JPH0140145B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polyester fibers with improved dyeability. More specifically, it has special micropores,
This invention relates to a method for producing polyester fibers that 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 woven fabric in the fiber part that will be in the shadow of the irradiated surface. There is a drawback that color spots appear on the skin. 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, magnesium phosphate, etc. to a polyester reaction system are prepared using an alkaline aqueous solution. A method for producing hygroscopic fibers has been proposed in which fine pores are formed by eluting inorganic fine particles through treatment. However, the fibers obtained by these methods do not have the effect of improving color depth, and instead show a decrease in visual density. In other words, in these methods, if the treatment with the alkaline aqueous solution is not sufficient, no effect of improving the depth of color is observed, perhaps because unevenness occurs only on the very surface of the fiber, and if the treatment with the alkaline aqueous solution is not sufficient, the effect of improving the depth of color is not observed. However, instead of improving the depth of the color, the visual density decreases, probably due to the diffuse reflection of light by the micropores, and even if the color is dark, it looks whitish, and the strength of the resulting fiber decreases. It is not suitable for practical use because it is easily fibrillated. In addition, fibers made of polyester containing inorganic fine particles such as silica with a particle diameter of 80 μm or less are subjected to alkali weight reduction treatment to give irregular irregularities of 0.2 to 0.7 μ on the fiber surface, and to create irregularities of 50 to 200 μm within these irregularities.
A method has been proposed for improving the depth of color by creating microscopic irregularities of mμ. However, even with this method, the effect of improving the depth of color is insufficient, and in addition, there is a drawback that fibrillation is likely to occur, probably due to the extremely complicated uneven structure. The inventor of the present invention has conducted extensive studies in an attempt to provide polyester fibers that do not have the above-mentioned drawbacks and have excellent color depth and clarity by adding micropores to polyester fibers, and as a result, surprisingly, a specific A polyester fiber obtained by melt-spinning a polyester produced by adding a specific amount of manganese acetate or magnesium acetate to the polyester reaction system without reacting the orthophosphoric acid with a specific amount of manganese acetate or magnesium acetate in advance is treated with an alkali. By doing so, it is possible to form a large number of special micropores, and by doing so, it is possible to obtain polyester fibers that have excellent color depth and clarity when colored and are sufficiently resistant to fibrillation due to friction. The present invention was completed as a result of further studies based on this knowledge. 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, (a) 0.3 to 5 mol% of orthophosphoric acid based on the dicarboxylic acid component and (b) the orthophosphoric acid. A polyester prepared by adding a compound of Mn and/or Mg in an amount of 1.2 to 2 times the mole of phosphoric acid without reacting (a) and (b) in advance is melt-spun into a fiber, and the fiber is This method of producing polyester fibers is characterized by treating with an alkaline aqueous solution to elute the salt produced by the reaction between (a) orthophosphoric acid and (b) a compound of Mn and/or Mg. The polyester thus obtained is melt-spun into fibers, and then the resulting fibers are treated with an aqueous solution of an alkaline compound to produce 2 to 50% by weight of the polyester.
By eluting, the fibers are arranged in the axial direction and the maximum value of the frequency distribution is
In the range of 0.1 to 0.3 μ and the length in the fiber axis direction is 0.1
It is possible to form a large number of micropores with a size in the range of ~5 μm, resulting in excellent color depth when dyed. The polyester 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. As the Mn or Mg compound used in the present invention,
Mn becomes insoluble in polyester by reacting with orthophosphoric acid
Or organic acid salts such as Mn, Mg acetate, oxalate, benzoate, phthalate, stearate, borates, etc., although there are no particular restrictions as long as they form Mg salts. , inorganic acid salts such as sulfates, silicates, carbonates, bicarbonates, halides such as chlorides, chelate compounds such as ethylenediaminetetraacetic acid complexes, hydroxides, oxides, methylates, ethylates, glycolates, etc. Examples include alcoholates, phenolates, etc., particularly organic acid salts that are soluble in ethylene glycol and react with orthophosphoric acid in the glycol to form a salt;
Halides, chelate compounds, and alcoholates are preferred, and organic acid salts are particularly preferred. The above Mn and Mg compounds may be used alone or in combination of two or more. The amounts of orthophosphoric acid and Mn and Mg compounds used in the present invention are closely related to each other in order to ultimately provide polyester fibers with excellent color depth and fibrillation resistance. Moreover, it is also necessary to specify the usage amount of each.
