JP2009263816A - Staple fiber nonwoven fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a staple fiber nonwoven fabric that can lower a processing temperature in a heat adhesion treatment, is obtained by heat adhesion processing in good formability, has a slight reduction in bond strength even in use in a high-temperature atmosphere, improved textures, excellent air permeability, bulkiness and softness and is suitably used as a pad for clothing. <P>SOLUTION: The staple fiber nonwoven fabric is a nonwoven fabric comprising ≥50 mass% of a staple fiber having a spiral crimp based on a constituent fiber and is composed of a polyester A that is made of a dicarboxylic acid component consisting essentially of terephthalic acid as a main component and a diol component containing ≥50 mol% of 1,6-hexanediol as components for bonding staple fiber mutually constituting the nonwoven fabric, contains 0.01-5.0 mass% of crystal nucleating agent and has a melting point (Tm) of 100-150°C, in which a DSC curve exhibiting a temperature-lowering crystallization obtained by DSC satisfies formula (1): b/a≥0.05(mW/mg°C). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a short fiber nonwoven fabric comprising polyester A, which has short fibers having spiral crimps as a main fiber and has a low melting point and excellent crystallinity and excellent thermal adhesiveness, and is bulky and flexible. It is related with the short fiber nonwoven fabric excellent in property, mechanical characteristics, and formation.

  Synthetic fibers, especially polyester fibers, are indispensable as clothing and industrial materials due to their excellent dimensional stability, weather resistance, mechanical properties, durability, and recyclability. Many polyester fibers are used.

  In the field of sanitary materials, various short fiber nonwoven fabrics in which constituent fibers are bonded using binder fibers have been proposed. Since most of these short fiber nonwoven fabrics are made of polyester fibers, it is preferable to use fibers made of polyester polymers as binder fibers as adhesive components from the viewpoint of recycling.

  For example, as such a short fiber nonwoven fabric, a core-sheath type composite short fiber having a polyethylene terephthalate copolymer copolymerized with an isophthalic acid component as a sheath is used as a binder fiber, and a short fiber made of polyethylene terephthalate is used as a main fiber. The thing which was done is mentioned. Since the binder fiber used for this short fiber nonwoven fabric consists of a high melting point core and a low melting point sheath, only the sheath melts into an adhesive component during the thermal bonding process, and the core does not melt. The fiber form is retained.

  However, since the polyethylene terephthalate copolymer obtained by copolymerizing the isophthalic acid component in the sheath is amorphous and does not exhibit a clear crystal melting point, softening starts at a temperature above the glass transition point. For this reason, when the obtained short fiber nonwoven fabric is used in a high temperature atmosphere, there is a problem that the adhesive strength is reduced or deformed, and this binder fiber has a high heat shrinkage rate, and shrinkage during the heat bonding treatment. However, the obtained short fiber nonwoven fabric has a problem of poor formation and poor flexibility.

  As a solution to the above problem, Patent Document 1 discloses a core-sheath type composite fiber. This fiber has a core sheath in which polyethylene terephthalate is disposed in the core portion and a polyester copolymer obtained by copolymerizing a terephthalic acid component, an aliphatic lactone component, an ethylene glycol component, and a 1,4-butanediol component is disposed in the sheath portion. Type composite fiber.

  In this composite fiber, the copolymer of the sheath part is crystalline and has a clear melting point, so the heat shrinkage rate is small, the shrinkage during thermal bonding treatment when making a nonwoven fabric is small, the formation is good, and the flexibility In addition, a nonwoven fabric having excellent heat resistance when used in a high-temperature atmosphere can be obtained.

  However, this copolyester has a melting point in the range of 150 to 200 ° C. and is not yet in the low melting point region, and it is necessary to increase the processing temperature when performing the thermal bonding treatment, which is costly. Was also disadvantageous.

  On the other hand, short fiber nonwoven fabrics are also used as clothing pads such as brassiere cups, and nonwoven fabrics composed mainly of crimped fibers have been proposed (see, for example, Patent Document 2). Conventionally, in such applications, since stretchability and flexibility are required, those using urethane or polyethylene foam sheets have been used (see, for example, Patent Document 3).

  However, the use of a foam sheet has a problem in that the breathability is poor, and there is a problem that stuffiness occurs due to an increase in body temperature. It can be made breathable by using a short fiber non-woven fabric using polyester fibers, but when used for clothing pads such as brassiere cups, it is used in areas close to the skin, Bulkiness is also required.

A short fiber nonwoven fabric that has all of air permeability, flexibility, and bulkiness and that can be suitably used for clothing pads such as brassiere cups has not yet been developed.
JP 2006-118066 A JP 2002-371405 A JP 2000-314011 A

  The present invention solves the above-mentioned problems, and can reduce the processing temperature during the thermal bonding treatment, can be obtained by thermal bonding with good moldability, and can be used in a high-temperature atmosphere. It is also a technical problem to provide a short fiber nonwoven fabric that has little decrease in adhesive strength, good formation, excellent breathability, bulkiness, flexibility, and can be suitably used as a clothing pad. To do.

The inventors of the present invention have arrived at the present invention as a result of studies to solve the above problems.
That is, the present invention is a non-woven fabric containing 50% by mass or more of constituent fibers of short fibers having spiral crimps, and a dicarboxylic acid containing terephthalic acid as a main component as a component for adhering the short fibers constituting the non-woven fabric. It is composed of a component and a diol component of 1,6-hexanediol of 50 mol% or more, contains 0.01 to 5.0% by mass of a crystal nucleating agent, has a melting point (Tm) of 100 to 150 ° C., and is determined from DSC. The short fiber nonwoven fabric is characterized in that the DSC curve showing the temperature drop crystallization contains polyester A satisfying the following formula (1).
b / a ≧ 0.05 (mW / mg · ° C.) (1)
Note that a is the temperature A1 (° C.) of the intersection between the tangent line and the baseline having the maximum inclination in the DSC curve indicating the temperature-falling crystallization, and the temperature A2 (° C.) of the intersection of the tangent line and the baseline having the minimum inclination. B) is the difference (B1-B2) between the baseline heat quantity B1 (mW) and the peak top heat quantity B2 (mW) at the peak top temperature (mg) The value divided by.

