JPS584818A - Polyester fiber and its production - Google Patents

Abstract

PURPOSE:A specific amount of inert inorganic particles of specific sizes is added to a polyester and they are made into fiber, then lengthwise depressions are formed on its surface to produce ultra-fine polyester fiber with improved color development, increased yarn strength and fibrilation properties on alkali treatment. CONSTITUTION:Inert inorganic fine particles of less than 100mmu average primary particle size such as hydrophobic dry-process silica with alkyl groups and blocked silanol groups on the surface are added by 0.12-0.50wt% on the polymerization of polyester to give a polyester, preferably containing less than 150 of coarse particles (secondary particles) of more than 40mu sizes paer gram. The polyester is made into fiber and the surface is eluted with, e.g., caustic soda to give the objective polyester fiber of less than 0.1 denier filament fineness with many of fine lengthwise depressions along the fiber axis on the surface, preferably with an intrinsic viscosity of more than 0.57.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyester fiber having a single fiber fineness of 1.0 denier or less, which has a unique surface morphology with improved color development, yarn strength, and fibrillation property after alkali dissolution treatment, and a polyester fiber thereof. This relates to a manufacturing method.

Polyester fibers have excellent physical and chemical properties and are therefore widely used for clothing and industrial purposes.

However, dyed fabrics obtained from polyester fibers with a single filament fineness of 1 denier or less have a higher surface reflectance of light on their surfaces, so they are better than dyed fabrics obtained from polyester fibers with a single filament fineness greater than 1 denier. Color development is poor, and this limits the use of polyester fibers with a single yarn fineness of 1 and a denier or less.

As a method for improving the color development of dyed fabrics, which is a drawback of polyester fibers with a single filament fineness of 1 denier or less, JP-A-55-112506 discloses that inorganic fine particles such as Nricazol having an average particle diameter of 100 mμ or less are mixed with 0.5 mμ or less. Ultrafine fibers with a single fiber fineness of 1 denier or less have been proposed, which are obtained by subjecting polyester fibers containing ~10% by weight to an alkali dissolution treatment to impart a specific surface structure.

It is true that the above-mentioned method can be expected to have a certain degree of color development improvement effect since it is possible to impart a specific surface roughness to the fibers. However, with this method, because the amount of inert inorganic fine particles added is large, extreme surface roughening occurs after the alkaline dissolution treatment.
When the fabric is rubbed, the vertical dents are destroyed and it becomes a mirror surface (there is a problem that the color changes as some parts of the fabric reflect light more easily, and fibrillation is also more likely to occur).

Furthermore, in the above method, since the amount of inert inorganic fine particles added is large, the blended fine particles tend to aggregate, which tends to cause deterioration in spinning properties (problems such as yarn breakage and increased filtration pressure during fiber production), and the agglomerated fine particles exists in the system, there is a problem that polyester fibers having satisfactory strength and a single fiber fineness of 1.0 denier or less after alkali treatment cannot be obtained. Therefore, with the above method, it is not possible to industrially and stably produce ultrafine polyester fibers with improved coloring properties due to the addition of inert inorganic fine particles.

In view of the above-mentioned problems, the present inventors have developed a single fiber fineness of 1.0 which has improved color development, fibrillation property after alkali dissolution treatment, and yarn strength. The present invention was arrived at by conducting a ribbon study on polyester fibers of Lovnir and lower grades.

That is, in the present invention, inert inorganic fine particles having an average primary particle diameter of 100 mμ or less are contained in an amount of 0.12% by weight or more and 0.50% by weight.
The present invention relates to a polyester fiber having a polyester fiber containing less than 1.0 denier by weight and having a single fiber fineness of 1.0 denier or less and having a large number of vertically elongated minute depressions in the fiber axis direction on the fiber surface, and a method for producing the same.゛The polyester in the present invention refers to a polyester containing ethylene glycol or 1,4-butanediol as the main glycol component and terephthalic acid or its ester as the main dicarboxylic acid component.

