JP2018104836A - Polyester fiber, and fiber structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester fiber structure very high in actual use characteristics such as sufficiently durable high hygroscopicity and wash resistance without temporal strength degradation, and yet soft in drape.SOLUTION: Regarding the polyester fiber structure of the present invention, a surface layer of a single fiber of the fiber structure is modified, ΔMR is not less than 0.5% and not greater than 10.0%, and above all, it is preferable that the polymer exists on a periphery of a fiber cross-section in a vertical direction to a fiber axis.

Description

  The present invention relates to a polyester fiber and a polyester fiber structure including the same.

  Synthetic fibers such as polyester fibers are widely used in clothing and industrial applications because they have many excellent properties. However, since these synthetic fibers have a hydrophobic and dense molecular structure, they are less hygroscopic and hygroscopic than natural fibers such as cotton and hemp, and chemical fibers such as rayon, and are comfortable to wear during exercise. The use in the field where sex is required was not suitable.

  Conventionally, various attempts to impart water absorption and hygroscopic functions to synthetic fibers such as polyester fibers have been studied.

  For example, Patent Document 1 proposes a method in which a hydrophobic radical initiator, a phthalimide compound and an ethylenically unsaturated organic acid are mixed and polymerized in a bath.

  Patent Document 2 proposes a method of treating in a bath using a treating agent containing a hydrophilic polymer, a divinyl monomer, and a polymerization initiator.

  Patent Document 3 proposes a polyester fiber excellent in hygroscopicity in which a vinyl monomer having a hydrophilic group is introduced onto the surface of a polyester synthetic fiber by graft polymerization.

  Patent Document 4 proposes a polyester fiber in which a polyalkylene oxide is blended inside the fiber and a polyalkylene glycol derivative is graft-polymerized on the fiber surface.

JP 2000-226767 A JP 2001-303447 A JP 2004-324008 A JP 2000-54262 A

  However, the technique described in Patent Document 1 has a problem that uneven polymerization tends to occur because the phthalimide compound and the ethylenically unsaturated organic acid are polymerized in the bath. In addition, hydrolysis was caused by repeated washing and moisture in the air, and the strength of the fiber gradually decreased with time, which had a very large problem in practical use.

  Moreover, since the technique described in Patent Document 2 imparts a hygroscopic polymer to the fiber surface in the form of a film, the technique lacks washing durability when the film is peeled off by repeated washing.

  Further, the polyester fiber described in Patent Document 3 is a product lacking in practicality because the graft polymerization component is present inside the fiber, so that the strength decrease with time increases.

  The polyester fiber described in Patent Document 4 has a low probability of contact with moisture outside the fiber because the polyalkylene oxide is present inside the fiber, and the polyalkylene glycol derivative is hygroscopic when present on the fiber surface. The effect to improve is small, and the hygroscopicity equivalent to a natural fiber is not obtained.

  The present invention provides a polyester fiber having excellent moisture absorption performance, extremely low practical durability with little deterioration in washing durability and strength over time, and a flexible structure, and a fiber structure including the same. .

  As a result of earnestly examining the creation of polyester fibers with little deterioration in strength over time while imparting moisture absorption similar to cotton to a polyester fiber structure, the present invention has fixed hygroscopic polymers on the fiber surface and the fiber surface layer. It was clarified that this problem can be solved at once by modifying the part.

  That is, the present invention has the following form. The polyester fiber of the present invention is a polyester in which the single fiber surface layer is modified with a polymer of an organic acid containing at least one carboxyl group and a compound having an amide bond, and ΔMR is 0.5% or more and 10.0% or less And a polyester fiber structure including the polyester fiber.

  Moreover, it is a manufacturing method of the said polyester-type fiber structure which performs the process in the bath selected from following (1)-(4).

  (1) A polyester fiber structure is immersed in a treatment liquid containing an emulsified and dispersed water-insoluble polymerization initiator, subjected to heat treatment in a bath, and then contains at least one carboxyl group-containing organic acid and an amide bond. A treatment in which a fiber structure is immersed in a liquid containing a compound to be heated and heat-treated in a bath.

  (2) Immerse the polyester fiber structure in a treatment solution containing an emulsified and dispersed water-insoluble polymerization initiator, perform heat treatment in a bath, and then contain a water-soluble polymerization initiator and at least one carboxyl group A treatment in which a fiber structure is immersed in a liquid containing a compound containing an organic acid and an amide bond, followed by heat treatment in a bath.