  The short fiber nonwoven fabric of the present invention is a nonwoven fabric containing 50% by mass or more of the constituent fibers of short fibers having spiral crimps, and uses polyester A having a low melting point and excellent crystallinity as an adhesive component. Further, the processing temperature when the polyester fiber A is melted to thermally bond the main fibers can be lowered, and the main fibers can be bonded to each other. Thereby, it can be set as the nonwoven fabric which is excellent in bulkiness and a softness | flexibility, and has few fall of adhesive strength also when used in a high temperature atmosphere. In particular, it was obtained by creating a web containing short fibers having spiral crimps and short fibers arranged so that polyester A occupies at least a part of the fiber surface as a binder fiber, and heat-bonding this. By making it into a thing, the shrinkage | contraction at the time of obtaining a nonwoven fabric is small, it can improve adhesiveness, and it can become more excellent in a softness | flexibility and bulkiness. As described above, the short fiber nonwoven fabric of the present invention has good formation, excellent breathability, bulkiness, and flexibility, and can be suitably used for various applications including clothing pads.

Hereinafter, the present invention will be described in detail.
The short fiber nonwoven fabric of the present invention uses polyester A, which will be described in detail below, as a component that bonds short fibers having spiral crimps as main fibers and bonds the short fibers constituting the nonwoven fabric. The short fiber nonwoven fabric of the present invention is preferably a dry nonwoven fabric, and the basis weight is not particularly limited.

  First, short fibers having spiral crimps will be described. The spiral crimp is a coil (spiral) spring-like crimp and is a three-dimensional solid crimp. The shape is different from that applied with mechanical crimping by a crimping device such as a push-in crimper. Spiral crimping does not collapse when it is processed into a non-woven fabric, and has a high ability to retain crimped shapes. Is.

And it is preferable that the short fiber which has a spiral crimp is that the number of crimps and a crimp rate satisfy | fill simultaneously following formula (2) and (3).
5 ≦ Number of crimps (pieces / 25 mm) ≦ 20 (2)
10 ≦ crimp rate (%) ≦ 40 (3)

  The number of crimps is measured and calculated based on JIS L1015 8.12.1, and the crimp rate is measured and calculated based on JIS L1015 8.12.2. When the fiber length is short in the measurement of both numerical values, measurement is performed on the fiber before crimping and before cutting, and converted to the number per 25 mm fiber length.

  If the number of crimps is less than the numerical value of formula (2) or the crimp rate is smaller than the numerical value of formula (3), it is difficult to impart bulkiness to the short fiber nonwoven fabric. On the other hand, if the number of crimps is larger than the numerical value of the formula (2) or the crimping ratio is larger than the numerical value of the formula (3), the short fiber nonwoven fabric can be given bulkiness but has poor flexibility and stretchability. Tend.

  In the short fiber nonwoven fabric of the present invention, since polyester A is used as an adhesive component, it is preferable that the short fiber having spiral crimp is also made of polyester. Among them, it is preferable that two types of polyesters having different intrinsic viscosities are used, and a spiral crimp is developed by forming a side-by-side type bonded shape or an eccentric type.

  When two kinds of polyesters having different intrinsic viscosities are used, it is preferable that the difference in intrinsic viscosities is 0.05 to 0.25. When the intrinsic viscosity difference is less than 0.05, the expression of crimping performance tends to be insufficient. On the other hand, when the intrinsic viscosity difference exceeds 0.25, when the composite spinning is performed, the filaments discharged from the nozzle The so-called kneeling that bends to the high viscosity polymer side becomes large, and the spinning operability is greatly impaired.

  In addition, the composite ratio and composite form of the two types of polyester are not particularly limited as long as they can provide crimping performance, but the shape of the side-by-side type bonded with a mass ratio of 30/70 to 70/30. Those are preferred.

  Furthermore, there are no particular limitations as long as there are two types of polyesters. Besides the combination of polyethylene terephthalates (PET), one is polyethylene terephthalate (PET) and the other is isophthalic acid (IPA). Polymerized PET, or PET obtained by copolymerizing isophthalic acid (IPA) and bisphenol A ethylene oxide adduct (BAEO) may also be used.

  The composite fiber spun and stretched with the combination of the polyesters described above can exhibit (prominent) spiral crimps by performing a relaxation heat treatment using a dryer or the like.

  In the short fiber nonwoven fabric of this invention, the short fiber which has a spiral crimp is contained 50 mass% or more of a constituent fiber, and it is preferable to contain 70 mass% or more especially. When the content of the short fiber having spiral crimp is less than 50% by mass, it is difficult to obtain a short fiber nonwoven fabric having sufficient bulkiness and stretchability.

  When using a fiber other than the short fiber having spiral crimp as the main fiber, another fiber may be used as the constituent fiber.

  Further, in the short fiber nonwoven fabric of the present invention, as described later, polyester A is a short fiber arranged so as to occupy at least a part of the fiber surface, and is preferably used as a binder fiber, and polyester A and other components In the case of a composite fiber made of the above, other components may not be melted during the thermal bonding process, and if the fiber form is maintained, the main fiber may be used together with the short fiber having spiral crimp.

  Next, polyester A, which is a component that bonds the short fibers constituting the nonwoven fabric, will be described in detail. In the short fiber nonwoven fabric of the present invention, polyester A is used as a component for adhering short fibers, and other adhesive components other than polyester A may also be contained, among which 50% by mass or more of the adhesive component. Further, 90% by mass or more is preferably polyester A.