A part of this dicarboxylic acid component is, for example, a monoalkali metal salt of 5-sulfoisophthalic acid, isophthalic acid, diphenyldicarboxylic acid, naphthalene dicarboxylic acid, adipic acid, and sepacic acid.

dicarboxylic acids or their esters, such as dodecanoic acid,
Oxy/carboxylic acids or esters thereof such as P-oxybenzoic acid and P-β-oxyethoxybenzoic acid may be substituted, and a portion of ethylene glycol or 1,4-butanediol may be replaced, for example, with carbon atoms of 2 to 10 alkylene/glycol, 1°4-cyclohexane dimetatool,
Glycols other than the main glycol component of 1.4-bis(β-okineethoxy7)benzene and bisphenol A bisglycol ether may be substituted.

Furthermore, it is also possible to use a small proportion of a chain branching agent such as pentaerythritol, trimethylolpropane, trimellitic acid, or trimesic acid, or a polymerization terminator such as 7-hydric polyalkylene oxide or phenylacetic acid.〇From such raw materials K for producing polyester is, for example, dimethyl terephthalate with ethylene glycol or 1.4
- The glycol ester of terephthalic acid and/or its low polymer is prepared by transesterification with butanediol, direct esterification of terephthalic acid with the glycol, or addition reaction of terephthalic acid with ethylene oxide. Combined and completed.

The most widely adopted method is to then subject the product to a polymerization reaction by a conventional method.

Further, in synthesizing the polyester according to the present invention, catalyst 1 coloring inhibitors, matting agents, ether bond by-product inhibitors, antioxidants, flame retardants, etc., which are well known in the art, can be appropriately used.

In the present invention, the vertically elongated minute dents in the fiber axis direction are dents that are long and narrow in the length direction of the fibers, and have a light tunneling effect that allows incident light to efficiently penetrate inside the fibers. It is something. That is, the presence of a large number of vertically elongated minute depressions in the fiber axis direction on the fiber surface exhibits the effect of improving color development. Note that there is no particular limitation on the size of the vertically long minute dents, but the maximum width is 0.05 to 1.5μ, and the length/maximum width ratio is 1.
．． It is particularly preferable to have a concavity of 5 or more in terms of color development of the obtained polyester fiber having a single fiber fineness of 1.0 denier or less.

Here, the maximum width of a vertically long recess means the maximum horizontal shortest distance of the recess, and for example, when the recess is circular, it means the short axis. Also.

The length of a vertically long recess means the maximum straight line distance of the recess,
For example, if the vertically elongated recess is oval, it means the major axis.

In the present invention, the inert inorganic fine particles include dry silica,
Special dry process silica such as wet process silica, dry process silica containing aluminum oxide, or dry process silica that has an alkyl group on the particle surface and blocks the silanol groups on the particle surface.

These include aluminum oxide, calcium carbonate, and special titanium oxide with a small average primary particle size.

Among these, the effect of improving color development and aggregation during polymerization.

From the viewpoint of yarn breakage during spinning e-drawing, dry method silica containing aluminum oxide or having an alkyl group on the particle surface,
Particularly preferred is dry process silica in which the silanol groups on the particle surface are blocked.

Furthermore, the particle surface has an alkyl group, and the particle surface has an alkyl group.
Dry process silica with blocked ranol groups also has the advantage of generating less diethylene glycol during polymerization.

Note that in the present invention K, silica refers to silicon oxide.
Refers to fine particles containing more than

In the present invention, the aluminum oxide-containing dry process silica is produced by making aluminum halogenide exist in silicon halide when producing silicon oxide by a dry process, and has an aluminum oxide content of 0.1 to 5% by weight. Preferably it is 0.3-2% by weight of silicon oxide.

In addition, in the present invention, the dry process silica having an alkyl group on the particle surface and blocking the silanol group on the particle surface is, for example, silanol on the particle surface obtained by reacting dry process silicon dioxide with dialkyldichlorosilane. It is silicon oxide with blocked groups.

