JP2013155462A - Fiber for airlaid nonwoven fabric and airlaid nonwoven fabric comprising thermoplastic elastomer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop and provide an elastomer-based eccentric core-sheath type conjugate fiber that has opening property as well as cushioning property, flexibility and elastic recovery by carrying out an application of a mechanical crimp and an oil solution (silicone oil) and forming a three-dimensional crimps with heat before and after a thermal adhesion, in order to overcome a defect in opening property in an airlaid step accompanied by a high friction which the elastomer staple fiber has, when producing an airlaid nonwoven fabric that is excellent in cushioning property, flexibility and elastic recovery.SOLUTION: There is provided a fiber for an airlaid nonwoven fabric which is an eccentric core-sheath type conjugate fiber comprising a core component and a sheath component in a weight ratio of 20/80-80/20, and the sheath component comprises thermoplastic polyester ether. The fiber has a fineness of 1.0-50.0 dtex, a fiber length of 3-30 mm, a number of crimps of 1.0-20.0 apexes/25 mm and a degree of crimps of 50-80%, and develops three-dimensional crimps or Ω type crimps by a heat treatment at a temperature of 100°C or higher.

Description

  The present invention relates to a fiber for an air laid nonwoven fabric made of a thermoplastic elastomer and an air laid nonwoven fabric.

  Airlaid nonwoven fabric has a uniform fiber orientation with no difference in the direction of travel and width, compared to nonwoven fabric produced by the card method, which is widely used in the past, and is more bulky than nonwoven fabric produced by papermaking. This is a growing field with easy-to-use features and increased production. In general, the airlaid nonwoven fabric fibers are imparted with a flat zigzag-like or spiral-like obvious crimp in order to impart bulkiness. However, if the number of crimps or the crimp rate is increased in order to improve bulkiness, the fiber opening property is reduced in the air opening process, and unopened bundles and web spots are more frequently generated. Often have poor appearance quality and poor nonwoven fabric strength.

  In addition, the finer the fineness, the more the surface area of the fiber and the easier it is to aggregate as a fiber bundle, making it difficult to open the fiber. Due to the large number, the spreadability was further deteriorated. On the other hand, when the fiber length is increased, the strength of the resulting nonwoven fabric can be increased. However, on the other hand, there is a drawback that the passability of the screen is deteriorated and the production capacity is lowered. A ratio of the height of the crimp to the crimp cycle, that is, the so-called crimp inclination is regulated so as to be optimum for each fineness, and a fiber having a good airlaid property has been proposed (for example, see Patent Document 1). However, the number of crimps exemplified as an example is too small when the fineness is small, so the stuffing pressure of the push-in crimper has to be lowered, and the crimp does not crimp. It was easy to develop near crimped spots. In addition, when the fineness is large, the number of crimps is set too large. Therefore, if the stuffing pressure is increased, the back pressure is increased and the crimper is likely to rattle. Heating the tow with steam or the like before the crimper reduces the rigidity of the fiber and reduces rattling, but the crimpability increases and the H / L becomes too high, so the screen does not pass well. As a result, not only the spinning amount is reduced, but also a fuzzy fiber mass tends to be formed. Here, H / L is the height (H) of the triangle connecting the two peak points of the valleys adjacent to the peak of the peak at the maximum peak of the crimped part in the form of the mechanical crimp of the single yarn. And the base (L) ratio.

Two-component polymer blend composite fibers cannot sufficiently heat-set on the low melting point side, so the shrinkage during heat bonding is large, and the web after heat bonding shrinks greatly, impairing aesthetics and adhesive strength. Screen during airlaid opening When a fine three-dimensional crimp develops due to a strong stimulus received by, etc., discharge from the screen tends to be poor and productivity tends to be poor.
An elastomer can be used for the sheath polymer in order to improve the cushioning property, etc., but there is a tendency that the air opening process in the air laying process with high friction is poor, the discharge from the screen is poor, and the productivity is poor ( For example, see Patent Document 2.) Therefore, a heat-adhesive conjugate fiber for airlaid nonwoven fabric that has excellent adhesive strength and remarkably excellent spinnability has not been proposed.

