JP2010189807A - Spun-dyed aliphatic polyester staple fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide spun-dyed aliphatic polyester staple fibers excellent in durability and suitable for use in fibrous structural body. <P>SOLUTION: The spun-dyed polyester staple fiber is constituted of aliphatic polyester, trifunctional or more epoxy compound, and pigment, wherein at least a part of the aliphatic polyester and trifunctional or more epoxy compound with are brought to react so that the epoxy residual content is 0.1 to 0.5 equivalent/kg in the aliphatic polyester staple fiber. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an original staple fiber using an aliphatic polyester.

  Recently, with increasing awareness of the environment on a global scale, there are concerns about global warming caused by mass consumption of petroleum resources and the depletion of petroleum resources associated with mass consumption. Against this background, there is a strong demand for environmentally friendly materials with natural circulation that consist of non-petroleum-based raw materials, especially plant-derived raw materials (biomass), and eventually decompose into water and carbon dioxide in the natural environment after use. Yes. One of the most promising materials for environmentally friendly natural circulation is polylactic acid (PLA).

  Under such circumstances, the development of polylactic acid fibers is preceded by agricultural materials and civil engineering materials that make use of biodegradability, but subsequent large-scale applications include clothing, hygiene, bedding and other Application to industrial materials is also expected.

  In addition, polylactic acid fibers (PLA fibers) have a good balance between strength and elongation, and since they have a low Young's modulus, they have a soft texture as a fabric.

  In recent years, research on the modification of polylactic acid polymers has progressed, and not only for clothing but also for industrial materials.

  For example, Patent Document 1 describes a technique in which the COOH end or alcohol end of a semi-aromatic polyester is substituted with another compound to suppress hydrolysis. The technique uses a carbodiimide compound or an epoxy compound as a terminal blocking agent, but these compounds have a slight effect of improving durability.

  Patent Document 2 discloses a staple fiber to which an aliphatic polyester, talc, and an epoxy compound are added. In this technique, talc, which is a crystal nucleating agent, is added to an aliphatic polyester staple fiber for the purpose of promoting crystallization, and an epoxy compound is added for the purpose of improving resistance to hydrolytic degradation. However, this technology is effective in increasing the molecular weight and improving durability when blending aliphatic polyester staple fibers and hot pressing, but it is used for interior materials and interior materials that do not perform hot pressing. The fiber structure such as a nonwoven fabric or tuft is not very advantageous.

  Patent Document 3 discloses a nonwoven fabric using short fibers of polylactic acid. In the technique, for the purpose of suppressing shrinkage at the time of forming the nonwoven fabric, heat shrinkage is performed in advance to obtain polylactic acid having a low dry heat shrinkage rate, thereby forming the nonwoven fabric. However, although this technique is effective in suppressing shrinkage, there are still insufficient points regarding durability.

JP-A-8-120520 JP 2007-270391 A JP 2005-307359 A

  An object of the present invention is to provide an original aliphatic polyester staple fiber that is excellent in durability and excellent in appearance when formed into a fiber structure.

  That is, the present invention mainly has the following configuration. That is, “a primary staple fiber composed of an aliphatic polyester, a trifunctional or higher functional epoxy compound and a pigment, wherein the aliphatic polyester and the trifunctional or higher functional epoxy compound react at least partially, A primary aliphatic polyester staple fiber having an epoxy residual value of 0.1 to 0.5 equivalent / kg.

  According to the present invention, it is possible to obtain a primary aliphatic polyester staple fiber having excellent productivity, high durability, and excellent appearance when formed into a fiber structure.

  In order to solve the above-mentioned problems, the present inventors comprise an aliphatic polyester, a trifunctional or higher functional epoxy compound and a pigment, and the polylactic acid and the trifunctional or higher functional epoxy compound at least partially react to form the aliphatic polyester. Fat having excellent productivity, high durability, and excellent appearance when formed into a fiber structure by having an epoxy residual value in the staple fiber of 0.1 to 0.5 equivalent / kg We have found that tribal polyester staple fibers can be obtained.