  Moreover, it is preferable that the ratio of the polyester A used as the adhesive component in the short fiber nonwoven fabric of this invention is 10-70 mass% of the whole short fiber nonwoven fabric, and it is preferable that it is 20-60 mass% especially. If the proportion of polyester A is too small, short fibers having spiral crimps as main fibers cannot be sufficiently bonded. On the other hand, if the proportion of polyester A is too large, the number of short fibers having spiral crimps that are the main fibers is reduced, resulting in a nonwoven fabric having poor bulkiness and flexibility.

  Polyester A is a copolyester composed of a dicarboxylic acid component containing terephthalic acid as a main component and a 1,6-hexanediol 50 mol% or more diol component, and having a melting point (Tm) of 100 to 150 ° C.

  It is preferable that Tm of polyester A is 110-140 degreeC especially. When the Tm is less than 100 ° C., the short fiber nonwoven fabric of the present invention is inferior in thermal stability (heat resistance) when used in a high temperature atmosphere. On the other hand, if the temperature exceeds 150 ° C., it is necessary to increase the heat bonding processing temperature when obtaining the nonwoven fabric, which is inferior in workability and economy. Moreover, the damage given to the main fiber by heat treatment is increased, which is not preferable because the quality and texture of the resulting nonwoven fabric are impaired.

  Polyester A has terephthalic acid as a main component as a dicarboxylic acid component, and terephthalic acid (hereinafter referred to as TPA) is preferably 60 mol% or more, more preferably 80 mol% or more. If the TPA is less than 60 mol%, the melting point of the polymer is not within the scope of the present invention, and the crystallinity tends to be lowered, which is not preferable.

  In addition, as copolymerization components other than TPA, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid are used as long as the effects are not impaired. Saturated aliphatic dicarboxylic acids exemplified by acids, 1,4-cyclohexanedicarboxylic acid, dimer acids and the like, or ester-forming derivatives thereof, unsaturated aliphatic dicarboxylic acids exemplified by fumaric acid, maleic acid, itaconic acid and the like Aromatic dicarboxylic acids exemplified by these ester-forming derivatives, phthalic acid, isophthalic acid, 5- (alkali metal) sulfoisophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, etc. These ester-forming derivatives can be used.

  As the diol component, 1,6-hexanediol (hereinafter referred to as HD) is 50 mol% or more, and as other components, ethylene glycol (hereinafter referred to as EG) or 1,4-butanediol (hereinafter referred to as HD). BD) is preferably used. In the diol component, HD is 50 mol% or more, and preferably 60 to 95 mol%. When HD is less than 50 mol%, the melting point exceeds 150 ° C.

  When EG or BD is used together with HD as the diol component, EG or BD is preferably 5 to 50 mol%, more preferably 5 to 40 mol% in the diol component.

  Furthermore, the diol component includes other copolymer components other than HD, EG and BD, as long as the properties are not impaired, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, tetra For ethylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, polyethylene glycol, polytrimethylene glycol, polytetramethylene glycol, etc. Exemplified aliphatic glycols, hydroquinone, 4,4′-dihydroxybisphenol, 1,4-bis (β-hydroxyethoxy) benzene, bisphenol A, 2,5-naphthalenediol, ethylene glycol Can be used aromatic glycols Sid is exemplified such as glycol was added.

  Polyester A has crystallinity due to the copolymer composition as described above, but it can improve the crystallization rate when the temperature is lowered by containing a crystal nucleating agent. Thus, the following expression (1) can be satisfied.

  In the present invention, since polyester A is excellent in crystallinity in this way, it has high fluidity, penetrates uniformly throughout the nonwoven fabric, and has many entanglement points between short fibers having spiral crimps constituting the nonwoven fabric. The short fiber nonwoven fabric obtained is excellent in flexibility and stretchability. Furthermore, since the shape of the spiral crimp of the main fiber is not crushed by the adhesive component, the bulkiness can be improved.

  Furthermore, in the present invention, it is preferable that the polyester A is made into a binder fiber by fiberizing, and this is heat-bonded to form an adhesive component. And when setting it as the binder fiber using polyester A, it is preferable to set it as the short fiber distribute | arranged so that the polyester A may occupy at least one part of the fiber surface.

  By using polyester A as the binder fiber, it becomes easy to point-bond the short fibers having spiral crimps as the main fiber, and the space between the short fibers having spiral crimps is also increased. The characteristics are further improved.

  The shape of the short fiber using polyester A consists of a single component consisting only of polyester A, polyester A and other components (component B), and polyester A is a fiber in the cross-sectional shape of a single yarn. The thing of the composite fiber distribute | arranged so that at least one part of the surface may be occupied is mentioned. Examples of the shape of the composite fiber include a side-by-side type, an eccentric core-sheath type, and a multi-layer type. Among them, in a cross-sectional shape of a single yarn, polyester A is a sheath part and component B is a core part in which a component B is arranged at the core part. The shape is preferred.

  In the case of a composite fiber using polyester A, if the other component (component B) has a higher melting point or flow starting temperature than polyester A, polyester A is the adhesive component and component B is the main fiber. And a short fiber nonwoven fabric in which the fiber composed of component B is used as the main fiber together with the short fiber having spiral crimps.

  And polyester A contains 0.01-5.0 mass% of crystal nucleating agents, and it is preferable to contain 0.5-3.0 mass% especially. When the content of the crystal nucleating agent in the polyester A is less than 0.01% by mass, the crystallization speed at the time of temperature reduction cannot be improved, and the polyester A cannot satisfy the formula (1) described later. . On the other hand, if it exceeds 5.0% by mass, the content of the crystal nucleating agent is excessively increased, and the operability during spinning and stretching is deteriorated when the polyester A is made into a fiber. In addition, the operability is deteriorated, so that the variation in the yarn quality is increased, and the dry heat shrinkage rate of the fiber made of polyester A is also increased.

