JP4581601B2 - Latent crimped conjugate fiber, fiber structure using the same, and absorbent article - Google Patents

Description

  The present invention relates to a conjugate fiber having latent crimpability, a fiber structure using the same, and an absorbent article. More specifically, the present invention relates to a novel latent crimpable conjugate fiber that exhibits spiral crimp upon contact with water, a fiber structure using the same, and an absorbent article.

  It has been conventionally known that a composite fiber in which two components having different heat shrinkage properties are eccentrically combined in the cross section of the fiber has latent crimpability, and exhibits spiral crimp by heat treatment (for example, patents). Literature 1, Patent Literature 2). Furthermore, these fibers having latent crimping properties are excellent in stretchability, bulkiness, texture, etc. by developing spiral crimps, and woven fabrics made of fibers having latent crimping properties. Alternatively, it is well known that a nonwoven fabric becomes a woven fabric or a nonwoven fabric excellent in stretchability, bulkiness, texture and the like due to the manifestation of spiral crimp (for example, Patent Document 3).

  However, fibers or nonwoven fabrics that exhibit spiral crimps are bulky themselves, which is not only uneconomical in packing, storage and transportation, but also bulky when stored in a compressed package. There was a problem of being lost.

  As an attempt to solve such problems, modified polyethylene terephthalate and nylon 6 copolymerized with 5-sodium sulfoisophthalic acid component satisfying specific conditions, characterized in that the reversible crimp rate changes with humidity. A side-by-side type composite fiber is proposed (for example, Patent Document 4).

  However, this composite fiber is substantially an actual crimped fiber, and the change in the crimp rate generated by moisture absorption by this fiber is small, so that spiral crimp does not occur.

Japanese Patent Publication No.52-35776 Japanese Patent Publication No.53-6263 JP-A-1-118617 Japanese Patent Publication No. 63-44843

  The problem of the present invention is that the spiral crimp is not expressed in each of the distribution stages of packing, storage, and transportation, so it does not take a place and expresses the spiral crimp originally required by contacting with moisture in the stage of use, It is an object to provide a latent crimpable fiber that is an excellent fiber such as stretchability, bulkiness, and texture, a fiber structure using the fiber, and an absorbent article.

The inventors of the present invention have made extensive studies in order to solve the above problems. As a result, it has been found that the above-described problems can be solved by having the following configuration, and the present invention has been completed based on this finding.
The present invention has the following configuration.

[1] A composite fiber composed of two different types of water-insoluble thermoplastic resin components (referred to as component A and component B, respectively),
Form of double engagement is eccentric ratio of 0.1 or more eccentric sheath-core type for a parallel-type or A component as a sheath, a block copolymer of component A is a polyether-polyamide block copolymer or polyamide and polyethylene glycol The component B is at least one selected from polyolefins, polyamides and polyamide alloys, and the difference in water absorption (% by weight) at 20 ° C. between the component A and the component B is 6% by weight or more, characterized in that the cross sectional area change ratio after moisture contact 10 sec at 20 ° C. of (V) is Ri following relationship near, 20 spiral crimps number of water contact 10 seconds after ° C. express eight /25.4mm more A product used in contact with moisture , using a fiber structure using at least part of the latent crimpable conjugate fiber.
A2 / A1> B2 / B1
Here, A1: Cross-sectional area before contact with moisture of A component A2: Cross-sectional area after 10 seconds of contact with moisture of A component B1: Cross-sectional area before contact with moisture of B component B2: Cross-sectional area after 10 seconds of contact with moisture of B component [ 2 ] The product according to [1] above, wherein the latent crimpable conjugate fiber has a water absorption rate of 1% or more at 20 ° C.
[ 3 ] The fiber structure is composed of at least one kind of fabric selected from non-woven fabrics, nets, knitted fabrics, and woven fabrics in which the fiber contacts of the latent crimpable composite fibers are fixed by thermal bonding or entanglement between the fibers. The product according to any one of [1] to [2], which is a structure.
[ 4 ] An absorbent article using at least a part of the product according to any one of [1] to [ 3 ].
[ 5 ] A composite fiber composed of two different water-insoluble thermoplastic resin components (referred to as component A and component B, respectively),
Form of double engagement is eccentric ratio of 0.1 or more eccentric sheath-core type for a parallel-type or A component as a sheath, a block copolymer of component A is a polyether-polyamide block copolymer or polyamide and polyethylene glycol The component B is at least one selected from polyolefins, polyamides and polyamide alloys, and the difference in water absorption (% by weight) at 20 ° C. between the component A and the component B is 6% by weight or more, characterized in that the cross-sectional area change ratio after moisture contact 10 sec at 20 ° C. of (V) is Ri following relationship near, 20 spiral crimps number of water contact 10 seconds after ° C. express eight /25.4mm more A method for using latent crimpable fibers , characterized in that a product using a fiber structure using at least a part of the latent crimpable conjugate fiber is brought into contact with moisture .
A2 / A1> B2 / B1
Here, A1: Cross-sectional area before contact with moisture of A component A2: Cross-sectional area after 10 seconds of contact with moisture of A component B1: Cross-sectional area before contact with moisture of B component B2: Cross-sectional area after 10 seconds of contact with moisture of B component

