JPS58149314A - Preparation of polyester fiber having improved color developing property - Google Patents

Abstract

PURPOSE:To obtain the titled fibers having improved transparency and glossy feeling, etc., by obtaining fibers from a polyester, prepared by using a magnesium compound as an ester interchange catalyst, and containing silica coated with alkyl groups, and treating the resultant fibers with an alkaline solution. CONSTITUTION:An ester-forming derivative consisting essentially of dimethyl terephthalate is subjected to the ester interchange reaction with a glycol consisting essentially of ethylene glycol in the presence of 0.03-0.20wt% magnesium compound, e.g., magnesium acetate, and silica coated with alkyl groups, having <=100mmu average primary particle diameter and 30% or more blocked silanol groups on the particle surfaces in an amount of 0.30-1.50wt% based on the polyester is then added to a reaction mixture in any stage till the completion of the polymerization reaction of the polyester to carry out the polymerization. The resultance polyester is then spun into fibers, which are then treated with an alkaline solution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyester fibers with excellent color development. More specifically, it relates to a method of producing polyester fibers using a specific transesterification catalyst and containing specific silica particles, and then subjecting the fibers to an alkali dissolution treatment to obtain polyester fibers with excellent color development. .

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

However, polyester fibers have been inferior to other fibers, such as acetate, rayon, wool, and silk, in the color development of dyed fabrics (deep black or sharpness of chromatic colors). In particular, since black deep bed is significantly inferior to the other fibers mentioned above, there has been a strong desire for improved black color development (improvement of deep bed) in the black formal field.

As a method for improving the color development of dyed fabrics, which is a drawback of conventional polyester fibers, (1) A method in which organic synthetic fibers are irradiated with plasma in a glow discharge plasma to impart irregularities of [L1 to α5μ] on the fiber surface. 1987-99400 (2) Method of applying a thin film of a low refractive index component to the fiber surface (Japanese Patent Laid-Open No. 55-1111
(No. 92) (3) A method of imparting a specific surface structure by subjecting polyethylene terephthalate fibers to which 5 to 10 wt. -120
7-28) and the like are known.

Among these methods, method (1) has problems such as high cost due to expensive plasma discharge equipment and no significant effect of improving color development.

On the other hand, method (2) is a method in which a low refractive index component is attached to the fiber surface, and although it certainly has a large effect of improving color development, it has the problem of poor abrasion fastness.

Furthermore, since the method (3) above can impart a specific surface roughness to the fibers, a certain degree of color development improvement effect can be expected. However, this method generates a granular structure on the fiber surface, which tends to reflect light on the fiber surface, and the effect of improving color development was not sufficient.

Further, when a granular structure is present, when the fabric is rubbed, the granular structure is easily destroyed and becomes a mirror surface, which tends to partially reflect light, causing a change in color.

In view of the above-mentioned problems, the present inventors conducted intensive studies on the effect of improving the fiber surface morphology and improving coloring properties by alkaline dissolution treatment of polyester fibers containing inert inorganic fine particles. It was discovered that polyester fibers with a specific surface morphology and suitable color development properties could be obtained by subjecting silicon-containing polyester fibers to an alkali dissolution treatment, and they proposed Japanese Patent Application No. 138,757/1983. However, as a result of detailed study by the present inventors regarding this method,
Depending on the transesterification catalyst used, particle dispersibility may deteriorate, the transparency of the obtained polyester may deteriorate, and the glossiness of the resulting fiber may decrease, or the catalyst may become foreign matter during the polymerization reaction, resulting in thread breakage during spinning. etc. may occur, and when fibers are subjected to alkali dissolution treatment due to catalyst foreign substances, the dents on the fiber surface may become large and the effect of improving color development may be slightly reduced. Therefore, it is necessary to use an appropriate transesterification catalyst, especially when using alkyl coated silica-added polyester. was found to be important.

In view of these problems, the present inventors conducted further intensive studies and arrived at the present invention.