As the crystal nucleating agent, it is preferable to use inorganic fine particles, polyolefin, sulfate or the like. As the inorganic fine particles, those mainly composed of silicon oxide such as talc are preferable, and inorganic fine particles having an average particle size of 3.0 μm or less or a specific surface area of 15 m ² / g or more are preferably used. When the average particle diameter or specific surface area is not satisfied, the function as a crystal nucleus is poor, and it is difficult for the polyester A to satisfy the formula (1) described later.

  The polyolefin contained as a crystal nucleating agent melts in the reaction system, so the shape is not particularly limited. For example, a chip-like one having a particle size of about 2 mm or a wax-like one having a particle size of several μm It may be.

  Examples of polyolefins include olefin homopolymers such as polyethylene, polypropylene, poly-1-butene, polymethylpentene, and polymethylbutene, and propylene / ethylene random copolymers. Polyethylene, polypropylene, poly-1- Butene and propylene / ethylene random copolymers are particularly preferred. When the polyolefin is a polyolefin obtained from an olefin having 3 or more carbon atoms, it may be an isotactic polymer or a syndiotactic polymer.

  Examples of the sulfate to be contained as a crystal nucleating agent include lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, barium sulfate, calcium sulfate, and aluminum sulfate. And magnesium sulfate are preferred.

  As a method for adding these crystal nucleating agents, they may be added at an arbitrary stage when the polyester is produced in the form of powder or in the form of a diol slurry. For example, it may be added at the time of esterification or transesterification, or may be added at the stage of polycondensation reaction. Among these, in order to improve the effect as a crystal nucleating agent, it is preferable to add in a slurry state or a dissolved state in a glycol such as ethylene glycol.

  In addition, polyester A contains a stabilizer such as a phosphate ester compound and a hindered phenol compound, a cobalt compound, a fluorescent brightening agent, a color tone improver such as a dye, and a dioxide dioxide within a range not impairing the effects of the present invention. One or more kinds of various additives such as matting agents such as titanium, plasticizers, pigments, antistatic agents, flame retardants and dyeing agents may be added.

In the polyester A, the DSC curve showing the temperature-falling crystallization obtained from DSC satisfies the following formula (1), and it is particularly preferable that b / a ≧ 0.06. On the other hand, the larger b / a, the better the crystallinity when the temperature is lowered. However, in order to achieve the intended effect of the present invention, b / a is preferably 0.5 or less.
b / a ≧ 0.05 (mW / mg · ° C.) (1)

  The DSC curve showing the melting temperature of polyester A in the present invention and the temperature-falling crystallization obtained from DSC is a temperature range of −20 ° C. to 250 ° C. in a nitrogen stream using a differential scanning calorimeter (Diamond DSC) manufactured by PerkinElmer. Measured at a rate of temperature rise (fall) of 20 ° C./min and a sample amount of 2 mg.

  Said b / a is calculated | required from the DSC curve which shows the temperature-fall crystallization calculated | required from DSC. As shown in FIG. 1, a is the temperature A1 (° C.) of the intersection of the tangent line and the base line with the maximum inclination in the DSC curve indicating the temperature-falling crystallization, the tangent line and the base line with the minimum inclination. Is the difference (A1−A2) from the temperature A2 (° C.) at the intersection of the two, and b is the difference (B1−B2) between the baseline heat amount B1 (mW) and the peak top heat amount B2 (mW) at the peak top temperature. ) Divided by the sample amount (mg).

  b / a is an index representing the crystallinity when the temperature is lowered, and the higher the b / a value, the faster the crystallization rate, and vice versa, the closer to 0, the slower the crystallization rate. When b / a is less than 0.05 (mW / mg · ° C.), the crystallization speed is slow, and it becomes difficult to bond the main fibers to each other. Further, when a fiber using polyester A is melt-spun, welding between single yarns occurs, and the spinning operability deteriorates. Further, when the heat treatment temperature in the drawing / heat treatment step is increased, the fibers are melted and glued, and heat treatment at a high temperature cannot be performed, so that a fiber having a low heat shrinkage rate cannot be obtained.

  As described above, b / a can be in the range specified in the present invention by setting the copolymer composition of polyester to a specific value and the content of the crystal nucleating agent in the above range. .

  And, when polyester A is made into fiber, since polyester A having excellent crystallinity is arranged so as to occupy at least a part of the fiber surface, welding between single yarns does not occur when melt spinning, Drawing and heat treatment can be performed at a high temperature, and a fiber having a low thermal shrinkage can be obtained.

  Specifically, the short fiber using polyester A preferably has a dry heat shrinkage rate of (TmA-30) ° C. of 7% or less, particularly 5% or less when the melting point of polyester A is TmA. It is preferable that the content be 4.5 to 0.5%.

  Here, the dry heat shrinkage is measured by the dry heat shrinkage measurement method in the measurement of the shrinkage of JIS L-1015. The initial load is 50 mg / dtex, the gripping interval is 25 mm, and the treatment temperature is ( TmA-30) Measured as ° C. In addition, when the fiber length is short and measurement is difficult, it shall measure using the fiber before cutting into a short fiber.

  (TmA-30) By making the dry heat shrinkage rate at 7 ° C. or less 7% or less, the shrinkage at the time of heat-bonding the web or the like is small when producing a nonwoven fabric using short fibers using polyester A as a binder fiber. Therefore, the nonwoven fabric obtained after the thermal bonding treatment is excellent in formation and uniformity. On the other hand, when the dry heat shrinkage at (TmA-30) ° C. exceeds 7%, it is difficult to achieve such an effect.

  When producing short fibers using polyester that does not exhibit a clear crystal melting point as in the prior art, welding between single yarns occurs during melt spinning, and if the heat treatment temperature is 100 ° C. or higher in the drawing and heat treatment steps, Fiber melting and sticking occur, making implementation difficult. Therefore, the drawing and heat treatment steps are performed at a low temperature, and the obtained short fibers have a high dry heat shrinkage rate. For this reason, when a nonwoven fabric is produced using such short fibers as binder fibers, the shrinkage when the web is thermally bonded increases, and the resulting nonwoven fabric has a large web shrinkage ratio compared to the area of the web before the thermal bonding treatment. It was inferior to formation and uniformity.

