JPS6244064B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing synthetic fibers. More particularly, the present invention relates to a method for producing synthetic fibers made of polyester that have special micropores and exhibit improved color depth and clarity when colored. Polyester is widely used as a synthetic fiber because it has many excellent properties. However, compared to natural fibers such as wool and silk, cellulose fibers such as rayon and acetate, and acrylic fibers, polyester fibers lack the depth of color when colored, resulting in inferior color development and clarity. There is. Conventionally, attempts have been made to improve dyes, chemically modify polyester, etc. in an attempt to overcome this drawback, but none of them have been sufficiently effective. In addition, methods have been proposed in which a transparent thin film is formed on the surface of polyester fibers, and a method in which plasma irradiation of 80 to 500 mA·sec/cm ² is applied to the surface of a woven or knitted fabric to form fine irregularities on the fiber surface. however,
Even with these methods, the effect of improving the depth of color is insufficient, and in addition, the transparent thin film formed on the fiber surface easily falls off when washed, etc., and its durability is insufficient. In the method of applying plasma irradiation, unevenness does not occur on the surface of the fiber in the part of the fiber that will be in the shadow of the irradiated surface, so the smooth fiber surface does not appear on the surface due to the rolling of threads within the fiber structure that occurs during wear. It has the disadvantage of causing color spots. On the other hand, as a method for imparting irregularities to the surface of polyester fibers, fibers made of polyoxyethylene glycol or polyester blended with polyoxyethylene glycol and a sulfonic acid compound are treated with an alkaline aqueous solution to form wrinkles arranged in the fiber axis direction. A method for producing hygroscopic fibers in which micropores are formed on the surface of the fibers, or polyester fibers prepared by adding fine particles of an inert inorganic substance such as zinc oxide, calcium phosphate, etc. to a polyester reaction system are treated with an alkaline aqueous solution. A method for producing hygroscopic fibers has been proposed in which fine pores are formed by eluting inorganic fine particles. however,
In the fibers obtained by these methods, no effect of improving the depth of color is observed, and on the contrary, a decrease in visual density is observed. That is, in these methods, if the treatment with the alkaline aqueous solution is not sufficient, no effect of improving the color depth is observed at all, and when the treatment with the alkaline aqueous solution is sufficient, the color depth is not improved, The visual density decreases, probably due to the diffuse reflection of light by the micropores.
Even if the fibers are dyed in a deep color, they look whitish, and furthermore, the strength of the obtained fibers is significantly reduced and they become easily fibrillated, making them unsuitable for practical use. In addition, fibers made of polyester containing inorganic fine particles such as silica with a particle size of 80 mμ or less are subjected to an alkali weight reduction treatment to give irregular irregularities of 0.2 to 0.7 μm on the fiber surface, and 50 to 50 μm in diameter within these irregularities.
A method has been proposed to improve the depth of color by creating fine irregularities of 200 mμ. However, even with this method, the effect of improving the depth of color is insufficient, and on top of that, perhaps due to the extremely complicated shape of the unevenness, the unevenness is destroyed and destroyed by external physical effects such as friction. There are disadvantages in that the damaged portions are significantly discolored or have a difference in gloss compared to other undestructed portions, and furthermore, they easily become fibrillated. The inventor of the present invention has conducted intensive studies to provide a polyester fiber that does not have the above-mentioned drawbacks and has excellent color depth and clarity by adding micropores to polyester fiber, and has found that a specific amount of 5 Without reacting a calcium compound in a specific amount ratio with a valent phosphorus compound and this pentavalent phosphorus compound in advance,
By treating the polyester fiber obtained by melt-spinning the polyester synthesized by adding it to the polyester reaction system with alkali, it is possible to form a large number of special micropores. It was discovered and proposed earlier that polyester fibers with excellent color depth and clarity, sufficiently small discoloration due to friction, and excellent fibril resistance can be obtained. However, it has been found that the polyester fibers obtained in this manner are sometimes unable to provide a sufficient sharpening effect. As a result of further studies aimed at improving these drawbacks, the present inventor found that by reacting a portion of the phosphorus compound used in the above method with a calcium compound in advance, the effect can be reliably obtained with good reproducibility. I learned. Based on this knowledge, we continued to consider
The invention has been completed. That is, the present invention involves a first step reaction in which a dicarboxylic acid, mainly terephthalic acid, or its ester-forming derivative is reacted with at least one type of glycol to produce a glycol ester of a dicarboxylic acid and/or a low polymer thereof. and a second stage reaction of polycondensing the reaction product, at any stage until the synthesis of the polyester is completed, (a) 0.5 to 3 mol% of the following general formula based on the acid component constituting the polyester (In the formula, R ¹ and R ² are monovalent organic groups,
R ¹ and R ² may be the same or different, M is an alkali metal or alkaline earth metal, and m is M
When M is an alkali metal, it is 1, and when M is an alkaline earth metal, it is 1/2. ) and (b) 0.5 to 1.2 for the metallized phosphorus compound.