  (3) The polyester fiber structure is immersed in a treatment liquid containing an emulsified and dispersed water-insoluble polymerization initiator, an organic acid containing at least one carboxyl group, and a compound containing an amide bond, and heat treatment is performed in a bath. processing.

  (4) The polyester fiber structure is immersed in a treatment liquid containing an emulsified and dispersed water-insoluble polymerization initiator, a water-soluble polymerization initiator, an organic acid containing at least one carboxyl group, and a compound containing an amide bond. And heat treatment in a bath.

  According to the present invention, a polyester fiber having properties of synthetic fiber, having durable moisture absorption performance similar to that of natural fibers and chemical fibers such as cotton, silk, and rayon, and having little change in physical properties over time. And a fiber structure containing the same can be provided.

  The fibers and fiber structure of the present invention reduce moisture sensation when worn by imparting hygroscopicity, so as well as innerwear such as underwear, clothing such as dress shirts and trousers, sheets, duvet covers, etc. It can be suitably used as a bedding material and a batting material for futons.

  The polyester fiber of the present invention is formed by modifying a single fiber surface layer with a polymer of an organic acid containing at least one carboxyl group and a compound having an amide bond.

In the present invention, ΔMR is 0.5% or more and 10.0% or less for a polyester fiber made of a polymer of an organic acid containing at least one carboxyl group and a compound having an amide bond.
ΔMR (%) = MR ₂ −MR ₁
MR ₁ ; moisture absorption (%) when left in an atmosphere of 20 ° C. × 65% RH for 24 hours
MR ₂ ; moisture absorption (%) when left in an atmosphere of 30 ° C. × 90% RH for 24 hours

  When the ΔMR is less than 0.5%, the force to absorb humidity is small and the wearing comfort is low. On the other hand, when ΔMR exceeds 10.0%, the force to absorb humidity is large and the wearing comfort is greatly improved, but it is difficult to suppress the deterioration of the polyester fiber over time. For practical use, ΔMR is 0.5% or more and 10.0% or less, and particularly in the range of 2.0 to 4.0% from the viewpoint of both hygroscopicity and suppression of fiber deterioration over time. Is preferred.

  In this invention, it is a preferable aspect that a polymer exists in a ring shape at the outer peripheral portion of the fiber cross section perpendicular to the fiber axis.

  Presence of the ring shape means that the carboxyl group of the polymer is converted into a carboxylic acid sodium salt using a metal salt, and the sodium element distribution of the sodium is obtained with an energy dispersive X-ray analyzer (EMAX). If it can be confirmed that the polymer is unevenly distributed on the outer peripheral portion of the fiber cross section in the vertical direction, it can be determined that “the polymer exists in a ring shape” on the outer peripheral portion.

  When the polymer is present in the ring shape, it is desirable that the polymer is not substantially present at the center of the fiber cross section perpendicular to the fiber axis. The fiber center part where the polymer is not substantially present is preferably a circular shape having a radius of 9/10 to 1/2 of the fiber cross-sectional radius length. In order to quantify such a ring shape, the ratio of the hollow portion of the fiber substantially free of polymer can be used. The ratio of the hollow portion of the fiber that is substantially free of a polymer is determined by taking a two-dimensional observation photograph with a scanning electron microscope (SEM), and the polymer with respect to the entire area of the fiber cross section with respect to the entire area of the fiber cross section. Area ratio (no Na element distribution in an energy dispersive X-ray analyzer (EMAX)). The ratio of the hollow portion of the fiber that is substantially free of polymer is preferably 0.25% to 0.81% from the viewpoint of hygroscopicity and suppression of deterioration over time due to hydrolysis. When the ratio of the hollow portion of the fiber substantially free of polymer is 0.81 or less, the hygroscopicity is further improved. When the ratio of the hollow portion of the fiber in which no polymer is present is 0.25 or more, the deterioration with time due to hydrolysis of the polyester fiber is excellently selected. In particular, the range of 0.50% to 0.70% is preferable from the viewpoint of both hygroscopicity and suppression of fiber deterioration over time.

  Such a polyester fiber can be produced by a method described later.

  The polyester fiber of the present invention may be a filament yarn such as false twisted yarn, strong twisted yarn, taslan processed yarn, thick yarn and mixed yarn other than ordinary flat yarn, staple fiber, tow, or Various forms of fibers such as spun yarn may be used.