That is, the present invention involves adding a magnesium compound to perform the transesterification reaction between an ester-forming derivative containing dimethyl terephthalate as the main component and a glycol containing ethylene glycol as the main component, and then polymerizing the polyester. At any stage until the reaction is complete,
0.60 to 1.50% by weight of alkyl coated silica having an average primary particle size of 100ffiμ or less and blocking silanol groups on the particle surface based on the resulting polyester.
This is a method for producing polyester fibers with excellent color development, which is characterized in that the polyester fibers obtained by spinning this polyester are subjected to alkali dissolution treatment.

The polyester forming the polyester fiber of the present invention is a polyester having an ester-forming derivative containing dimethyl terephthalate as a main component as a dicarboxylic acid component and ethylene glycol as a main glycol component.

Note that a part of the terephthalic acid component may be replaced with, for example, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid,
p-β-hydroxyethoxybenzoic acid, p-hydroxybenzoic acid, isophthalic acid, 4.4′-diphenylsulfo/dicarboxylic acid, 4.4′-diphenylmethanedicarboxylic acid, 4′,4-diphenyl ether dicarboxylic acid,
Difunctional carboxylic acids such as 4.4'-diphenyldicarboxylic acid, 1.2-diphenoxyethane-2% p'-dicarboxylic acid, 2.6-naphthalenedicarboxylic acid, adipic acid, and sebacic acid! Lico-h component part w) Rimethylene glycol, tetramethylene glycol, hexamethylene glycol, diethylene glycol, Trie fL/N glycol, polyethylene glycol, 1.4
- Substituted with an aliphatic, alicyclic, or aromatic dioxy compound such as cyclohexanediol, 1,4-cyclohexane dimetatool, 1,4-bis-β-hydroxyethoxybenzene, or bisphenol A, or an ester-forming derivative thereof More than 70 mol% of the repeating units in the main chain are ethylene terephthalate units ゛-- -
Order −
It may also be a copolymerized polyester. In particular, from the viewpoint of improving color development, it is more preferable to replace it with an inphthalic acid component having a polyalkylene glycol and an alkali metal sulfonate group.

Furthermore, the polyester of the present invention may further contain a small proportion of a chain branching agent such as pentaerythritol, trimethylolfuropane trimellitic acid, or trimesic acid, or a polymerization terminator such as monohydric polyalkylene oxide or phenylacetic acid. It is possible.

The magnesium compound of the transesterification catalyst used in the present invention is not particularly limited, but magnesium acetate, magnesium carbonate, magnesium oxalate, magnesium hydroxide, magnesium oxide, etc. are preferred, and among these, p-gnesium acetate is particularly preferred. preferable. like this~
The amount of the gnesium compound added is 0.03 to [120% by weight]
is preferred, and 0.07 to 0.15% by weight is particularly preferred.

When a magnesium compound is used as a transesterification catalyst, catalyst foreign matter generated by other transesterification catalysts may cause decreased transparency of the polymer, decreased color development, decreased gloss, increased Toda during spinning, thread breakage during stretching, and poor heat resistance. This results in a reduction in the increase in coarse particles of alkyl-coated silica, and an overall excellent polyester.

In addition, when synthesizing polyester in the present invention, catalysts, coloring inhibitors, ether bond by-product inhibitors, antioxidants, flame retardants, and the like that are well known in the art can be appropriately used.

The alkyl-coated silica added to the polyester in the present invention is one in which 60% or more of the silanol groups on the particle surface are blocked by, for example, reacting dry silicon oxide with dialkyldichlorosilane.

The silicon oxide produced by the dry process here generally refers to halogen oxides, such as those described on page 524 of the "Practical Handbook of Additives for Plastics and Rubber" (Kagaku Kogyosha, published on August 10, 1972). This is a method in which silicon oxide is thermally decomposed together with moisture and oxygen in the gas phase.

The alkyl group present on the particle surface of the alkyl-coated silica is not particularly limited, but methyl and ethyl groups are preferable, and the blocking rate of silanol groups on the particle surface of the alkyl-coated silica is 60% or more, particularly 60% or more. is preferred.

If it is less than 30%, the polyester will aggregate violently during the polymerization reaction, the number of coarse particles in the polymer will increase, and the color development and hydrolysis resistance of the resulting polyester will decrease, which is not preferred.

