JP2005256184A - Cellulose fatty acid mixed ester fiber and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cellulose fatty acid ester fiber being efficiently produceable by melt-spinning method without applying load on natural environment and having good mechanical properties as a fiber. <P>SOLUTION: The cellulose fatty acid mixed ester fiber is composed of a composition containing at least 70-95 wt.% cellulose fatty acid mixed ester and 5-30 wt.% polyhydric alcohol-based plasticizer and the fiber has 0.9-4.5 cN/dtex strength, 5-50% breaking elongation and 0-6 fiber color tone b value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a thermoplastic cellulose fatty acid mixed ester fiber having good fiber characteristics and suppressed fiber coloring, and a method capable of producing the fiber with good spinning properties.

  Cellulose derivatives such as cellulose, cellulose ester, and cellulose ether are attracting great attention as biomass materials that are produced most in the world and as biodegradable materials in the environment. Representative examples of cellulose esters currently used commercially include cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate and the like, and are used in a wide range of fields such as plastics, filters and paints.

  Regarding the use of cellulose as a fiber, it has long been practiced to spin and use short fibers such as cotton and hemp produced in nature. In order to obtain a filament material instead of short fibers, cellulose is dissolved in a special solvent system such as carbon disulfide and ray spinning is performed, or the yarn is formed by a wet spinning method, or cellulose is derivatized like cellulose acetate. Then, after dissolving in an organic solvent such as methylene chloride or acetone, there is only a method for producing yarn by a dry spinning method in which spinning is performed while evaporating the solvent. In these wet spinning methods or dry spinning methods, there is a strong concern that the organic solvents such as carbon disulfide, acetone, and methylene chloride that are used will adversely affect the environment, so it is never good when considering harmony with the environment. It cannot be said that it is a proper yarn making method. Furthermore, since spinning is performed using a large amount of solvent, there is a problem that a great amount of energy is required for spinning and solvent recovery, and the spinning speed is low, resulting in low productivity and high manufacturing cost. On the other hand, the melt spinning method has the advantages of low energy cost, high productivity, and the ability to spin various types of fibers.

  However, cellulose esters such as cellulose acetate are inferior in thermal fluidity to thermoplastic polymers such as polyester and polyamide, so it is necessary to add a large amount of plasticizer for melt spinning. It becomes. It is basically possible to add a large amount of plasticizer to cellulose ester and melt-spin it below the thermal decomposition temperature of cellulose ester, for example, to obtain cellulose fatty acid ester fiber for hemodialysis or ultrafiltration membrane Various proposals have been made for this purpose (see Patent Documents 1 to 3). Since the cellulose ester fiber obtained by the above-mentioned method contains a large amount of plasticizer of about 50% by weight in the composition, the mechanical properties of the obtained fiber are very inferior and practically used. It has no mechanical properties that can be tolerated, and is very limited in terms of applications.

  As an example of the mechanical properties of cellulose ester fibers obtained by the melt spinning method, Patent Document 4 describes the fiberization of cellulose acetate by the melt spinning method, and the strength of the obtained fibers is 0.44 cN / The dtex and elongation are 15%, and only fibers with poor mechanical properties are obtained. Furthermore, since the spinning temperature was as high as 255 ° C., only a very yellowish color tone was obtained (see Patent Document 4).

In addition to the above, a composition comprising cellulose acetate and a plasticizer (caprolactone tetraol, polyethylene succinate, etc.) for the purpose of reducing the rate of breakage during melt spinning and obtaining a cellulose ester fiber having high fiber strength. Is obtained by melt spinning. However, even though it has a high fiber strength, only a fiber with a low strength of 0.89 cN / dtex is obtained at most, and the spinning rate during spinning is 5 times per hour. ) Stability was extremely poor. (See Patent Document 5).
JP 56-91006 A (pages 1 and 2) JP 59-49806 (first page) JP 54-42420 A (first page) JP-A-10-130957 (page 5) JP-A-10-317228 (pages 1-3, 5, 7)

  The object of the present invention is to solve the above-mentioned problems of the prior art, and to produce high-quality thermoplastic cellulose fatty acid mixed ester fibers having excellent fiber characteristics and suppressing fiber coloring, and to produce the fibers with good yarn production It is to provide a method that can.

  In order to solve the above problems, the present invention adopts the following configuration.

  (1) A fiber comprising a composition comprising at least 70 to 95% by weight of a mixed ester of cellulose fatty acid and 5 to 30% by weight of a polyhydric alcohol plasticizer, the strength of the fiber being 0.9 to 4.5 cN Cellulose fatty acid mixed ester fiber having a / dtex, a breaking elongation of 5 to 50%, and a fiber color tone b value of 0 to 6.