JP 2005-042289 A International Publication No. 97/023670 Pamphlet

  In the production of an air laid nonwoven fabric excellent in cushioning property, flexibility and elastic recovery property, the present invention provides a mechanical crimp and an oil agent (in order to overcome the opening failure of the air laid process associated with the high friction of the elastomer short fiber). Elastomer-based eccentric core-sheath type composite fiber that achieves both openability, cushioning, flexibility, and elastic recovery by applying three-dimensional crimps by heat before and after thermal bonding Is to develop and provide

  As a method for producing a fiber that solves the above problems, a three-dimensional crimp or an Ω-type crimp is used in a stretching step before crimping with a crimper, a drying step after crimping, or a heat treatment step in an airlaid nonwoven fabric manufacturing step. Heat treatment conditions that can suppress these crimps are applied so that the crimps can be expressed. In addition, since elastomer short fibers are accompanied by high friction, adding dimethylsiloxane, polyoxyalkylene-modified dimethylsiloxane, or amide-modified dimethylsiloxane to the spun yarn will reduce friction and improve openness. Therefore, the inventors have arrived at the invention of a composite fiber for airlaid nonwoven fabric that recovers its bulk performance after passing through the screen without any problem.

  More specifically, the above-mentioned problem is an eccentric core-sheath type composite fiber in which the weight ratio of the core component to the sheath component is 20/80 to 80/20, wherein the sheath component contains a thermoplastic polyester ether, and the fineness Has a mechanical crimp of 1.0 to 50.0 dtex, fiber length of 3 to 30 mm, crimp number of 1.0 to 20.0 mountain / 25 mm, crimp rate of 50 to 80%, 100 ° C. or more This can be solved by an airlaid nonwoven fabric characterized in that a three-dimensional crimp or an Ω-type crimp is expressed by the heat treatment. Furthermore, the crimp ratio after 120 ° C. dry heat treatment is 90% or more, and further, an oil agent is applied to the surface of the airlaid nonwoven fabric fiber. As the oil agent, dimethylsiloxane, polyoxyalkylene-modified dimethylsiloxane, or It is preferable to apply the amide-modified dimethylsiloxane to the surface of the fiber for an airlaid nonwoven fabric in an amount of 0.15 to 0.50% by mass. By adopting such a configuration, the passage of the screen is improved by improving the spreadability, and the problem of the invention can be solved even by an airlaid nonwoven fabric excellent in cushioning property, flexibility and elastic recovery property.

  The present invention relates to an eccentric core-sheath composite fiber containing a thermoplastic polyester ether elastomer in a sheath, which has excellent screen-passability, that is, extremely high productivity, cushioning property, flexibility, and elastic recovery rate. It was possible to provide an adhesive conjugate fiber.

It is an example of the airlaid method nonwoven fabric manufacturing apparatus for evaluating screen permeability.

Hereinafter, embodiments of the present invention will be described in detail.
First, the present invention is an eccentric core-sheath composite fiber composed of a fiber-forming resin component and a heat-adhesive resin component, having a fineness of 1.0 to 50 dtex, a fiber length of 3 to 30 mm, and a crimp number of 1.0. A composite fiber for an airlaid nonwoven fabric, characterized by having a mechanical crimp of -20 peaks / 25 mm, a crimp rate of 50-80%, and exhibiting a three-dimensional crimp or Ω-type crimp by heat treatment at 100 ° C. or higher. It is. When the fineness, fiber length, number of crimps, and crimp rate are out of these ranges, it is generally difficult to pass through a screen provided in an airlaid nonwoven fabric manufacturing apparatus. The reason is that if the fineness is small, the aggregation between the fibers is strong and it is difficult to open the fibers, and if the fiber length is long, the fibers are not rounded to the size that passes through the holes of the screen. From this tendency, when the number of crimps is further increased, or when three-dimensional crimps or Ω-type crimps are developed and the crimping performance is strong, the fibers are entangled to form a hairball shape, and the screen holes are easily blocked. Moreover, when the pill ball accidentally passes the screen, it becomes easy to produce a fuzz ball-like defect and a textured spot on the web, which causes a problem in quality of the nonwoven fabric. Here, the term “mechanical crimp” refers to a form of crimp provided by a mechanical device such as a push-in type crimper, which is originally intended for imparting crimp.

  In view of this point, the present invention provides a three-dimensional crimp or Ω-type crimp that has been problematic in terms of quality. It is necessary to obtain a non-woven fabric with good formation and quality by suppressing the expression and expressing a three-dimensional crimp or Ω-type crimp in the heat treatment step after the airlaid screen. The present invention has been invented. Note that the three-dimensional crimp and the Ω-type crimp are different from the mechanical crimp here, in the fiber production stage and the subsequent production stage of the non-woven fabric etc. It represents the form of crimp given naturally.