The average primary particle diameter of the alkyl coated silica is 100
mμ or less, preferably 40 mμ or less. If the average primary particle diameter exceeds 100 mμ, the effect of improving color development will be reduced, which is not preferable.

Further, the amount of the alkyl coated silica added is in the range of 0.30 to 1.50% by weight, particularly preferably in the range of 0.40 to 1.0% by weight, based on the polyester to be produced. 0
．． If the amount is less than 60% by weight, the effect of improving color development will be insufficient, which is undesirable, and if the amount exceeds 1.5% by weight, the effect of improving color development will decrease and the effect of increasing the amount added will be lost, so it is not preferable. do not have.

Such alkyl coated silica contains aliphatic glycol,
It can be dispersed in aliphatic alcohol or water by a known method and added to the polyester as a fractionated slurry, but it is particularly preferable to disperse it in glycol, which is the raw material for the polyester.

A dispersion slurry of alkyl-coated silica can be prepared by a conventionally known method, but alkyl-coated silica and ethylene glycol can be prepared using a plurality of shearing blades parallel to the rotating direction of stirring blades as disclosed in JP-A-55-125495. Preferred methods include dispersion in a high-speed stirrer, separation of coarse particles by centrifugal sedimentation, separation of coarse particles by filtration, and the like in combination with the present technique. Furthermore, it is particularly preferable to use the conventionally known ultrasonic dispersion method in combination with the method. Furthermore, conventionally known dispersants can also be used as dispersants.

Use of a dispersant is particularly preferred since it is effective in preparing a glycol dispersion of alkyl-coated silica and preventing aggregation during polymerization. General dry process silica is relatively easy to disperse in ethylene glycol, so it is possible to disperse it without using a dispersant, but the alkyl coated silica used in the present invention certainly reduces agglomeration during polymerization. Its dispersibility in ethylene glycol is extremely poor compared to general dry process silica, and it is almost impossible to form it into a slurry, leaving it floating in ethylene glycol. However, it has been found that the dispersibility in ethylene glycol is dramatically improved by adding a dispersant such as a tetraalkylammonium compound, sodium hydroxide, or potassium hydroxide. Among these dispersants, tetraalkylammonium compounds are particularly preferred because they do not form foreign substances during polymerization.

Here, examples of the tetraalkylammonium compound include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetraisoglobyl ammonium hydroxide, tetrabutylammonium hydroxide, etc. is particularly preferred.

When such a dispersant, such as a tetraalkylammonium compound, is used, its preferred amount is 5 to 30% by weight based on the alkyl coated silica of the present invention. If the amount used is less than 5% by weight, the effect of preventing aggregation during polymerization due to the use of a dispersant will be poor, and if it exceeds 60% by weight, not only will the effect be saturated, but the polymer will be colored yellowish brown and the physical properties of the polyester fiber will deteriorate. It may also cause defects such as deterioration.

The alkyl-coated silica slurry can be added at any stage until the polymerization of the polyester is completed, but it is particularly preferable to add it before the start of the transesterification reaction, since this reduces the number of coarse particles of the alkyl-coated silica of the present invention.

However, if the alkyl coated silica is dispersed in a high concentration in the same polyester as the polyester of the present invention by changing the dispersion medium of the alkyl coated silica, it can be added either after completion of polymerization or during spinning.

Incidentally, the coarse particles in the polymer 1i in the present invention are preferably 300 or less, particularly preferably 200 or less. When the number of coarse particles exceeds 300, there is a tendency for the increase in bag internal pressure during spinning to become large.

That is, the upper limit of the bag internal pressure in a normal spinning device is 450 to 500 9/c! However, when producing polyester in the present invention, sand with a mesh of 80 or more and/or a metal nonwoven filter with an absolute filtration diameter of 60 microns or less is used to avoid thread breakage during spinning and drawing. Since this is necessary, the bag internal pressure at the start of spinning is 150 to 200 kg/crl. Therefore, the total bag internal pressure increase should be 250~'500 K9/cr
/1 or less. On the other hand, in normal industrial production, the bag replacement cycle needs to be short, at least 15 to 20 days, and the pack internal pressure rises at a maximum of 15 to 20 edges/ctl.
, must be 7 days.

