JP6149726B2 - Method for producing environmentally-friendly and easily-eluting polyester composition - Google Patents

Description

The present invention relates to a method for producing an alkali-soluble polyester composition. More specifically, it is environmentally friendly without the use of heavy metal compounds, has excellent alkali elution that enables complete elution of easily eluting components in the composite fiber without the use of solvents or acids, and increases the filtration pressure during spinning. The present invention relates to a method for producing an environmentally-friendly and easily-eluting polyester composition that can reduce discharge hole contamination and simultaneously achieve good yarn production.

Polyester is used for various purposes due to its usefulness due to its excellent mechanical, physical, and chemical performance. For example, it is widely used for clothing, materials, film, bottle, and medical use. . Among them, polyethylene terephthalate is excellent in terms of versatility and practicality and is preferably used.

  Polyethylene terephthalate is produced from terephthalic acid or its ester-forming derivative and ethylene glycol. In general processes, antimony compounds are widely used as polycondensation catalysts.

  However, antimony catalysts are classified as heavy metals, and there is concern about the impact on the environmental load. Also, when melt spinning continuously for a long time, the antimony catalyst residue in the polymer tends to become relatively large particles, which becomes a foreign substance, clogs the filter and increases the filtration pressure, and the antimony metal becomes a foreign substance and the mouthpiece hole. The residue accumulates in the surrounding area, contributing to a decrease in operability. It is believed that the accumulation of antimony catalyst residue occurs because the antimony compound in the polymer is transformed near the die, partially vaporizes and dissipates, and then an antimony-based component remains in the die. . As this deposition progresses, it becomes a factor of yarn breakage during spinning or film breakage during film formation.

  In view of the above background, there has been a demand for polyesters having very little or no antimony. In recent years, titanium compounds have been actively studied as polycondensation catalysts other than antimony compounds (Patent Documents 2 and 4). For example, it is clearly shown about a polyester fiber excellent in cationic dyeability by copolymerizing a sulfoisophthalic acid component in the presence of a titanium catalyst. Certainly, although effects are recognized in terms of color tone, cationic dyeability, and suppression of pack pressure increase, no consideration is given to heat resistance and solubility. In addition, when a titanium compound is used alone as a catalyst, the titanium catalyst has a high polycondensation catalytic activity, so that side reactions such as a thermal decomposition reaction and an oxidative decomposition reaction are large, resulting in a problem that the heat resistance is poor.

With respect to such problems, studies have been made to improve the heat resistance of polymers by using a titanium compound in combination with a phosphorus compound having a specific structure (Patent Documents 1 and 3).
A certain improvement in the heat resistance of the polymer was obtained by these methods. And the method of copolymerizing a metal sulfonate group containing isophthalic acid, mixing a titanium compound, a phosphorus compound, and a lithium compound beforehand, and adding is reported (patent document 1). However, by premixing the titanium compound, phosphorus compound and lithium compound, the three types of compounds react with each other and become foreign substances, and crystal nuclei are likely to be formed. It must be treated.

On the other hand, it has also been attempted to apply a metal sulfonate group-containing isophthalic acid without copolymerization such as polyalkylene glycol to an easily eluted component (Patent Document 3). However, in this method, the content of the metal sulfonate group-containing isophthalic acid is too small, and thus undissolved residue due to insufficient elution performance occurs. And pre-treatment with a solvent or an acidic solution is required at the time of elution.

  As described above, the conventional technology does not use heavy metal compounds typified by antimony, has excellent heat resistance, has good yarn-making properties, has no undissolved residue at the time of elution, and is easily dissolved in an alkali-friendly environment. A process for producing polyester has been awaited.

JP 2010-70739 A CN1010020053A JP 61-143426 A JP 2011-213880 A

The present invention is environmentally friendly without using a heavy metal compound that could not be achieved by the prior art, and has excellent alkali elution that enables complete elution of easily eluted components in a composite fiber without using a solvent or acid, and spinning. It is an object of the present invention to provide a method for producing an environmentally-friendly and easily-eluting polyester composition that can suppress an increase in filtration pressure at the time, reduce stains on a nozzle discharge hole, and achieve good yarn-making properties.