That is, if the amount of orthophosphoric acid 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 improve. If the amount is too large, the depth of the color will no longer be significantly improved, the fibril resistance will deteriorate, and furthermore, it will be difficult to obtain a polyester with a sufficient degree of polymerization, and troubles will likely occur during spinning. For this reason, the amount of orthophosphoric acid added is 0.3 to 5
The range should be in the range of mol %, with a range of 0.4 to 3 mol % being particularly preferred. In addition, if the amount of Mn and Mg compounds added is less than 1.2 times the amount of orthophosphoric acid added, the color depth of the resulting polyester fibers will be insufficient, and furthermore, the resulting polyester will be significantly colored. As a result, vivid colors cannot be obtained in the final fiber. On the other hand, if the amount is more than twice the molar amount of orthophosphoric acid, the thermal decomposition of the polyester will be significantly accelerated, the resulting polyester will be colored, and problems will likely occur during spinning. Therefore, the amount of Mn and Mg compounds to be added should be in the range of 1.2 to 2 times the amount of orthophosphoric acid, particularly preferably 1.4 to 1.6 times the amount. The Mn and Mg compounds and orthophosphoric acid need to be added to the polyester reaction system without reacting in advance. By doing so, the insoluble particles can be produced in the polyester in the form of ultrafine particles and uniformly dispersed. If the above Mn and Mg compounds are reacted with orthophosphoric acid in advance to form a Mn and Mg salt of orthophosphoric acid and then added to the polyester reaction system, the insoluble particles in the polyester will be As the dispersibility deteriorates and coarse agglomerated particles are included, the effect of improving the color depth of the final polyester fiber is no longer recognized.
Moreover, the fibril resistance is also inferior, which is not preferable. The above-mentioned Mn and Mg compounds and orthophosphoric acid may be added at any time until the production of polyester is completed, but the Mn and Mg compounds are added significantly later than the orthophosphoric acid. As a result, the coloring of the resulting polyester increases,
Also, since the softening point tends to decrease, Mn, Mg
The time of addition of the compound may be delayed from the time of addition of orthophosphoric acid as long as it does not have such an adverse effect on the reaction system, but it is preferable to add the compound at substantially the same time as or before the time of addition of orthophosphoric acid. preferable. Also, regarding the timing of adding orthophosphoric acid, if the first stage reaction is not yet completed, the completion of the first stage reaction may be inhibited, and if the second stage reaction is completed, the reaction may be too slow. At advanced stages, troubles such as coloring of the resulting polyester may occur, so orthophosphoric acid should be added after the first stage reaction is substantially completed and after the second stage reaction is completed. It is preferable that the intrinsic viscosity of the reaction mixture at is before reaching 0.4. Specifically, the preferred timing for adding Mn and Mg compounds is the first
Examples of preferable times for adding orthophosphoric acid include: before the start of the step reaction, during the first step reaction, after the end of the first step reaction and before the start of the second step reaction, etc. can include the period from after the end of the first stage reaction to before the start of the second stage reaction. The above-mentioned Mn, Mg compounds and orthophosphoric acid may be added in their entirety at one time at the above-mentioned addition time, or may be added in two or more divided doses at the above-mentioned addition time. . In the present invention, any catalyst can be used for the first stage reaction, but some of the Mn and Mg compounds mentioned above have the ability to catalyze the first stage reaction, and when such compounds are used, It is not necessary to use a separate catalyst, and the Mn and Mg compounds can be added in whole or in part before the start of the first-stage reaction to serve also as a catalyst. As explained above, the above orthophosphoric acid and Mn,
By using the above specified amount without reacting the Mg compound in advance, it is possible to obtain a polyester that provides fibers with excellent color depth and fibril resistance. There is no need to employ any special method to melt-spun the polyester obtained in this manner to form fibers, and any method for melt-spinning polyester fibers may be employed. The fibers spun here may be solid fibers without hollow portions or hollow fibers with hollow portions, but in the case of hollow fibers, even if fine pores are formed, the depth of color It is preferable to use solid fibers, as they tend to be somewhat inferior to those of solid fibers. 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. Furthermore, when spinning, a modified polyester to which the above-mentioned orthophosphoric acid and compounds of Mn and Mg are added and an unmodified polyester to which no additives are added are used to create a core having the modified polyester as a sheath component and the unmodified polyester as a core component. Even for sheath-type composite fibers, two or more layers of side layers are made using modified polyester and unmodified polyester.