Double the molar amount of an alkaline earth metal compound is added without reacting (a) and (b) in advance, and then the synthesis of polyester is completed. After melt-spinning the obtained polyester, it is This is a method for producing synthetic fibers having micropores, characterized in that 2% by weight or more of the synthetic fibers is eluted by treatment. The polyester as used in the present invention is a polyester having terephthalic acid as the main acid component and at least one type of glycol, preferably at least one alkylene glycol selected from ethylene glycol, trimethylene glycol, and tetramethylene glycol as the main glycol component. The main target is It may also be a polyester in which a part of the terephthalic acid component is replaced with another difunctional carboxylic acid component, and/or a part of the glycol component is replaced with the above-mentioned glycol other than the main component or other diol component. It may also be made of polyester. Examples of difunctional carboxylic acids other than terephthalic acid used here include isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid,
Diphenoxyethanedicarboxylic acid, β-hydroxyethoxybenzoic acid, p-oxybenzoic acid, 5-
Examples include aromatic, aliphatic, and alicyclic difunctional carboxylic acids such as sodium sulfoisophthalic acid, adipic acid, sebacic acid, and 1,4-cyclohexanedicarboxylic acid. In addition, examples of diol compounds other than the above-mentioned glycols include cyclohexane-1,4-dimethanol, neopentyl glycol, bisphenol A, and bisphenol S.
Examples include aliphatic, alicyclic, and aromatic diol compounds such as, and polyoxyalkylene glycols. Such polyesters may be synthesized by any method. For example, in the case of polyethylene terephthalate, usually terephthalic acid and ethylene glycol are directly esterified, a lower alkyl ester of terephthalic acid such as dimethyl terephthalate is transesterified with ethylene glycol, or terephthalic acid and ethylene glycol are transesterified. The first stage reaction is to react with terephthalic acid to produce a glycol ester and/or its low polymer, and the first stage reaction product is heated under reduced pressure until the desired degree of polymerization is achieved. It is produced by a second step of polycondensation reaction. The metal-containing phosphorus compound used in the present invention has the following general formula: It is a phosphorus compound represented by the formula, where R ¹ and
R ₂ is a monovalent organic group. This monovalent organic group is specifically an alkyl group, an aryl group, an aralkyl group, or [-(CH ₂ ) _l O] _k R ³ (wherein R ³ is a hydrogen atom,
An alkyl group, an aryl group, an aralkyl group, l is an integer of 2 or more, k is an integer of 1 or more), etc. are preferred, and R ¹ and R ² may be the same or different.
M is an alkali metal or an alkaline earth metal,
Li, Na, K, Mg, Ca, Sr, and Ba are preferred, and Ca, Sr, and Ba are particularly preferred. m is 1 when M is an alkali metal, and when M is an alkaline earth metal
It is 1/2. R ¹ and/or in place of the above metal-containing phosphorus compound
If you use a phosphorus compound in which R ² is replaced with a metal (especially an alkali metal or alkaline earth metal),
The micropores formed in the resulting polyester fibers become larger, making it impossible to achieve the desired sharpening effect.