In addition, the web shrinkage | contraction rate of the above-mentioned short fiber nonwoven fabric in this invention is calculated | required as follows. A sample having an area A0 (vertical 20 cm × width 20 cm = 400 cm ² ) was cut from the web obtained when the short fiber nonwoven fabric was obtained, and when the melting point of the polyester A was Tm, this sample was set to (Tm + 10) ° C. It is allowed to stand for 15 minutes in a hot air drier (thermal bonding treatment is performed), and the area of the non-woven fabric thereafter is A1, and is calculated by the following formula.
Web shrinkage (%) = {(A0−A1) / A0} × 100

  And in the short fiber nonwoven fabric of this invention, it is preferable that a web shrinkage rate is 10% or less, especially 9.5% or less. When the web shrinkage rate exceeds 10%, the shrinkage at the time of thermal bonding treatment when making a nonwoven fabric increases, and the resulting nonwoven fabric tends to be inferior in formation and flexibility.

  In the short fiber nonwoven fabric of the present invention, when the short fiber using polyester A is a single component consisting only of polyester A, the short fiber having spiral crimp is the main fiber, and the short fiber using polyester A (single component type) ) To make a web with binder fibers. The web is heat-treated at a temperature 10 ° C. higher than the melting point of polyester A to melt all the binder fibers (polyester A) and bond the short fibers having spiral crimps as main fibers to each other. It is preferable to obtain

  In the short fiber nonwoven fabric of the present invention, when the short fiber using polyester A is a composite fiber comprising polyester A and component B, the short fiber having spiral crimp is the main fiber, and the short fiber using polyester A (composite fiber) ) To make a web with binder fibers. Then, the web is heat-treated at a temperature 10 ° C. higher than the melting point of the polyester A, so that all of the polyester fiber A of the binder fiber is melted to be an adhesive component, and a short fiber having a spiral crimp and a short fiber composed of the component B are obtained. It is preferable to obtain a short fiber nonwoven fabric in which these fibers are bonded to each other as the main fiber.

  In addition, when the short fiber using polyester A is a composite fiber composed of polyester A and component B, the melting point or flow start temperature of component B is 20 ° C. higher than the melting point of polyester A, so that component B is melted. However, if the difference between the polyester A and the component B becomes too large, the spinning operability deteriorates, so the difference is preferably 100 ° C. or less.

  As the component B, in consideration of compatibility with the polyester A, it is preferable to use a polyester, and those mainly composed of polyalkylene terephthalate such as polyethylene terephthalate (PET), polybutylene terephthalate, and polytrimethylene terephthalate are preferable. And in order to adjust melting | fusing point and flow start temperature of the component B, it is preferable to copolymerize the following components.

  Examples of copolymer components include aromatic dicarboxylic acids such as isophthalic acid and 5-sulfoisophthalic acid, aliphatic dicarboxylic acids such as adipic acid, succinic acid, suberic acid, sebacic acid, and dodecanedioic acid, and ethylene glycol, propylene glycol, Aliphatic diols such as 1,4-butanediol and 1,4-cyclohexanedimethanol, and hydroxycarboxylic acids such as glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxypentanoic acid, hydroxyheptanoic acid and hydroxyoctanoic acid Examples thereof include aliphatic lactones such as acid and ε-caprolactone.

  Component B contains various stabilizers, cobalt compounds, optical brighteners, color tone improvers such as dyes, matting agents such as titanium dioxide, plasticizers, pigments, antistatic agents, and easy dyeing agents. One type or two or more types of additives may be added.

  The composite ratio (mass ratio) of polyester A and component B is preferably 20/80 to 80/20, and more preferably 30/70 to 70/30.

  Moreover, it is preferable to make fiber length into 25-100 mm, and it is preferable to set it as 30-80 mm especially in the short fiber which uses the spiral crimp, and the short fiber using the polyester A. If the fiber length is less than 25 mm, the fibers fall off during fiber opening in the card machine, and the operability deteriorates. On the other hand, when the fiber length exceeds 100 mm, the defibration property in the card machine is deteriorated, and the resulting nonwoven fabric tends to be inferior in uniformity.

Next, the manufacturing method of the short fiber nonwoven fabric (dry type) of this invention is demonstrated using an example.
Short fibers having spiral crimps and short fibers using polyester A (polyester A single component) are weighed at an arbitrary ratio, and mixed cotton and defibrated using a card machine to prepare a dry web. The obtained web is subjected to a thermal bonding treatment at a temperature 10 ° C. higher than the melting point (TmA) of polyester A by a continuous heat treatment machine, and is a dry type having polyester A as an adhesive component and short fibers having spiral crimps as main fibers. A short fiber nonwoven fabric is obtained.

  Next, the manufacturing method of the short fiber which has spiral crimps is demonstrated using an example. Two types of polyesters having different intrinsic viscosities are bonded to a side-by-side type using a compound spinning device, compound-spun, and the spun yarn is cooled and solidified, and then stored in a container. These yarns are converged to form a yarn bundle, which is stretched between rollers at a stretching ratio of about 2 to 4 times. Subsequently, after picking up with a reel or the like and applying a finishing oil, a relaxation heat treatment is performed through a hot air dryer at about 100 to 200 ° C., and a crimp caused by a difference in thermal shrinkage between two types of PET components is expressed, and then the desired fiber length Cut to obtain short fibers.