Note that the dry method for producing silica in the present invention refers to, for example, [Practical Handbook of Additives for Plastics and Rubbers] (
Generally, it is a method of thermally decomposing Rogge'/silicon oxide together with hydrogen and oxygen in the gas phase, as described on page 524 of Kagaku Kogyosha, August 10, 1970.

In the present invention, the particle has an alkyl group on its surface.

In addition, the blocking rate of silanol groups on the particle surface of the dry process silica in which the silanol groups on the particle surface are blocked is preferably 50 or more.

Further, in the present invention, the alkyl group of the silica having an alkyl group on the particle surface and blocking the silanol group on the particle surface is particularly limited, and electrostatic methyl groups and ethyl groups are preferable.

The average primary particle diameter of the inert inorganic fine particles in the present invention is 100 mμ or less, preferably 50 mμ or less, particularly preferably 20 mμ or less.
If it exceeds μ, the effect of improving color development will decrease, which is not preferable.

The content of inert inorganic fine particles in the ultrafine polyester fiber in the present invention must be 0.12% by weight or more and less than 0.50% by weight, and 0.50% by weight or more and 0.48% by weight.
The following is preferable: The ultrafine polyester fiber has an inert inorganic fine particle content of 0.12% by weight or more and less than 0.50% by weight,
Since there are minute depressions in the fiber axis direction, the color development is improved, and the fibrillation properties of the dyed fabric obtained from the fibers are not deteriorated.

If the content of the inert inorganic fine particles is less than 0.12% by weight, the effect of improving color development is insufficient. - If the amount of blade metal is more than O, SO weight %, the number of coarse particles in the polyester increases, deteriorating yarn spinning properties and decreasing yarn strength after alkali dissolution treatment. Further, when the amount is 0.50% by weight or more, the fiber surface has an extremely roughened surface, so that the effect of improving color development is small and the fibrillarity of the dyed cloth obtained is deteriorated.

The number of coarse particles of 40μ or more in the polymer before spinning the ultrafine polyester fiber of the present invention is preferably 150 particles/g or less, more preferably 100 particles/g or less. 1
If a polymer with more than 50 particles/g is used, yarn breakage during spinning, decrease in drawn yarn strength, and increase in door pressure due to high internal pressure during spinning dart due to excessive P reinforcement due to the large number of coarse particles, etc. This is not desirable because it causes problems. The number of coarse particles increases as the content of inert inorganic fine particles increases, and the number of coarse particles increases when the content of inert inorganic fine particles in the polymer is 0.500.
If the weight percentage is exceeded, the number of coarse particles of 40μ or more in Polymer 2 will be 150 or more/g, for example, as disclosed in JP-A-55-1121.
By the method disclosed in No. 6, it is not possible to stably obtain electric wire polyester fibers having a single fiber fineness of 1 denier or less. That is, in order to stably obtain ultrafine polyester fibers with a single fiber fineness of 1 denier or less, it is preferable that the number of coarse particles of K in the polymer be 150 or less/g.

The number of secondary particles contained in the polyester fiber of the present invention having a diameter three times or more the average primary particle diameter is preferably 5 or more per 10 square microns. If the number is less than 5, the effect of improving color development tends to be small. The reason for this is thought to be that the shape, number, etc. of the vertically long depressions that occur when the fibers are subjected to the alkali elution treatment are different.

The number of secondary particles having a diameter that is three times or more than the average primary particle diameter described above can be determined by measuring a thread sample cut into 100 mμ pieces with a microtome using a Hitachi HU-12 transmission electron microscope (accelerating voltage 75 KV). The number of secondary particles per 7.3m x 11m was counted using a photograph taken at a magnification of 30°000.

The value is calculated as the average of 20 samples, calculated per 10μ2 of polymer.

The intrinsic viscosity [η] of the polyester fiber according to the present invention is 0
．． 48 or more is preferable, and 0.57 or more is more preferable.

If it is less than 048, strength, fibrillation, etc. may become a problem depending on the use, so it is not preferable or not.

The diethylene gelcol content in the present invention is 2% by weight.
It is preferably at most 1% by weight, more preferably at most 1% by weight. If the amount exceeds 2% by weight, as will be described later, the OR value when fabricated into a textured yarn tends to decrease and the feel of the fabric tends to deteriorate.

