol% diethylene glycol, 30 mol% terephthalic acid, 20 mol% IPA, and 46.8 mol ethylene glycol % Polyester resin B containing 3.2 mol% of diethylene glycol was prepared by using a composite melt spinning apparatus with a round cross-section die at a spinning temperature of 295 ° C., a composite ratio (A / B) = 50/50 (weight ratio), Spinning was carried out by bonding the polyester resin A to the sheath component and the polyester resin B to the core component at a hole discharge rate of 0.4 g / min. The spun yarn was cooled and solidified, and then wound on a bobbin via a take-up roller.
(2) Next, this crimped yarn was heat-drawn at a drawing temperature of 90 ° C. at a draw ratio of 3 times, and after applying an oil agent in an oil agent bath, a mechanical crimping treatment was performed. The mechanical crimping treatment was performed using a crimping device such as a normal stuffer type crimping device. Subsequent to the crimping treatment, the fibers were dried with hot air at 80 ° C. and then cut to 51 mm to obtain short fibers having a single yarn fineness of 1.7 dtex and a crimp number of 12/25 mm. Both spinnability and stretchability were good. Table 2 shows the physical properties of the obtained fibers after various heat treatments.

The composite fiber of the present invention is a latent crimpable fiber that develops crimps by heat treatment at 100 ° C. or higher, and in a relatively low temperature (˜50 ° C.) atmosphere as in a normal drawing step and a drying step. The process can be passed through without developing crimps.
Therefore, it has the advantage that there is no fear of winding around the fiber spreader due to the latent crimps that are developed before the fiber-opening treatment, compared to fibers that develop latent crimps at low temperatures.
Moreover, since the temperature required for the expression of latent crimp is sufficient at a heat treatment of less than 120 ° C., there is an advantage that there is no possibility of fusion between fibers due to high temperature treatment or thermal degradation.

ADVANTAGE OF THE INVENTION According to this invention, the polyester composite fiber which is excellent in process passage property, and was able to express the latent crimpability which was excellent in the stretchability or bulkiness by heat processing by comparatively low temperature can be provided.
Further, the fiber of the present invention has an advantage that a stable nonwoven fabric can be obtained at a low cost without causing thermal degradation of the fiber due to heat treatment at a high temperature.
Furthermore, the fiber assembly composed of the conjugate fiber of the present invention can be used as a base material for various cushioning materials, for example, cushioning materials and protective materials, specifically, cushioning materials for furniture, bedding, vehicles, etc. It can also be used effectively as a protective material for clothing and footwear.

Claims (5)

  A side-by-side type composite fiber comprising a polyester resin A and a polyester resin B, wherein the weight ratio of the polyester resin A to the polyester resin B is in the range of 40:60 to 60:40, and polyester. A composite fiber, wherein the resin B contains 10 to 30 mol% of isophthalic acid and 2 to 10 mol% of diethylene glycol.   The composite fiber according to claim 1, wherein the melting point of the polyester resin B is 180 to 250 ° C.   The number of crimps developed during a dry heat treatment at 110 ° C is 20 or more and 80 or less per 25 mm fiber length, and the crimp rate developed during a dry heat treatment at 110 ° C is 20% or more and 50% or less. The composite fiber according to 1 or 2.   Area shrinkage when the web made of the conjugate fiber according to any one of claims 1 to 3 is dry heat-treated at 90 ° C for 1 minute is less than 50%, and area shrinkage when dry-heat treated at 110 ° C for 1 minute. A composite fiber having a rate of 70% or more.   The fiber assembly comprised from the composite fiber in any one of Claims 1-4.