  The aliphatic polyester particularly preferably used in the present invention is polylactic acid. Two types of polylactic acid are known, one mainly composed of L-lactic acid and the other mainly composed of D-lactic acid. In the present invention, polylactic acid mainly composed of either may be used. If the optical purity of lactic acid in polylactic acid is 97% or more, the melting point of the resin can be increased and the heat resistance is excellent, which is preferable. In general, since polylactic acid decreases in crystallinity when optical purity decreases, a molded product obtained from polylactic acid having low optical purity generally decreases in heat resistance, and a practical molded product cannot be obtained. For this reason, polylactic acid having an optical purity of 98% or more is preferably used. When the optical purity in one polymer molecule satisfies the above value, for example, polylactic acid obtained by melt-mixing a polymer mainly composed of L-lactic acid and a polymer mainly composed of D-lactic acid can be used. In this case, the aliphatic polyester molecular chain mainly composed of L-lactic acid and the aliphatic polyester molecular chain mainly composed of D-lactic acid form a stereocomplex crystal, which has a higher melting point than that of the homopolymer. Therefore, when the staple fiber of the present invention or the fiber structure produced from the staple fiber is used, the heat resistance is excellent.

  The weight average molecular weight of the aliphatic polyester is preferably 80,000 or more from the viewpoints of heat resistance and moldability. By setting the weight average molecular weight to 80,000 or more, not only the mechanical properties of the resulting molded article are improved and a product having excellent durability can be obtained, but also the fluidity and crystallization characteristics at the time of melting are in a preferable range. Therefore, stable production is possible even when the staple fiber of the present invention is obtained. For this reason, the weight average molecular weight is more preferably in the range of 80,000 to 400,000, and most preferably in the range of 100,000 to 250,000.

  As other aliphatic polyesters, those obtained by polycondensation of saturated dicarboxylic acid and diol, or those obtained by polycondensation of hydroxycarboxylic acid are preferably used. Examples of aliphatic polyesters obtained by polycondensation include polyglycolic acid, poly (3-hydroxybutyrate), poly (3-hydroxybutyrate · 3-hydroxyvalerate) copolymer in addition to polylactic acid , Polycaprolactone, polypivalolactone, or a polyester composed of glycol such as ethylene glycol or 1,4-butanediol and dicarboxylic acid such as succinic acid or adipic acid.

  The aliphatic polyester used in the present invention may contain other modifiers, additives and other polymers as long as the characteristics are not changed. These modifiers, additives, and other polymers may be added during polymerization, may be in the form of master pellets previously kneaded, or may be directly mixed with aliphatic polyester pellets and melt molded. . Furthermore, the aliphatic polyester in the present invention can be copolymerized with other monomers as long as the characteristics are not changed. Examples of the copolymer component include dicarboxylic acid, diol, hydroxycarboxylic acid, and modified products thereof. The content of these copolymerization components is not particularly limited, but if the copolymerization is carried out in a range not exceeding 40 mol% with respect to the aliphatic polyester, the characteristics of the aliphatic polyester as a substrate are significantly changed. Therefore, the modification effect is preferable.

  In addition, in the original aliphatic polyester staple fiber of the present invention, it is important to contain an epoxy compound as an endblocker for the aliphatic polyester. In particular, a trifunctional or higher functional epoxy compound is contained, and the trifunctional or higher functional epoxy compound is reacted with at least a part of the aliphatic polyester, preferably with at least a part of the terminal of the aliphatic polyester. Is preferred. The trifunctional or higher functional epoxy compound is a compound having 3 or more epoxy groups in one molecule of the compound. The reason for having 3 or more epoxy groups per molecule of compound is that, when melt kneading with an aliphatic polyester, a part of the epoxy group reacts with the aliphatic polyester, and the epoxy remaining after melt molding again When the group further reacts with the aliphatic polyester, the molecular weight increases, and the durability of the final molded product can be drastically improved. In addition, the epoxy compound has a slower reaction rate with respect to the aliphatic polyester as compared with other terminal reactive substances such as carbodiimide compounds. For this reason, if an epoxy compound is used as the material added to the aliphatic polyester, the molecular weight of the aliphatic polyester will not become extremely large. It is easy to obtain a structure in which unreacted epoxy groups remain.

  The trifunctional or higher functional epoxy compound used in the present invention is more preferably a compound having at least one glycidyloxycarbonyl group or N- (glycidyl) amide group in one molecule.