A bi-side type composite fiber may also be used. Part of the polyester fiber thus obtained can be easily removed by subjecting it to stretching heat treatment or false twisting as necessary, or by immersing it in an aqueous solution of an alkali compound after making it into a fabric. can be done. The alkaline compounds used here include sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, sodium carbonate,
Examples include potassium carbonate. Among them, 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 treatment temperature is preferably in the range of room temperature to 100℃, and the treatment 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 to 50% by weight based on the weight of the fiber. By treating with an aqueous solution of an alkaline compound in this way, the fibers are arranged in the axial direction and the maximum value of the frequency distribution is widened in the direction perpendicular to the fiber axis.
In the range of 0.1 to 0.3 μ and the length in the fiber axis direction is 0.1
It is possible to form a large number of micropores with a size in the range of ~5 μm, resulting in excellent color depth when dyed. Note that the polyester obtained by the method of the present invention may contain optional additives, such as catalysts, color inhibitors, heat resistant agents, flame retardants, fluorescent brighteners,
A matting agent, a coloring agent, inorganic fine particles, etc. may be included. Further explanation will be given below with reference to Examples. In the examples, parts indicate parts by weight, and the depth of color when dyeing the resulting polyester fibers, rate of decrease in strength after alkali treatment, fibrillation resistance, and size of micropores were measured by the following methods. (i) Color depth A standard fabric knitted with 73 denier/36 filament multifilaments made of polyethylene terephthalate and a test fabric with the same fabric composition as this standard fabric were dyed under the same conditions, and both were dyed next to each other. They were lined up and observed near the north window under daylight on a cloudy day, and the average of the five judges was taken based on the following criteria, and those of grade 4 or higher were considered to have passed. Grade 1: Less depth than standard cloth. Grade 2: No difference from the standard cloth. Grade 3: A difference from the standard cloth is recognized, but the difference is small. Grade 4: There is a sense of depth compared to standard cloth. Grade 5: Noticeable depth compared to standard cloth. (ii) Strength reduction rate due to alkali treatment The strength of the fibers obtained by unwinding the fabric before alkali treatment was compared with the strength of the fibers obtained by unwinding the fabric after alkali treatment. (iii) Fibril resistance 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 500g using a dioset made of 100% polyethylene terephthalate as the friction cloth. ,
The presence or absence of fibrillation was investigated. (iv) Size of micropores The surface of the fibers obtained by unwinding the fabric after alkali treatment was visually determined using an electron micrograph at 3000 times magnification. Example 1 100 parts of dimethyl terephthalate, 60 parts of ethylene glycol, and 0.06 parts of calcium acetate monohydrate were placed in a transesterification tank, and the temperature was raised from 140°C to 230°C over 4 hours in a nitrogen gas atmosphere to produce methanol. The transesterification reaction was carried out while distilling it out of the system. The resulting product was then treated with trimethyl phosphate.
Then, after 5 minutes, 0.06 part of antimony trioxide and 2.62 parts of manganese acetate tetrahydrate (2.08 mol% based on dimethyl terephthalate) were added, and after a further 5 minutes, 0.7 part of orthophosphoric acid (dimethyl terephthalate) was added. 1.39 mol%) and 0.07 part of titanium dioxide were added and transferred to a polymerization can. Then over an hour
Depressurize from 760mmHg to 1mmHg for 1 hour at the same time.
The temperature was raised from 230°C to 285°C over 30 minutes. 1mmHg
Under the following reduced pressure, polymerization was carried out at a polymerization temperature of 285°C for an additional 3 hours, for a total of 4 hours and 30 minutes, resulting in an intrinsic viscosity of 0.641 and a softening point of 260.