  In order to solve the above-mentioned problems, the assigned mechanical crimp is determined by the degree of crimp (CD) and the number of crimps (CN) defined in JIS L 1015: 2005 8.12.1 to 8.12.2. The ratio, CD / CN, is set to 1.0 to 2.0 at the raw cotton production stage. Further, the crimping rate (described in JIS L1015: 2005 8.12.3. The crimping rate is divided by the number of crimps and expressed as a percentage) is set to be 50 to 80% or more. By setting the number of crimps and the crimp rate low, it is easy to pass through the screen, and the crimp rate after 120 ° C. dry heat treatment is preferably 90% or more. Further, in the raw cotton showing a crimp rate of 90% or more after the dry heat treatment at 120 ° C., the crimped fibers are recovered after passing through the screen, so that the bundled fiber mass breaks the aggregation between the fibers and is easily opened. This is because the spinning property further increases. In order to make the crimp rate after the 120 ° C. dry heat treatment 90% or more, as described later, an eccentric core-sheath type composite fiber, a weight ratio of the core component and the sheath component is set to a predetermined ratio, It is preferable to select a specific polymer as a polymer constituting the core component and the sheath component, and perform melt spinning / drawing treatment and imparting mechanical crimp. The range of CN is suitably about 1.0 to 20 peaks / 25 mm. If the CN exceeds 20 peaks / 25 mm, the entanglement between the fibers is too strong, and pills are likely to occur. Conversely, if the CN is less than 1.0 peaks / 25 mm, it becomes difficult to pass through the screen when the fiber length becomes long, Fiber bundles on the bundle are likely to be formed, and the opening property and screenability may be deteriorated. CN is preferably 2.0 to 15 peaks / 25 mm, more preferably 7.0 to 10 peaks / 25 mm. When the ratio of CD to CN, CD / CN (crimp rate) exceeds 80%, the crimp peaks become sharp and the entanglement between the fibers becomes stronger, so that the screen passability is deteriorated. If the crimp rate is less than 50%, the bundled fibers are likely to remain after passing through the screen. The crimp rate is preferably 60 to 75%, more preferably 65 to 80%.

  In order to achieve such a range of CD / CN ratio and a range of crimp ratio, for example, in the case of an eccentric core-sheath conjugate fiber, in the step between crimpers for applying crimp from the end of the warm drawing device, 70 It is preferable to heat the tow to ˜130 ° C. If it is less than 70 ° C., three-dimensional crimps or Ω-type crimps appear in the drying process after crimping, and if it exceeds 130 ° C., three-dimensional crimps or Ω-type crimps in the airlaid heat treatment process due to thermal history. Shrinkage does not occur. Further, in the drying step in the subsequent step of the crimper, the tow is preferably dried at 70 to 130 ° C. in accordance with the heat treatment temperature before the crimper. If it is less than 70 degreeC, the dry heat shrinkage rate of raw cotton will become high, and a wrinkle will generate | occur | produce in a nonwoven fabric in the heat treatment process of airlaid. When the temperature exceeds 130 ° C., three-dimensional crimps or Ω-type crimps develop, and sticking occurs, resulting in poor opening.

  Further, the fiber of the present invention is required to be a fiber that expresses a three-dimensional crimp or an Ω-type crimp by heat treatment at 100 ° C. or higher. From the crimp application step, tow, so as not to perform the heat treatment at 100 ° C. or higher after the drying step at 70 to 130 ° C. in the heat treatment step before crimper, adopting the configuration of the composite fiber as described above. In the step of cutting into short fibers and the air-laid nonwoven fabric manufacturing step, it is preferable to select the conditions of the manufacturing step so as to pass through the steps before the step of thermally bonding and heat treating the short fibers with each other by thermal bonding. As a result, a nonwoven fabric having a high cushioning property, flexibility, and high elastic recovery rate can be obtained while having good screen-passability in the air-laid nonwoven fabric production process.

  The fineness is preferably 1.0 to 50 dtex. If it is less than 1.0 dtex, poor opening occurs, and if it exceeds 50 dtex, three-dimensional crimps or Ω-type crimps are hardly expressed, and the bulkiness of the airlaid nonwoven fabric cannot be obtained. The fineness is preferably 2.0 to 20 dtex, more preferably 3.0 to 8.0 dtex. The fiber length is preferably 3 to 30 mm. If it is less than 3 mm, the bonding property between fibers is low and the adhesive strength is weakened. When it exceeds 30 mm, the bonding property between the fibers is high, resulting in poor opening. The fiber length is preferably 3.5 to 20 mm, more preferably 4 to 10 mm.