Therefore, the furnace pressure increase when spinning normal 75 denier polyester fiber is 0.6 to 4 Ky/crl.
It is necessary to make it less than /~polymer. Furthermore, when using a spinning device with an upper limit of pressure resistance of 250 to 500 Kg/crd, the upper limit of furnace pressure rise becomes even lower, and in this case, the upper limit is considered to be about 0-2 Kg/cal/Kg polymer at 75 denier.

On the other hand, the polyester used in the present invention contains alkyl-coated silica'k at 0.50% by weight or more and 1.50% by weight or less, and the number of coarse chip particles is 300 pieces/y or less. The furnace pressure increase when spinning using sand is approximately 0.2 Kg/crA/
Kg polymer, and can be preferably applied to the above-mentioned low pressure spinning machine.

In addition, in the present invention, heat resistance is measured by the method described below and is 0.25% in terms of polymerization productivity, viscosity reduction during spinning, etc.
The following are preferred.

In addition, in the present invention, by replacing a part of the glycol component constituting the polyester with polyalkylene glycol and/or replacing a part of the terephthalic acid component with an inphthalic acid component having an alkali gold bullion sulfonate group, the effect is further improved. It is possible to achieve the effect of improving color development. The effect of the copolymerization of polyalkylene glycol components is thought to be due to the improvement in the dispersibility of the disperse dye inside the fibers, thereby increasing the amount of light absorption inside the fibers. Furthermore, the effect of copolymerizing an isophthalic acid component having an alkali metal sulfonate group is that it becomes possible to dye with a cationic dye that originally has a large molecular extinction coefficient, and it is thought that this is also caused by an increase in the amount of light absorption inside the fiber.

Polyalkylene glycols that can be used in the present invention include polyethylene glycol, Bo! j-1.2-Propylene glycol, polytrimethylene glycol, polytetramethylene glycol, etc. Among these, polyethylene glycol is more suitable for dry oxidation in the polyester obtained than other polyalkylene glycols. It is particularly preferred because silicon agglomeration is less likely to occur and the effect of improving color development is large at the same amount added.

The molecular weight of the polyalkylene glycol in the present invention is not particularly limited, but it is preferably a molecular weight that does not cause layer separation in the resulting polyester.

For example, in the case of polyethylene glycol, the molecular weight is 5.00
It is preferably 0 or less.

The amount of polyalkylene glycol added in the present invention is preferably 1 to 10% by weight, more preferably 3 to 7% by weight, based on the polyester obtained. If the amount is less than 1% by weight, the effect of improving the coloring property of the resulting polyester fiber by polyalkylene glycol copolymerization will be small, and if the amount exceeds 10% by weight, the light resistance of the resulting polyester may decrease.

Further, specific isophthalic acid components having an alkali metal sulfonate group that can be used in the present invention include lithium 6,5-bis(methoxycarbonyl)benzenesulfonate, sodium 5,5-bis(methoxycarbonyl)benzenesulfonate, 5.5-bis(methoxycarbonyl)potassium benzenesulfonate, lithium 5.5-bis(β-hydroxyethoxycarbonyl)benzenesulfonate, sodium 3,5-bis(β-hydroxyethoxycarbonyl)benzenesulfonate, 3,5-bis(β-
Potassium hydroxyethoxycarbonyl)benzenesulfonate, lithium 3.5-bis(δ-hydroxybutoxycarbonyl)benzenesulfonate, 3.5-bis(δ-hydroxybutoxycarbonyl)benzenesulfonate
Sodium (hydroxybutoxycarbonyl)benzenesulfonate, etc. can also be used.

The amount of the isophthalic acid component having an alkali metal sulfonate group is preferably in the range of 0.5 to 10 mol%, particularly preferably in the range of 1 to 6 mol%, based on the total acid components constituting the polyester. If the amount used is less than 0.5 mol%, the affinity for cationic dyes will be poor, and if it exceeds 10 mol%, the excellent physical properties peculiar to polyester may be impaired.