The polyester fiber of the present invention, which has a single fiber fineness of 1.0 denier or less and has a large number of vertically elongated fine depressions in the fiber axis direction on the fiber surface, has an average primary 0.12% by weight or more of inert inorganic fine particles with a particle size of 100 mμ or less, 0.50% by weight
After completing the polymerization by adding less than % by weight, this is spun and drawn to obtain a drawn polyester yarn with a single fiber fineness of 1.3 denier or less, and then heated in an alkaline aqueous solution such as sodium hydroxide to determine the weight loss rate. It is obtained by dissolving the fiber surface so that the amount of K is 25% by weight.

The inert inorganic fine particles used in the present invention can be dispersed in aliphatic glycol, aliphatic alcohol, water, etc. by a known method, and can be used at any time during the esterification reaction, transesterification reaction, or polymerization reaction, for example, before one polymerization reaction is completed. Although it can be added at this stage, it is particularly preferable to add it before or after transesterification in terms of the number of coarse particles in the resulting polymer.

The inert inorganic fine particles are produced by natural sedimentation, centrifugation, etc. in order to prevent troubles such as clogging of p-sand or thread breakage during the spinning process.

It is preferable to use a material that has been classified by a generally well-known method to remove coarse particles as much as possible.

Additionally, the inert inorganic fine particles may be glycol.

When dispersing in water or the like, conventionally known dispersants can also be preferably used. Suitable dispersants vary depending on the particle type, but
In the case of silicon-containing inorganic fine particles, aluminum oxide, etc., quaternary aluminum compounds such as tetraethylammonium hydroxide are particularly preferred.

The transesterification catalyst and polymerization catalyst used in the present invention are not particularly limited, but in order to prevent diethylene glycol from being generated during polymerization in the case of inert inorganic fine particles, the transesterification catalyst is preferably a lithium, calcium, magnenium compound, etc. .

The polymerization catalyst is particularly preferably an antimony compound.

In order to obtain polyester fibers having a single fiber fineness of 1.0 denier or less, a preferred specific example of subjecting the fibers to surface elution treatment with a soluble or degradable solvent is an alkali dissolution treatment. This alkaline dissolution treatment is
caustic soda.

Fiber cutting or weaving in an aqueous solution of basic alkali metal compounds such as alkali metal hydroxides such as caustic potash, alkali metal compounds that form alkali metal hydroxides when dissolved in water, and alkali metal carbonates. This can be achieved by heating the knitted fabric or by applying/steaming the woven or knitted fabric with an aqueous solution of a basic alkali metal compound.

In the alkali dissolution treatment, the weight loss rate is preferably 5 to 50% by weight, more preferably 10 to 30% by weight, based on the fiber or woven or knitted fabric. 5
If it is less than 50% by weight, the effect of improving color development will not be sufficient, which is not preferable, and if it exceeds 50% by weight, the strength of the yarn will be too low, which is not preferable. Further, in this alkali dissolution treatment, an alkaline dissolution promoter such as cetyltrimethylammonium bromide or lauryldimethylbenzylammonium chloride can be appropriately used.

The ultrafine polyester fiber of the present invention can also be obtained by using a false twisted yarn, and in order to obtain this false twisted yarn, the content/amount of inert inorganic fine particles is 0.12% by weight or more and 0.50% by weight.
Must be less than

If the content is less than 0.12% by weight, the number of fine irregularities formed on the fiber surface is insufficient, and there is no effect of improving color development. Moreover, if the content is 0.50 weight or more, the expansion/contraction elongation rate (OR value) of the false twisted yarn due to the inert inorganic fine particles decreases, which is not preferable. The content of the inert inorganic fine particles is more preferably 0.30% by weight or more and 0.48% by weight or less.