The latent crimpable conjugate fiber of the present invention exhibits spiral crimp due to contact with moisture during use, and thus has excellent stretchability, bulkiness, texture, and the like.
In addition, the fiber structure and absorbent article using the latent crimpable conjugate fiber of the present invention do not take a storage place due to bulk at each distribution stage of packing, storage and transportation, and contact with moisture during use. A crimped structure is obtained, and a fiber structure and absorbent article with good texture having stretchability and bulkiness are obtained, and these fiber structure and absorbent article have good moisture retention.

Hereinafter, the present invention will be described in detail.
The latent crimpable conjugate fiber of the present invention is a conjugate fiber having latent crimping property that exhibits spiral crimp upon contact with moisture. Specifically, the component A is a water-insoluble thermoplastic resin, and the component A. The B component, which is a water-insoluble thermoplastic resin having different components, is arranged in a parallel type or an eccentric sheath core type having an eccentric ratio of 0.1 or more with the A component as a sheath. Here, the eccentric ratio (E) is the center point of the composite fiber as shown in FIG. 1 (O ₁₎ and the center point of the core component and (O ₂₎ distance (d) and the radius of the composite fiber (R) It is represented by the ratio (Formula 1).
E = d / R (Formula 1)
In the latent crimpable conjugate fiber of the present invention, if the A component and the B component are not in parallel or the eccentricity ratio is less than 0.1, the latent crimp performance (the number of crimps expressed) ), And it becomes difficult to sufficiently satisfy the performance such as bulkiness, stretchability, and texture.

Next, in the latent crimpable conjugate fiber of the present invention, it is important that the cross-sectional area change rate of the A component and the B component satisfies the following relational expression (Formula 2).
A2 / A1> B2 / B1 Formula 2
here
A1: Cross-sectional area before moisture contact of A component
A2: Cross-sectional area 10 seconds after contact of component A with water
B1: Cross-sectional area of B component before moisture contact
B2: Cross-sectional area after 10 seconds of moisture contact with B component

  If the cross-sectional area change rates of the A component and the B component satisfy this relationship, the target latent crimpability can be obtained. The relationship between the cross-sectional area change rates of the A component and the B component is also related to the water absorption rate, which will be described later. The greater the difference between the two relationships, the more pronounced the crimp expression. This difference allows the number of crimps that develop upon moisture contact to be adjusted. Further, in order to adjust the number of crimps, the composite ratio of the A and B components may be changed.

  In the present invention, “moisture contact” and “water absorption” mean contact with liquid moisture at room temperature and thereby absorb water in a short time (several seconds to several tens of seconds). When a resin that swells due to contact with moisture (moisture absorption) is used, it is not an object of the present invention. Further, in the latent crimpable conjugate fiber of the present invention, when crimp is expressed by contact with moisture, the crimp is retained even after drying, and the crimp is not reversibly lost by drying. If the condition is satisfied, the crimp is retained after drying. This is supported by the “example” of the present invention. In addition, regarding the holding | maintenance of the crimp after drying, the crimp should just be hold | maintained to such an extent that effects, such as a stretching property, bulkiness, and a texture, are not impaired after drying. However, if there is a resin combination in which crimps disappear after drying and a sufficient effect cannot be obtained, it should be excluded from the object of the present invention.

  Next, the latent crimpable conjugate fiber of the present invention changes the difference in the cross-sectional area change rate of the above-mentioned formula 2 so that a spiral crimp that appears after 10 seconds of moisture contact at 20 ° C. ) Can be adjusted. When the number of latent crimps to be expressed is 8 / 25.4 mm or more, the effects of the present invention are remarkably exhibited, which is preferable. The latent crimpable conjugate fiber of the present invention is preliminarily provided with a mechanical crimp when performing card processing or the like before the crimp due to moisture contact is expressed, and further subjected to spiral crimp due to moisture contact in a later step. It can also be expressed. In such a case, the mechanical crimp given in advance (simply called mechanical crimp) is usually 10 to 15 / 25.4 mm in many cases, and when latent crimp is expressed in a later step, The total number of crimps is the sum of the number of machine crimps and the number of potential crimps. The total of the mechanical crimps and the latent crimps to be expressed is a range of the most preferable aspect of the present invention, and the potential to be expressed according to the number of the mechanical crimps is about 18 to 25 / 25.4 mm. The number of crimps may be adjusted. In the present invention, if necessary, it can also be configured to express further latent crimps, and the potential to develop unless the card-passability at the time of making into a nonwoven fabric is reduced or the texture of the resulting nonwoven fabric is not reduced. The number of crimps may be increased.