  As aliphatic polyester used for this invention, it is preferable that the COOH terminal group density | concentration in aliphatic polyester which shows the reactivity with an epoxy-type compound exists in the range of 1-20 equivalent / t. More preferably, it is in the range of 1 to 10 equivalent / t. The reason why the COOH end group concentration of the aliphatic polyester is 20 equivalents / t or less is that it is possible to improve the durability of the aliphatic polyester that is susceptible to degradation due to hydrolysis during storage or transportation by sea. It can be mentioned. Moreover, it is excellent in durability as it is 10 equivalent / t or less, and application to a severer condition becomes possible. Further, when the COOH end group concentration is 1 equivalent / t or less, it becomes very difficult to produce staple fibers.

  As a method of controlling the COOH end group in the aliphatic polyester, the esterification rate in the polymerization process of the aliphatic polyester is increased to prevent polycondensation between the terminal OH groups, monocarbodiimide, polycarbodiimide, and Examples include a method of reacting an epoxy compound used in the invention with an aliphatic polyester to block a COOH end group.

  By using an aliphatic polyester staple fiber end-capped with an epoxy compound, the original aliphatic polyester staple fiber of the present invention can have durability that can be used as an interior material and an interior material.

  The concentration of the epoxy compound contained in the aliphatic polyester staple fiber is preferably 0.1 to 0.5 equivalent / kg of the epoxy residual value in the aliphatic polyester staple fiber.

  The epoxy residual value indicates the amount of the epoxy compound remaining in the original aliphatic polyester staple fiber, and the unreacted epoxy compound is newly added in the process in which the aliphatic polyester is hydrolyzed by storage and processing. By reacting and reacting with the COOH end group in the aliphatic polyester staple fiber, there is an effect of further suppressing hydrolysis of the aliphatic polyester molecular chain. Therefore, it is more useful as an index for controlling the hydrolysis characteristics of the aliphatic polyester than the COOH terminal concentration in the aliphatic polyester. The present inventors have found that the hydrolysis property of the aliphatic polyester staple fiber can be controlled more finely by examining the epoxy residual value in the aliphatic polyester staple fiber in detail. If the epoxy residual value in the aliphatic polyester staple fiber is 0.1 equivalent / kg or less, since the amount of the epoxy compound remaining in the aliphatic polyester staple fiber is small, the aliphatic polyester starts to be hydrolyzed. Since the COOH end group in the aliphatic polyester staple fiber increases at an accelerated rate, and the high elongation of the aliphatic polyester staple decreases, it is not preferable. Further, when the amount is 0.5 equivalent / kg or more, the amount of the epoxy compound in the aliphatic polyester staple fiber is increased, and the spinnability is deteriorated, and the epoxy compound in the aliphatic polyester staple fiber is bleed. , Not preferable for use.

  If the epoxy residual value in the aliphatic polyester staple fiber is in the range of 0.1 to 0.5 equivalent / kg, the aliphatic polyester reacts again in the process of hydrolysis, so it can be stored for a longer period of time. It is suitable for suitability and durability when used as a fiber structure, and is useful for expanding the range of use of aliphatic polyester.

  The epoxy residual value is determined according to JIS K7236: 2001: Determination of epoxy equivalent of epoxy resin. Take a sample in a beaker, add 20 ml of chloroform, dissolve, 40 ml of acetic acid and 10 ml of tetraethylammonium bromide acetic acid solution. And potentiometric titration with 0.1 mol / L perchloric acid acetic acid solution. Thereafter, in order to correct the 0.1 mol / L perchloric acid acetic acid solution consumption by the sample, only chloroform / acetic acid was added to the sample, and the titrated value was subtracted and calculated by a correction method.

  As a method for controlling the epoxy residual value in the aliphatic polyester, the amount of the epoxy compound to be added, the amount of the epoxy compound that reacts with the COOH terminal of the aliphatic polyester, and the number of epoxy groups in one molecule of the epoxy compound are adjusted. To do. In particular, in order to adjust the amount of the epoxy compound that reacts with the COOH terminal of the aliphatic polyester, as a first step, a base chip in which 10 to 20% by mass of the epoxy compound is added to the virgin chip of the aliphatic polyester is used. A master chip is prepared by kneading at 0 ° C., and the reaction is further advanced by kneading the virgin chip and the master chip at 220 to 240 ° C. in a spinning extruder. By this, reaction of the COOH terminal of aliphatic polyester and an epoxy compound is advanced, and an epoxy residual value is adjusted to a predetermined range. Although it depends on the aliphatic polyester used, it is preferable that the epoxy compound is produced by adding 2 to 5% by mass as a guide to the staple fiber content.