Alkali metal hydroxides, alkali metal compounds that form alkali metal hydroxides when dissolved in water, and alkali metals such as the polyester fibers containing silica fine particles of the present invention (which can be treated with a caustic sorter or caustic force), etc. This can be accomplished by heating a basic alkali metal compound such as carbonate, or by padding/steaming a woven or knitted fabric with an aqueous solution of a basic alkali metal compound.

In the alkali dissolution in the present invention, it is necessary to use the above-mentioned alkali dissolution treatment method so that the weight loss rate is in the range of 3 to 50% by weight, preferably 5 to 60% by weight, based on the fiber or woven or knitted fabric. If the alkali dissolution loss rate is less than 3%, the effect of improving color development will not be sufficient, and if it exceeds 50% by weight, the effect of improving color development will be saturated and the strength of the yarn will decrease too much, which is not preferable.

Further, in the alkaline dissolution treatment, an alkaline dissolution promoter such as cetyltrimethylammonium bromide and lauryldimethylbenzylammonium chloride can be used as appropriate.

As detailed above, the effect of the present invention is that a magnesium compound is used as a transesterification catalyst in the transesterification process, and a specific alkyl coat 7 lyca is added, whereby fibers obtained from polyester are treated with alkali. It is expressed by this.

Such effects can be obtained by (a) using a dispersant such as a tetraalkylammonium compound during the production of the polyester, (b) copolymerizing the polyester with a polyalkylene glycol or an isophthalic acid component having an alkali metal sulfonate group, It can be made to express even more clearly.

The present invention will be specifically explained below with reference to Examples.

In addition, parts in Examples mean parts by weight, and % means weight %. Further, various measurement and evaluation methods and alkali dissolution treatment conditions in the present invention are as follows.

(Average primary particle diameter) A photograph of alkyl-coated silica powder magnified 100,000 times was taken using an electron microscope, the longest diameter of each primary particle was measured from the obtained image, and the average of 1,000 particles was measured. Display the obtained value.

(Method of measuring intrinsic viscosity [η]) The value is expressed as the value measured at 25°C after dissolving the polymer fo-chlorophenol.

(Number of coarse particles) Polyester chips were formed into a biaxially stretched film with a thickness of 25μ by a conventional method, and this film (25crl) was examined under a stereoscopic microscope (
Observe with a magnification of 60 times), measure coarse particles with a maximum length of 50 μm or more, and calculate the number of coarse particles per sample.

Incidentally, the number of coarse particles is measured 10 times per level and is expressed as the average value.

(b value) The polymer is molded into a cylindrical shape with a diameter of 2.5 to 3.5 U and a height of 4.5 to 5.5 mm, and measured using a direct-reading color difference computer manufactured by Suga Test Instruments Co., Ltd. The larger the b value, the greater the yellowing tendency of the polymer.

(Hydrolysis Resistance) A hexahedral polymer with a side of about 5 mm was sealed in a glass ampoule with 20 mm of distilled water, and heated in a 130° C. oil bath for 1 hour.

After cooling, the polymer was taken out and dried at 60'C for 6 hours, then the terminal groups were measured by a conventional method, the number average molecular weight was calculated, and the polyhydrolysis rate was calculated from the number average molecular weight before and after heat treatment using the following formula. do.

0 (H-1) Degree of hydrolysis (%n””)

-Field 6 (Mo and M represent the respective number average molecular weights before and after heat treatment) (Transparency) The polyester chip is judged with the naked eye.

(Heat resistance) After vacuum drying 8f polyester chips in a test tube with a diameter of 16u1 and a length of 15°C for 16 hours at 140°C,
Calculated by heating at 00°C for 1 hour under a N2 stream.

Heat resistance (%) = X10.06 (MoXM represents the number average molecular weight before and after heat treatment) (Method for creating tubular knitting) The filament yarn to be evaluated was used on a 27-gauge sock knitting machine [manufactured by Koike Kikai Seisakusho ■] ] to knit a tubular knitted fabric.