Further, the latent crimpable conjugate fiber of the present invention configured to satisfy the relationship of the above formula 2 usually has a water absorption rate (20% by weight) at 20 ° C. represented by the following formula 3 of usually 1% by weight or more. become. In other words, it may be considered that the fact that the water absorption rate is 1% by weight or more serves as a standard for satisfying the relationship of Formula 2.
Water absorption rate (% by weight) = [(fiber weight after draining) / (initial fiber weight)] × 100 Equation 3
When the water absorption rate is 1% or more, a difference in elongation due to the swelling process occurs in a short time after contact with moisture, leading to the generation of a spiral, and spiral crimps usually appear within 10 seconds.

The water absorption can be measured for each of the A and B components at the raw material resin stage, and an A component having a higher water absorption than the B component can be selected. If such a combination of resins is selected, a configuration satisfying the relationship of Formula 2 is obtained.
Thus, when each component of A and B is selected, it is more preferable if the difference in water absorption (wt%) is 6 wt% or more.

  If the difference in water absorption between the A component and the B component is 6% by weight or more, there is a sufficient expansion difference due to the swelling process due to moisture contact between the A component having a high water absorption rate and the B component having a low water absorption rate. As a result, a noticeable spiral is generated and crimp development is improved.

  As described above, each of the components A and B constituting the latent crimpable conjugate fiber of the present invention is composed of a water-insoluble thermoplastic resin. If one or both components of the latent crimpable conjugate fiber are water-soluble, the desired spiral crimp does not appear when contacting with moisture. The water-insoluble thermoplastic resin used here is not particularly limited as long as it satisfies the above-mentioned conditions, and may be either a homopolymer or a copolymer of a thermoplastic resin described later. Also good. Moreover, it may be used independently or may be a mixture of two or more.

  Furthermore, the thermoplastic resin used in the present invention includes an antioxidant, a light stabilizer, an ultraviolet absorber, a neutralizer, a nucleating agent, an epoxy stabilizer, a lubricant, within a range that does not interfere with the effects of the present invention. In addition to antibacterial agents, flame retardants, antistatic agents, pigments, plasticizers, hydrophilic agents, additives such as compatibilizers may be added as necessary for improving the adhesiveness of the A and B components.

  The melt-mass flow rate (hereinafter referred to as “MFR”) of the water-insoluble thermoplastic resin used in the present invention is within the melt-spinnable range, that is, when the molten resin is spun until the resin solidifies. It may be in a range that maintains an appropriate viscosity so that it does not occur. The spinning conditions such as the spinning temperature and the pressure of the extruder may be changed in accordance with the physical properties of the resin so that the MFR is in a range suitable for spinning. Specifically, the MFR after fiber molding is preferably within a range of 10 to 100 g / 10 minutes, more preferably 10 to 70 g / 10 minutes, under a temperature and load corresponding to the properties of the resin. . When the MFR after fiber molding is in the range of 10 to 100 g / 10 min, it is easy to maintain the parallel-type cross-sectional structure or the eccentric sheath-core cross-sectional structure, and the spinnability is also good.

  Examples of the combination of the A and B components of the latent crimpable conjugate fiber of the present invention include, for example, thermoplastic resins such as polyether / polyamide block copolymers and polyamide / polyethylene glycol block copolymers as the A component. Examples of the component B include polyolefin resins, polyamide resins such as nylon 6 and nylon 66, and thermoplastic resins such as polyamide alloy.

  As the block copolymer of polyamide and polyethylene glycol and polyether / amide block copolymer used for the component A, various types can be used. As the block copolymer with polyethylene glycol, for example, PEBAX manufactured by ATOFINA (Trade name), Hydrofil (trade name) manufactured by Allied Signal, for example, is sold as a polyether / amide block copolymer, and preferable results can be obtained by using the present invention.