Furthermore, the fibril resistance also becomes poor. The above-mentioned metal-containing phosphorus compounds can be easily produced by subjecting the corresponding orthophosphoric acid ester (mono-, di-, or tri-) to a heat reaction with a predetermined amount of the corresponding metal compound in the presence of a solvent. It will be done. In this case, it is most preferable to use glycol, which is used as a raw material for the target polyester, as the solvent. The alkaline earth metal compound to be used in combination with the metal-containing phosphorus compound is not particularly limited as long as it reacts with the metal-containing phosphorus compound to form a salt insoluble in polyester, and alkaline earth metal acetates, alkaline earth metal acetates, Organic carboxylates such as oxalates, benzoates, phthalates, stearates, inorganic salts such as borates, sulfates, silicates, carbonates, bicarbonates, chlorides etc. Examples include halides, chelate compounds such as ethylenediaminetetraacetic acid complex, hydroxides, oxides, alcoholates such as methylates, ethylates, and glycolates, and phenolates. organic carboxylates, halides, especially soluble in ethylene glycol;
Chelate compounds and alcoholates are preferred, and organic carboxylates are particularly preferred. The above alkaline earth metal compounds may be used alone or in combination of two or more. When adding the above-mentioned metal-containing phosphorus compounds and alkaline earth metal compounds, the amount of metal-containing phosphorus compounds to be used and It is necessary to specify the ratio of the amount of the alkaline earth metal compound used to the amount of the phosphorus compound used. That is, if the amount of the metal-containing phosphorus compound used in the present invention is too small, the color depth of the final polyester fiber obtained will be insufficient, and as the amount is increased, the color depth will increase. If the amount is too large, the depth of the color will no longer be significantly improved, the abrasion resistance will deteriorate, and furthermore, it will be difficult to obtain a polyester with a sufficient degree of polymerization and softening point, and furthermore, yarn breakage will occur during spinning. This causes problems that occur frequently. Therefore, the amount of metal-containing phosphorus compound added should be in the range of 0.5 to 3 mol% based on the acid component constituting the polyester, and especially
A range of 0.6 to 2 mol% is preferred. In addition, if the amount of the alkaline earth metal compound added is less than 0.5 times the amount of the metal-containing phosphorus compound added, the color depth of the resulting polyester fiber will be insufficient and the polycondensation rate will decrease. It becomes difficult to obtain a polyester with a high degree of polymerization, and the softening point of the polyester produced is significantly lowered. On the other hand, if an alkaline earth metal compound is used in an amount exceeding 1.2 times the mole of the metal-containing phosphorus compound, large particles will be produced, and the depth of the color will not be improved, but rather
On the contrary, visual density begins to decrease. Therefore, the amount of the alkaline earth metal compound added to the metal-containing phosphorus compound should be in the range of 0.5 to 1.2 times the mole, and particularly preferably in the range of 0.5 to 1.0 times the mole. It is necessary to add the metal-containing phosphorus compound and the alkaline earth metal compound to the polyester reaction system without reacting them in advance. By doing so, the insoluble particles can be produced in the polyester in the form of uniform ultrafine particles.
If the above-mentioned metal-containing phosphorus compound and alkaline earth metal compound are reacted externally in advance to form insoluble particles and then added to the polyester reaction system, the dispersibility of the insoluble particles in the polyester becomes poor and coarse agglomerated particles are formed. This is not preferable because the effect of improving the depth of color of the finally obtained polyester fiber is no longer recognized. The metal-containing phosphorus compound and the alkaline earth metal compound can be added in any order at any stage until the synthesis of the polyester is completed. However, if only the metal-containing phosphorus compound is added before the first stage reaction is completed, the completion of the first stage reaction may be inhibited, and if only the alkaline earth metal compound is added to the first stage reaction. If added before the end of the reaction, if this reaction is an esterification reaction, coarse particles may be generated during the reaction, or if it is an interesterification reaction, the reaction may proceed abnormally quickly and cause bumping. In this case, it is preferable to reduce the amount to about 20% by weight or less. It is preferable that at least 80% by weight of the alkaline earth metal compound and the total amount of the metal-containing phosphorus compound be added after the first stage reaction of polyester synthesis is substantially completed. In addition, if the metal-containing phosphorus compound and the alkaline earth metal compound are added at a stage when the second stage reaction has progressed too much, the particles tend to aggregate and become coarser, and the color depth of the final polyester fiber becomes worse. Since this tends to be insufficient, it is preferable that the intrinsic viscosity of the reaction mixture in the second stage reaction is before reaching 0.3. The above-mentioned metal-containing phosphorus compound and alkaline earth metal compound may be added all at once, added in two or more divided portions, or added continuously. In the present invention, any catalyst can be used for the first stage reaction, but among the above alkaline earth metal compounds, there are some that have the ability to catalyze the first stage reaction, particularly the transesterification reaction. When such a compound is used, it is not necessary to use a separate catalyst, and the alkaline earth metal compound can be added before or during the first stage reaction to also serve as a catalyst. Since the bumping phenomenon may occur as described above, the amount used is preferably limited to less than 20% by weight of the total amount of the alkaline earth metal compound added. As explained above, a specific amount of the metal-containing phosphorus compound and an alkaline earth metal compound in a specific amount ratio to the phosphorus compound are added to a polyester reaction system without reacting in advance, and then polyester is synthesized. High degree of polymerization, by completing