  Moreover, the manufacturing method of the short fiber (the composite fiber which consists of polyester A and the component B) using the polyester A in the short fiber nonwoven fabric of this invention is demonstrated using an example. First, the dicarboxylic acid component and the diol component are esterified or transesterified, and a polynuclear reaction is performed by adding a crystal nucleating agent. When the polyester reaches a predetermined intrinsic viscosity in the polycondensation reaction, it is discharged into a strand, cooled, and cut into chips. Next, this chip (polyester A) and the chip of component B are supplied to an ordinary composite melt spinning apparatus, and melt spinning is performed with polyester A serving as a sheath and component B serving as a core. After spinning and solidifying the spun yarn, it is once stored in a container. Then, the yarns are converged into a yarn bundle, and stretched at a stretch ratio of about 2 to 4 times between rollers. Subsequently, heat treatment is performed at 100 to 120 ° C., and after applying the finishing oil, mechanical crimping is applied with a stuffing box or the like, and the fiber is cut into the target fiber length to obtain a core-sheath type composite short fiber.

Next, the present invention will be specifically described using examples. The measurement and evaluation methods for various characteristic values in the examples are as follows.
(A) Intrinsic viscosity [η]
Measurement was carried out based on a conventional method under the conditions of a sample concentration of 0.5% by mass and a temperature of 20 ° C. using an equal mass mixture of phenol and ethane tetrachloride as a solvent.
(B) Melting point of polyester A, DSC curve showing temperature drop crystallization determined from DSC Measured by the above method.
(C) Melting | fusing point The temperature which gives the extreme value of the melting absorption curve measured with the temperature increase rate of 20 degree-C / min using the differential scanning calorimeter (Diamond DSC by Perkin Elmer) was made into melting | fusing point.
(D) Polymer composition The obtained short fiber was dissolved in a mixed solvent having a volume ratio of 1/20 of deuterated hexafluoroisopropanol and deuterated chloroform, and 1H- was measured with a LA-400 NMR apparatus manufactured by JEOL Ltd. NMR was measured and determined from the integrated intensity of the proton peak of each copolymer component in the obtained chart.
(E) Dry heat shrinkage (%) of short fibers using polyester A
Measurement was performed by the method described above.
(F) Crimp rate, number of crimps Measured by the method described above.
(G) Evaluation of short fiber nonwoven fabric Formation The formation of the surface of the obtained nonwoven fabric was judged by visual observation and evaluated in two stages: good (◯) and defective (×).
2. Flexibility (feel)
The softness of the obtained nonwoven fabric was judged by tactile sensation, and was evaluated in three stages: good (◯), slightly bad (Δ), and bad (x).
3. Elasticity (feel)
The stretchability of the obtained nonwoven fabric was judged by tactile sensation, and was evaluated in three stages: good (◯), slightly bad (Δ), and bad (x).
4). Bulkiness The obtained non-woven fabric was cut into 20 cm × 20 cm to make a sample, and 10 cm of the samples were stacked and an acrylic plate (370 g) of 25 cm × 25 cm × 5 mm was placed, and a 1 kg weight was placed on the acrylic plate. The height of the center of each of the four sides of the lower surface was measured, and the average value of the four points was obtained. The average value was evaluated in three stages as follows.
○: The height is 25.0 mm or more. Δ: The height is 15.0 mm or more and less than 25.0 mm. X: The height is less than 15.0 mm. Web shrinkage rate Measured by the method described above.

Example 1
[Short fibers with spiral crimps]
Using a PET having a melting point of 256 ° C. and an intrinsic viscosity of 0.64 and a PET having a melting point of 256 ° C. and an intrinsic viscosity of 0.52, using an ordinary composite melt spinning apparatus, the spinning temperature is 290 ° C., the discharge rate is 237 g / min, Spinning was performed with a nozzle having a round cross section with a number of holes of 344 under a spinning speed of 1200 m / min to obtain a composite undrawn yarn having a side-by-side bonded shape with a mass ratio of 1/1. The resulting undrawn yarn was focused on a 11.9 ktex tow and then subjected to a first drawing at a drawing temperature of 65 ° C. and a draw ratio of 2.80 times, and then at a draw temperature of 80 ° C. and a draw ratio of 1.15 times. The film was stretched and stretched at a total stretching ratio of 3.22. Thereafter, the material is taken up with a reel, and continuously subjected to relaxation heat treatment with a hot air dryer at 170 ° C., and a spiral crimp is expressed by a difference in heat shrinkage between two kinds of PET components, and then cut into a fiber length of 51 mm to obtain a single yarn fineness of 2 .2 dtex short fibers (S-1) were obtained. The number of crimps of the obtained short fibers was 12.5 pieces / 25 mm, and the crimp rate was 18.5%.

[Short fiber (single component) using polyester A]
Polyester A comprising an intrinsic viscosity of 0.95, a melting point of 128 ° C., an acid component of TPA of 100 mol%, a glycol component of EG of 15 mol% and HD of 85 mol%, and containing 0.5% by mass of talc as a crystal nucleating agent ( A-1) was used.
The polyester A pellets were supplied to a spinning device and spun under the conditions of a spinning temperature of 220 ° C., a discharge rate of 307 g / min, a spinning hole number of 518, and a spinning speed of 850 m / min. Next, the spun yarn was cooled with cold air at 18 ° C. and taken out to obtain an undrawn yarn.
The unstretched fibers obtained by concentrating the unstretched yarn into a tow shape were stretched at a stretching ratio of 2.62 times and a stretching temperature of 40 ° C., and then heat-treated with a heat drum (temperature of 110 ° C.). Next, crimping was applied with a push-in crimper, and the fiber length was cut to 51 mm to obtain a short fiber having a single yarn fineness of 2.2 dtex and a dry heat shrinkage of 4.3%.

(Dry short fiber nonwoven fabric)
The short fiber having spiral crimps obtained as described above is the main fiber, the short fiber using polyester A is the binder fiber, and the mixing ratio is 50/50 (binder fiber / main fiber). A dry web was prepared. Using a continuous heat treatment machine, the obtained dry web was subjected to a thermal bonding treatment at a temperature 10 ° C. higher than the melting point of polyester A (138 ° C.) and an air volume of 20 m ³ / min for 1 minute, and a dry type having a basis weight of 100 g / m ² . A short fiber nonwoven fabric (short fibers having spiral crimps is 100% by mass of the constituent fibers) was obtained.