  In this invention, it is an eccentric core-sheath-type composite fiber whose weight ratio of a core component and a sheath component is 20 / 80-80 / 20, Comprising: A sheath component needs to contain thermoplastic polyester ether. More preferably, the weight ratio of the core component to the sheath component is 30/70 to 70/30. The sheath component is preferably a thermoplastic polyester ether elastomer. Crystalline thermoplastic polyester ether elastomer (E) constituting the sheath component and crystalline inelastic polyester (P) having a melting point higher than that of the elastomer (E) [this component constitutes the core component. Is a weight ratio of E: P = 20: 80 to 80:20 in a unit volume formed from a constant fiber length including the entire cross section of a circular fiber, and is a composite fiber in which the P side is eccentric. It is preferable. In particular, E: P = 30: 70 to 70:30 is preferable. When the ratio on the P side is less than 20, the fiber strength cannot be obtained and the nonwoven fabric strength becomes weak. In addition, when the ratio on the P side exceeds 80, the nonwoven fabric adhesion strength is weakened. Here, in E and P, the ratio of E: P is sometimes defined by the area occupied by the cross section of the conventional fiber, but it is considered that the specific gravity of E and P is substantially the same. As a matter of specifying the invention, the provision of the fiber manufacturing method is defined as a weight ratio that is easier to define.

  Here, the P component is not particularly limited as long as it is a polyester. However, ordinary polyethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polytetramethylene terephthalate, poly-1,4-dimethylcyclohexane terephthalate, polypivalolactone. Or it is preferable that it is polyester which consists of these copolymer esters, and since it is a use which requires a repeated distortion, the polyalkylene terephthalate which does not leave distortion easily is preferable. In particular, when the hard segment of the elastomer used for the fusion component of the composite fiber is polybutylene terephthalate or polyethylene terephthalate, there is no problem such as peeling, which is favorable. The melting point of the P component is preferably in the range of 110 to 290 ° C.