It is possible to obtain a polyester that has a high softening point and good passability through the spinning process, and can finally provide fibers with excellent color depth and friction durability. There is no need to employ any special method to melt-spun the polyester obtained in this manner to form fibers, and any ordinary melt-spinning method for polyester fibers may be employed. The fibers spun here may be solid fibers having no hollow portions or hollow fibers having hollow portions. Further, the outer shape and the shape of the hollow portion in the cross section of the fiber to be spun may be circular or irregular. Further, when spinning, a modified polyester to which the metal-containing phosphorus compound and alkaline earth metal compound are added and an unmodified polyester to which no addition is made are used to form a core having the modified polyester as a sheath component and the unmodified polyester as a core component. It may be made into a sheath-type conjugate fiber or a side-by-side type conjugate fiber with two or more layers using modified polyester and unmodified polyester. To remove a part of the polyester fiber thus obtained, after subjecting it to stretching heat treatment or false twisting as necessary, or after making it into a fabric,
This can be easily carried out by treatment with an aqueous solution of an alkaline compound. Examples of the alkali compound used here include sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, sodium carbonate, potassium carbonate, and the like. Among these, sodium hydroxide and potassium hydroxide are particularly preferred. The concentration of such an aqueous solution of an alkali compound varies depending on the type of alkali compound, processing conditions, etc., but is usually preferably in the range of 0.01 to 40% by weight, particularly
A range of 0.1 to 30% by weight is preferred. The processing temperature is preferably in the range of room temperature to 100°C, and the processing time is 1 minute to 1 minute.
It is usually carried out for a period of 4 hours. Further, the amount of the alkali compound eluted and removed by treatment with the aqueous solution should be in the range of 2% by weight or more based on the weight of the fiber. By treating with an aqueous solution of an alkaline compound in this way, the fibers are aligned in the axial direction,
And the maximum value of the frequency distribution is when the width in the direction perpendicular to the fiber axis is
The length in the fiber axis direction is in the range of 0.1 to 0.3 μ.
A large number of micropores having a size ranging from 0.1 to 5 μm can be formed on the fiber surface and its vicinity, resulting in excellent color depth when dyed. Note that the polyester fiber obtained by the method of the present invention may contain optional additives such as catalysts, color inhibitors, heat resistant agents, flame retardants, fluorescent brighteners, matting agents, colorants, etc. as necessary. May be included. Further explanation will be given below with reference to Examples. Parts and % in Examples indicate parts by weight and % by weight, and the depth of color and frictional discoloration when the resulting polyester fibers were dyed were measured by the following methods. (i) Depth of color As a measure of depth of color, bathochromicity (K/
S) was used. This value was determined by measuring the spectral reflectance (R) of the sample cloth using a Shimadzu RC-330 self-recording spectrophotometer and using the KubelkaMunk equation shown below. The larger this value is, the greater the deep color effect is. K/S=(1-R) ² /2R In addition, K shows an absorption coefficient, and S shows a scattering coefficient. (ii) Resistance to friction discoloration Using a Gakushin type flat abrasion machine for friction fastness testing, the test cloth was abraded a specified number of times under a load of 500 g using a dioset made of 100% polyethylene terephthalate as the friction cloth. hand,
The degree of discoloration was determined using a gray scale for discoloration. The case where the wear resistance was extremely low was rated as 1st grade, and the case where it was extremely high was rated as 5th grade. For practical purposes, level 4 or above is required. Example 1 100 parts of dimethyl terephthalate, 60 parts of ethylene glycol, and 0.06 parts of calcium acetate monohydrate (0.066 mol% relative to dimethyl terephthalate) were charged into a transesterification tank, and heated from 140°C over 4 hours under a nitrogen gas atmosphere. The transesterification reaction was carried out while raising the temperature to 230°C and distilling the generated methanol out of the system. Subsequently, 0.5 part of trimethyl phosphate (relative to dimethyl terephthalate) is added to the resulting reaction product.
0.693 mol%) and 0.31 part of calcium acetate monohydrate (1/2 mole relative to trimethyl phosphate) at 8.5%
At room temperature, 9.31 parts of a clear solution of phosphoric acid diester calcium salt prepared by reacting in 100% ethylene glycol at a temperature of 120°C for 60 minutes under total reflux was added.