  The polyester contained in the polyester fiber used in the present invention may be polybutylene terephthalate, polyethylene naphthalate, polytributylene terephthalate, etc. in addition to polyethylene terephthalate.

  In the present invention, the polyester fiber structure includes the polyester fiber. As the fiber structure, those in the form of a fabric-like material such as a woven fabric, a knitted fabric and a non-woven fabric can be used.

  In this invention, it is preferable that the decomposition yarn strength retention of the said polyester-type fiber structure is 50% or more. When the degradation yarn strength retention rate decreases, it becomes difficult to wear for a long period of time. Therefore, in the present invention, the degradation yarn strength retention rate is preferably 50% or more, and more preferably 70% or more. The upper limit is ideally 100%, but if it is about 90%, it can withstand wearing for a very long period of time, so there is no practical problem. Here, the decomposed yarn strength retention is measured by a method described later.

  Such a polyester fiber can be produced by a method described later.

  In the present invention, an organic acid containing at least one carboxyl group and a compound containing at least one amide bond are used in combination as a polymer for modifying the single fiber surface layer (hereinafter referred to as “grafting treatment”). Usually, when an organic acid containing at least one carboxyl group is graft-polymerized on a fiber, the resulting polyester fiber deteriorates with time. Therefore, this technology has not yet been put into practical use. Although this deterioration over time is not clear, it is presumed to be due to the following mechanism. That is, the organic acid permeates into the fiber center by simply graft polymerization of the organic acid onto the fiber. That is, when the polymerization rate of the organic acid is large, it is naturally easy to polymerize near the fiber surface compared to when the polymerization rate is low, and the penetration into the fiber can be reduced. Since the polymerization rate in the vicinity is small, the organic acid easily penetrates into the fiber and easily diffuses in the fiber. Therefore, when the organic acid that has penetrated into the fiber is graft-polymerized there, the polyester contained in the fiber is hydrolyzed over time due to the carboxyl group derived from the organic acid residue in the graft chain, resulting in deterioration of the polyester fiber over time. It is thought to do. In the present invention, the organic fiber containing at least one carboxyl group on the polyester fiber surface layer and a compound having an amide bond are used in combination to suppress the diffusion of the organic acid into the fiber, The organic acid reacts on the surface of the polyester fiber, and using this as an anchor, the compound having an amide bond is graft-copolymerized, and the graft chain extends toward the outside of the polyester fiber, resulting in graft reaction. It is thought that it stayed at the surface layer portion of the polyester fiber and the penetration of the organic acid into the fiber center portion was suppressed, and the deterioration with time due to hydrolysis of the polyester fiber was finally suppressed.

  The organic acid containing at least one carboxyl group is not particularly limited as long as it can be made into a polymer, and among them, a hydrophilic vinyl monomer is preferably used. Examples of the hydrophilic vinyl monomer include acrylic acid, methacrylic acid and maleic acid, itaconic acid, crotonic acid and the like. Among these organic acids, acrylic acid and methacrylic acid are particularly preferable. These may be used alone or in combination. In order to obtain higher hygroscopicity, methacrylic acid is preferably used.

  Examples of the compound having an amide bond include acrylamide, methacrylamide, acetone acrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N-ethylmethacrylamide, N-ethylacrylamide, N, N-diethylacrylamide, N-propylacrylamide, N-acryloylpyrrolidine, N-acryloylpiperidine, N-acryloylmorpholine, N-isopropylacrylamide and the like can be mentioned. Among the compounds having such an amide bond, acrylamide is particularly preferably used.

  The method for obtaining a modified polyester fiber structure by fixing the polymer to the fiber surface is not particularly limited, but in a bath selected from the following (1) to (4) A method for performing processing can be applied.

  (1) The first method is to immerse the polyester fiber structure in a treatment liquid containing an emulsified and dispersed water-insoluble polymerization initiator, and heat treatment in the bath (if the temperature condition is too low, the polyester fiber When the introduction of the insoluble polymerization initiator to the structure tends to be insufficient and is too high, 60 to 90 ° C. is preferable, and 75 to 85 ° C. is more preferable because polymerization due to decomposition of the insoluble polymerization initiator tends to be insufficient. After that, the fiber structure is immersed in a liquid containing a compound containing an organic acid and an amide bond, and heat treatment in a bath (when the temperature condition is too low, the polymerization tends to be insufficient and is too high). In the case, since it is easy to form a polymer gel, it is a treatment (two-stage treatment method) in which 100 to 120 ° C is preferable, and 105 to 115 ° C is more preferable.