Example 2
Using the short fiber (S-1) having spiral crimps obtained in Example 1 as a main fiber and the short fiber using polyester A (A-1) obtained in Example 1 as a binder fiber, the mixing ratio is determined. A dry short fiber nonwoven fabric was obtained in the same manner as in Example 1 except that the mass ratio was 30/70 (binder fiber / main fiber).

Example 3
Polyester A comprising an intrinsic viscosity of 0.98, a melting point of 130 ° C., an acidic content of TPA, a glycol component of BD 20 mol% and an HD of 80 mol%, and containing 0.5% by mass of talc as a crystal nucleating agent (A-2) A short fiber (dry heat shrinkage 4.5%) using polyester A (A-2) was obtained in the same manner as in Example 1 except that was used.
And this short fiber was made into the binder fiber, and it carried out similarly to Example 1, and obtained the dry-type short fiber nonwoven fabric.

Example 4
In the production of short fibers having spiral crimps, the same procedure as in Example 1 was performed except that PET having a melting point of 256 ° C. and an intrinsic viscosity of 0.64 and PET having a melting point of 256 ° C. and an intrinsic viscosity of 0.43 were used. A short fiber (S-2) having spiral crimps with a crimp number of 17.9 pieces / 25 mm and a crimp rate of 28.5% was obtained. Using this short fiber as the main fiber, the short fiber using the polyester A (A-2) obtained in Example 3 was used as the binder fiber, and a dry short fiber nonwoven fabric was obtained in the same manner as in Example 1.

Example 5
In the production of short fibers having spiral crimps, the same procedure as in Example 1 was performed except that PET having a melting point of 256 ° C. and an intrinsic viscosity of 0.64 and PET having a melting point of 256 ° C. and an intrinsic viscosity of 0.57 were used. A short fiber (S-3) having a spiral crimp of 9.8 crimps / 25 mm and a crimp rate of 13.5% was obtained. Using this short fiber as the main fiber, the short fiber using the polyester A (A-2) obtained in Example 3 was used as the binder fiber, and a dry short fiber nonwoven fabric was obtained in the same manner as in Example 1.

Comparative Example 1
Instead of short fibers with spiral crimp, polyester single fiber (single component) consisting only of PET with a melting point of 256 ° C. and an intrinsic viscosity of 0.64 (fiber length 51 mm, single yarn fineness 2.2 dtex, push-in crimper Then, a mechanical crimp (12.3 crimps / 25 mm, 13.5% crimp, N-1) was used, and this short fiber was obtained as the main fiber, Example 1. A short fiber using polyester A (A-1) was used as a binder fiber, and a dry short fiber nonwoven fabric was obtained in the same manner as in Example 1.

Comparative Example 2
PET in which 33 mol% of isophthalic acid was copolymerized was supplied to a spinning device and spun under the conditions of a spinning temperature of 265 ° C., a discharge rate of 183 g / min, a spinning hole number of 1040, and a spinning speed of 800 m / min. Next, the spun yarn was cooled with cold air at 18 ° C. and taken out to obtain an undrawn yarn.
The unstretched fiber that is formed by concentrating the unstretched yarn into a tow-like shape is crimped by a push-in crimper without stretching, cut to a fiber length of 51 mm, and a short fiber (100 ° C., 15 The dry heat shrinkage in minutes was 29.8%).
Instead of the short fibers using polyester A, the short fibers were used as binder fibers, the short fibers (S-1) having spiral crimps obtained in Example 1 were used as the main fibers, and the same procedure as in Example 1 was performed. A dry short fiber nonwoven fabric was obtained.

  Table 1 shows the characteristic values and evaluation results of the dry short fiber nonwoven fabrics obtained in Examples 1 to 5 and Comparative Examples 1 and 2.

As is clear from Table 1, the dry short fiber nonwoven fabrics obtained in Examples 1 to 5 had a low web shrinkage, good formation, and excellent flexibility, stretchability, and bulkiness.
On the other hand, the dry short fiber nonwoven fabric of Comparative Example 1 did not use short fibers having spiral crimps as the main fiber, and thus was poor in bulkiness and stretchability. Since the dry short fiber nonwoven fabric of Comparative Example 2 did not have polyester A as an adhesive component, the web shrinkage ratio was high, the formation was inferior, and the crimped form of short fibers having spiral crimps It was damaged and inferior in bulkiness. Furthermore, the bonding between the main fibers was not point bonding, and the flexibility and stretchability were inferior.

Example 6
[Short Fiber (Composite Fiber) Using Polyester A] As polyester A, (A-1) similar to Example 1 was used. As component B, the polyester of B-1 in Table 3 was used.
The polyester A chip and the polyester B chip were supplied to the composite spinning apparatus, and the melt spinning was performed with the polyester A serving as the sheath and the polyester B serving as the core, and the mass ratio of both components being 50/50. At this time, spinning was performed under the conditions of a spinning temperature of 280 ° C., a discharge rate of 520 g / min, a spinning hole number of 1014, and a spinning speed of 800 m / min. Next, the spun yarn was cooled with cold air at 16 ° C. and taken out to obtain an undrawn yarn.
The unstretched yarn is bundled into a 110,000 dtex tow-shaped unstretched fiber and stretched at a stretching ratio of 2.91 times and a stretching temperature of 40 ° C., and then heat-treated with a heat drum (temperature of 110 ° C.). gave. Next, mechanical crimping was applied with a push-in crimper, and the fiber length was cut to 51 mm to obtain a composite short fiber (AB-1) having a single yarn fineness of 2.2 dtex.
Using this composite short fiber (AB-1) as a binder fiber and the short fiber (S-1) having spiral crimps obtained in Example 1 as a main fiber, a dry short fiber nonwoven fabric was obtained in the same manner as in Example 1. It was.