  On the other hand, it is appropriate to select the melting point of the E component so that it is 100 to 220 ° C. and lower than the P component. If the melting point is less than 100 ° C., the sticking of fibers during spinning may not be completely prevented. In addition, when the composite fibers are stacked in multiple stages in, for example, a warehouse without a temperature control device in summer, there is a concern that the fibers may become stuck. If the melting point exceeds 220 ° C., the upper limit of the stable processing temperature of the heat treatment machine is full, and uneven adhesion strength is partially generated, causing unevenness in hardness, which is not preferable. The melting point of the sheath component (E) is more preferably in the range of 130 to 180 ° C. from the viewpoint of preventing sticking and stability in heat treatment. The component E is preferably a crystalline polyester ether elastomer or a polymer obtained by further blending or copolymerizing a polyurethane elastomer or the like with a crystalline ether ether elastomer or a polyester ether elastomer from the viewpoint of proper spinning and physical properties. Examples of polyurethane elastomers include low melting point polyols having a weight average molecular weight of about 500 to 6000, such as dihydroxy polyether, dihydroxy polyester, dihydroxy polycarbonate, dihydroxy polyester amide, and the like, and organic diisocyanates having a weight average molecular weight of 500 or less, such as p, p. '-Diphenylmethane diisocyanate, tricine diisocyanate, isophorone diisocyanate, p, p'-hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, 2,6-diisocyanate methylcaproate, hexamethylene diisocyanate, and the like, chain extender having a weight average molecular weight of 500 or less Examples thereof include polymers obtained by reaction with glycol, amino alcohol or triol. Among these polymers, particularly preferred are polytetramethylene glycol or poly-ε-caprolactone as a polyol. As the organic diisocyanate, p, p'-diphenylmethane diisocyanate is suitable. As the chain extender, p, p'-bishydroxyethoxybenzene, ethylene glycol and 1,4-butanediol are suitable. On the other hand, as the crystalline polyester ether elastomer, a polyester ether block copolymer obtained by copolymerizing a thermoplastic polyester as a hard segment and poly (alkylene oxide) glycol as a soft segment, more specifically terephthalic acid, Isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethanedicarboxylic acid (structures in which the bonding positions of two carboxyl groups are different Isomers), diphenyl ether dicarboxylic acid (including structural isomers with different bonding positions of two carboxyl groups), diphenylthioether dicarboxylic acid (including structural isomers with different bonding positions of two carboxyl groups), benzophenone dicarbo Aromatic acids such as acid (including structural isomers with different bonding positions of two carboxyl groups), diphenylsulfone dicarboxylic acid (including structural isomers with different bonding positions of two carboxyl groups), sodium 3-sulfoisophthalate Alicyclic dicarboxylic acids such as dicarboxylic acid and 1,4-cyclohexanedicarboxylic acid, aliphatic dicarboxylic acids such as succinic acid, oxalic acid, adipic acid, sebacic acid, decanedicarboxylic acid and dodecanedicarboxylic acid, or ester-forming derivatives thereof At least one dicarboxylic acid selected from the group consisting of ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol , An aliphatic diol such as decamethylene glycol, an alicyclic diol such as 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, or ester-forming derivatives thereof. Polyethylene glycol, poly (1,2-propylene oxide) glycol, poly (1,3-propylene oxide) glycol, poly (tetramethylene oxide) glycol having at least one diol component and a weight average molecular weight of about 300 to 5,000, It is preferably a terpolymer composed of at least one of poly (alkylene oxide) glycols such as a copolymer of ethylene oxide and propylene oxide and a copolymer of ethylene oxide and tetrahydrofuran. However, a polyester ether block copolymer having polybutylene terephthalate as a hard segment and polyoxytetramethylene glycol as a soft segment is particularly preferable from the viewpoint of physical properties such as adhesion to a polyester composite component, heat resistance, and strength. In this case, the polyester portion constituting the hard segment has a copolymerization ratio (in mol% based on the total acid component) of 40 to 100 mol% of terephthalic acid based on the total acid component of the copolymer, and isophthalic acid. Containing 0 to 50 mol% is used. Acid components other than terephthalic acid and isophthalic acid include phthalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 1,4-cyclohexanedicarboxylic acid, etc. Is preferred because it improves the quality such as elasticity and durability in order to obtain a predetermined melting point. In particular, those containing 50 to 90 mol% of terephthalic acid and 10 to 35 mol% of isophthalic acid are more preferably used. The main component of the glycol component of the polyester part is preferably 1,4-butanediol. As used herein, “main” means that 80 mol% or more of all glycol components are glycols such as ethylene glycol or 1,4-butanediol, and other types of glycol components are commonly used within a range of 20 mol% or less. It may be polymerized. Preferred examples of the copolymer glycol component include 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and the like. Furthermore, the polyester ether block copolymer contains a poly (alkylene oxide) glycol component having a weight average molecular weight of 300 to 5000 and a weight average molecular weight of 800 to 4000 and a glycol component of 30 to 70% by weight. It is particularly preferred. When the weight average molecular weight is less than 300, the block property of the resulting block copolymer is lowered and the elastic recovery performance is insufficient. On the other hand, when the weight average molecular weight exceeds 5,000, the poly (alkylene oxide) ) Since the copolymerization property of the glycol component is lowered and the elastic recovery performance is insufficient, it is not preferable. When the copolymerization amount of the glycol component is less than 5% by weight, even if the composite fiber is heat-bonded and molded into a cushioning material or the like, the desired elastic property of the present invention cannot be obtained. On the other hand, if it exceeds 80% by weight of the glycol component, the mechanical properties, heat resistance, and durability of light resistance of the resulting block copolymer are undesirably lowered. The poly (alkylene oxide) glycol preferably used is preferably a homopolymer of polyethylene glycol, poly (propylene oxide) glycol, or poly (tetramethylene oxide) glycol. Furthermore, a random copolymer or block copolymer obtained by copolymerizing two or more repeating carriers constituting the homopolymer in a random or block form may be used, and the homopolymer or copolymer may be used. A mixed polymer in which two or more of these are mixed may be used. Such a polyester ether block copolymer can be obtained using a known method for producing a copolyester. In producing the conjugate fiber of the present invention, the E component and the P component are each dried to a normal moisture content of 0.1% or less and then subjected to spinning. The E component and the P component may contain other polymers such as polyester, polyamide, aramid, and polyolefin as long as the effects of the present invention are not impaired.

  Moreover, the fiber for air-laid nonwoven fabrics of this invention is a composite fiber, and needs to be an eccentric core-sheath type composite fiber. In the concentric core-sheath type, it is very difficult to give three-dimensional crimp or Ω-type crimp by heat treatment as described later. On the other hand, in the side-by-side type, since there is a portion where the thermoplastic polyester ether component is not exposed on the outer surface of the fiber, a nonwoven fabric having sufficient strength is sufficiently bonded to other fibers when the nonwoven fabric is produced. I can't.