  (2) The second method is to immerse the polyester fiber structure in a treatment solution containing an emulsified and dispersed water-insoluble polymerization initiator, and heat treatment in the bath (if the temperature condition is too low, the polyester fiber When the introduction of the insoluble polymerization initiator to the structure tends to be insufficient and is too high, it is preferably 60 to 90 ° C, more preferably 75 to 85 ° C because polymerization due to decomposition of the insoluble polymerization initiator tends to be insufficient. ), And then immersing the fiber structure in a solution containing a water-soluble polymerization initiator, a compound containing an organic acid and an amide bond, and heat treatment in a bath (if the temperature condition is too low, When the polymerization tends to be insufficient and is too high, it is easy to form a polymer gel, and preferably 100 to 120 ° C., more preferably 105 to 115 ° C.) (two-stage treatment method) A.

  (3) The third method is to immerse the polyester fiber structure in a treatment liquid containing a compound containing an emulsified and dispersed water-insoluble polymerization initiator, an organic acid and an amide bond, and heat treatment in a bath (as temperature conditions) Is too low, the polymerization tends to be insufficient, and if it is too high, a polymer gel is likely to be formed, and therefore a treatment of 100 to 120 ° C. is preferred (105 to 115 ° C. is more preferred) (one-step treatment) Method).

  (4) The fourth method is to immerse the polyester fiber structure in a treatment liquid containing a water-insoluble polymerization initiator emulsified and dispersed, a water-soluble polymerization initiator, a compound containing an organic acid and an amide bond, Heat treatment in bath (when the temperature condition is too low, the polymerization tends to be insufficient, and when it is too high, the polymer gel is easily formed, preferably 100 to 120 ° C, more preferably 105 to 115 ° C. ) (One-stage processing method).

  Among the methods of immersing in the treatment liquid, the first and second methods are most preferable from the viewpoint of process passability and processing cost. After performing the heat treatment in the bath as described above, washing with hot water at a temperature of 50 to 95 ° C., preferably 60 to 70 ° C., is performed in order to remove unreacted monomers and ensure fastness to dyeing. Is preferred.

  In the processing bath as described above, it is preferable to add a processed product to water and adjust the bath ratio (dough weight (Kg): total amount of processing liquid (L)) with a Mini color dyeing machine (manufactured by Tecsum Giken). The bath ratio is preferably 1: 5 to 1:50, more preferably 1:10 to 1:20.

  In order to adjust such a processing bath, the amount of the organic acid containing at least one carboxyl group is preferably about 1 g / L to 20 g / L, more preferably 4 g / L to 16 g / L. It exhibits excellent hygroscopicity at 1 g / L or more, and by selecting it at 20 g / L or less, it is excellent in texture.

  The amount of the compound having an amide bond in the processing bath is preferably about 1 g / L to 20 g / L, and more preferably 4 g / L to 16 g / L. When the amount is 1 g / L or more, more excellent hygroscopicity is obtained, and when the amount is 20 g / L or less, the texture is further improved. The preferable mixing ratio of the two is preferably 1: 9 to 9: 1 on a weight basis as a compound having an organic acid: amide bond containing a carboxyl group, and more preferably 3: 1 to 5: 1 is highly hygroscopic. This is a preferable mixing ratio for obtaining the ability to suppress the decrease in strength over time.

  In order to polymerize an organic acid containing at least one carboxyl group as described above and a compound having an amide bond, it is preferable to use a polymerization initiator. As such a polymerization initiator, a normal radical polymerization initiator can be used. As the polymerization initiator, either a water-soluble polymerization initiator or a water-insoluble polymerization initiator can be used.

  Examples of water-soluble polymerization initiators include inorganic polymerization initiators such as ammonium persulfate, potassium persulfate, and hydrogen peroxide, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2 Organic polymerization initiators such as' -azobis (N, N'-dimethyleneisobutyramide) dihydrochloride, 2- (carbamoylazo) isobutyronitrile can be used.

  In addition, as a water-insoluble polymerization initiator, an organic peroxide such as benzoyl peroxide, toluyl peroxide, methoxybenzoyl peroxide, butyl peroxyhexahydroterephthalate, or a water-insoluble polymerization initiator such as azobisisobutylnitrile should be used. Can do.

  In particular, in order to prevent high washing durability and strength reduction, it is preferable to use a mixture of both.