  Polyolefin resins used for component B include high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polypropylene, polymethylpentene, 1,2-polybutadiene, and 1,4-polybutadiene, as well as ethylene. , Butene-1, hexene-1, octene-1, 4-methylpentene-1, and other homopolyolefins or crystalline copolymers with aliphatic α-olefins. For example, copolymer polyolefin such as ethylene-propylene copolymer and ethylene-propylene-1-butene terpolymer can be used. The α-olefin is copolymerized with other olefins or a small amount of other ethylenically unsaturated monomers such as styrene unsaturated monomers such as butadiene, isoprene, 1,3-pentadiene, styrene and α-methylstyrene. It may also be a mixture of the above polyolefin resins. Further, not only these polyolefins polymerized from ordinary Ziegler-Natta catalysts, but also polyolefins polymerized from metallocene catalysts and copolymers thereof can be exemplified. Furthermore, stereoregular polystyrene can be mentioned as other polyolefin.

  Stereoregular polystyrene is a tacticity measured by the 13C-NMR method. The presence ratio of a plurality of continuous structural units, for example, 2 for diat, 3 for triad, and 5 for pendant. The stereoregular polystyrene that may be used in the present invention is usually polystyrene having a syndiotacticity of a pendant fraction of 85% or more, preferably 95% or more, polymethylstyrene, polyethylstyrene. Polyalkyl styrene such as polyisopropyl styrene, polyhalogenated styrene such as polychlorostyrene, polybromostyrene and polyfluorostyrene, polyhalogenated alkyl styrene such as polychloromethyl styrene, polymethoxy styrene and polyethoxy styrene Alkoxy Styrene, a poly benzoate styrene, These can be used singly or in combination. Furthermore, a copolymer of monomers constituting these polymers or a copolymer containing these monomers as main components can also be used.

  That is, the copolymer includes at least one monomer selected from the monomers constituting the above-mentioned stereoregular polystyrene, olefinic monomers such as ethylene, propylene, butene, hexene, heptene, octene, and decene, butadiene, It is a copolymer having a syndiotactic styrene structure with a diene monomer such as isoprene, a cyclic olefin monomer, a cyclic diene monomer, or a polar vinyl monomer such as methyl methacrylate, maleic anhydride, or acrylonitrile. For these, commercially available homopolymers and copolymers can be used.

  Examples of the polyolefin-based resin used for the component B include these, but polypropylene and polyethylene are particularly preferable.

  The polyamide resin used for the component B includes nylon-4, nylon-6, nylon-46, nylon-66, nylon-610, nylon-11, nylon-12, polymetaxylene adipamide (MXD -6), polyparaxylenedecanamide (PXD-12), and polybiscyclohexylmethanedecanamide (PCM-12) can be used. Furthermore, an amide copolymer and an alloy thereof having the monomer used in these polyamide resins as a structural unit can also be used.

  Examples of the polyamide-based resin used for the component B include these, and nylon-6 and nylon-66 are particularly preferable. Moreover, as a polyamide alloy, for example, ORGALLOY (trade name) manufactured by ATOFINA is sold, and a preferable result can be obtained by using the present invention.

  The composite ratio of the A component and the B component is preferably in the range of 20:80 to 80:20, and more preferably in the range of 30:70 to 70:30. When the composite ratio of both components is within this range, the spinnability is good and the desired spiral crimp can be easily expressed.

  The parallel-type or eccentric sheath-core type composite spinning device used for the production of the latent crimpable conjugate fiber of the present invention is not special and may be a normal one. The obtained undrawn yarn may or may not be drawn, and may be mechanically crimped in the same manner as ordinary fibers. The thus obtained latent crimpable conjugate fiber of the present invention can be used in various forms such as staple fibers and filaments, and has a latent crimp property that develops spiral crimps upon contact with moisture. Yes.

  The latent crimpable conjugate fiber of the present invention can be mixed with other types of fibers to form a fiber structure as long as the effects of the invention are not hindered. Other type fibers are not particularly limited. For example, natural fibers such as cotton and wool, semi-synthetic fibers such as viscose rayon and acetate fiber, polyolefin fibers, polyamide fibers, polyester fibers, acrylonitrile fibers, acrylic fibers, and polyvinyl alcohol fibers One kind or two or more kinds of fibers such as synthetic fibers and inorganic fibers such as glass fibers can be appropriately selected and used.

  It is preferable to mix the use amount of the other kinds of fibers at a ratio of 70% by weight or less with respect to the total amount of the latent crimpable conjugate fibers. When the amount of the latent crimped conjugate fiber of the present invention is 30% by weight or more, the effect of the present invention that the crimp develops when the moisture comes into contact and the nonwoven fabric becomes bulky is remarkably exhibited.