  In the present invention, by adding a master chip obtained by pre-kneading a pigment and an epoxy compound at a high concentration to a virgin chip, a staple fiber having high dispersibility of the pigment and excellent spinnability and color development can be obtained. By kneading the pigment and epoxy compound before spinning, the effect of pre-dispersing the pigment before spinning, and blocking the COOH end in the base aliphatic polyester, the pigment reacts with the COOH end of the aliphatic polyester. This is because it can be prevented. For this reason, compared with the method of adding a pigment directly at the time of spinning, it is possible to obtain an original aliphatic polyester staple fiber in a fiber structure for interior materials and interior materials, which has good dispersibility of the pigment and good color development. it can. Further, since no foreign matter such as a crystal nucleating agent is added, the pack life is long and the productivity is excellent. The pigment to be pre-kneaded is preferably a pigment having low reactivity with the epoxy compound, and is preferably an inorganic pigment. Examples of inorganic pigments include carbon blacks, titanium dioxide, ultramarine blue, cobalt blue, and petals. Among organic pigments, polycyclic pigments such as anthraquinone pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, diketopyrrolopyrrole pigments, and dioxazine pigments having low reactivity are preferable. Among the inorganic pigments, carbon black is suitable, and the particle diameter is preferably 10 to 25 μm in average particle diameter, and the upper limit of the particle diameter is preferably 40 μm or less. By setting it as such a range, favorable dispersibility can be maintained and clogging in a spinning pack during spinning can be suppressed.

  The concentration of the pigment to be added and the epoxy compound in the master chip is preferably 20% by mass or less. When the content is 20% by mass or more, the dispersibility of the pigment and the epoxy compound is deteriorated, and the color developability and color variation when the fiber structure is obtained are increased. In addition, 0.1-0.25 mass% of content with respect to the staple fiber of a pigment is preferable.

  When considering the heat resistance and the reaction efficiency due to the epoxy index as a tri- or higher functional epoxy compound of the present invention, 7,8-dimethyl-1,7,8,14-tetradecanetetracarboxylic acid tetrakis (oxiranylmethyl), 7 -Oxabicyclo [4.1.0] heptane-3,4-dicarboxylate diglycidyl and triglycidyl isocyanurate are preferred, and since they are highly reactive and easy to handle, when triglycidyl isocyanurate is used as a monomer Particularly preferred. Triglycidyl isocyanurate is a powder having a melting point of about 100 ° C. and is easy to handle, and when triglycidyl isocyanurate is melt-mixed with the aliphatic polyester polymer used in the present invention, the aliphatic polyester It is possible to make a structure in which a tri- or higher functional epoxy compound is finely dispersed in the resin, to reduce the melt viscosity and molecular weight spots of the resin, and to stably manufacture the aliphatic polyester staple fiber used in the present invention. Become. Further, since the compound itself is excellent in crystallinity, it is preferable because it is possible to suppress fuming due to the scattering of the epoxy compound, particularly in the production of a melt-formed product using the aliphatic polyester staple fiber used in the present invention. It is.

  The primary aliphatic polyester staple fiber used in the present invention preferably has a single fiber fineness of 0.01 to 25 dtex. From the passability of a card | curd and a needle punch process, 1.5-20 dtex is preferable. In addition, the cross section of the aliphatic polyester staple fiber is not particularly limited, and can be freely designed such as a round cross section, a trilobal cross section, a ten o'clock cross section, a W-shaped cross section, a round hollow cross section, and a tabular hollow cross section. However, a round cross section is preferable because of ease of manufacture.

  The strength of the original aliphatic polyester staple fiber of the present invention is preferably 0.8 cN / dtex or more. When the strength is 0.8 cN / dtex or more, yarn breakage in the card or needle punching process is small, and stable processing is possible. Further, although the upper limit is not particularly defined, there is no problem if it is 8 cN / dtex or less in view of the normal strength of the aliphatic polyester fiber. Therefore, the strength of the original aliphatic polyester staple fiber of the present invention is preferably in the range of 0.8 to 8 cN / dtex.