(2) Spinning temperature (T1), spinneret surface temperature (T2) when melt spinning a composition comprising at least 70 to 95% by weight of a cellulose fatty acid mixed ester and 5 to 30% by weight of a polyhydric alcohol plasticizer And a method for producing a cellulose fatty acid mixed ester fiber, wherein the composition passes through a spinneret and is spun and wound under conditions where the shear stress (τ) of the composition satisfies the following formula.
220 ° C. ≦ T1 ≦ 250 ° C., 190 ° C. ≦ T2 ≦ 280 ° C., τ ≦ 6 × 10 ⁵ Pa

  The thermoplastic cellulose fatty acid mixed ester fiber composed of the composition comprising at least the cellulose fatty acid mixed ester and the polyhydric alcohol plasticizer of the present invention greatly suppresses the coloring of the fiber and has excellent fiber characteristics. It is possible to perform stable spinning for a long time with a low yarn breaking rate during melt spinning.

  The fibers can be used as clothing fibers, industrial fibers, non-woven fabrics, and the like, and particularly preferably used as clothing fibers.

  Hereinafter, the cellulose fatty acid mixed ester fiber of the present invention will be described in detail.

  In the cellulose fatty acid mixed ester in the present invention, at least a part of the acyl group has 3 to 18 carbon atoms. When the number of carbon atoms is 3 to 18, the compatibility with the polyhydric alcohol plasticizer is good, and the addition of a small amount of the polyhydric alcohol plasticizer has heat fluidity that enables melt spinning, which is preferable. Specific examples of the cellulose fatty acid mixed ester include cellulose acetate propionate, cellulose acetate butyrate, cellulose propionate butyrate, cellulose acetate valerate, cellulose acetate laurate, and cellulose acetate oleate. Of these, cellulose acetate propionate and cellulose acetate butyrate are preferred, and cellulose acetate propionate is most preferred from the viewpoint of good mechanical properties of the fiber obtained, moderate hygroscopicity, and biodegradability. In this case, the average degree of substitution between the acetyl group and the acyl group (propionyl group or butyryl group) preferably satisfies the following formula.

2.0 ≦ (average degree of substitution of acetyl group + average degree of substitution of acyl group) ≦ 3.0
0.1 ≦ (average degree of substitution of acetyl group) ≦ 2.5
0.5 ≦ (Average substitution degree of acyl group) ≦ 2.9
A cellulose fatty acid mixed ester satisfying the above formula is preferable because of its good compatibility with the polyhydric alcohol plasticizer and good mechanical properties.

  The weight average molecular weight (Mw) of the cellulose fatty acid mixed ester is preferably 50,000 to 250,000. By setting Mw to 50,000 to 250,000, fibers having good mechanical properties can be obtained, and fibers can be stably obtained by melt spinning. Mw is more preferably 70000-200000, and most preferably 80000-18000. The weight average molecular weight (Mw) means a value calculated by gel permeation chromatography (GPC) measurement, and will be described in detail in Examples.

  The content of the polyhydric alcohol plasticizer is preferably 5 to 30% by weight. By setting the content of the polyhydric alcohol plasticizer to 5 to 30% by weight, the heat fluidity of the composition comprising at least the cellulose fatty acid mixed ester and the polyhydric alcohol plasticizer is improved. Production by a high melt spinning method becomes possible, whereby it becomes possible to arbitrarily control the fiber cross section or to make composite spinning. Furthermore, drawing and false twisting can be easily performed by making use of good thermoplasticity. The content of the polyhydric alcohol plasticizer is more preferably 7 to 25% by weight, and most preferably 10 to 20% by weight.

  The polyhydric alcohol plasticizer that can be specifically used in the present invention is an ester compound or polyalkylene glycol having a glycerin skeleton that has good compatibility with a mixed ester of cellulose fatty acid and a remarkable thermoplastic effect. It is.

  Specific ester compounds having a glycerol skeleton include glycerol acetate stearate, glycerol acetate palmitate, glycerol acetate laurate, glycerol acetate caprate, glycerol acetate oleate, diglycerol tetraacetate, diglycerol tetrapropionate, di Examples thereof include, but are not limited to, glycerin tetrabutyrate, diglycerin tetracaprylate, and diglycerin tetralaurate, and these can be used alone or in combination.

  Specific examples of the polyalkylene glycol include polyethylene glycol and polypropylene glycol having an average molecular weight of 200 to 4000, but are not limited thereto, and these can be used alone or in combination.

  The fiber comprising the composition comprising at least 70 to 95% by weight of a cellulose fatty acid mixed ester and 5 to 30% by weight of a polyhydric alcohol plasticizer in the present invention has a strength of 0.9 to 4.5 cN / dtex, elongation at break The degree is 5 to 50%, and the fiber color tone b value is 0 to 6.