  Fibers mixed with 100% latent crimped composite fibers or other types of fibers of the present invention can be made into a non-woven fabric by focusing into a suitable form such as a parallel web, a cross web, a random web, or a tow web according to the purpose.

  The method of making the latent crimped composite fiber web of the present invention into a non-woven fabric is a method using a fiber entanglement such as a needle punching method, a high-pressure liquid flow treatment, a method using an adhesive, or a method using thermal bonding of the fiber itself, Further, an adhesive component or a welding component can be used in combination, and the components can be more firmly integrated. As these components, it is good to mix the fiber which consists of a thermoplastic resin. At this time, in order to bond the latent crimpable conjugate fiber to form a nonwoven fabric, a fiber comprising a thermoplastic resin of the same type as the thermoplastic resin constituting the latent crimpable conjugate fiber is composed of a thermoplastic resin. It is preferable that In addition, when the mixed cotton fiber is melted by heat treatment and bonded, a latent crimpable composite is obtained by using a thermoplastic resin that melts at a temperature lower than the low melting point resin of the latent crimpable composite fiber as an adhesive component. This is preferable because the nonwoven fabric can be formed without melting the fibers, and the splitting and finening can be facilitated. Moreover, the strength of the nonwoven fabric can be further increased by using composite fibers as the adhesive fibers.

  In the case of using adhesive or thermal bonding of the fiber itself, apply adhesive by printing method or emboss with hot roll so that the adhesion point forms a polka dot pattern and the area is 15% or less of the nonwoven fabric area Process. If the area of the adhesion point is 15% or less, the occurrence of crimping of the fiber is not hindered and the expression of bulkiness is sufficient. The lower limit of the area of the adhesion point is not particularly limited, but 3% or more is preferable in order to satisfy the practical strength of the nonwoven fabric.

  The latent crimpable conjugate fiber of this invention and the manufacturing method of a fiber structure using the same are illustrated. Using an ordinary melt composite spinning machine, a composite fiber having a latent crimping property composed of an A component and a B component is spun. In spinning, it is preferable to spin at a spinning temperature of 120 to 330 ° C., and a take-up speed is preferably about 40 m / min to 1500 m / min. Stretching may be performed as necessary or not, and multistage stretching may be performed. The draw ratio is usually about 1.2 to 9.0 times, and the draw temperature is usually heated at a temperature at which the composite fiber is not fused. Furthermore, the composite fiber that has undergone the above processing is crimped with a crimper such as a stuffing box, if necessary, and then cut into a predetermined length to form a short fiber, a known card method, airlaid method, dry pulp method, wet type The web can be made by a papermaking method or the like.

  Further, the composite fiber can be formed into a web by a splitting guide or the like in a tow state without being cut into a predetermined length. Further, the web may be formed directly from the spinning process by a known spunbond method or melt blow method. The obtained web is subjected to known high-order processing steps such as a needle punch method and high-pressure liquid flow treatment, as well as known heat treatment steps such as hot air or hot rolls, as necessary, and includes absorbent articles such as disposable diapers. It is formed into a fiber structure according to various uses such as sanitary materials, or industrial materials such as sound absorbing materials, wiping materials, filters, cushion materials, and oil adsorbing materials.

  Further, after spinning and drawing, it may be wound as a filament yarn, knitted or woven to form a knitted fabric, and a fiber structure may be formed through a heat treatment step. Moreover, after making the said short fiber into a spun yarn, this may be knitted or woven to make a knitted fabric, and may be formed into a fiber structure through a heat treatment step. Furthermore, other structures made of web, woven fabric, knitted fabric, non-woven fabric, film, etc., made uniform by methods such as the card method, airlaid method, spunbond method, papermaking method, etc., are made of the latent crimpable conjugate fiber of the present invention. Various layers may be laminated on the web or the fiber structure, and the fiber structure may be formed through a heat treatment process.

  In the heat treatment step, a method using a dryer such as a hot air dryer, a suction band dryer or a Yankee dryer, or a method using a pressure roll such as a flat calender roll or an emboss roll can be used. The heat treatment temperature is preferably a temperature between the melting points of the components A and B of the latent crimped composite fiber (a temperature at which only the component having a lower melting point melts), and depending on the type of thermoplastic resin used, 60 A range of ˜165 ° C. is suitable. Further, the treatment time is generally about 5 seconds or more when using the dryer or the like, and 5 seconds or less when using the pressure roll.