In order to achieve the above object, the present invention employs the following configuration.
In the production of an environmentally-friendly easily-eluting polyester composition capable of completely eluting easily-eluting components in composite fibers, polyester is obtained by polycondensation of terephthalic acid or its ester-forming derivative and ethylene glycol in the presence of a polymerization catalyst. In the method for producing the composition, 7 to 10 mol% of an isophthalic acid component having a metal sulfonate group is added to the total acid component constituting the polyester composition, and the composition is soluble in the polyester represented by the following formula as a polymerization catalyst. The titanium compound is added to the polyester composition in an amount of 0.3 to 3 ppm in terms of titanium element, the alkali metal compound is added in an amount of 315 to 410 ppm in terms of metal element, the phosphorus compound is added in an amount of 20 to 36 ppm in terms of P element, and the titanium compound Ester reaction started as the order of addition of alkali metal compound and phosphorus compound Method of manufacturing a titanium compound and an alkali metal compound mixture was added, followed by environmentally friendly easy dissolution polyester composition characterized by the addition of the phosphorus compound after the esterification reaction completed.

(R1 represents a hydrocarbon group having 1 to 10 carbon atoms that does not contain an oxygen element.)

According to the present invention, it is environmentally friendly without using heavy metal compounds that could not be achieved by the prior art, and has excellent alkali elution that enables complete elution without using a solvent or acid, and the filtration pressure during spinning. Since the rise and contamination of the nozzle discharge hole can be reduced and good yarn-making properties can be achieved at the same time, it can be suitably used in a method for producing a composite fiber that can easily obtain ultrafine fibers and hollow fibers by removing alkali.

The production method of the environmentally friendly and easy-eluting polyester composition of the present invention will be described in detail in the following order.
First, it is necessary to add terephthalic acid or an ester-forming derivative thereof and ethylene glycol as main raw materials and an isophthalic acid component having 7 to 10 mol% of a metal sulfonate group based on the total acid component.

  The environmentally friendly and easily-eluting polyester obtained by the production method of the present invention is polyethylene terephthalate obtained after esterification or transesterification of dicarboxylic acid or its ester-forming derivative and diol or its ester-forming derivative. is there. In the polyethylene terephthalate, it is necessary to add 7 to 10 mol% of an isophthalic acid component (hereinafter referred to as SSIA) containing a metal sulfonate group as a copolymerization component with respect to the total acid component. The term “isophthalic acid component only” as used herein is generally an example in which another copolymer, such as polyalkylene glycol (hereinafter referred to as PAG), is commonly used as the copolymer component. While imparting characteristics to the polymer, it has the disadvantage that it alone undergoes a polymerization reaction to form a self-polymerized product having a large molecular weight, which tends to be a foreign substance. Therefore, the present application aims at a fully-eluting polyester having a slight dissolution residue, and it is essential to not use any copolymerization component that generates a self-polymerized product.

  And it is preferable to add 7-10 mol% of SSIA only. It is preferable that SSIA is 7 mol% or more because sufficient elution can be obtained. Moreover, it is preferable that SSIA is 10 mol% or less without SSIA reacting with each other to form a self-polymerized product as a foreign substance, and for this reason, there remains no undissolved residue based on the self-polymerized product. More preferably, it is the range of 8-9 mol%.

  Next, as a catalyst, it is necessary to add 0.3 to 3 ppm of a titanium compound soluble in the polyester represented by the following formula in terms of titanium element.

(R1 represents a hydrocarbon group having 1 to 10 carbon atoms that does not contain an oxygen element.)
It is preferable to add 0.3 to 3 ppm of a titanium compound that is soluble in the polyester to the environment-friendly easily-eluting polyester obtained by the production method of the present invention. More preferably, it is 0.8-2 ppm. When it is more than 0.3 ppm, the polymerization reaction activity is not insufficient and the reaction is not delayed, which is preferable. When the content is 3 ppm or less, polymerization reaction activity is sufficiently obtained and high activity is obtained. However, decomposition reaction is not promoted, heat resistance is not deteriorated, and yarn maneuverability is improved.

The titanium compound soluble in the polyester used in the production method of the present invention is preferably a titanium complex having a polyvalent diol as a chelating agent from the viewpoint of the thermal stability of the polymer.
Examples of chelating agents for titanium compounds include polyhydric alcohols such as ethylene glycol, propylene glycol, and 1,4-butanediol.
The titanium compound used in the production method of the present invention is excluded because titanium oxide generally used as a matting agent for fibers is not soluble in polyester.