  When using such a water-soluble polymerization initiator, it is dissolved in water.

  When such a water-insoluble polymerization initiator is used, pretreatment (emulsification dispersion) is more effective. First, in order to make it adsorb | suck to fiber surface layer vicinity, it is preferable to melt | dissolve a polymerization initiator with an organic solvent and to use as a polymerization initiator solution. Further, a surfactant is added to this initiator solution and emulsified in water for use.

  The surfactant is not particularly limited.

  Although it does not specifically limit as said organic solvent, In addition to aromatic hydrocarbons, such as toluene and xylene, the carrier agent used in order to improve dyeability when dyeing polyester fiber is used as a solvent. It is also possible to use it. Such a carrier agent is usually preferably composed of a carrier main component and a surfactant. Examples of the carrier main component include phthalimide compounds, benzoic acid derivatives, salicylic acid derivatives, ketones, phenol derivatives, ethers, halogen compounds, phenolmethane derivatives, diphenyl derivatives and the like. The surfactant added to the carrier agent is not particularly limited. When these carrier agents contain a surfactant in the carrier agent when used as an organic solvent, when adding a polymerization initiator for pretreatment (emulsification dispersion), the polymerization initiator is added directly to the carrier agent. And may be emulsified in water.

  Among the above carrier agents, phthalimide compounds and benzoic acid derivatives are preferred because of their influence on the environment and dyeing fastness when remaining inside the fiber.

  The amount of the water-soluble polymerization initiator used is preferably about 1 g / L to 10 g / L. By setting it to 1 g / L or more, the degree of polymerization can be obtained effectively, and even if it exceeds 10 g / L, the polymerizability does not improve.

  The amount of the water-insoluble polymerization initiator used is preferably about 1 g / L to 10 g / L. By setting it to 1 g / L or more, the degree of polymerization can be obtained effectively, and even if it exceeds 10 g / L, the polymerizability does not improve.

  When a water-insoluble polymerization initiator is used, a preferable embodiment of the polymerization initiator solution contains an organic solvent, a carrier, a surfactant and the like in the polymerization initiator. As the ratio of use, water-insoluble polymerization initiator weight: organic solvent weight: surfactant weight is 2: 3: 5, and water-insoluble polymerization initiator weight: organic solvent weight: carrier weight is 2: 3: 5 is preferable. It is noted that this ratio is not strict and is preferably in the vicinity of this, and can be appropriately adjusted as necessary.

  The carrier agent comprises a carrier main component and a surfactant, but the preferred mixing ratio is not particularly limited. General commercial products can be used.

  In the present invention, in order to obtain higher hygroscopicity, it is preferable to substitute at least a part of the carboxyl groups in the polymer introduced into a part of the fiber by grafting treatment with a metal salt. Examples of the metal compound used to replace the metal salt as described above include metal salts such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, etc., and these are used as at least one kind. be able to.

  In order to replace at least a part of the carboxyl groups in the polymer introduced into a part of the fiber by the grafting process with a metal salt, the grafted polyester fiber is immersed in a water bath in which the metal salt is dissolved. The treatment may be performed at a temperature of 60 to 80 ° C. for 10 to 30 minutes.

  The amount of metal salt used in the water bath is preferably about 1 g / L to 10 g / L. When it is 1 g / L or more, particularly excellent hygroscopicity is obtained, and even if it exceeds 10 g / L, the hygroscopicity is not improved.

  The ratio of the metal salt to water in the water bath is preferably 1: 5 to 1:50.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. Moreover, the performance evaluation in an Example was measured with the following method.

<Weight change rate (graft rate) (%)>
A sample piece of 10 cm × 10 cm is taken. The test piece is preliminarily dried for 30 minutes with a hot air dryer at 60 ° C. or less. The pre-dried test piece is put in a weighing bottle in a hot air dryer at 105 ± 2 ° C., and the lid is removed and the test piece is completely dried for 2 hours in a state where it is easy to dry. After drying completely, immediately close the weighing bottle, put it in a desiccator, and let it cool for about 30 minutes. The weighing bottle is taken out from the desiccator after being allowed to cool and weighed (read up to 4 decimal places, and the value excluding the weight of the weighing bottle is used as the weight before processing).

  Next, after performing moisture absorption processing using the sample piece, weigh it by the weighing method as described above (read up to 4 digits after the decimal point, and remove the weight of the weighing bottle from this value) And).