  The composite fiber is preferably provided with an oil agent. As the oil agent to be provided, 0.15 to 0.50% by mass of air-laid nonwoven fabric containing dimethylsiloxane, polyoxyalkylene-modified dimethylsiloxane, or amide-modified dimethylsiloxane. It is preferable to give to the surface of the fiber. If it is less than 0.15% by weight, static electricity is likely to be generated in the airlaid opening process, which causes pills and the like. Moreover, when it exceeds 0.50 weight%, the adhesiveness of the fibers by an oil agent will rise, and it will cause a fiber opening defect. More preferably, polyoxyalkylene-modified dimethylsiloxane is used. Moreover, it is more preferable that it is 0.16-0.30 weight% as an oil agent provision amount.

The airlaid nonwoven fabric preferably has a weight recovery rate of 80 to 100% after being weighted after applying a weight of 100 g / m ² , a thickness of 10 mm, and a load of 10 kPa for 20 minutes. When the thickness recovery rate is 80% or less, it cannot be said that the bulkiness of the conventional airlaid nonwoven fabric has increased.
The spinning speed needs to be 1800 m / min or less, preferably 1500 m / min or less, and more preferably 1300 m / min or less. If it exceeds 1800 m / min, the orientation of the undrawn yarn is increased, which hinders the high adhesiveness targeted by the present invention and increases the number of yarn breaks, resulting in poor productivity. Moreover, even if the spinning speed is slower than this range, the productivity is naturally deteriorated.

  In the above polyester and / or crystalline polyester elastomer, additives, fluorescent brighteners, stabilizers, flame retardants, flame retardant aids, ultraviolet absorbers and antioxidants are within the range not impairing the effects of the present invention. Further, various pigments for coloring may be contained. In order to improve the concealability, about 10% of titanium oxide may be kneaded.

  The short fiber of the present invention described above can be produced, for example, by the following method. A polyalkylene terephthalate and a crystalline polyester elastomer are discharged from a die using a known spinning equipment and taken up at a speed of 100 to 2000 m / min while cooling with cooling air to obtain an undrawn yarn. At this time, an undrawn yarn is obtained in the same manner as described above except that the polymer is separately supplied to the composite spinneret, and the polyalkylene terephthalate is combined and discharged using the die so that it accounts for 50% or more of the fiber surface area. . Subsequently, the undrawn yarn obtained is stretched in warm water at 70 to 100 ° C. or in steam at 100 to 125 ° C. to give crimps as necessary, and to give an oil agent according to the purpose and purpose. After performing the drying and relaxation heat treatment, it is cut into a predetermined fiber length to obtain the short fiber of the present invention. In this case, the oil agent may contain an amount or type of silicone compound that does not hinder the achievement of the object of the present invention.