  The strength needs to be 0.9 to 4.5 cN / dtex. If the strength is 0.9 cN / dtex or more, it is preferable because it is easy to pass through high-order processing steps such as weaving and knitting, and the strength of the final product is not insufficient. From the viewpoint of good strength characteristics, the higher the strength, the more preferable, specifically 1.0 cN / dtex or more is more preferable, and 1.1 cN / dtex or more is most preferable.

  The breaking elongation needs to be 5 to 50%. A breaking elongation of 5 to 50% is preferable because yarn breakage does not occur frequently in higher processing steps such as during weaving and knitting. The good elongation is more preferably 10 to 45%, and most preferably 15 to 40%.

  The fiber color tone (b value) indicating yellowness needs to be 0-6. By setting the fiber color tone (b value) to 0 to 6, the yellowness is not strong, the quality of the product is excellent, and the color tone such as clothing can be used. Further, it is preferable because the color developability during dyeing is improved. The fiber color tone (b value) should be low, preferably 5 or less, and more preferably 4 or less.

  Regarding the improvement of the fiber color tone (b value), it is possible to use a bluing compound such as cobalt acetate or a colorant used in general-purpose polyester, but if it is used in a large amount, the heat resistance is improved. Therefore, not only the yarn-making property is impaired, but also the color becomes cloudy at the time of dyeing, and the color developability is impaired. Therefore, even when used in combination, the amount added is preferably 0.3% by weight or less based on the cellulose fatty acid mixed ester / polyhydric alcohol plasticizer mixed composition.

  The cellulose fatty acid mixed ester fiber in the present invention preferably has a boiling water shrinkage of 0 to 10%. It is preferable that the boiling water shrinkage is 0 to 10% because the thermal dimensional stability is good, the problem due to shrinkage does not occur in the dyeing step and the higher processing step, and the handling becomes good.

  The single yarn fineness is preferably 0.5 to 50 dtex. By setting the single yarn fineness to 0.5 to 50 dtex, fibers can be obtained with good spinning properties by the melt spinning method, and due to the appropriate bending rigidity of the fiber structure, it can be used for clothing fabrics that require softness. Can also be applied. The single yarn fineness is more preferably 0.7 to 40 dtex, and most preferably 1 to 25 dtex.

  U% (Worster normal%) is preferably 0 to 3%. U% is a value obtained by a Worcester tester manufactured by Zerbegger Worcester, and is used to measure fluctuations in fiber thickness. If U% is 3% or less, it is a fiber having excellent uniformity in fineness, and no fluff or thread breakage occurs in the high-order processing step, and dyed spots do not occur. The smaller the U% value is, the more preferable, more preferably 2.5% or less, still more preferably 2% or less, and most preferably 1% or less. The U% measurement conditions will be described in detail in the examples.

  The cross-sectional shape of the cellulose fatty acid mixed ester fiber in the present invention is not particularly limited as long as it is a cross-sectional shape that can be adopted by melt spinning, and may be a substantially perfect circular circular cross-section, or a multileaf shape, a flat shape It may be an irregular cross section such as a shape, an ellipse, a W shape, an L shape, an S shape, an X shape, an H shape, a C shape, a paddle shape, a cross beam shape, and a hollow shape. Further, it may be a composite fiber such as a core-sheath composite, an eccentric core-sheath composite, a side-by-side composite, or a different fiber mixture.

  In the composition of the present invention, various additives such as matting agents, deodorants, defoaming agents, color modifiers, flame retardants, yarn friction reducing agents, ultraviolet absorbers, infrared absorbers, crystal nucleating agents, An antioxidant, a coloring pigment, an electrostatic agent, an antibacterial agent, etc. can be contained as needed.

  The method for producing the cellulose fatty acid mixed ester fiber in the present invention may be any of a melt spinning method, a wet spinning method, a dry spinning method, and a semi-wet semi-dry spinning method. Above all, it can be obtained with high productivity, the fiber cross section can be precisely and arbitrarily controlled, various types of composite fibers such as core-sheath composites, eccentric core-sheath composites, side-by-side composites can be obtained, Considering not using an organic solvent that has an impact on the environment, low energy costs, and taking advantage of good thermoplasticity, drawing of spun yarns, yarn processing such as false twisting, etc. becomes possible easily. The melt spinning method is most preferred.

  The preferable manufacturing method of the cellulose fatty acid mixed ester fiber in this invention is illustrated below. A composition comprising at least 70 to 95% by weight of a cellulose fatty acid mixed ester and 5 to 30% by weight of a polyhydric alcohol plasticizer is heated in a melt extrusion spinning machine such as a pressure melter type or an extruder type. After melting, the molten multifilament extruded from the spinneret is cooled, and the yarn is converged and wound by applying an oil agent. Since the composition has a higher melt viscosity than polyester and polyamide, an extruder type melt extrusion spinning machine is preferred from the viewpoint of efficient extrusion.