From the weight of the sample piece before and after processing obtained above, the weight change rate (%) is calculated by the following formula (up to 1 decimal place).
Weight change rate (%)
= ((Weight after processing (g) −weight before processing (g)) / weight before processing (g)) × 100

<Difference in moisture absorption; △ MR (%)>
Three test pieces of about 1 g are collected. The test piece is placed in a weighing bottle with a known weight, and a hot air dryer set at 60 ° C. is covered and preliminarily dried for 30 minutes. After the preliminary drying, the humidity is adjusted for 24 hours in a thermo-hygrostat set at 20 ° C. × 65% RH (wind speed of about 1 m). After the lid of the weighing bottle was removed from the constant temperature constant humidity chamber and immediately weighed (read below decimal point 4 Ketama, a value obtained by subtracting the weight of the weighing bottle from which the W _1).

Next, the lid of the weighing bottle is removed for 24 hours in a thermo-hygrostat set at 30 ° C. × 90% RH (wind speed of about 1 m). After covering the weighing bottle, take it out of the thermo-hygrostat and immediately weigh it (read up to 4 digits after the decimal point and set the value excluding the weight of the weighing bottle as W ₂ ).

Cover the weighing bottle in a hot air dryer at 105 ± 2 ° C. and dry for 2 hours. After drying completely, the weighing bottle is immediately covered, and then placed in a desiccator and allowed to cool in the room for 30 minutes. Weighing removed weighing bottle from the desiccator after cooling (read at the decimal point 4 Ketama, a value obtained by subtracting the weight of the weighing bottle from which the W _3).

The moisture absorption rate (%) of 20 ° C. × 65% RH and 30 ° C. × 90% RH is obtained from the weight of the test piece before and after absolutely dryness obtained above, and the moisture absorption difference ΔMR (%, moisture absorption) (Rate difference) is calculated and expressed as the average value of the three images (up to one decimal place).
ΔMR (%) = MR ₂ −MR ₁
MR ₁ = ((W ₁ −W ₃ ) / W ₃ ) × 100 (%)
MR ₂ = ((W ₂ −W ₃ ) / W ₃ ) × 100 (%)
W ₁ : Weight of test piece (excluding weighing bottle) at 20 ° C. × 65% RH (g)
W ₂ : Weight (g) of test piece (excluding weighing bottle) at 30 ° C. × 90% RH
W ₃ : Weight of the test piece (excluding weighing bottle) in the absolutely dry state (g)

<Deterioration test over time; Degraded yarn strength measurement after accelerated test>
Five pieces of about 30 cm broken yarn are collected from the test piece, measured according to JIS L1013 (1999) using an autograph manufactured by Shimadzu Corporation, and the strength is obtained. (Read up to 2 digits after the decimal point, and use this as the strength before deterioration over time).

  Next, the test piece was left to stand in a 70 ° C. × 90% RH atmosphere for 1 week, then taken out and air-dried. Then, about 30 cm decomposed yarns were collected, and in accordance with JIS L1013 (1999), Measure using a Shimadzu autograph to determine the strength. (Read up to 2 digits after the decimal point, and use this as the strength value after deterioration over time).

The strength retention (%) is calculated by the following formula from the decomposed yarn strength of the test piece before and after deterioration with time obtained above, and is expressed as an average value of five pieces.
Strength retention (%)
= ((Strength before aging (cN / dtex) -Strength after aging (cN / dtex)) / Strength before aging (cN / dtex)) × 100

<Washing durability>
Dissolve weak alkaline synthetic detergent specified in JIS L0217 103 method to a concentration of 0.2% in a household electric washing machine and wash for 5 minutes at a temperature of 40 ± 2 ° C at a bath ratio of 1:50. Then, the liquid is drained, rinsed with water for 2 minutes, dehydrated and rinsed again for 2 minutes once, and this is repeated 20 times.

  That is, the evaluation of the drop-off property of the hygroscopic polymer is performed by evaluating ΔMR (%) before and after washing.

<Confirmation of ring-shaped confirmation as to whether or not the polymer exists in a ring shape at the outer peripheral portion of the fiber cross section perpendicular to the fiber axis and the ratio of the hollow portion of the fiber substantially free of polymer>
The ratio of the hollow portion of the fiber that is substantially free of a polymer is determined by taking a two-dimensional observation photograph with a scanning electron microscope (SEM) to confirm the presence or absence of a ring shape, and the fiber relative to the entire area of the fiber cross section. Calculate the ratio of the hollow part of the fiber that does not substantially contain the polymer from the area ratio in which the polymer does not substantially exist with respect to the entire area of the cross section (no Na element distribution in the energy dispersive X-ray analyzer (EMAX)). did.