(Color development evaluation method) The fabric to be evaluated was mixed with 0.2% nonionic activator [SANDETSU] ()-900 (manufactured by Sanyo Kasei ■) and 0.2% by a conventional method.
After boiling and scouring in boiling water containing soda ash for 5 minutes, washing with water and drying.

Next, using a baking test device [MODEL-DK-II manufactured by Ohtsuka Kagaku Seiki Seisakusho ■] adjusted to 180°C,
The tube knitted fabric is set after drying for a few seconds without tension. Next Sumikaron Black 5-BB 1
0% owf (dispersed dye manufactured by Jujutsu Kagaku ■) Acetic acid cL5c
c/, #Sodium acetate 0.2 f/i
After staining for 60 minutes in an aqueous solution at 160°C with a bath ratio of 1:60, dyeing with hydrosulfide was carried out according to a conventional method.
2f/, 1 caustic soda 2?
/! Light cleaning is performed for 20 minutes in an aqueous solution of a nonionic activator 2 f/A (Sanded G-900) at 80°C, followed by water washing and drying.

The evaluation of color development is performed using the L value measured using a digital colorimetric color difference calculator [manufactured by Suga Test Instruments ■] with six or more layers of tubular knitted fabric stacked together and the irradiated light not passing through. The lighter the color, the smaller the value, and the lighter the color, the larger the 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 (6% by weight), treated for a predetermined time with stirring, washed with water, and then immersed in a 1% acetic acid aqueous solution. - Neutralize with liquid, then wash and dry. The alkali dissolution treatment time is preliminarily examined and set so as to achieve a predetermined weight loss rate.

The weight loss rate is calculated by drying the cylindrical knitted fabric before and after treatment in hot air at 100°C for 20 minutes, and then determining the weight (the weight at this time is t-A1B).

(Observation of surface condition of fibers) 6. Observation of fibers using a field emission scanning electron microscope manufactured by Hitachi. Photographs are taken at OO0x magnification, and judgment is made with the naked eye from the resulting photographs. For the purpose of the present invention, better results are obtained when there are no large dents and there are only a large number of lJ/dip dents.

Example 1 100 parts of dimethyl terephthalate, 64 parts of ethylene glycol including the amount brought in from the alkyl-coated silica slurry, and the transesterification catalyst listed in Table 1 were charged, and then the average primary particle diameter was 16 mμ, and methyl-coated silica with 75% of the silazyl groups on the particle surface blocked,
A mixture of a 20% aqueous solution of tetraethylammonium hydroxide and ethylene glycol in a weight ratio of 5:2.5:92.5 was added to Ult manufactured by Janke & Kunkel.
ra Turrax T45DX (10,0[1
0 rpm) for 30 minutes. Next, a slurry filtered through a nickel filter having square holes with a side length of 25 mμ was added at a concentration of 1.0% to the polyester obtained in terms of alkyl-coated silica, and the slurry was filtered under a nitrogen atmosphere. 150~ for 4 hours'50 minutes
The transesterification reaction was carried out while the methanol produced by raising the temperature to 230° C. was continuously distilled out of the system. In this case, when the reaction was slow and the temperature at the top of the rectifying column exceeded 170° C., the reaction was continued until the theoretical amount of methanol was distilled out. After adding 0.04 parts of trimethyl phosphate and 0.03 parts of antimony trioxide to the reaction product, the pressure of the polymerization reaction system was gradually reduced to 76011LxH over 1 hour and 60 minutes.
Depressurize from y to 11j110' and reduce pressure for 1 hour 30
The temperature was raised from 260°C to 280°C over several minutes. 1UH
The polymer was further polymerized at a polymerization temperature of 280°C under a reduced pressure of y- or less until the polymer reached the target intrinsic viscosity. After the reaction was completed, the resulting polymer was discharged into water in the form of a rod with a diameter of 5AlII, and the length was 5B.
Polyester chips were obtained by cutting into polyester chips.