  At this time, the spinning temperature (T1) is preferably 220 ° C. ≦ T1 ≦ 250 ° C. By setting the spinning temperature to 220 ° C. or higher, the elongation viscosity of the composition discharged from the spinneret is lowered, so that the fiber characteristics are improved and the spinning property is stabilized, which is preferable. Further, it is preferable to set the spinning temperature to 250 ° C. or lower because coloring due to thermal decomposition of the composition is suppressed, and high-quality fibers without coloring can be obtained.

  The spinneret surface temperature (T2) is preferably 190 ° C. ≦ T2 ≦ 280 ° C. The spinneret surface temperature mentioned here refers to the temperature at the center of the spinneret surface. Since the spinneret surface is in contact with the atmosphere, the spinneret surface is cooled, the fluidity of the polymer is lost, and the spinnability is impaired. As a method of increasing the die surface temperature, there is a method of increasing the spinning temperature. However, this does not suppress the coloring of the polymer, and the b value which is the object of the present invention cannot be achieved. Therefore, it is preferable to actively heat only the periphery of the die in order to increase the spinneret surface temperature while keeping the spinning temperature low. As a heating method, an external die heater as shown in 4 of FIG. 1 or a melt spinning pack built-in die heater may be used. Moreover, it is not limited to these, You may heat a nozzle | cap | die by other means, and you may strengthen the heat insulation and heat insulation of a nozzle | cap | die. By setting the spinneret surface temperature to 190 ° C. ≦ T2 ≦ 280 ° C., the fiber has excellent fiber characteristics and the coloration of the fiber due to thermal decomposition of the composition is suppressed, and the spinneret surface is contaminated by pyrolyzate. Stable yarn production for a long time without any problems is possible. The spinneret surface temperature is more preferably 200 ° C. ≦ T2 ≦ 280 ° C., and most preferably 220 ° C. ≦ T2 ≦ 280 ° C.

The shear stress (τ) when passing through the spinneret is preferably 6 × 10 ⁵ Pa or less. By setting the shear stress to 6 × 10 ⁵ Pa or less, the polymer streamline turbulence is suppressed at the time of melt spinning to stabilize spinning, so that fibers with excellent uniformity can be obtained, and stable spinning can be performed for a long time. It can be carried out. Shear stress is more preferably at most ⁵ × 10 5 Pa, and most preferably not more than 4 × 10 ⁵ Pa.

  The spun yarn extruded from the spinneret is preferably cooled at a wind speed of 0 to 1.0 m / sec. By cooling at a wind speed of 0 to 1.0 m / sec, the spun yarn can be cooled uniformly, and the resulting fibers can obtain high-quality fibers with small fineness spots. Furthermore, the spinning yarn does not fluctuate and stable yarn production can be performed for a long time. The wind speed of the cooling air is more preferably 0.1 to 0.8 m / sec, and most preferably 0.2 to 0.6 m / sec.

  In melt spinning, the spinning speed is preferably 750 to 3000 m / min. By setting the spinning speed to 750 to 3000 m / min, molecular orientation of the obtained fiber is promoted, and a fiber having excellent mechanical properties can be obtained. The spinning speed is more preferably 800 to 2500 m / min, and most preferably 900 to 2000 m / min.

  Hereinafter, the present invention will be specifically described with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a melt spinning apparatus used in the method for producing a cellulose fatty acid mixed ester fiber of the present invention.

  In FIG. 1, 1 is a spin block, 2 is a melt spinning pack, 3 is a spinneret, 4 is a cap heater, 5 is a cooling device, and 6 is a spun yarn.

  The molten polymer is extruded from the pores of the spinneret 3 attached to the lower part of the melt spinning pack 2 attached to the spin block 1. The extruded spun yarn 6 passes while being cooled by the cooling device 5 and is wound up via a roller. The spinneret 3 is heated by a cap heater 4 and the spinneret surface is controlled to a specific temperature range.

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, although each characteristic value in an Example was calculated | required with the following method, this invention is not limited to these.

A. Substitution degree of cellulose fatty acid ester The calculation method of the substitution degree of cellulose fatty acid mixed ester is as follows.

  0.9 g of cellulose fatty acid mixed ester which was completely dried by vacuum drying at 80 ° C. for 8 hours was weighed and dissolved by adding 35 ml of acetone and 15 ml of dimethyl sulfoxide, and further 50 ml of acetone was added. While stirring, 30 ml of 0.5N sodium hydroxide aqueous solution was added and saponified for 2 hours. After adding 50 ml of hot water and washing the side of the flask, it was titrated with 0.5N sulfuric acid using phenolphthalein as an indicator. Separately, a blank test was performed in the same manner as the sample. The supernatant of the solution after titration was diluted 100 times, and the composition of the organic acid was measured using an ion chromatograph. From the measurement result and the acid composition analysis result by ion chromatography, the substitution degree was calculated by the following formula.