  As described above, the latent crimpable conjugate fiber of the present invention exhibits good stretchability, bulkiness, texture and the like due to spiral crimp expression by contact with moisture during use. In addition, the fiber structure and absorbent article using the latent crimpable conjugate fiber of the present invention do not take up space in each stage of packing, storage, and transportation, so it takes up space and comes into contact with moisture during use. A crimped structure is obtained, and a fiber structure and absorbent article having a good texture having excellent stretchability and bulkiness are obtained.

  These fiber structures and absorbent articles have good moisture retention, including industrial materials such as sound-absorbing materials, wiping materials, filters, cushioning materials, oil adsorbing materials, hygiene materials, medical fields, etc. Also, it can be suitably used. In particular, when used for absorbent articles such as disposable diapers, many products can be packed in the sales pack before contact with moisture, and when used, the product comes in bulk due to contact with moisture and retains much moisture. Shows the effect of being able to.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these. In addition, the term and the measuring method of a physical property in an Example and a comparative example are as follows.

(MFR)
The measurement was performed according to JIS K 7210, ASTM D638, and the like. The MFR measurement conditions of various resins are shown.
Polyether / polyamide block copolymer: Measuring temperature 235 ° C./nominal load 1 kgf
Polypropylene: Measurement temperature 230 ° C./nominal load 2.16 kgf (condition M in JIS K 7210 Annex A Table 1)
Polyethylene: Measurement temperature 230 ° C./Nominal load 2.16 kgf (JIS K 7210 Annex A, Table 1, Condition D)
Polyamide alloy: Measurement temperature 235 ° C./nominal load 5 kgf

(Melting point)
The measurement was performed according to JIS K 7122 using a DuPont thermal analyzer DSC10 (trade name).

(Eccentric ratio)
Eccentric ratio (E) uses the value of the center point of the composite fiber (O ₁₎ and the center point of the core component distance between (O _{2) (d)} and the radius of the composite fiber (R) as shown in FIG. 1, It calculated | required by Formula 1.
E = d / R (Formula 1)

(Water absorption rate)
After 10 g of the measurement sample is immersed in water at 20 ° C. for 60 seconds, water is drained by applying a pressure of 0.5 kg / cm ² between three sheets of filter paper (Toyo Filter Paper Co., Ltd. NO.2 filter paper). The filter paper was replaced with a new one, this draining operation was repeated twice more, the weight was measured, and the water absorption was determined according to Equation 2.
Water absorption rate (% by weight) = ((weight after draining−initial weight) / initial weight) × 100 (Formula 2)

(Cross-sectional area change rate)
The cross-sectional area change rate (V) of the composite fiber 10 seconds after contact with water at 20 ° C. was obtained by the following formula 3 and expressed as a percentage (%).
A1: Cross-sectional area before water contact of A component A2: Cross-sectional area after 10 seconds of water contact with A component B1: Cross-sectional area before water contact of B component B2: Cross-sectional area after 10 seconds of water contact of B component

V (%) = A2 / A1 × 100 or V (%) = B2 / B1 × 100 Equation 3

The cross-sectional area of each component before immersion in water and the cross-sectional area of each component after immersion in water at 20 ° C. for 10 seconds were determined by Equation 3.

(Crimp number)
Before the moisture contact (initial stage) and after 10 seconds of moisture contact at 20 ° C., the number of peaks at 25.4 mm per fiber bundle (10 fibers) was counted, and the average value was defined as the number of crimps.

Resins indicated by symbols in the examples are as follows. (Write the product name and grade number.)
PX: Polyether / polyamide block copolymer PEBAX MV1074 manufactured by ATOFINA
MFR: 14g / 10min MP: 158 ° C
NP: Polyethylene glycol / polyamide block copolymer Hydrofil CFX-6809 manufactured by Allied Signal
PP: Polypropylene Novatec PP SA2E manufactured by Nippon Polypro Co., Ltd.
MFR: 14 g / 10 min MP: 160 ° C.
PE: polyethylene Keiyo Polyethylene Co., Ltd. S6900
MFR: 16g / 10min MP: 132 ° C
Ny6: Nylon 6
UBE nylon 6 1011FB made by Ube Industries, Ltd.
Ny66: Nylon 66
Leona FR200 manufactured by Asahi Kasei Chemicals Corporation
PAA: Polyamide alloy ORGALLOY RS60E10 manufactured by ATOFINA
MFR: 13g / 10min MP: 220 ° C

Example 1
A parallel type composite fiber was produced using a composite spinning apparatus having two extruders equipped with a parallel type composite spinning base. PX is introduced into the A component side of the hopper, PE is introduced into the B component side, and a parallel fiber cross-sectional shape in which the volume ratio of the first component to the second component is 50/50 at a spinning temperature of 230 ° C. Then, the composite fiber was discharged so as to become, and this was taken up by a winder. In the take-up step, an alkyl phosphate potassium salt was adhered as a surfactant to the surface of the discharged composite fiber. Next, the composite fiber (unstretched yarn) wound up by a winder is stretched 2.0 times (stretching temperature 90 ° C.) by a stretching machine, then passed through a stuffing box to give mechanical crimp, and then length A 1.0 dtex sufu cut to 51 mm and crimped was obtained. Next, each fiber was immersed in water at 20 ° C. to develop spiral crimps. The expression of spiral crimps due to moisture contact of the obtained fibers is shown in Table 1.