Next, it is necessary to add 20 to 36 ppm of a phosphorus compound in terms of P element as a catalyst.
The environment-friendly easily-eluting polyester obtained by the production method of the present invention adds a phosphorus compound in an amount of 20 to 36 ppm in terms of phosphorus element. When it is 20 ppm or more in terms of phosphorus element, since the isophthalic acid component containing a metal sulfonate group is copolymerized, the decomposition reaction of the polyester is not accelerated, and the resulting polyester has good heat resistance, The spinning operability in the spinning process is also favorable and preferable. Moreover, it is preferable that it is 36 ppm or less in terms of phosphorus element because the polymerization reaction catalyst is not deactivated, the polymerization reactivity is not lowered, and the polymerization reaction is good. More preferably, it is 25-33 ppm.

  As a phosphorus compound, the phosphorus compound represented by (Formula 2)-(Formula 4) can be added. When the phosphate compound represented by (Formula 2) and the phosphonite compound represented by (Formula 3) or (Formula 4) are used, the isophthalic acid component containing a metal sulfonate group is copolymerized. Alkali easily-eluting polyesters are preferred because they are excellent in color tone and heat resistance and can greatly improve the yarn-manufacturability. In addition, as a phosphorus compound represented by (Formula 2), it is available as TMP (made by Daihachi Chemical).

(In the above (Formula 2), R1 to R3 each independently represents a hydroxyl group or a hydrocarbon group having 1 to 20 carbon atoms.)

(In the above (Formula 3), R1 and R2 each independently represent a hydroxyl group or a hydrocarbon group having 1 to 20 carbon atoms.)

(In the above (Formula 4), R 1 and R 2 each independently represents a hydrocarbon group having 1 to 20 carbon atoms.)
As a manufacturing method of this polyester composition, it is necessary to add and mix the titanium compound and the alkali metal compound before the start of the ester reaction, and to add the phosphorus compound after the end of the ester reaction. As a catalyst addition order, it is preferable to add a mixture of a titanium compound and an alkali metal compound after adding a phosphorus compound, because the phosphorus compound becomes a foreign substance and crystal nuclei are liable to be produced, making it impossible to obtain a completely soluble polymer. Absent. If three types of titanium compound, phosphorus compound, and alkali metal compound are mixed and added in advance, the three types of compounds react with each other to become foreign substances, and crystal nuclei are likely to be produced, making it impossible to obtain a polymer that can be completely eluted. It is not preferable. Moreover, when a titanium compound and a phosphorus compound are mixed and added in advance, the catalytic activity of the titanium compound decreases due to the reaction between the titanium compound and the phosphorus compound, resulting in poor polymerization reactivity.

Next, it is preferable to add an alkali metal and a phosphorus element as a catalyst so as to satisfy the following formula 1 in terms of molar amount.
M / P = 39 to 92 Equation 1
(M: alkali metal element molar amount, P: phosphorus element molar amount)
Here, the alkali metal compound plays a role as a transesterification catalyst and a diethylene glycol by-product inhibitor, and the phosphorus compound is used as an activity inhibitor and an antioxidant for the reaction catalyst. When the value of M / P = is 39 or more, it is preferable that phosphorus does not destroy the charge of SSIA and does not induce formation of a self-polymerized product. On the other hand, when the value of M / P = is 92 or less, it is preferable that the effect of suppressing the activity of alkali metal by phosphorus is sufficient and crystal nuclei that become foreign matters derived from alkali metal are not formed. A more preferred M / P value is 45-80.

  Further details will be described. The environmentally-friendly and easily-eluting polyester of the present invention aims to achieve complete dissolution without leaving undissolved when the polymer is eluted with alkali. For this purpose, thorough removal of microcrystals and foreign substances formed in the polymer is required. Is preferably excluded.

  However, the metal compound added as a catalyst, on the other hand, makes it easy to form crystals as reaction products. Therefore, in order to suppress this excessive reaction and to suppress the formation of crystals as much as possible, many experimental results have been obtained. The importance / validity of the above formula has been found, and it is extremely important to keep the above formula. By keeping the above range, the desired completely eluted polymer can be obtained.

  As the metal compound used in the production method of the present invention, a lithium compound is preferably used, and examples of the lithium compound include lithium acetate, lithium carbonate, and lithium formate. Among these, lithium acetate is preferably used from the viewpoints of polymer yarn-making property and color tone. As an addition amount of a lithium compound, it is necessary to add so that it may become 315-410 ppm in conversion of a lithium atom with respect to the polymer obtained. More preferably, it is 330-380 ppm. It is preferable that it is 315 ppm or more in terms of lithium atom, since the by-product suppressing effect of diethylene glycol (hereinafter referred to as DEG) during the polymerization reaction is exhibited, and DEG does not increase. Since DEG does not increase, gelation due to oxidative degradation of the polymer is difficult to occur. Therefore, it is preferable that the gelled product generated thereby does not cause undissolved residue in the polymer. On the other hand, if it is 410 ppm or less, the alkali metal does not become excessive, and it is preferable because it does not form crystal nuclei as foreign matters without binding to dimethyl terephthalate (hereinafter referred to as DMT) or SSIA. It is preferable that the polymer is not left undissolved due to the generated foreign matter.