TA = (B−A) × F / (1000 × W)
DSace = (162.14 × TA) / [[1− (Mwase− (16.00 + 1.01)) × TA] + [1− (Mwacy− (16.00 + 1.01)) × TA] × (Acy / Ace)]
DSacy = DSace × (Acy / Ace)
TA: Total organic acid amount (ml)
A: Sample titration (ml)
B: Blank test titration (ml)
F: titer of sulfuric acid W: sample weight (g)
DSace: substitution degree of acetyl group DSacy: substitution degree of acyl group Mwash: molecular weight of acetic acid Mwacy: molecular weight of other organic acid Acy / Ace: molar ratio of acetic acid (Ace) to other organic acid (Acy) 162.14 : Molecular weight of cellulose repeating unit 16.00: Atomic weight of oxygen 1.01: Atomic weight of hydrogen Weight average molecular weight (Mw)
The cellulose fatty acid mixed ester was completely dissolved in chloroform so as to have a concentration of 0.01% by weight, and used as a sample for GPC measurement. Using this sample, GPC measurement was performed with Waters 2690 under the following conditions, and the weight average molecular weight (Mw) was determined in terms of polystyrene.

Column: Showa Denko's Shodex K-805L, 2 connected detector: Waters 2410 Differential refractometer RI
Moving bed solvent: Chloroform Flow rate: 1.0 ml / min Injection volume: 200 μl
C. Spinneret temperature The center of the spinneret surface was measured using a thermocouple.

D. Shear stress The shear stress of the composition at the time of passing through the spinneret was determined using the following equation.

Shear stress τ (Pa) = shear rate γ (sec ⁻¹ ) × melt viscosity η (Pa · sec)
The shear rate and melt viscosity were determined as follows.
(1) Shear rate γ
γ = (32 × Q) / (π × D ³ × ρ)
Q: 1 hole, discharge rate per second (g / sec · hole)
D: Die diameter of the die ρ: Density when the composition is melted (2) Melt viscosity η
A melt viscosity was measured using a Capillograph manufactured by Toyo Seiki Co., Ltd., with a measurement temperature of 20 g of the composition vacuum-dried at 80 ° C. for 12 hours in the same manner as the spinneret surface temperature. Next, a relational expression for the shear rate dependence of the melt viscosity was obtained, and using this formula, the melt viscosity at the shear rate γ calculated from the above formula was calculated and used as the melt viscosity (Pa · sec) of the composition.

E. Rate of thread breakage The number of times of thread breakage (thread breakage) in 24 hours was measured.

F. Strength and Elongation at Break Using Tensilon UCT-100 type manufactured by Orientec Co., Ltd., a tensile test was conducted under the conditions of a sample length of 20 cm and a tensile speed of 20 cm / min. The value divided by the value was defined as fiber strength (cN / dtex). The elongation at break was defined as the elongation at break (%). The number of measurements was 5 times, and the average values were taken as strength and elongation.

G. U% (Wooster Normal%)
The U% measurement was obtained by measuring under the following conditions using a Worcester tester 4-CX manufactured by Zerbegger Worcester.

Measurement speed: 200 m / min Measurement time: 5 minutes Twist: S twist, 12000 / min U% is measured with a multifilament yarn. The number of measurements was 3, and the average value was U%.

H. Fiber color tone b value A fiber was wound on a plate, L, a, and b values were measured with an SM color computer manufactured by Suga Test Instruments Co., Ltd., and the b value representing yellowishness was used as the color tone. The amount of fiber wound on the plate is measured using, for example, a fiber having a fineness of 110 dtex and 180 m of fibers wound on a plate having a width of 6 cm to a length of 4 cm, and the average thickness of the yarn on the plate is about 2 mm. went. Further, the incident angle of light of the color computer is 45 degrees.

I. Boiling water shrinkage rate Fiber (multifilament yarn) is scraped and the sample length L0 is measured under a load of 0.09 cN / dtex, and then treated in boiling water for 15 minutes under no load. After the treatment, the sample was air-dried, the sample length L1 was measured under a load of 0.09 cN / dtex, and calculated by the following formula.

Boiling water shrinkage (%) = {(L0−L1) / L0} × 100
The number of measurements was 5, and the average value was defined as the boiling water shrinkage.