  In addition, the original aliphatic polyester staple fiber of the present invention is configured to heat-set the staple fiber to shrink the fiber, thereby reducing the dry heat shrinkage rate of the staple fiber in a dry heat treatment at 150 ° C. for 20 minutes. Is preferred. If the shrinkage ratio is in the range of 0.05 to 2.0%, the dimensional change when the nonwoven fabric is molded can be reduced, which is preferable.

  The fiber length is not particularly defined, and those in the range of 0.1 to 100 mm used for known staple fibers can be used. From the viewpoint of the passability of the card and needle punching step, 20 to 80 mm is preferable, and more preferably 30 to 70 mm.

  When the original aliphatic polyester staple fiber of the present invention is used as a fiber structure, it is preferable to use it after crimping. A method for imparting crimp to the original aliphatic polyester staple fiber may be a known method, and examples thereof include a stuffing box method, an indentation heating gear method, and a high-speed air jet indentation method. Further, if necessary, it is also preferable to apply an oil agent as a finishing agent after stretching or crimping.

  The original aliphatic polyester staple fiber of the present invention has excellent productivity, high durability, and excellent appearance when formed into a fiber structure, and is suitable for interior materials and interior materials.

[Measuring method]
(1) Single fiber fineness (dtex)
JIS L 1015 (1999) 8.5.1 Based on the A method, a small amount of the sample was drawn in parallel with a hammer, and this was placed on Rasha paper placed on a cutting table, and stretched straight with moderate force. The gauge plate was crimped as it was, cut into a length of 30 mm with a safety razor blade, 300 fibers were counted as a set, the mass was measured, and the apparent fineness was determined. From the apparent fineness and the equilibrium moisture content measured separately, the single yarn fineness (dtex) was calculated from the average value of 5 times by the following equation.
F ₀ = D ′ × {(100 + R ₀ ) / (100 + R _e )}
F ₀ = Positive fineness (dtex)
D ′ = apparent fineness (dtex)
R ₀ = Moisture content of aliphatic polyester (0.5%)
R _e = parallel to pull aligned in Gushi gold sample based on the equilibrium moisture content (2) Fiber length JIS L 1015 (1999) 8.4.1 A method to create a staple diagram to about 25cm width in pairs form sorter. At the time of preparation, the number of times the fibers are grasped and pulled out to arrange all the fibers on the velvet plate is about 70 times. Place a celluloid board with ticks on it and draw it on graph paper. The staple diagram illustrated in this way is equally divided into 50 fiber length groups, the boundary and fiber lengths of each section are measured, 49 boundary fiber lengths are added to the average of the fiber lengths at both ends, and the result is divided by 50. The average fiber length (mm) was calculated.

(3) Strength and elongation Based on JIS L 1015 (1999) 8.7.1, the distance is 20 mm, the fibers are loosely stretched one by one on the parting line, and the ends are glued together with an adhesive and fixed. Each sample is one sample. Attach the sample to the grip of the tensile tester, cut the piece of paper near the upper grip, pull at a grip interval of 20 mm, and a tensile speed of 20 mm / min, and load (N) and elongation (mm) when the sample is cut. The tensile strength (cN / dtex) and the elongation (%) were calculated by measurement and the following formula.
T _b = SD / F ₀
T _b : Tensile strength (cN / dtex)
SD: Load at break (cN)
F ₀ : Positive fineness (dtex) of sample
S = {(E ₂ −E ₁ ) / (L + E ₁ )} × 100
S: Elongation rate (%)
E ₁ : Looseness (mm)
E ₂ : Elongation at cutting (mm) or Elongation at maximum load (mm)
L: Grasp interval (mm).

(4) Residual epoxy value JIS K7236: 2001: It was carried out according to the method for obtaining the epoxy equivalent of the epoxy resin.

  The sample was taken in a beaker, dissolved in 20 ml of chloroform, dissolved, 40 ml of acetic acid and 10 ml of tetraethylammonium bromide solution were added, and potentiometric titration was performed with a 0.1 mol / L perchloric acid acetic acid solution. Thereafter, in order to correct the 0.1 mol / L perchloric acid acetic acid solution consumption by the sample, only the chloroform / acetic acid was added to the sample, and the titrated value was subtracted and calculated by a correction method.