Further, the false twisted yarn preferably has a diethylene glycol (hereinafter referred to as DEG) content of 2.0% by weight or less, more preferably 1.0% by weight or less. If the content of DEG exceeds 2.0% by weight, the heat setting property during false twisting becomes insufficient and the OR value tends to decrease. D.K.
In order to keep the G content below 2.0% by weight, it is important to select the type of inert inorganic fine particles, the conditions during polymerization, and the catalyst system. The inert inorganic fine particles used are particularly preferably dry process silica having an alkyl group on the particle surface and blocking 7-ranol groups on the particle surface.

Furthermore, the above-mentioned polyester false twisted yarn has a 2.500
When drawing and false twisting is performed using highly oriented undrawn yarn spun at ~4,000 m/a+1, the added inorganic fine particles have the effect of promoting crystallization, which has the advantage of increasing the false twisting speed. ing.

Methods for obtaining the above-mentioned false-twisted yarn include 1) a method of false-twisting a drawn yarn obtained by ordinary spinning and drawing using a known method, and a method of drawing and false-twisting a highly oriented undrawn yarn as described above. Either can be adopted.

The ultrafine polyester fiber of the present invention can be subjected to conventionally known spinning processes such as DSD, POY, ultra-high speed spinning, and staple production as a means of improving color development without deteriorating spinning properties.

The present invention will be specifically explained below with reference to Examples, in which "part" means "part by weight" and "1%" means weight %.

Further, the average primary particle diameter [η], diethylene glycol content, number of coarse particles, color development evaluation method, fibrillation evaluation method, and alkali dissolution conditions of the inert inorganic particles in the following examples are as follows.

(Average primary particle size) A photograph of aluminum oxide-containing silicon oxide powder was taken using an electron microscope and magnified 100,000 times.

The longest diameter of each particle was measured from the obtained image, and 1.00
Displayed as the value determined as the average of 0.

(Intrinsic viscosity [η]) Ho IJ? -woO-Soluble in chlorophenol.

Displayed as a value measured at 25°C.

(Diethylene glycol content) 2.5 g of monoethanolamine is added to 1 g of polymer and heated under reflux to depolymerize. 20mt of methyl alcohol after cooling
In addition, after neutralizing with acetic acid, it was quantified by gas chromatography, and the ratio of the obtained diethylene glycol to the polymer was expressed as a ratio.

(Number of Coarse Particles) Observe a polyester chip with a thickness of 25 μm using a stereomicroscope (60 times magnification) using a conventional method, measure coarse particles with a maximum length of 40 μm or more, and calculate the number of coarse particles per 1 g of sample.

In addition, the number of coarse particles is 1 level! Measure 710 times and display the average value.

(Method for creating tubular knitted fabric) A tubular knitted fabric was knitted from the filament system to be evaluated using a 27-gauge sock knitting machine (manufactured by Koike Kikai Seisakusho ■).

(Color development evaluation method) The fabric to be evaluated was mixed with 2% nonionic activator [Sanded G-900 (manufactured by Sanyo Kasei)] and 0.0% by conventional method.
Scour by boiling in boiling water containing 2 g of soda ash for 5 minutes, then rinse and dry.

Next, we used a baking test device [MODEL-DK (H) manufactured by Ohtsuka Kagaku Seiki Seisakusho ■] adjusted to 180°C.
The tube knitted fabric is set after drying for a few seconds without tension. After dyeing for 60 minutes in an aqueous solution of 0.2 g/l of sodium acetate at a bath ratio of 1:50 at 130°C, 2 g/l of hydrosulfide and 2 g/l of caustic soda are added, washed with water, and dried.

The color development was evaluated using a digital colorimetric color difference calculator (manufactured by Suga Shikenki ■) using the L value measured with six or more layers of tubular knitted fabrics stacked together and no irradiated light transmitted.

The darker the color, the smaller the L value, and the lighter the color, the larger the L value.

(Alkali dissolution conditions) 1 part by weight of tubular knitted fabric is hydroxylated) It is immersed in 50 parts by weight of a boiling aqueous solution of IJum (3% by weight), treated for a predetermined time with stirring, washed with water, and then 1% acetic acid aqueous solution. Neutralize with
Further wash and dry. The alkali dissolution treatment time is
A preliminary study is conducted in advance and settings are made to achieve a predetermined weight loss rate. The weight loss rate was calculated by drying the tubular knitted fabric before and after treatment in hot air at 100° C. for 20 minutes, and measuring the weight (the weights at this time are referred to as A and B).