From the viewpoint of the environment, it is preferable that the metal element used in the method for producing the environment-friendly easily-eluting polyester of the present invention has zero true heavy metal having a true specific gravity of 5 or more. The heavy metal element content of the present application is preferably 0 to 10 ppm in content of a metal element having a true specific gravity of 5.0 or more.
Here, the true specific gravity refers to the specific gravity that does not include voids, and the specific gravity refers to the ratio of the mass of a substance at the same volume to water at 4 ° C., which is a standard substance.

Specific examples of the metal having a true specific gravity of 5.0 or more include antimony, germanium, manganese, cobalt, tin, zinc, and the like, and these are usually polyester as a catalyst, a metallic color adjuster, an additive, and the like. It is contained in. Other examples include iron, nickel, niobium, molybdenum, tantalum, and tungsten. On the other hand, titanium, calcium, potassium, aluminum, magnesium, sodium, lithium, and the like do not correspond to metals having a true specific gravity of 5.0 or more.
The environmentally-friendly easily-eluting polyester of the present invention does not use a metal element having a true specific gravity of 5.0 or more, and is substantially equal to zero. For example, when the antimony metal content is 10 ppm or less, it does not become a foreign matter and does not accumulate around the die during yarn production or film formation, and does not cause an increase in filtration pressure or yarn breakage. It is preferable without adversely affecting the sex. The content of the metal element having a true specific gravity of 5.0 or more is preferably 5 wtppm or less, and more preferably 0 ppm.

  It is preferable that the environment-friendly easily-eluting polyester fiber obtained by the production method of the present invention has an elution rate of 5 wt% / min or more with only an alkaline solution. The term “alkaline solution only” as used herein refers to an easily-eluting polyester that is environmentally friendly because it can be completely eluted without any pretreatment when the polymer is eluted, and does not require solvent or acid treatment. For example, when sea components of commonly-used sea-island composite fibers are eluted and removed to obtain ultrafine fibers, pretreatment with a solvent or acidic solution makes the easily eluted components brittle and creates cracks on the fiber surface. In order to facilitate elution, a gap for the alkaline solution to enter is made. The environment-friendly and easily-eluting polyester of the present application is preferable because it has an elution rate of 5 wt% / min or more with only an alkaline solution, and does not require any pretreatment. More preferably, it is 10 wt% / min or more. Although there is no particular upper limit, it is within 50 wt% / min in consideration of the overall balance of polymer characteristics, handling properties, and the like.

  The elution rate (alkaline weight loss rate) referred to here is that the sea-island composite fiber is made into a tubular knitting, and this knitted fabric is subjected to an alkali weight loss treatment at a NaOH concentration of 4 wt% aqueous solution, a bath ratio of 1: 100, and a temperature of 98 ° C. The weight of the cylindrical knitted fabric before and after the alkali weight reduction was compared, and the time taken to reach the 20% weight loss was measured. Details are described in the examples.

  The environment-friendly easily-eluting polyester fiber obtained by the production method of the present invention is preferable because it can be completely dissolved without being dissolved only by treatment with an alkaline solution. As described above, the alkaline solution only means that when eluting easily eluted polymer, it is generally pre-treated with a solvent or an acidic solution to make it easy to elute, but it is eluted without any pre-treatment. This is preferable.

  Moreover, complete elution without undissolved refers to eluting 95 wt% or more easily eluting polymer. By eluting at 95 wt% or more, it is preferable that there is no unsuccessful opening of the ultrafine fiber and a uniform single yarn is obtained, and there is no quality abnormality such as abnormal dyeing or thick abnormality. And since no alkali solution is used at all, it is preferable because it is environmentally friendly and the load can be reduced.

  The elution step mentioned here refers to, for example, a step of obtaining a superfine fiber by leaching the sea component and leaving only the island component in the sea-island composite fiber. Moreover, in the core-sheath composite fiber, the core component is eluted to obtain a highly hollow fiber, or when applied to the sheath component, the sheath component is eluted, and the fiber having an arbitrary cross-sectional shape of the core component and a novel functional component It refers to the process of obtaining.