Synthesis example 1
67 parts by weight of acetic acid and 300 parts by weight of propionic acid were added to 100 parts by weight of cellulose (Nippon Paper Industries Co., Ltd. dissolved pulp, α-cellulose 92 wt%), and mixed at 50 ° C. for 30 minutes. After the mixture was cooled to room temperature, 17 parts by weight of acetic anhydride cooled in an ice bath and 500 parts by weight of propionic anhydride were added as an esterifying agent, and 4 parts by weight of sulfuric acid was added as an esterification catalyst, followed by stirring for 150 minutes. An esterification reaction was performed. In the esterification reaction, when it exceeded 40 ° C., it was cooled in a water bath. After the reaction, a mixed solution of 100 parts by weight of acetic acid and 33 parts by weight of water was added as a reaction terminator over 20 minutes to hydrolyze excess anhydride. Thereafter, 333 parts by weight of acetic acid and 100 parts by weight of water were added, and the mixture was heated and stirred at 60 ° C. for 1.5 hours. After completion of the reaction, an aqueous solution containing 6 parts by weight of sodium carbonate was added, and the precipitated cellulose ester was filtered off, washed with water, and dried at 60 ° C. for 4 hours. The degree of substitution of the obtained cellulose fatty acid ester was 2.6 (acetyl group 0.1, propionyl group 2.5), and the weight average molecular weight (Mw) was 155,000.

Example 1
90% by weight of the cellulose fatty acid mixed ester produced in Synthesis Example 1 and 10% by weight of glycerin diacetate monooleate were kneaded at 190 ° C. using a biaxial extruder, and cut to about 5 mm to obtain a cellulose fatty acid mixed ester composition pellet. Obtained.

The pellets were vacuum dried at 80 ° C. for 8 hours, melted at a melter temperature of 240 ° C. using a single-screw melt spinning machine, and introduced into a melt spinning pack having a spinning temperature of 230 ° C. Spinning was performed from a spinneret (spinner base surface temperature 210 ° C., shear stress 3.5 × 10 ⁵ Pa) having 36 holes of 0.30 mmφ−0.75 mmL base holes under the conditions of 1 g / min. The spun yarn is cooled by a cooling air at 25 ° C. and a wind speed of 0.3 m / sec, applied with an oil agent, converged, and taken up by a first godet roller rotating at 1000 m / min. It wound up with the winder rotated at the speed | rate from which the winding tension | tensile_strength became 0.1 cN / dtex through the 2nd godet roller rotated at the same speed as a dead roller.

  The obtained fiber had a strength of 1.15 cN / dtex, a breaking elongation of 25.0%, a fiber color tone of 1.9, good mechanical properties and high quality without coloration. It was. The boiling water shrinkage was 4.0% and U% was 0.5%.

  When winding for 24 hours, yarn breakage did not occur at all, and the yarn forming stability was very good.

Example 2
Cellulose fatty acid mixed ester composition prepared by synthesizing 87% by weight of the cellulose fatty acid mixed ester prepared in Synthesis Example 1 and 13% by weight of polyethylene glycol (average molecular weight 600) at 190 ° C. using a biaxial extruder and cutting to about 5 mm. Pellets were obtained.

The pellets were vacuum dried at 80 ° C. for 8 hours, melted at a melter temperature of 225 ° C. using a single-screw melt spinning machine, and introduced into a melt spinning pack having a spinning temperature of 225 ° C. Spinning was performed from a spinneret (spinner base surface temperature 235 ° C., shear stress 2.1 × 10 ⁵ Pa) having 48 holes of 0.20 mmφ−0.50 mmL base holes under the condition of 8 g / min. The spun yarn is cooled by a cooling air at 25 ° C. and a wind speed of 0.4 m / sec, applied with an oil agent, converged, and taken up by a first godet roller rotating at 1850 m / min. It wound up with the winder rotated at the speed | rate from which the winding tension | tensile_strength became 0.1 cN / dtex through the 2nd godet roller rotated at the same speed as a dead roller.

  The obtained fiber has a strength of 1.20 cN / dtex, a breaking elongation of 23.5%, a fiber color tone of 0.8, and has good mechanical properties and high quality without coloring. It was. Further, the boiling water shrinkage was 4.8%, and U% was 1.2%.

  When winding for 24 hours, yarn breakage occurred twice, but the yarn-making stability was very good.

Example 3
A cellulose fatty acid mixed ester composition prepared by synthesizing 93% by weight of the cellulose fatty acid mixed ester prepared in Synthesis Example 1 and 7% by weight of polyethylene glycol (average molecular weight 600) at 205 ° C. using a biaxial extruder and cutting to about 5 mm. Pellets were obtained.

The pellets were vacuum dried at 80 ° C. for 8 hours, melted at a melter temperature of 235 ° C. using a single-screw melt spinning machine, and introduced into a melt spinning pack having a spinning temperature of 235 ° C. Spinning was performed from a spinneret (spinner base surface temperature 240 ° C., shear stress 2.9 × 10 ⁵ Pa) having 24 holes of 0.18 mmφ−0.36 mmL on the condition of 0 g / min. The spun yarn is cooled by a cooling air at 25 ° C. and a wind speed of 0.2 m / sec, applied with an oil agent, converged, and taken up by a first godet roller rotating at 1500 m / min. It wound up with the winder rotated at the speed | rate from which the winding tension | tensile_strength became 0.1 cN / dtex through the 2nd godet roller rotated at the same speed as a dead roller.