Formula □xlooo = weight loss rate Seek more.

(Fibrillation) The attached drawing shows a schematic diagram of the fibrillation tester.

A wet sample (dyed knitted fabric) 1 is attached to the head 3 using the holder 4 so that the friction area with the friction cloth 2 is 12.5-, and the sum of the loads 5 is 750 g. Do it like this.

On the other hand, the friction table 6 was attached via a non-slip sand plate ζ-7, rotated eccentrically at 85 rpm, and rubbed for 10 minutes, after which the sample 1 was removed and the degree of fibrillation was visually determined.

In other words, if fibrillation has occurred, the rubbed area will appear whiter than the unrubbed area, so observe whether the rubbed area looks white and judge it in the following 5 stages. Grade 5: Frosting is not acceptable.

Grade 4: Slight frosting is observed.

Grade 3: Slightly 70 stings are recognized.

Grade 2: Frosting is quite noticeable.

Grade 1: Frosting is significantly observed.

Among the above five grades, in the present invention, grade 5 or above is considered a passing level.

Example 1 10011 t of dimethyl terephthalate, 60 parts of ethylene glycol, 5 parts of manganese acetate "4" hydrate, O, 5 parts, and 0.04 part of antimony trioxide were charged into a transesterification can.
The temperature was raised from 140° C. to 250° C. over 4 hours under a nitrogen gas atmosphere, and the transesterification reaction was carried out while the generated methanol was continuously distilled out of the system. Subsequently, O,OS parts of trimethyl sulfur/acid were added to the obtained product.

Furthermore, various inert inorganic fine particles shown in Table 1.

20% aqueous solution of tetraethylammonium hydroxide.

Weight ratio of ethylene glycol is 5:2.5:92.5
The mixture was made by Janke & Kunke 1
ra TurrazT45DX (10,OOOrpm)
The slurry dispersed for 45 minutes was added to the polyester from which inorganic fine particles were obtained in various amounts.

The system was then gradually depressurized to 760°C over 1 hour and 30 minutes.
The pressure was reduced from wnmHg to jam Hg, and at the same time the temperature was raised from 230°C to 280°C over 1 hour and 30 minutes. 1
Polymerization was carried out for an additional 2 hours at a polymerization temperature of 2801:3, under reduced pressure of less than wm Hg, for a total of 3 hours and 30 minutes. After the reaction was completed, it was discharged into water and polyethylene terephthalate chips were obtained by a conventional method.

After drying the obtained polyethylene terephthalate under reduced pressure at 160°C for 4 hours, a 72-hole gold plate was obtained.

Spinning temperature 3001m using 100 mesh sand.

The yarn was spun at a take-up speed of 1.350 m/ajm and then stretched at a stretching ratio of 5.09 times, using a hot roll at 85°C and a hot pin at 125°C.

Stretched to 75 denier using a 155°C hot plate.

A drawn yarn of 72 filaments was obtained.

Using the obtained drawn yarn, a tubular knitted fabric was created by the method described above, and then refined and subjected to alkali dissolution treatment so that the weight loss rate was 20%. was evaluated.

Table 1 shows the evaluation results of the polymer chip's intrinsic viscosity, spinning properties in the spinning and drawing steps, tube knitted fabric construction strength 1 color development, and fibrillation properties.

Comparative Example Experiment/162.12.15.18.21.
In the case of 24°, the amount of added particles was less than 0.12% by weight, the number of particles with a diameter of 5 times or more the average primary particle size was small, and the color development was poor.

This is also a comparative example. In Experiment No. 11, the average primary particle diameter of the particles exceeds 100 mμ, and the number of particles with a diameter 5 times or more larger than the average primary particle diameter is also small (color development is insufficient).

Also, 6, 14.17.20. which are also comparative examples. '
2B.