The precautions for the method for producing the polyester composition of the present invention will be described in more detail.
Using terephthalic acid or its ester-forming derivative and ethylene glycol as the main raw materials, an isophthalic acid component having 7 to 10 mol% of a metal sulfonate group is added as a copolymerization component to the total acid component, and the following formula is used. It is necessary to add 0.3 to 3 ppm of a titanium compound soluble in polyester to be converted into titanium element.

(R1 represents a hydrocarbon group having 1 to 10 carbon atoms that does not contain an oxygen element.)
Specifically, tetra-n-butoxytitanium (TBT) is preferable as the titanium compound used here, and as described above, when it is 0.3 ppm or more in terms of titanium element, the polymerization reaction activity is not insufficient and the reaction is delayed. It is preferable. When the content is 3 ppm or less, polymerization reaction activity is sufficiently obtained and high activity is obtained. However, decomposition reaction is not promoted, heat resistance is not deteriorated, and yarn maneuverability is improved.

  It is particularly important to add more than 3 ppm, since the titanium compound has a strong activity and is likely to cause oxidative degradation of the polymer. Therefore, when it adds excessively, gelatinization by the oxidative degradation of a polymer will occur, and the polymer melt | dissolution residue will arise by this due to the gelled material produced | generated. If it is within 3 ppm, it is preferable because sufficient polymerization activity and the generation of a gelled substance which is a foreign matter causing undissolved polymer are suppressed.

By using the environmentally-friendly and easily-eluting polyester obtained by the production method of the present invention as a component of the composite fiber, it shows the yarn stability, good alkali solubility, can reduce unprecedented environmental load, and alkali elution It is possible to obtain a fiber that does not impair the physical properties of the hardly-eluting component that remains behind.
Examples of the fiber that can be preferably used for the easily-eluting polyester obtained by the production method of the present invention include a core-sheath type composite fiber, a core-sheath type composite hollow fiber, and a sea-island type composite fiber. It can be suitably used for the sea component of the fiber.
The environment-friendly easily-eluting polyester obtained by the production method of the present invention can be used as a constituent component at an arbitrary ratio. For example, the composite ratio of the sea component used in the sea-island composite fiber is preferably 5 to 90 wt%. More preferably, it is 7-60 wt%, Most preferably, it is 10-40 wt%. The composite ratio can be arbitrarily designed from the single yarn fineness of the island component after alkali weight reduction processing. The lower limit of the composite ratio is set based on the ease of imparting fusing properties, alkali weight loss, and moldability between the island components, and the upper limit of the composite fiber ratio can be set from the viewpoint of spinnability and fiber physical properties.

  Moreover, in the case of a core-sheath type composite fiber and a core-sheath type composite hollow fiber, it is preferable that the composite ratio (wt%) of the copolymer polyester in the core part is core / sheath = 5/95 to 90/10. More preferably, it is 7/93-70/30, Most preferably, it is 10/90-50/50. The composite ratio can be designed by arbitrarily selecting the hollow ratio of the resulting composite fiber after alkali weight reduction processing. The lower limit of the composite ratio of the core is set for the purpose of imparting a sufficient hollow ratio, and the upper limit of the composite fiber ratio is set from the viewpoint of preventing a decrease in spinnability and a decrease in fiber properties.

  In the method for producing environment-friendly and easy-eluting polyester fiber of the present invention, when a metal nonwoven fabric having a limit filtration diameter of 10 μm is used as a filter, the pack filtration pressure increase after continuous spinning for 72 hours may be 10 MPa or less. preferable. An increase in the filtration pressure of 10 MPa or less is a proof that the polymer is a clean polymer with few foreign matters that induce yarn breakage during spinning, and there is no undissolved residue in the elution step. Furthermore, the smaller the increase in the filtration pressure, the longer the replacement cycle due to exceeding the limit pressure of the pack, which is preferable because the work is reduced and the yarn operability is improved. More preferably, it is 5 MPa or less.

  In the method for producing an environment-friendly easily-eluting polyester fiber of the present invention, the soil deposit around the mouthpiece discharge hole when spinning continuously for 72 hours or more is hardly observed, and can be continuously spun for 72 hours or more. preferable. The phrase “continuous spinning for 72 hours or more” means that there is no stain around the nozzle discharge hole, and there is no occurrence of spun yarn due to the stain. If there is no dirt around the discharge hole, as a measure against yarn breakage, the frequency of cleaning work that interrupts spinning and removes dirt around the discharge hole is reduced.As a result, the cleaning cycle can be extended and the work can be reduced. This is preferable since the yarn operability is improved. More preferably, it is 120 hours or more.