(5) Color developability The color developability of the sample (staple fiber, fiber structure) is evaluated by 10 panelists. As a result, when 7 or more people feel that there is no color variation or white blurring, ◎, When 5-6 or more people feel good, ○, when 3-4 or less people feel good, △, when less than 2 people feel good , ◎ and ○ are outside the practical range, and Δ and × are outside the practical range.

  In the evaluation of the staple fiber, 10 g of raw cotton (staple fiber) was weighed and put into a cylinder having a diameter of 3 cm and a height of 5 cm so that the raw cotton was uniform, and the color of the raw cotton was evaluated under a D65 light source.

[Example 1]
Weight average molecular weight (Mw) of 140,000, dispersity (Mw / Mn) of 1.7, particle size of 35 mg / piece of L-polylactic acid having an optical purity of 97% or more, COOH end group concentration of 25.2 equivalent / t 10.8 parts by weight of triglycidyl isocyanurate (“TEPIC-S” manufactured by Nissan Chemical Industries) as an epoxy compound and 2.4 parts by weight of carbon black having a particle size of 40 μm or less are added to 86.8 parts by weight of the polylactic acid chip. And it knead | mixed for 10 minutes at 220 degreeC with the biaxial kneader, and it was set as the master chip.

  12 parts by weight of the obtained master chip and 88 parts by weight of the above polylactic acid chip are charged into a spinning machine hopper, melted at 220 ° C. using a twin-screw extruder type spinning machine, and discharged from a die having 300 holes at a discharge rate of 510 g / min. Spinning was carried out at a spinning speed of 1000 m / min. The obtained plurality of yarns were combined and received by a can. This drawn yarn was further combined to make a 27.7 ktex tow, drawn 3.5 times in a water bath at 80 ° C., and then crimped by a stuffing box. Next, after relaxing heat treatment at 130 ° C. and applying an oil agent, it was cut and cut, single fiber fineness 6.7 dtex, fiber length 51 mm, strength 2.1 cN / dtex, elongation 71.8%, epoxy residual value 0.404 An equivalent / kg polylactic acid staple fiber SF1 was obtained.

  SF1 was excellent in durability because it has good spinnability, excellent color developability, and a high epoxy residual value of 0.165 to 0.404 after production.

The obtained SF1 was introduced into a sample roller card at an input amount of 100 g / min, and 5 webs having a basis weight of 12.5 g / m ² were stacked to obtain a fiber structure.

  The obtained SF1 and fiber structure were free of color variation and white blurring and had good color development.

[Examples 2 to 5]
SFs 2 to 5 were obtained in the same manner as in Example 1 except that the amount of the epoxy compound and the amount of the pigment added were adjusted so as to achieve the addition amount shown in Table 1. In addition, a fiber structure was obtained in the same manner as in Example 1 using the obtained SF2 to SF5.

  SFs 2 to 5 were excellent in durability because they had good spinnability, excellent color developability, and a high epoxy residual value after production of 0.165 to 0.404.

  The obtained SFs 2 to 5 and their fiber structures were free of color variation and white blurring and had good color development.

[Comparative Example 1]
A single fiber fineness of 6.6 dtex, a fiber length of 51 mm, and a strength of 2.0 cN were obtained in the same manner as in Example 1 except that the amount of the epoxy compound and the amount of the pigment were adjusted so as to achieve the addition amount shown in Table 1. Polylactic acid staple fiber SF6 having a / dtex, elongation of 83.7%, and epoxy residual value of 0.091 equivalent / kg was obtained. Further, a fiber structure was obtained in the same manner as in Example 1 using the obtained SF6.

  SF6 had an epoxy residual value immediately after production as low as 0.091 equivalent / kg as compared with Examples, and was inferior in durability as compared with Examples. In addition, the dispersibility of the pigment was slightly inferior to that of the example, and SF6 and its fiber structure had large color variations and poor color developability.