Examples 2-9
A latent crimpable conjugate fiber was produced by the production method according to Example 1 with the combinations of raw resin shown in Table 1, the cross-sectional shape of the fiber, and production conditions. However, in Example 5, spinning was performed by setting the spinning temperature of the second component to 50 ° C. higher than in Example 1. The expression of spiral crimps due to moisture contact of the obtained fibers is shown in Table 1.

Example 10
Using the first component and the second component used in Example 1, a latent crimpable composite long fiber having a parallel-type cross-sectional shape was spun. The spinning temperature condition is 240 ° C. on both the first component side and the second component side. The spun long fiber group was pulled by a slot-type air soccer, and the web was collected by a collecting device. The blown air was sucked from a suction device provided in the collection device, and the web was brought into close contact with the conveyor. The obtained web was transferred to a thermocompression bonding apparatus and subjected to thermocompression bonding under conditions of an embossing roll temperature of 130 ° C., a flat roll of 130 ° C., and a linear pressure of 50 N / mm, and a basis weight of 31 g / m ² and a specific volume of 10 cm ³ / g. A fiber nonwoven fabric (fiber structure) was obtained. Next, when this nonwoven fabric was immersed in water at 20 ° C. to develop spiral crimps, the specific volume increased to 25 cm ³ / g.

Comparative Examples 1-3
The composite fiber was manufactured by the manufacturing method based on Example 1 with the combination of raw material resin shown in Table 2, the cross-sectional shape of the fiber, and the manufacturing conditions. Next, each obtained fiber was immersed in 20 degreeC water, and the behavior was observed. The number of crimps of the obtained fiber is shown in Table 2. Even if the fibers obtained in Comparative Examples 1 to 3 were immersed in water at 20 ° C., no significant change could be confirmed.

Comparative Example 4
The first component and the second component used in Comparative Example 3 were used, and a composite long fiber in which the first component had a parallel cross-sectional shape was spun into the core component. The spinning temperature condition was 240 ° C. on both the first component side and the second component side. The spun long fiber group was pulled by a slot-type air soccer, and the web was collected by a collecting device. The blown air was sucked from a suction device provided in the collection device, and the web was brought into close contact with the conveyor. The web is transferred to a thermocompression bonding apparatus and subjected to thermocompression bonding under the conditions of an embossing roll temperature of 130 ° C., a flat roll of 130 ° C., and a linear pressure of 50 N / mm, and a long fiber nonwoven fabric having a basis weight of 30 g / m ² and a specific volume of 11 cm ³ / g. Fiber structure) was obtained. Next, the nonwoven fabric was immersed in water at 20 ° C. and the behavior thereof was observed, but no significant change was confirmed.

  The data obtained in Examples 1 to 9 are shown in Table 1, and the data obtained in Comparative Examples 1 to 3 are shown in Table 2.

  As is apparent from Table 1, the latent crimpable conjugate fibers of Examples 1 to 9 of the present invention exhibited good crimp expression after moisture contact. Moreover, the long-fiber nonwoven fabric obtained in Example 10 was a nonwoven fabric having a novel feature that the specific volume was increased by contact with moisture.

  On the other hand, as is clear from Table 2, the composite fibers of Comparative Examples 1 to 3 had no significant difference in the number of crimps after contact with moisture, and the long-fiber nonwoven fabric of Comparative Example 4 The specific volume remained unchanged after contact.

Example 11
The soot obtained in Example 1 was carded with a card machine to form a web, and the web was heat-treated with a hot air penetration type dryer at a temperature of 110 ° C. and a treatment time of 1 minute 40 seconds, and the intersection of the composite fibers was A heat-sealed nonwoven fabric (fiber structure) was obtained. This nonwoven fabric was used for the second sheet layer, and was sandwiched between the top sheet layer and the back sheet layer together with the absorbent material to produce an absorbent article. The obtained absorbent article was excellent in liquid absorbency, was very useful as an absorbent article, and was judged to be highly practical.