  The obtained fiber has a strength of 1.30 cN / dtex, an elongation at break of 20.5%, a fiber color tone of 2.5, has good mechanical properties and is high-quality without coloring. It was. Further, the boiling water shrinkage was 3.8%, and U% was 1.2%.

  When winding for 24 hours, thread breakage occurred once, but the yarn-making stability was very good.

Synthesis example 2
240 parts by weight of acetic acid and 67 parts by weight of propionic acid were added to 100 parts by weight of cellulose (Nippon Paper Industries Co., Ltd. dissolved pulp, α-cellulose 92 wt%), and mixed at 50 ° C. for 30 minutes. After the mixture was cooled to room temperature, 172 parts by weight of acetic anhydride cooled in an ice bath and 168 parts by weight of propionic anhydride were added as an esterifying agent, and 4 parts by weight of sulfuric acid was added as an esterification catalyst, followed by stirring for 150 minutes. An esterification reaction was performed. In the esterification reaction, when it exceeded 40 ° C., it was cooled in a water bath. After the reaction, a mixed solution of 100 parts by weight of acetic acid and 33 parts by weight of water was added as a reaction terminator over 20 minutes to hydrolyze excess anhydride. Thereafter, 333 parts by weight of acetic acid and 100 parts by weight of water were added, and the mixture was heated and stirred at 80 ° C. for 1 hour. After completion of the reaction, an aqueous solution containing 6 parts by weight of sodium carbonate was added, and the precipitated cellulose ester was filtered off, washed with water, and dried at 60 ° C. for 4 hours. The substitution degree of the obtained cellulose fatty acid mixed ester was 2.4 (acetyl group 1.9, propionyl group 0.5), and the weight average molecular weight (Mw) was 120,000.

Example 4
Cellulose fatty acid mixed ester composition pellets obtained by kneading 82 wt% of the cellulose fatty acid mixed ester produced in Synthesis Example 2 and 18 wt% of polyethylene glycol at 220 ° C. using a biaxial extruder and cutting to about 5 mm were obtained.

The pellets were vacuum-dried at 80 ° C. for 8 hours, melted at a melter temperature of 240 ° C. using a single-screw melt spinning machine, and introduced into a melt spinning pack having a spinning temperature of 240 ° C. Spinning was performed from a spinneret (spinner base surface temperature 250 ° C., shear stress 2.1 × 10 ⁵ Pa) having 36 holes of 0.23 mmφ−0.30 mmL base holes under the condition of 9 g / min. The spun yarn is cooled by a cooling air at 25 ° C. and a wind speed of 0.5 m / sec, and applied with an oil agent to be converged. Then, the spun yarn is taken up by a first godet roller rotating at 1250 m / min. It wound up with the winder rotated at the speed | rate from which the winding tension | tensile_strength became 0.1 cN / dtex through the 2nd godet roller rotated at the same speed as a dead roller.

  The obtained fiber has a strength of 1.35 cN / dtex, a breaking elongation of 26.5%, a fiber color tone of 4.5, and has good mechanical properties and high quality without coloring. It was. Moreover, the boiling water shrinkage ratio was 4.4%, and U% was 1.4%.

  When winding for 24 hours, yarn breakage did not occur at all, and the yarn forming stability was very good.

Example 5
Cellulose fatty acid mixed ester composition pellets obtained by kneading 85 wt% of the cellulose fatty acid mixed ester produced in Synthesis Example 2 and 15 wt% of polyethylene glycol at 220 ° C. using a biaxial extruder and cutting to about 5 mm were obtained.

The pellets were vacuum dried at 80 ° C. for 8 hours, melted at a melter temperature of 245 ° C. using a single-screw melt spinning machine, and introduced into a melt spinning pack having a spinning temperature of 245 ° C. Spinning was performed from a spinneret (spinner base surface temperature 255 ° C., shear stress 2.4 × 10 ⁵ Pa) having 48 holes of 0.25 mmφ−0.625 mmL base holes under the condition of 0 g / min. The spun yarn is cooled with a cooling air at 25 ° C. and a wind speed of 0.7 m / sec, applied with an oil agent, converged, and taken up by a first godet roller rotating at 1000 m / min. It wound up with the winder rotated at the speed | rate from which the winding tension | tensile_strength became 0.1 cN / dtex through the 2nd godet roller rotated at the same speed as a dead roller.