The properties of the polyester chips obtained by the above method are as shown in Table 1. After drying these polyester chips under reduced pressure at 160°C for 5 hours, they were spun at a spinning temperature of 6 using a combination of 48-hole gold, 100-mesh sand, and 50-mesh sand.
The yarn was spun at 00°C and a take-up speed of 1650 m/min to obtain an undrawn yarn. Then, the stretching ratio was 3.09 times,
Stretched under the conditions of pin temperature 125°C and hot plate 155°C,
A drawn yarn having a denier of 48 filaments was obtained.

The drawn yarn was made into a tubular knitted fabric by the method described above, and then scoured and treated with alkali so that the weight loss rate was 20%, and its surface condition and color development were evaluated.

Table 1 shows the spinning properties in the spinning and drawing steps, the surface condition of the thread after alkali treatment, and the coloring properties.

Experiment I@1.6.9.10.11 in Table 1 is a comparative experimental example for clarifying the effects of the present invention. In other words, the first
Because the amount of magnesium acetate was too small, the transesterification reaction was not completed and a satisfactory polymer could not be obtained.In Experimental Rope 6, the amount added was too large, so the effect of the present invention was not only saturated, but also The b value of the polymer increases slightly. In addition, in experiment Nα9.11, the number of coarse particles increased slightly, and the rise in Te pressure decreased slightly. Furthermore, in Experiment N [Llo, there were many catalytic foreign substances, and the transparency of the polymer was lowered, and even though the coarse particles were within a preferable range, the silk-spinning property was lowered. On the other hand, when a magnesium compound is used as a transesterification catalyst and is added in a preferred amount, the effects of the present invention are exhibited for each characteristic value.

Example 2 Polymerization, spinning, and stretching were carried out in the same manner as in Example 1, except that the silica particle type, particle size, amount added, amount of dispersant, etc. in Experiment 3 of Example 1 were changed as shown in Table 2. Did. however,
The polymerization time was changed appropriately in order to make a yarn with the target [η]. The obtained drawn yarn was knitted in the same manner as in Example 1, subjected to alkali dissolution treatment, fiber surface observation, and color development evaluation. The evaluation results are shown in Table 2). In Table 2, experiments Nα12.19.23.24.27 are comparative experimental examples to clarify the effects of the present invention, but Nl112
Because the amount added is small, color development is poor, and I@19 has many coarse particles because the amount added is large, and the increase in P pressure is somewhat large. In addition, No. 26 has poor color development because the primary particle size is too large.
No. 24 has a low silanol group blocking rate, has large coarse particles, and has a slightly high furnace pressure rise. Furthermore, since m27 does not block silanol groups, its coarse particles are extremely large and its hydrolysis resistance is poor. Also, the F pressure rises rapidly.

On the other hand, it is clear that all cases in which the alkyl-coated silica defined in the present invention is used are within suitable ranges. In addition, the test result was 14.15, which was slightly higher.

Claims (1)

[Claims] (1) A transesterification reaction was carried out by adding a magnesium compound before the transesterification reaction between an ester-forming derivative containing dimethyl terentate as a main component and a glycol containing ethylene glycol as a main component. After that, at any stage until the polymerization reaction of the polyester is completed, alkyl-coated silica having an average primary particle diameter of 100 mμ or less and blocking 7 lanol groups on the particle surface is added to the obtained polyester by l1lL60 to 1. A method for producing polyester fibers with excellent color development, characterized by adding 50% by weight to complete the polymerization, and then subjecting the polyester fibers obtained by spinning this polyester to alkali dissolution treatment. (2) A method for producing polyester fibers with excellent color development properties. A method for producing a polyester fiber according to claim (1), characterized in that the fiber is magnesium acetate. (3) The amount of the magnesium compound added is 0.CI3 to
(120% by weight of the polyester fiber manufacturing method according to claims (1) and (2)). (4) The average primary particle diameter of the alkyl coated silica is 40 mμ or less. Claims characterized in (
The method for producing polyester fibers and fibers described in items 1) to (3). (5) A method for producing a polyester fiber according to claim (5), characterized in that the alkyl-coated silica is methyl-coated silica. On the other hand, the method for producing polyester fibers according to claims <1) to (5), characterized in that IXL is 4 to 1.0% by weight.