If there is a foreign substance in the polymer, a residue accumulates around the nozzle discharge hole. What is taken into the fiber without breaking the yarn remains undissolved in the elution process, resulting in a decrease in quality.
It is preferable to check the dirt deposit by using a long focus microscope during spinning because the substance can be grasped well. There is also a method of forcibly stopping spinning, removing the base, and quickly observing the removed base with water, but in this method, when the spinning is forcibly interrupted, discharge of polymer residual liquid, discoloration, etc. occur. This is not preferable because it makes it difficult to determine whether this is a foreign matter generated during spinning or a forced foreign interruption.

In the present invention, as a method for producing a composite fiber using an environmentally-friendly and easily-eluting polyester and polyester, it can be produced by a conventionally known method. The following is a representative method for producing a sea-island type composite fiber. In the case of a sea-island type composite fiber, the island-friendly polyester and sea component are separately melted with the environment-friendly easily-eluting polyester of the present invention, led to a spinning pack, and a sea-island composite flow is formed in the mouthpiece device. Spin out. After the spun yarn is taken up at a predetermined speed, it is once wound on a package, and the obtained undrawn yarn is drawn by a normal drawing machine. Further, the drawing may be performed continuously without winding after taking up the spun yarn, and it may be wound at a high speed of 4000 m / min or more, and the desired fiber performance can be obtained at once without substantially drawing. You may take the method of obtaining. Examples of the direct spinning drawing method include a method in which a spun yarn is taken up at 1000 to 5000 m / min, and subsequently drawn and heat-set at 3000 to 6000 m / min.
The filamentous form of the fiber may be either a filament or a staple, and is appropriately selected depending on the application. The fabric form can be appropriately selected according to the purpose, such as woven fabric, knitted fabric, and non-woven fabric.

  Moreover, as a method of reducing the amount of the environment-friendly easily-eluting polyester component of the polyester composite fiber of the present invention, an alkali weight loss method can be suitably used. As the alkali, a compound such as sodium hydroxide, potassium hydroxide, lithium hydroxide or the like can be used as an aqueous solution, and among them, sodium hydroxide can be preferably used. The concentration is preferably in the range of 0.5 to 10 wt%. The environmentally-friendly easily-eluting polyester of the present invention does not require any weight loss processing accelerator, and can be eluted at 95 wt% or more without causing any undissolved residue, so that good elution can be obtained. is there.

  Further, the polyester composition of the present invention is within the range not impairing its purpose, a pigment such as carbon black, a surfactant such as alkyl benzene sulfonate, a conventionally known antioxidant, anti-coloring agent, light resistance agent, antistatic agent, etc. Of course, it may be added.

Hereinafter, the present invention will be described in more detail with reference to examples. In addition, the physical-property value in an Example was measured by the method described below.

(1) Intrinsic viscosity of polymer IV
Measurement was performed at 25 ° C. using orthochlorophenol as a solvent.

(2) After the polymer heat-resistant polyester was dried under reduced pressure at 150 ° C. for 12 hours and then heated and melted at 300 ° C. for 360 minutes in a nitrogen atmosphere, the intrinsic viscosity was measured by the method of (1), and before and after heating and melting. Was measured as polymer heat resistance, calculated using (Equation 5), and judged according to the following criteria.

  The intrinsic viscosity before treatment is IV1, and the intrinsic viscosity after treatment is IV2.

Polymer heat resistance ^{= 0.27 × [(1 / IV2} ) 4/3 - (1 / IV1) 4/3] ( Equation 5)
Judgment Less than 1.00;
1.00 or more; x.

(3) Content of Titanium Element, Phosphorus Element, Sulfur Element in Polyester The metal content other than titanium element was determined using a fluorescent X-ray elemental analyzer (manufactured by Horiba, Ltd., MESA-500W type).
In addition, the titanium compound insoluble in polyester was removed after the following pretreatment and subjected to fluorescent X-ray analysis. That is, polyester is dissolved in orthochlorophenol (5 g of polyester with respect to 100 g of solvent), and after adding the same amount of dichloromethane as this polyester solution to adjust the viscosity of the solution, a centrifuge (rotation speed 18000 rpm, 1 hour) To settle the particles. Thereafter, only the supernatant liquid is collected by the gradient method, and the polyester is reprecipitated by adding the same amount of acetone as the supernatant liquid, and then filtered through a glass filter (manufactured by IWAKI). After washing, the acetone was removed by vacuum drying at room temperature for 12 hours. The polyester obtained by carrying out the above pretreatment was analyzed for titanium element.