  The obtained fiber had a strength of 1.37 cN / dtex, a breaking elongation of 20.1%, a fiber color tone of 4.8, good mechanical properties and high quality without coloration. It was. Moreover, the boiling water shrinkage ratio was 4.4%, and U% was 1.6%.

  When winding for 24 hours, yarn breakage occurred twice, but the yarn-making stability was very good.

Comparative Example 1
The cellulose fatty acid mixed ester composition used in Example 1 was vacuum-dried at 80 ° C. for 8 hours and melted at a melter temperature of 215 ° C. using a single-screw melt spinning machine to obtain a spinning temperature of 215 ° C. Introduced into the pack, a spinneret (spinner base surface temperature 185 ° C., shear stress 6.5 × 10 ⁵ ) having 24 holes of 0.30 mmφ−0.75 mmL at a discharge rate of 8.33 g / min. Spinning from Pa). The surface of the spun yarn was uneven (so-called melt fracture), and winding was impossible.

Comparative Example 2
The cellulose fatty acid mixed ester composition pellets used in Example 2 were vacuum-dried at 80 ° C. for 8 hours, and melted at a melter temperature of 265 ° C. using a single-screw melt spinning machine to achieve a spinning temperature of 265 ° C. A spinneret (spinner base surface temperature 265 ° C., shear stress 1.0 × 10 8) having 48 hole holes of 0.20 mmφ−0.50 mmL under conditions of a discharge rate of 30.8 g / min. Spinned from ⁵ Pa). The spun yarn is cooled by a cooling air at 25 ° C. and a wind speed of 0.4 m / sec, applied with an oil agent, converged, and taken up by a first godet roller rotating at 1850 m / min. Winding was performed with a winder rotating at a speed at which the winding tension was 0.1 cN / dtex via a second godet roller rotating at the same speed as the dead roller.

  The obtained fiber had a strength of 0.75 cN / dtex, a breaking elongation of 40.5%, a fiber color tone of 8.5, a poor quality with poor mechanical properties and intense coloring. Further, the boiling water shrinkage was 5.6%, and U% was 2.5%.

  Attempts were made to wind up for 24 hours, but the yarn breaking stability was extremely poor with 8 yarn breaks per hour.

Comparative Example 3
The cellulose fatty acid mixed ester composition used in Example 4 was vacuum-dried at 80 ° C. for 8 hours and melted at a melter temperature of 240 ° C. using a single-screw melt spinning machine to obtain a spinning temperature of 240 ° C. When introduced into the pack, a spinneret having 36 hole holes of 0.23 mmφ−0.30 mmL at a discharge rate of 13.9 g / min (spinner face temperature 290 ° C., shear stress 0.6 × 10 ⁵ Spinning from Pa). The spun yarn is cooled by a cooling air at 25 ° C. and a wind speed of 0.5 m / sec, and applied with an oil agent to be converged. Then, the spun yarn is taken up by a first godet roller rotating at 1250 m / min. It wound up with the winder rotated at the speed | rate from which the winding tension | tensile_strength became 0.1 cN / dtex through the 2nd godet roller rotated at the same speed as a dead roller.

  The obtained fiber had a strength of 1.20 cN / dtex, a breaking elongation of 30.5%, and a fiber color tone of 9.1. Although the mechanical properties were good, the color was intense and the quality was low. there were. The boiling water shrinkage was 4.8%, and U% was 1.7%.

  When winding was performed for 24 hours, yarn breakage occurred six times, and the yarn making stability was poor.

  The obtained fibers can be used as clothing fibers, industrial fibers, non-woven fabrics, and the like, and can be particularly suitably used for clothing fibers.

It is a figure which shows one embodiment of the melt spinning apparatus used for the manufacturing method of the cellulose fatty acid mixed ester fiber of this invention.

Explanation of symbols

1: Spin block 2: Melt spinning pack 3: Spinneret base 4: Base heater 5: Cooling device 6: Spinning yarn

Claims (2)

  A fiber comprising a composition comprising at least 70 to 95% by weight of a mixed ester of cellulose fatty acid and 5 to 30% by weight of a polyhydric alcohol plasticizer, the strength of the fiber being 0.9 to 4.5 cN / dtex, Cellulose fatty acid mixed ester fiber having a breaking elongation of 5 to 50% and a fiber color tone b value of 0 to 6. In melt spinning a composition comprising at least 70 to 95% by weight of a cellulose fatty acid mixed ester and 5 to 30% by weight of a polyhydric alcohol plasticizer, the spinning temperature (T1), the spinneret surface temperature (T2), and the spinneret A process for producing a cellulose-fatty acid mixed ester fiber, wherein the composition is passed through a fiber and spun and wound under conditions that satisfy the following formula:
220 ° C. ≦ T1 ≦ 250 ° C., 190 ° C. ≦ T2 ≦ 280 ° C., τ ≦ 6 × 10 ⁵ Pa

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