Hereinafter, the present invention will be described more specifically with reference to examples. In addition, the process tone and mechanical characteristics (general physical properties) in Examples and Comparative Examples were measured by the following methods.
(A) Fineness Measured by the method described in JIS L 1015 7.5.1 Method A.
(B) Dry strength and dry elongation Measured by the method described in JIS L 1015: 2005 8.7.1.
(C) Number of crimps and degree of crimping Measured by the method described in JIS L 1015 7.12.
(D) Fiber length Measured by the method described in JIS L 1015 7.4.1 C method.
(E) Crimp rate after 120 ° C. dry heat treatment After heating in a 120 ° C. atmosphere by the method described in JIS L 1015: 2005 8.15 b), the crimp rate after cooling to room temperature was measured.
(F) Nonwoven fabric appearance The appearance of the web is observed and evaluated according to the following criteria.
Level 3: Unopened lumps and spotted spots (shading) are not seen, and the texture is uniform.
Level 2: Unopened lumps are not conspicuous, but spotted spots (shading) can be visually confirmed.
Level 1: Unopened lumps and spotted spots (light and shade) are conspicuous and the texture is uneven.
(G) Screen permeability In the airlaid nonwoven fabric manufacturing apparatus described in Japanese Patent Application Laid-Open No. 2004-11027 (FIG. 1), a perforated flat plate made of a stainless steel wire mesh having an inner diameter of 310 mm and a 10 mesh (hole diameter 1.9 mm, wire diameter 0.635 mm) A cylindrical columnar body having a circular opening having an inner diameter of 25 mm at the upper center of the screen (1), an inner diameter of 310 mm, a height of 600 mm (h1), a thickness of 5 mm and an open lower portion is 0.8 mm on the screen. A short fiber opening chamber (2) provided with a gap, a short fiber collecting net (3) made of a stainless steel wire mesh having an inner diameter of 310 mm and a 100 mesh (hole diameter of 0.14 mm, wire diameter of 0.114 mm), An airtight chamber (4) and an upper part, in which a cylindrical columnar body having an open inner diameter of 310 mm, a height of 400 mm (h2), and a thickness of 5 mm is closely attached to (1) and (3) An airlaid nonwoven fabric illustrated in FIG. 1 having a funnel-type airtight chamber (5) having an outer shape congruent with the net (3), an upper portion being open, and an upper portion being in close contact with the net (3) A manufacturing apparatus was produced. Further, an exhaust device is connected to the lower part of the funnel-type airtight chamber (5) via a hose, and the exhaust device is operated. (5) After making the inside negative pressure, 8 g of the opening portion of (2) A process of making a web by putting a short fiber sample and opening the short fiber was performed. As an exhaust device, J-75 made by Wonder Gun OSAWA and 0.4 MPa compressed air were used (theoretical displacement 20 m ³ / min). In this measurement method, evaluation was made in the following three stages by the number of seconds that the short fiber passed through the perforated flat screen.
Level 3: All 8 g passes in less than 120 seconds.
Level 2: The entire amount of 8 g passes in 120 to 180 seconds.
Level 1: The fibers remain on the screen even after 180 seconds.
(H) Nonwoven fabric bulk recoverability The obtained short fiber was passed through a card to prepare a web, and measured by the method described in JIS L-1097 5.3. That is, the thickness recovery rate is 10 g / m ² , the thickness is 10 mm, the load is 10 kPa for 20 minutes, and the thickness is recovered relative to the initial thickness of 10 mm after dewetting.
(I) Composition The core component of the composite fiber, the polymer type constituting the sheath component, and the type of the oil agent component were sampled or extracted from the composite fiber and identified by H-NMR analysis.

Example 1
A polyethylene terephthalate (PET) polymer melted at 280 ° C. and a thermoplastic polyester ether elastomer melted at 260 ° C. are separately supplied to a known composite spinneret, and from a die having a 0.3 mm round hole capillary 1032H hole. Extrusion was performed at a discharge rate of 700 g / min. This was air-cooled with cooling air at 20 ° C. and wound at 1150 m / min to obtain unstretched. This undrawn yarn is stretched in one step or in two or more stages, and after applying an oil agent made of polyoxyalkylene-modified dimethylsiloxane by 0.17% by weight dipping, the preheating temperature before crimper is raised to 73 ° C. It was. A flat-type zigzag crimp having a crimp number of 9 ridges / 25 mm and a crimp rate of 12% was imparted by an indentation type crimper, further dried with hot air at 90 ° C., and then cut into a fiber length of 5 mm. When an airlaid nonwoven fabric was prepared using these short fibers, the screen permeability, nonwoven fabric formation, and nonwoven fabric bulk recovery rate were good. Moreover, when the crimp form after heat-processing at 100 degreeC was observed, three-dimensional crimp was expressing. The results are shown in Table 1.

(Example 2)
The same operation as in Example 1 was performed except that the pre-crimper preheating temperature was further increased to 80 ° C. When the airlaid nonwoven fabric was produced using the obtained short fiber, the screen permeability, nonwoven fabric formation, and nonwoven fabric bulk recovery rate were good. When the crimp form after heat-processing at 100 degreeC was observed similarly to Example 1, the three-dimensional crimp was expressing. The results are shown in Table 1.

(Example 3)
The same operation as in Example 1 was performed except that the third stretching temperature was set to 98 ° C. using warm water instead of heating at the pre-crimper preheating temperature. When the airlaid nonwoven fabric was produced using the obtained short fiber, the screen permeability, nonwoven fabric formation, and nonwoven fabric bulk recovery rate were good. Moreover, when the crimp form after heat-processing at 100 degreeC was observed, three-dimensional crimp was expressing. The results are shown in Table 1.

Example 4
The same operation as in Example 1 was performed except that the tension heat set temperature was set to 115 ° C. using a high-temperature roller instead of heating at the pre-crimper preheating temperature. When the airlaid nonwoven fabric was produced using the obtained short fiber, the screen permeability, nonwoven fabric formation, and nonwoven fabric bulk recovery rate were good. Moreover, when the crimp form after heat-processing at 100 degreeC was observed, three-dimensional crimp was expressing. The results are shown in Table 1.