(Examples 1-6, Comparative Examples 1-4)
Polyester terephthalate (PET) yarn composed of 167 decitex 30 filaments was used to create a knitted fabric with a basis weight of 356 g / m, scouring by a conventional method, and then heat setting at 180 ° C. using a pin tenter, and the resulting polyester fiber Tables 1 and 2 show the results of processing the structures by the methods shown below and evaluating the performance.

<Polymerization initiator>
Water-insoluble polymerization initiator Benzoyl peroxide in xylene solution ("Nyper" (registered trademark) BMT-K40 (manufactured by NOF Corporation))
In the xylene solution, the weight of benzoyl peroxide: xylene is 2: 3. Water-soluble polymerization initiator Ammonium persulfate (manufactured by Nacalai Tesque)

<Polymerizable monomer>
Organic acid: acrylic acid (manufactured by Nacalai Tesque), methacrylic acid (manufactured by Nacalai Tesque)
Compounds having an amide bond: Acrylamide (manufactured by Nacalai Tesque), methacrylamide (manufactured by Nacalai Tesque)

<Carrier agent>
Mixtures such as benzyl benzoate, triethylene glycol monobutyl ether, sulfated castor oil ("UNIVADINE" (registered trademark) DFM (manufactured by HUNTSMAN))
In the above mixture, benzyl benzoate weight: triethylene glycol monobutyl ether weight: sulfated castor oil weight is 14: 3: 2.

<Processing method>
Treatment in bath (two-stage method A): “NIPER” (registered trademark) BMT-K40 as a water-insoluble polymerization initiator is mixed with carrier “UNIVADINE” (registered trademark) DFM, emulsified and dispersed in water, and then a polyester fiber structure The mixture was added and adjusted to a bath ratio of 1:20 with a Mini color dyeing machine (manufactured by Tecsum Giken Co., Ltd.), then heated from 40 ° C. at a rate of 2 ° C./min and treated at 85 ° C. for 15 minutes. Subsequently, after cooling, washing with hot water and washing with water, an organic acid, a compound containing an amide bond and the polyester fiber structure are added to water, and the bath ratio is 1:40 using a Mini color dyeing machine (manufactured by Texam Giken). The temperature was raised from 40 ° C. at a rate of 2 ° C./min, treated at 110 ° C. for 30 minutes, washed with hot water at 60 ° C., washed with water, and then an alkaline aqueous solution of 5 g / L sodium carbonate. After adjusting the bath ratio to 1:20, treating at 60 ° C. for 30 minutes, performing a substitution treatment with a metal salt, subsequently washing with hot water, washing with water, dehydrating, drying at 130 ° C., and then at 160 ° C. A heat treatment was performed for 3 minutes. The results of evaluating the performance are shown in Tables 1 and 2.

  Treatment in bath (two-stage method B): “NIPER” (registered trademark) BMT-K40 as a water-insoluble polymerization initiator is mixed with carrier “UNIVADINE” (registered trademark) DFM, emulsified and dispersed in water, and then a polyester fiber structure The mixture was added and adjusted to a bath ratio of 1:20 with a Mini color dyeing machine (manufactured by Tecsum Giken Co., Ltd.), then heated from 40 ° C. at a rate of 2 ° C./min and treated at 85 ° C. for 15 minutes. Subsequently, after cooling, washing with hot water and washing with water, a water-soluble polymerization initiator, an organic acid, a compound containing an amide bond and the same polyester fiber structure are added, and a Mini color dyeing machine (manufactured by Texam Giken Co., Ltd.). ), The bath ratio is adjusted to 1:40, the temperature is raised from 40 ° C. at a rate of 2 ° C./min, treated at 110 ° C. for 30 minutes, washed with hot water at 60 ° C., washed with water, An alkaline aqueous solution of sodium carbonate 5 g / L was prepared, adjusted to a bath ratio of 1:20, treated at 60 ° C. for 30 minutes, subjected to substitution treatment with a metal salt, subsequently washed with hot water, washed with water, dehydrated, 130 ° C. Then, heat treatment was performed at 160 ° C. for 3 minutes. The results of evaluating the performance are shown in Tables 1 and 2.