Comparative Example 5
The soot obtained in Comparative Example 1 was carded with a card machine to form a web, and the web was heat-treated with a hot-air penetrating dryer under conditions of a temperature of 110 ° C. and a treatment time of 1 minute 40 seconds. A heat-sealed nonwoven fabric (fiber structure) was obtained. This nonwoven fabric was used for the second sheet layer, and was sandwiched between the top sheet layer and the back sheet layer together with the absorbent material to produce an absorbent article. Although the obtained absorbent article absorbs liquid, the absorptivity was equivalent to a general absorbent article.

  The absorbent article obtained in Example 11 has excellent liquid absorbency and good performance as an absorbent article, and is excellent in practicality, whereas the absorbent article obtained in Comparative Example 5 The absorptivity was the same as that of general absorbent articles and was not characteristic.

The latent crimpable conjugate fiber of the present invention exhibits spiral crimp due to contact with moisture during use, and thus has excellent stretchability, bulkiness, texture, and the like.
In addition, the fiber structure and absorbent article using the latent crimpable conjugate fiber of the present invention do not take a storage place due to bulk at each distribution stage of packing, storage and transportation, and contact with moisture during use. A crimped structure is formed, and a fiber structure and absorbent article with a good texture having stretchability and bulkiness are formed. In addition, these fiber structures and absorbent articles have good moisture retention.
Utilizing the characteristics of the latent crimpable conjugate fiber of the present invention, sanitary materials such as disposable diapers and sanitary products, industrial materials such as sound absorbing materials, wiping materials, filters, cushion materials, oil adsorbing materials, and medical fields For example, it can be suitably used.

It is sectional drawing of the eccentric sheath core type composite fiber used in the Example of this invention.

Explanation of symbols

O ₁ : Center point of composite fiber O ₂ : Center point of core component d: Distance between O ₁ and O ₂ R: Radius of composite fiber

Claims (5)

A composite fiber composed of two different types of water-insoluble thermoplastic resin components (referred to as component A and component B, respectively),
Form of double engagement is eccentric ratio of 0.1 or more eccentric sheath-core type for a parallel-type or A component as a sheath, a block copolymer of component A is a polyether-polyamide block copolymer or polyamide and polyethylene glycol The component B is at least one selected from polyolefins, polyamides and polyamide alloys, and the difference in water absorption (% by weight) at 20 ° C. between the component A and the component B is 6% by weight or more, characterized in that the cross-sectional area change ratio after moisture contact 10 sec at 20 ° C. of (V) is Ri following relationship near, 20 spiral crimps number of water contact 10 seconds after ° C. express eight /25.4mm more A product used in contact with moisture , using a fiber structure using at least part of the latent crimpable conjugate fiber.
A2 / A1> B2 / B1
Here, A1: Cross-sectional area before contact with moisture of A component A2: Cross-sectional area after 10 seconds of contact with moisture of A component B1: Cross-sectional area before contact with moisture of B component B2: Cross-sectional area after 10 seconds of contact with moisture of B component The product according to claim 1, wherein the latent crimpable conjugate fiber has a water absorption rate of 1% or more at 20 ° C. The fiber structure is a structure composed of at least one kind of fabric selected from a nonwoven fabric, a net-like material, a knitted fabric and a woven fabric in which the fiber contacts of the latent crimpable composite fiber are fixed by thermal bonding or entanglement between the fibers. product according to any one of claims 1-2. An absorbent article using at least a part of the product according to any one of claims 1 to 3 . A composite fiber composed of two different types of water-insoluble thermoplastic resin components (referred to as component A and component B, respectively),
Form of double engagement is eccentric ratio of 0.1 or more eccentric sheath-core type for a parallel-type or A component as a sheath, a block copolymer of component A is a polyether-polyamide block copolymer or polyamide and polyethylene glycol The component B is at least one selected from polyolefins, polyamides and polyamide alloys, and the difference in water absorption (% by weight) at 20 ° C. between the component A and the component B is 6% by weight or more, characterized in that the cross-sectional area change ratio after moisture contact 10 sec at 20 ° C. of (V) is Ri following relationship near, 20 spiral crimps number of water contact 10 seconds after ° C. express eight /25.4mm more A method for using latent crimpable fibers , characterized in that a product using a fiber structure using at least a part of the latent crimpable conjugate fiber is brought into contact with moisture .
A2 / A1> B2 / B1
Here, A1: Cross-sectional area before contact with moisture of A component A2: Cross-sectional area after 10 seconds of contact with moisture of A component B1: Cross-sectional area before contact with moisture of B component B2: Cross-sectional area after 10 seconds of contact with moisture of B component

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