9.88 parts of a mixed transparent solution of diester calcium phosphate and calcium acetate obtained by dissolving 0.57 parts of calcium acetate monohydrate (0.9 times the mole relative to trimethyl phosphate) were added, and then 0.04 parts of antimony trioxide was added. was added and transferred to a polymerization can. Next, the pressure was reduced from 760 mmHg to 1 mmHg over 1 hour, and at the same time the temperature was raised from 230°C to 285°C over 1 hour and 30 minutes. Under reduced pressure of 1 mmHg or less, polymerization temperature 285
Polymerization was carried out for an additional 3 hours at °C for a total of 4 hours and 30 minutes to obtain a polymer having an intrinsic viscosity of 0.641 and a softening point of 259 °C. After the reaction was completed, the polymer was made into chips according to a conventional method. This chip was dried using a conventional method, and a spinneret with 36 circular spinning holes with a hole diameter of 0.3 mm was used.
The mixture was melt-spun at 290°C and then drawn at a draw ratio of 3.5 times according to a conventional method to obtain a raw yarn of 75 denier/36 filaments. This yarn has S twist of 2500T/m and Z twist of 2500T/m.
The highly twisted yarn was then subjected to a steam treatment at 80° C. for 30 minutes to untwist it. The twisted yarn has a warp density of 47 threads/cm and a weft density of 32.
A satin jersey fabric was woven by alternately arranging two S and Z twists at a thread/cm ratio. The obtained gray fabric was relaxed with a rotary washer for 20 minutes at boiling temperature, then grained, preset using a conventional method, and then treated with a 3.5% aqueous sodium hydroxide solution at boiling temperature to achieve a weight loss rate of 10. %, 20% and 30% fabrics were obtained. After these alkali treatments, the fabrics are treated with Dianix Black.
HG-FS (Mitsubishi Chemical Industries, Ltd. product) 130℃ at 15% owf
After dyeing for 60 minutes, the cloth was reduced and washed in an aqueous solution containing 1 g of sodium hydroxide and 1 g of hydrosulfite at 70° C. for 20 minutes to obtain a black dyed cloth. Table 1 shows the color depth and friction discoloration resistance of these black cloths after 200 wears. Example 2 760 mmH in the polymer synthesis reaction of Example 1
Example 1 was carried out in the same manner as in Example 1, except that the time (1 hour) required to reduce the pressure from g to 1 mmHg was shortened to 30 minutes. The intrinsic viscosity of the obtained polymer is
0.641, and the softening point was 260.1°C. Using this polymer, yarn spinning was carried out in the same manner as in Example 1.
Twisted, heat treated, dyed and washed. The results were as shown in Table 1. Example 3 The same procedure as in Example 2 was carried out except that the time required to reduce the pressure from 760 mmHg to 1 mmHg in Example 2 was changed to 1 hour and 30 minutes, and the results are shown in Table 1. Comparative example 1 High-speed stirring disperser (stirring blade outer diameter 28 mm, outer cylinder ring inner diameter
29mm, using a laboratory mixer emulsifier made by Silverson Machine Co., Ltd. in the UK.
100 parts of monomethyl phosphate and 3933 parts of a 4% ethylene glycol solution of calcium acetate monohydrate (containing an equimolar amount of calcium acetate to monomethyl phosphate) were stirred at high speed for 60 minutes at 120°C at a rotation speed of 5000 rpm. The reaction yielded a cloudy slurry of phosphoric acid monoester calcium salt. Example 1 except that this slurry and a corresponding amount of calcium acetate monohydrate were added instead of the mixed transparent solution of diester calcium phosphate and calcium acetate monohydrate added after the transesterification reaction in Example 1. I did the same thing. The results are shown in Table 1, and instead of improving the depth of color, a decrease in visual density was observed. Also, after 200 wears, it became noticeably whiter. 【table】

Claims (1)

[Claims] 1. A first step of reacting a dicarboxylic acid, mainly terephthalic acid, or an ester-forming derivative thereof with at least one glycol to produce a glycol ester of a dicarboxylic acid and/or a low polymer thereof. In producing synthetic fibers made of a polyester synthesized by the reaction of )
0.5 to the acid component constituting the polyester
3 mol% of the following general formula (In the formula, R ¹ and R ² are monovalent organic groups, and R ¹
and R ² may be the same or different, M is an alkali metal or an alkaline earth metal, and m is 1 when M is an alkali metal and 1/2 when M is an alkaline earth metal. ) and (b) 0.5 to 1.2 for the metallized phosphorus compound.
Double the molar amount of an alkaline earth metal compound is added to (a) and (b) without reacting them in advance, and then the synthesis of polyester is completed. A method for producing synthetic fibers, which comprises forming micropores by eluting 2% by weight or more.