Examples 7-10
A core-sheath type composite short fiber is obtained in the same manner as in Example 6 except that the polyester shown in Table 3 is used as Component B of the composite short fiber using Polyester A and spinning is performed at the spinning temperature shown in Table 2. It was.
Using these composite short fibers as binder fibers and the short fibers (S-1) having spiral crimps obtained in Example 1 as main fibers, dry short fiber nonwoven fabrics were obtained in the same manner as in Example 1.

Example 11
Using the same short fibers (S-2) as in Example 4 as the short fibers having spiral crimps, and using the same composite short fibers (AB-1) as in Example 6 as the composite short fibers using polyester A, Using these as main fibers and binder fibers, a dry short fiber nonwoven fabric was obtained in the same manner as in Example 1.

Example 12
Using the same short fiber (S-3) as in Example 5 as the short fiber having spiral crimp, and using the same composite short fiber (AB-1) as in Example 6 as the composite short fiber using polyester A, Using these as main fibers and binder fibers, a dry short fiber nonwoven fabric was obtained in the same manner as in Example 1.

Example 13
Using the same short fiber (S-2) as in Example 4 as the short fiber having spiral crimp, and using the same composite short fiber (AB-4) as in Example 9 as the composite short fiber using polyester A, Using these as main fibers and binder fibers, a dry short fiber nonwoven fabric was obtained in the same manner as in Example 1.

Example 14
Using the same short fiber (S-3) as in Example 5 as the short fiber having spiral crimp, and using the same composite short fiber (AB-4) as in Example 9 as the composite short fiber using polyester A, Using these as main fibers and binder fibers, a dry short fiber nonwoven fabric was obtained in the same manner as in Example 1.

Comparative Example 3
Instead of short fibers having spiral crimps, polyester short fibers (single component) consisting only of PET having a melting point of 256 ° C. and an intrinsic viscosity of 0.64 (fiber length 51 mm, single yarn fineness 2.2 dtex, N-1 Was used). Then, a dry short fiber nonwoven fabric was obtained in the same manner as in Example 1 except that the short fiber was a main fiber and the polyester composite short fiber (AB-1) obtained in Example 6 was a binder fiber.

Comparative Example 4
Instead of short fibers having spiral crimps, polyester short fibers (single component) consisting only of PET having a melting point of 256 ° C. and an intrinsic viscosity of 0.64 (fiber length 51 mm, single yarn fineness 2.2 dtex, N-1 Was used). Then, a dry short fiber nonwoven fabric was obtained in the same manner as in Example 1 except that the short fiber was a main fiber and the polyester composite short fiber (AB-4) obtained in Example 9 was a binder fiber.

Comparative Example 5
As a binder fiber, a core-sheath type composite short fiber having a PET copolymer copolymer polyester copolymerized with an isophthalic acid component as a sheath part and PET as a core part, having a single yarn fineness of 2.2 decitex, a fiber length of 51 mm, 100 ° C. Polyester short fibers (Melty <3380> manufactured by Unitika Fiber Co., Ltd.) having a dry heat shrinkage of 15.2% in 15 minutes were used. Using the short fibers (S-1) having spiral crimps obtained in Example 1 as main fibers, a dry short fiber nonwoven fabric was obtained in the same manner as in Example 1.

  Table 2 shows the characteristic values and evaluation results of the dry short fiber nonwoven fabrics obtained in Examples 6 to 14 and Comparative Examples 3 to 5.

As is clear from Table 2, the dry short fiber nonwoven fabrics obtained in Examples 6 to 14 had a low web shrinkage, good formation, and excellent flexibility, stretchability, and bulkiness.
On the other hand, the dry short fiber nonwoven fabrics of Comparative Examples 3 and 4 did not use short fibers having spiral crimps as main fibers, and thus were poor in bulkiness and stretchability. Since the dry short fiber nonwoven fabric of Comparative Example 5 did not have polyester A as an adhesive component, the web shrinkage ratio was high, the formation was inferior, and the crimped form of short fibers having spiral crimps It was damaged and inferior in bulkiness. Furthermore, the bonding between the main fibers was not point bonding, and the flexibility and stretchability were inferior.

It is an example of the DSC curve which shows the temperature-fall crystallization calculated | required from DSC of the polyester A in this invention.

Claims (3)

A non-woven fabric containing 50% by mass or more of the short fibers having spiral crimps, the dicarboxylic acid component having terephthalic acid as a main component as a component for adhering the short fibers constituting the non-woven fabric, and 1,6 -It comprises a diol component of 50 mol% or more of hexanediol, contains 0.01 to 5.0 mass% of a crystal nucleating agent, has a melting point (Tm) of 100 to 150 ° C, and shows temperature-falling crystallization determined by DSC. A short fiber nonwoven fabric comprising a polyester A whose DSC curve satisfies the following formula (1).
b / a ≧ 0.05 (mW / mg · ° C.) (1)
Note that a is the temperature A1 (° C.) of the intersection between the tangent line and the baseline having the maximum inclination in the DSC curve indicating the temperature-falling crystallization, and the temperature A2 (° C.) of the intersection of the tangent line and the baseline having the minimum inclination. B) is the difference (B1-B2) between the baseline heat quantity B1 (mW) and the peak top heat quantity B2 (mW) at the peak top temperature (mg) The value divided by. The short fiber nonwoven fabric according to claim 1, wherein the short fibers having spiral crimp satisfy the following expressions (2) and (3) at the same time.
5 ≦ Number of crimps (pieces / 25 mm) ≦ 20 (2)
10 ≦ crimp rate (%) ≦ 40 (3) 2. A web obtained by heat-treating a web containing short fibers having spiral crimps and short fibers arranged so that polyester A occupies at least a part of the fiber surface in a cross-sectional shape of a single yarn. Or the short fiber nonwoven fabric of 2.