No. 26 is because the amount of particles added exceeds 0, swt%.

The spinning property is poor, the increase in internal pressure is large, the strength of the constituent yarns of the tubular knitted fabric is low, and the fibrillation property is poor.

On the other hand, this is an example of the present invention. Experiment A 1.5~5°7~1o
, 1s, 16.19; 22.25 had good spinning properties, high strength of the constituent yarns of the tubular knitted fabric, and sufficient color development and fibrillation properties.

Furthermore, using the drawn yarn of experiment As, 13.16.

After knitting and weaving, taffeta, strongly twisted fabrics, false-twisted textured yarn fabrics, false-twisted textured yarn fabrics, tricots, circular knits, etc., were subjected to weight reduction treatment with alkali, and further dyed and printed using conventional methods. The obtained fabric exhibited good color development in both light to dark colors and black dyeing.

Example 2 Catalyst of the polymers of Example 1 Experiments A5 and 15-17,
By changing the polymerization time, polymers with different intrinsic viscosities were obtained.

After spinning the obtained polymer in the same manner as in Example 1.

A drawn yarn of 75 denier 72 filaments was obtained by spinning the yarn in the same manner as in Example 1, except that it was drawn using an 85°C hot roll and a 110°C hot plate at a draw ratio that gave a residual elongation of the drawn yarn of 35 to 40%. .

The obtained drawn yarn was subjected to a spindle-type false twisting machine with a heater length of 110 crn at a heater temperature of 210°C, a temporary pressing speed of 100 rn/min, and a heating number of 5,450 tpm.
After false twisting, knitting and alkali dissolution treatment were performed in the same manner as in Example 1, and color development was evaluated.

Table 2 shows the expansion/contraction elongation rate (OR value) of the obtained false twisted yarn, the fibrillation property evaluation of the tubular knitted fabric after the alkali dissolution treatment, and the strength of the constituent yarns of the tubular knitted fabric.

In Table 2, experimental point 27, which is a comparative example, has a DEG of 2.
．． It exceeds 0% by weight and the false twisted yarn OR is low 0 Also, experiment! Using the same polymer as used in 5.16, spun yarn, highly oriented undrawn yarn, drawn false twisted yarn, direct spun drawn yarn, and directly spun yarn by ultra-high speed spinning are obtained by conventional method, and these are treated with alkali. After the weight reduction treatment, dyeing was performed and the result showed good color development.

Further, when these drawn yarns, false twisted yarns, etc. were yarn-dyed and then subjected to weight reduction treatment with an alkali, they showed similarly good color development.

Further, even when the fabric obtained above was subjected to finishing treatments such as electric shock treatment and refractory melting in the usual manner, the color development did not deteriorate.

On the other hand, in experimental point 31, which is a comparative example, the fibrillation property was poor due to the low intrinsic viscosity, and the strength of the constituent yarns of the tubular knitted fabric was also low.

In Experiments A 28 to 30 of the present invention examples, the OR value of the false-twisted yarn was high, the fibrillation property and the yarn strength of the tube knitted fabric were also good, and the fabric using this false-twisted yarn was dyed after alkali weight loss treatment. As a result, good color development was obtained.

In addition, in Experiment A32, which is a comparative example, the amount of inorganic particles added was small and the effect of improving color development was not exhibited.

Experimental Rei 34, which is also a comparative example, has a large amount of inorganic particles added.
There are problems in that the OR value is low and the fibrillation property is poor.

On the other hand, the textured yarn experimental Arashi 65 of the present invention had good OR value, fibrillation property, tube knitted fabric constituent yarn strength, and coloring property.

The methyl group-blocked dry silica in Tables 1 and 2 was a dry process silica that had methyl groups on the particle surface and had 75 7ranol groups on the particle surface blocked.

Further, the state of dispersion of particles in a chip is the number of particles having a diameter 5 times or more of the average primary particle size, expressed as (number/10μ2).