[Comparative Example 2]
Spinning machine of polylactic acid chip having a weight average molecular weight of 140,000, a dispersity of 1.7, an optical purity of 97 mg or more and a particle size of 35 mg / piece, a COOH end group concentration of 25.2 equivalents / t The other hopper is charged with 0.2% by mass of carbon black having a particle size of 40 μm or less, melted at 220 ° C. using an extruder-type spinning machine, and discharged from a die having 300 holes at a discharge rate of 510 g / Spinning in minutes, it was taken up at a spinning speed of 1000 m / min. A plurality of similar yarns were combined and received by a can. This drawn yarn was further combined to make a 27.7 ktex tow, drawn 3.5 times in a water bath at 80 ° C., and then crimped by a stuffing box. Next, after relaxing heat treatment at 130 ° C. and applying an oil agent, it was cut and cut to a single fiber fineness of 6.7 dtex, a fiber length of 51 mm, a strength of 2.2 cN / dtex, an elongation of 79.1%, and an epoxy residual value of 0.005. Polylactic acid staple fiber SF7 having an equivalent weight / kg was obtained. Further, a fiber structure was obtained in the same manner as in Example 1 using the obtained SF7.

  SF7 had an epoxy residual value immediately after production of <0.005 equivalent / kg as compared with the examples, and was inferior in durability as compared with the examples.

[Comparative Example 3]
The single fiber fineness was 6.6 dtex, the fiber length was 51 mm, and the strength was 2 in the same manner as in Example 1 except that the addition amount of the epoxy compound, the pigment, and the addition amount of talc were adjusted so as to be the addition amount shown in Table 1. A polylactic acid staple fiber SF8 having a weight of 0.2 cN / dtex, an elongation of 77.6%, and an epoxy residual value of 0.102 equivalent / kg was obtained. Further, a fiber structure was obtained in the same manner as in Example 1 using the obtained SF8.

  Since SF5 kneaded talc, an increase in pack pressure was observed during spinning, and the productivity was slightly inferior to the examples. In addition, the color developability of SF8 and its fiber structure was slightly blurred compared to the examples, which was inferior to the examples.

[Comparative Example 4]
Spinning machine of polylactic acid chip having a weight average molecular weight of 140,000, a dispersity of 1.7, an optical purity of 97 mg or more and a particle size of 35 mg / piece, a COOH end group concentration of 25.2 equivalents / t The other hopper is charged with 0.2% by mass of carbon black having a particle size of 40 μm or less and 1.0% by mass of triglycidyl isocyanurate (“TEPIC-S” manufactured by Nissan Chemical Industries). It was melted at 220 ° C. using a ruder type spinning machine, spun from a die having 300 holes at a discharge rate of 510 g / min, and taken up at a spinning speed of 1000 m / min. The obtained plurality of yarns were combined and received by a can. This drawn yarn was further combined to make a 27.7 ktex tow, drawn 3.5 times in a water bath at 80 ° C., and then crimped by a stuffing box. Next, after relaxing heat treatment at 130 ° C. and applying an oil agent, it was cut and cut, single fiber fineness 6.6 dtex, fiber length 51 mm, strength 2.0 cN / dtex, elongation 72.5%, epoxy residual value 0.099 An equivalent / kg polylactic acid staple fiber SF9 was obtained. Further, a fiber structure was obtained in the same manner as in Example 1 using the obtained SF9.

  SF9 had slightly poor dispersibility of the pigment and triglycidyl isocyanurate at the time of spinning, and was inferior in productivity as compared with Examples. In addition, the color developability of the fiber structure was inferior due to slight variations in color.

  The original aliphatic polyester staple fiber of the present invention has excellent productivity, high durability, and excellent appearance when formed into a fiber structure, and can be suitably used for interior materials and interior materials.

Claims (4)

  An original staple fiber composed of an aliphatic polyester, a tri- or higher functional epoxy compound and a pigment, wherein the aliphatic polyester and the tri- or higher functional epoxy compound are at least partially reacted, and the epoxy residual value in the staple fiber Is an aliphatic polyester staple fiber having an intrinsic weight of 0.1 to 0.5 equivalent / kg.   The primary aliphatic polyester staple fiber according to claim 1, wherein the trifunctional or higher functional epoxy compound has at least one glycidyloxycarbonyl group or N- (glycidyl) amide group in one molecule.   The primary aliphatic polyester staple fiber according to claim 1 or 2, wherein the trifunctional or higher functional epoxy compound is triglycidyl isocyanurate and a modified product thereof.   The primary aliphatic polyester staple fiber according to claim 1, which is used for a fiber structure.