  Treatment in bath (one-step method A): “NIPER” (registered trademark) BMT-K40 as a water-insoluble polymerization initiator is mixed with carrier “UNIVADINE” (registered trademark) DFM, emulsified and dispersed in water, and then an organic acid, amide A compound containing a bond and a polyester fiber structure are added, and the bath ratio is adjusted to 1:40 with a Mini color dyeing machine (manufactured by Tecsum Giken Co., Ltd.). Warm, treat at 110 ° C. for 30 minutes, wash in hot water at 60 ° C., wash with water, then make an aqueous alkaline solution of sodium carbonate 5 g / L, adjust the bath ratio to 1:20 and treat at 60 ° C. for 30 minutes Then, after the metal salt was replaced and treated, it was subsequently washed with hot water, washed with water, dehydrated, dried at 130 ° C., and then heat treated at 160 ° C. for 3 minutes. The results of evaluating the performance are shown in Tables 1 and 2.

  Treatment in bath (one-step method B): “NIPER” (registered trademark) BMT-K40 as a water-insoluble polymerization initiator is mixed with carrier “UNIVADINE” (registered trademark) DFM, emulsified and dispersed in water, and then water-soluble. A polymerization initiator, an organic acid, a compound containing an amide bond and a polyester fiber structure are added, and the bath ratio is adjusted to 1:40 with a Mini color dyeing machine (manufactured by Tecsum Giken Co., Ltd.). The temperature is raised at a rate of 1 minute / minute, treated at 110 ° C. for 30 minutes, washed with hot water at a temperature of 60 ° C., washed with water, and then an alkaline aqueous solution of 5 g / L of sodium carbonate is prepared. After adjustment and treatment at 60 ° C. for 30 minutes and substitution treatment with a metal salt, hot water washing, water washing and dehydration were continued, followed by drying at 130 ° C., followed by heat treatment at 160 ° C. for 3 minutes. The results of evaluating the performance are shown in Tables 1 and 2.

  From Tables 1 and 2, it can be said that the polyester fiber structure according to the present invention has high hygroscopicity, washing durability and little deterioration with time.

Since the polyester fiber and structure of the present invention reduce moisture sensation by imparting hygroscopicity, not only innerwear such as underwear, but also clothing such as dress shirts and trousers, and bedding items such as sheets and duvet covers. , And cotton can also be suitably used for futon cotton.

Claims (6)

A polyester fiber in which a single fiber surface layer is modified with a polymer of an organic acid containing at least one carboxyl group and a compound having an amide bond, and ΔMR is 0.5% or more and 10.0% or less. The polyester fiber according to claim 1, wherein the polymer is present in a ring shape on the outer peripheral portion of the fiber cross section perpendicular to the fiber axis. In the ring shape according to claim 2, the area ratio in which the polymer does not substantially exist with respect to the entire area of the fiber cross section is 0.25% or more and 0.81% or less. A polyester fiber structure comprising the polyester fiber according to claim 1. The polyester fiber structure according to claim 1 or 2, wherein the fiber structure has a decomposition yarn strength retention of 50% or more. The method for producing a polyester fiber structure according to claim 4 or 5, wherein treatment in a bath selected from the following (1) to (4) is performed.
(1) A polyester fiber structure is immersed in a treatment liquid containing an emulsified and dispersed water-insoluble polymerization initiator, subjected to heat treatment in a bath, and then contains at least one carboxyl group-containing organic acid and an amide bond. A process in which a fiber structure is immersed in a liquid containing a compound to be heated and heat-treated in a bath under temperature conditions.
(2) Immerse the polyester fiber structure in a treatment solution containing an emulsified and dispersed water-insoluble polymerization initiator, perform heat treatment in a bath, and then contain a water-soluble polymerization initiator and at least one carboxyl group The fiber structure is immersed in a liquid containing an organic acid and a compound containing an amide bond, and is heated in a bath under temperature conditions.
(3) The polyester fiber structure is immersed in a treatment liquid containing an emulsified and dispersed water-insoluble polymerization initiator, an organic acid containing at least one carboxyl group, and a compound containing an amide bond, and heat treatment is performed in a bath. processing.
(4) The polyester fiber structure is immersed in a treatment liquid containing an emulsified and dispersed water-insoluble polymerization initiator, a water-soluble polymerization initiator, an organic acid containing at least one carboxyl group, and a compound containing an amide bond. And heat treatment in a bath.