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus for measuring fibrillation. Patent applicant: Toshi Co., Ltd. Figure 1

Claims (1)

[Scope of Claims] (1) Contains 0.12% by weight or more and less than 0.12% by weight of inert inorganic fine particles with an average primary particle size of 100 mμ or less, and has a single fiber fineness of 1.0 denier or less. A polyester fiber characterized by having a large number of fine vertically elongated dents in the fiber axis direction on a certain fiber surface. +21 The average primary particle diameter of inert inorganic fine particles is 50
Claim No. 1 (1) characterized in that it is less than mμ.
Polyester [fiber] according to item 1. (3) The average primary particle diameter of the inert inorganic fine particles is 20
Claim f1 is characterized in that it is less than or equal to mμ.
Polyester fiber according to item i. (4) The polyester fiber according to claims 11 to 3, wherein the inert inorganic fine particles are silica. (5) The inert inorganic fine particles are hydrophobic dry process silica having an alkyl group on the particle surface and blocking the silanol groups on the particle surface. ) The polyester fiber described in (6) The content of inert inorganic fine particles is 0.50% by weight.
The polyester fiber according to claims 11 to 5, wherein the content is 0.48% by weight or less. (7) Claim No. +1) characterized in that the polymer is produced by spinning a polymer in which the number of inert inorganic fine particles of 40 μ or more present in 1 g of polymer is 150 or less.
The polyester fiber described in item (6) above. (8) Claim No. 1, characterized in that there are at least 5 particles per 10 square microns whose secondary particle diameter is three times or more the average primary particle diameter of the inert inorganic fine particles contained therein. The polyester fiber described in items 1) to (7). (9) The polyester fiber according to claims 11) to (8), which has an intrinsic viscosity of 0.48' or more. The polyester fiber according to claims (1) to (8), which has an OI intrinsic viscosity of 0.57 or more. The polyester fiber according to claim 1, wherein the content of αυ diethylene glycol is 2% by weight or less. Polyester fiber according to item 01. 03 A polyester fiber obtained by false twisting the polyester fiber according to claims 1 to 62. 0411 0.12% by weight or more and 0.50% by weight of inert inorganic fine particles with an average primary particle diameter of 100 mμ or less
The polyester fiber containing less than
A method for producing polyester fibers, characterized in that the single fiber fineness after elution treatment is 1.0 denier or less. (I!9 The average primary particle diameter of the inert inorganic fine particles is 5
The method for producing a polyester fiber according to claim 1, wherein the polyester fiber has a particle diameter of 0 mμ or less. aQ The average primary particle diameter of inert inorganic fine particles is 20 m
The method for producing a polyester fiber according to claim 1, characterized in that the polyester fiber has a particle diameter of μ or less. The method for producing polyester fibers according to claims 04 to 01, wherein the αD inert inorganic fine particles are silica. Q8 Claim No. 4, characterized in that the inert inorganic fine particles are hydrophobic dry process silica having an alkyl group on the particle surface and blocking silanol groups on the particle surface.
A method for producing polyester fibers according to items 0 to 00. Q1 The method for producing polyester fibers according to claims 04 to 01, wherein the content of inert inorganic fine particles is 0.30% by weight or more and 0.48% by weight or less. (2) The number of inert inorganic fine particles of 40μ or more present in 1 g of polymer is 150 or less. Production of polyester fibers according to claims 4 to 5, characterized in that there are at least 5 particles per 10 square microns whose diameter is three times or more that of the contained inert inorganic fine particles. Method. (c) A method for producing a polyester fiber according to claims 04 to 01, characterized in that the intrinsic viscosity is 0.48 or more. @ The intrinsic viscosity is 0.57 or more 241 The method for producing polyester fibers according to Claims 041 to 01, characterized in that the content of diethylene glycol is 2% by weight or less. 4. The method for producing polyester fibers according to claims 1 to (c), characterized in that the diethylene glycol content is less than 1% by weight. (To) Claim No. 14, Q9.Q14°, characterized in that the polyester fiber is a false twisted yarn
The method for producing the polyester fiber described in item (c) above. (5) The method for producing polyester fibers according to claims 4 to 4, wherein the solvent for the fibers is a caustic soda solution.