(4) Content of lithium element in polyester was analyzed by atomic absorption spectrometry. The analysis method used was a wet decomposition method. Sulfuric acid is added “5 ml of sulfuric acid to 0.7 to 1.5 g of polyester”, and the polyester is dissolved and decomposed at 200 to 250 ° C. on a sand bath. Further, 1.5 ml of perchloric acid is added to cause decomposition at 250 to 300 ° C. The decomposition was continued at 300 ° C. to 350 ° C. until the sample became transparent, the decomposition was continued until the sulfuric acid was sufficiently refluxed, and the liquid was measured with pure water and analyzed. As a blank, the reference solution was sampled to 2 ppm with Li, and after treatment, the volume was fixed with pure water.

(5) Alkali weight loss rate Using the obtained drawn yarn, three samples of each level of cylindrical knitted fabric were prepared. This tubular knitted fabric was subjected to an alkali weight loss treatment for 3 minutes at a NaOH concentration of 4 wt% aqueous solution, a bath ratio of 1: 100, and a temperature of 98 ° C. without any other solvent or acid treatment. The weight of the tubular knitted fabric before weight reduction (A) and after weight reduction (B) was measured, and the alkali weight reduction rate was measured from (Equation 6) and judged.
Alkali weight loss rate (wt% / min) = (A−B) / A × 100/3 (Formula 6)
5 wt% / min or more; ○ less than 5 wt% / min passed;

(6) In the yarn breakage evaluation example, spinning was performed for 72 hours at each level, the number of yarn breakage was measured, and the number of yarn breakage was less than 3 times, and 3 or more times were rejected.

    (7) Increase in filtration pressure In the evaluation method of (6), the determination was made from the pack pressure after 72 hours and the difference at the start of spinning. An increase in pack pressure was 0 to 10 MPa, and an increase in filtration pressure was 10 MPa or more.

    (8) Observation of the deposit on the die In the evaluation method of (6), the amount of deposit around the die hole 72 hours after the start of the evaluation was observed using a long focus microscope. The state in which deposits were hardly recognized was judged as ◯, the state in which deposits were recognized but operable was judged as Δ, and the state in which deposits were seen and operation became difficult was judged as ×.

[Example 1]
(1) Polymerization method Total acid in polyester obtained by charging dimethyl terephthalate in 1020 wt parts and ethylene glycol in 830 wt parts in a transesterification reaction tank equipped with a rectifying column to obtain dimethyl 5-sodium sulfoisophthalate. It charges so that it may become 8.0 mol% with respect to a component (1.25 wt% with respect to a dicarboxylic acid component as a sulfur component). Thereafter, a tetra-n-butoxytitanium compound mixed to 1 ppm in terms of titanium element is added for 1 hour before adding lithium acetate monohydrate to 340 ppm in terms of lithium element. Thereafter, the temperature of the transesterification reaction tank was gradually raised, and the reaction was allowed to proceed while distilling off methanol generated during the transesterification reaction out of the reaction system to obtain a low polymer. Tetramethylphosphate is added to the low polymer so that the concentration is 32.5 ppm in terms of phosphorus element. Thereafter, the low polymer is transferred from the transesterification reaction tank to the polymerization reaction tank. Five minutes after the completion of the transfer, the temperature in the reaction vessel was gradually raised from 240 ° C. to 270 ° C., and the pressure was reduced to 50 Pa while distilling off ethylene glycol. When the predetermined agitator torque (power value) was reached, the reaction system was purged with nitrogen to return to normal pressure, the polymerization reaction was stopped, discharged in a strand form, cooled, and immediately cut to obtain polyester pellets. The time from the start of decompression to the arrival of the predetermined agitator torque was approximately 2 hours and 40 minutes. The obtained polyester had an intrinsic viscosity of 0.52 and heat resistance of 0.78. The obtained chip of the present application and a known polyethylene terephthalate chip were subjected to a spinning process after drying.