A polymer with temperature Col-L75 and Col-(b) 5.0 was obtained. After the reaction was completed, the polymer was made into chips according to a conventional method. This chip was dried in a conventional manner, and melt-spun in a conventional manner using a spinneret having 36 circular spinning holes with a hole diameter of 0.3 mm to obtain an undrawn yarn of 306 denier/36 filaments. Next, this undrawn yarn was drawn 4.2 times according to a conventional method to obtain a multifilament of 73 denier/36 filaments. The obtained filament is knitted into stockinette fabric,
After scouring and presetting in a conventional manner, it was treated with a 3.5% aqueous sodium hydroxide solution at boiling temperature so that the weight loss rate was 20%. Table 1 shows the strength reduction rate and the size of micropores due to this alkali treatment. After this treatment, the fabric was high-pressure dyed black using a conventional method, and the depth of color of the dyed fabric is shown in Table 1. Furthermore, microscopic observation after 200 wears revealed no fibrillation. Example 2 Calcium acetate monohydrate and trimethyl phosphate used as the transesterification catalyst and stabilizer in Example 1 were not used, and instead, manganese acetate tetrahydrate was used after completion of the transesterification reaction in Example 1. Of the 2.62 parts, 0.03 parts (0.024 mol% based on dimethyl terephthalate) are added before the start of the transesterification reaction and used as a transesterification reaction catalyst, and the remaining 2.59 parts (2.05 mol% based on dimethyl terephthalate) The same procedure as in Example was carried out, except that the mixture was added after the transesterification reaction was completed. The results were as shown in Table 1. Example 3 The same procedure as in Example 1 was carried out except that the timing of addition of manganese acetate tetrahydrate used in Example 1 was changed from after the end of the transesterification reaction to before the start of the transesterification reaction. The results were as shown in Table 1. Example 4 1.10 parts of magnesium acetate tetrahydrate (1.0 mol % based on dimethyl terephthalate) was added in place of the manganese acetate tetrahydrate used in Example 1,
The same procedure as in Example 1 was conducted except that the amount of orthophosphoric acid added was 0.34 parts (0.67 mol % based on dimethyl terephthalate). The results were as shown in Table 1. Example 5 In place of the manganese acetate tetrahydrate used in Example 1, 0.90 parts of magnesium acetate tetrahydrate (0.81 mol% based on dimethyl terephthalate) was added,
The same procedure as in Example 1 was conducted except that the amount of orthophosphoric acid added was 0.34 parts (0.67 mol % based on dimethyl terephthalate). The results were as shown in Table 1. Comparative Example 1 1.10 parts of magnesium acetate tetrahydrate (1.0 mol % based on dimethyl terephthalate) was used in place of the manganese acetate tetrahydrate used in Example 1,
In addition, the addition timing was changed from after the end of the transesterification reaction in Example 1 to before the start of the transesterification reaction, and the amount of orthophosphoric acid used was changed to 0.57 parts (1.13 mol% based on dimethyl terephthalate). The same procedure as in Example 1 was carried out. The results are shown in Table 1, and the depth of color was not improved. Comparative example 2 High-speed stirring disperser (stirring blade outer diameter 28 mm, outer cylinder ring inner diameter
Using a 29mm laboratory mixer emulsifier manufactured by Silverson Machine Co., Ltd. in the UK,
56% aqueous solution of orthophosphoric acid under rotation speed of 5000 rpm 100
20% ethylene glycol solution of manganese acetate tetrahydrate in a mixture of 150 parts and 150 parts of ethylene glycol
1050 parts were gradually added and the mixture was subjected to high-speed stirring and dispersion treatment for 60 minutes. The final internal temperature reached at this time was 70°C, and a slurry was obtained in which most of the manganese salt of orthophosphoric acid was uniformly dispersed as fine particles of 0.3μ or less. This slurry was left in a container for 72 hours to separate coarse agglomerated particles. This slurry is added in an amount corresponding to the amount of orthophosphoric acid and manganese acetate tetrahydrate used in Example 1, instead of the orthophosphoric acid and manganese acetate tetrahydrate in Example 1, 5 minutes after the addition of trimethyl phosphate. The procedure was the same as in Example 1 except for this. The results are shown in Table 1, and instead of improving the depth of color, a decrease in visual density was observed.
Fibrillation was observed after 200 wears.

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Claims (1)

[Claims] 1. A first step reaction in which a dicarboxylic acid, mainly terephthalic acid, or its ester-forming derivative is reacted with at least one glycol to produce a glycol ester of a dicarboxylic acid and/or a low polymer thereof, and the reaction product. In producing polyester by the second step of polycondensation with (a) the dicarboxylic acid component,
5 mol% of orthophosphoric acid and (b) relative to the orthophosphoric acid.
1.2 to 2 times the mole of Mn and/or Mg compound (a)
A polyester obtained by adding (b) without reacting with the polyester is melt-spun into fibers, and the fibers are treated with an alkaline aqueous solution to combine the orthophosphoric acid of (a) and the Mn of (b).
and/or a method for producing polyester fibers, which comprises eluting a salt produced by a reaction with a compound of Mg.