(Example 5)
The same operation as in Example 2 was performed except that the weight ratio of the core component was increased to 70%. When the airlaid nonwoven fabric was produced using the obtained short fiber, the screen permeability, nonwoven fabric formation, and nonwoven fabric bulk recovery rate were good. Moreover, when the crimp form after heat-processing at 100 degreeC was observed, the omega-type crimp was expressing. The results are shown in Table 1.

(Comparative Example 1)
The same operation as in Example 1 was performed except that the relaxation heat set temperature was 70 ° C., which was not heated at the pre-crimper preheating temperature. When the airlaid nonwoven fabric was produced using the obtained short fiber, the three-dimensional crimp was expressed and the screen passage property was bad. Moreover, when the crimp form after heat-processing at 100 degreeC was observed, three-dimensional crimp was expressing. The results are shown in Table 1.

(Comparative Example 2)
The same operation as Comparative Example 1 was performed except that the number of crimps was increased. When the airlaid nonwoven fabric was produced using the obtained short fiber, the three-dimensional crimp was expressed and the screen passage property was bad. Moreover, when the crimp form after heat-processing at 100 degreeC was observed, three-dimensional crimp was expressing. The results are shown in Table 1.

(Comparative Example 3)
The same operation as Comparative Example 1 was performed except that the number of crimps was lowered and the heat of relaxation setting was raised. When the air-laid nonwoven fabric was prepared using the obtained short fibers, the number of crimps was lowered, but the three-dimensional crimps became an obstacle, and the screen permeability was poor. Moreover, when the crimp form after heat-processing at 100 degreeC was observed, three-dimensional crimp was expressing. The results are shown in Table 1.

(Comparative Example 4)
The same operation as Comparative Example 1 was performed except that the relaxation heat set temperature was raised. When the airlaid nonwoven fabric was created using the obtained short fibers, three-dimensional crimps were developed before the 120 ° C. dry heat treatment, and the screen passing property was poor. The results are shown in Table 1.

(Comparative Example 5)
Short fibers were obtained by the same operation as in Comparative Example 1 except that the number of crimps was increased. When the airlaid nonwoven fabric was produced using the obtained short fiber, the three-dimensional crimp was expressed and the screen passage property was bad. The results are shown in Table 1.

  The present invention relates to an eccentric core-sheath composite fiber whose sheath is a thermoplastic polyester ether elastomer, which has excellent screen-passability, that is, extremely high productivity, cushioning property, flexibility, and elastic recovery rate. It has become possible to provide adhesive conjugate fibers. This fact has a great impact on the industry.

1 Opening member (perforated flat screen)
2 Short fiber opening room 3 Short fiber collection net 4 Airtight room 5 Funnel-type airtight room 6 Exhaust device 7 Duct s Short fiber inlet (opening part)
d Gap h1 Length of opening chamber h2 Length of airtight chamber

Claims (6)

  An eccentric core-sheath composite fiber having a weight ratio of the core component to the sheath component of 20/80 to 80/20, wherein the sheath component contains thermoplastic polyester ether, and the fineness is 1.0 to 50.0 dtex, fiber It has a mechanical crimp of 3-30 mm in length, 1.0-20.0 crests / 25 mm in crimps, and a crimp rate of 50-80%. A fiber for an airlaid nonwoven fabric characterized by crimping.   The airlaid nonwoven fabric according to claim 1, wherein the crimped rate after a dry heat treatment at 120 ° C. is 90% or more.   Further, an oil agent is applied to the surface of the airlaid nonwoven fabric fiber, and as the oil agent, 0.15 to 0.50% by mass of airlaid nonwoven fabric fiber containing dimethylsiloxane, polyoxyalkylene-modified dimethylsiloxane, or amide-modified dimethylsiloxane. The fiber for air laid nonwoven fabric according to claim 1, wherein the fiber is applied to a surface.   The fiber for air laid nonwoven fabric according to any one of claims 1 to 3, wherein the core component is polyalkylene terephthalate.   The air-laid nonwoven fabric which consists of the fiber for air-laid nonwoven fabrics in any one of Claims 1-4. A basis weight of 100 g / ^{m 2,} a thickness of 10 mm, after the load is 10 kPa 20 minutes giving, according to claim 5, wherein the air-laid nonwoven fabric thickness recovery rate after unloading is 80 to 100%.

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