(2) Spinning method A sea-island composite fiber is produced by using the alkali-eluting polyester of the present invention as a sea component at a composite ratio of 20 wt% and using a known IV0.71 polyethylene terephthalate as a composite ratio as 80 wt% as an island component. Both dried chips are subjected to a spinning machine, each of which melts the sea component at 295 ° C. and the island component at 300 ° C., then leads to a spin block, and filters as a filter with a metal nonwoven fabric having a limit filtration diameter of 10 μm. The melt is spun at a spinning temperature of 298 ° C. from a base of φ0.8 mm, 24 holes (total island number 60 × 24 = 1440), and the discharged yarn is 0.4 m / s by a cooling chimney. Cooling and solidifying with cooling air, concentrating with an oil supply device at a position 2 m below the base, applying 0.75 wt% of the oil as pure oil to the fiber wt, winding it at a speed of 1500 m / min with a winder, 170 dtex An undrawn yarn of -24 filaments was obtained.
As a result of spinning, there was no yarn breakage and excellent spinning performance, and the filtration pressure at the time of spinning increased and deposits around the die were not recognized.

(3) Stretching method When the obtained unstretched yarn is stretched, it is stretched at a stretching speed of 800 m / min, a stretching temperature of 92 ° C, and a residual elongation of about 30 to 50%, and then heated at 130 ° C. The drawn yarn of 66 dtex-24 filament was obtained. The yarn breakage did not occur during drawing, and the rolled-up pan had no fuzz on the surface, and the drawability was excellent.

(4) Alkali weight loss Two drawn yarns obtained were combined, and three samples of each level of cylindrical knitted fabric were prepared with a 22 gauge. This tubular knitted fabric was subjected to an alkali weight loss treatment for 3 minutes at a NaOH concentration of 4 wt% aqueous solution, a bath ratio of 1: 100, and a temperature of 98 ° C. without any other solvent or acid treatment. The elution rate was very good at 10 wt% / min or more, and the complete elution was almost 100 wt%. The results are shown in Table 1.

[Examples 2 and 3], [Comparative Examples 1 and 2]
Example 2 is Example 1 except that the amount of SSIA added is 7.1 mol% near the lower limit of the present invention, and Example 3 is that the amount of SSIA added is changed to 9.8 mol% near the upper limit of the present invention. According to the conditions. In Example 2, the elution rate was slightly inferior to that in Example 1, but was within the acceptable range. Moreover, Example 3 was good without SSIA reacting and forming the self-polymerization thing called a foreign material.

  On the other hand, in Comparative Example 1, the amount of SSIA added was outside the lower limit of the present application, and the elution performance was poor as expected. In Comparative Example 2, the amount of SSIA added was outside the upper limit of the present application. Foreign matter was generated by the reaction between SSIAs, the pack internal pressure increased rapidly, and yarn breakage during spinning occurred frequently. The results are shown in Table 1.

[Examples 4 and 5], [Comparative Examples 3 and 4]
Example 4 is the same as in Example 1 except that the titanium compound soluble in polyester is changed to 0.35 ppm in the vicinity of the lower limit of the present invention in terms of titanium, and Example 5 is changed to 2.95 ppm in the vicinity of the upper limit of the present invention. According to In Example 4, the polymerization reaction activity was not insufficient, and the reaction was not delayed. Further, in Example 5, the decomposition reaction was not promoted, the heat resistance was not particularly deteriorated, and the yarn maneuverability was good. The elution property of the obtained fiber was also good.

  On the other hand, in Comparative Example 3, since the titanium compound was insufficient, the polymerization reaction activity was insufficient, the reaction was delayed, and a polymer having the target viscosity could not be obtained. In Comparative Example 4, the decomposition reaction progressed, the heat resistance deteriorated, and yarn breakage occurred frequently during spinning, which was poor.

[Examples 6 and 7], [Comparative Examples 5 and 6]
In Example 6, the addition amount of lithium acetate which is an alkali metal compound is 320 ppm in the vicinity of the lower limit range of the present invention in terms of lithium element, and in Example 7, the addition amount of lithium acetate is 405 ppm in the vicinity of the upper limit range of the present invention in terms of lithium element. Except for the above, the conditions of Example 1 were followed. In Example 6, there was no increase in DEG, no gelation caused by oxidative degradation of the polymer, and there was no undissolved polymer. Further, in Example 7, no foreign matter was generated due to binding with DMT or SSIA, and both the yarn forming property and the dissolution property were good.
On the other hand, in Comparative Example 5, the addition amount of lithium acetate, which is an alkali metal compound, was insufficient, and a gelled product was generated. Therefore, the dissolution property due to undissolved residue was poor. Further, in Comparative Example 6, a large amount of foreign matter was generated, and both the yarn forming property and the elution property were poor. The results are shown in Table 2.

[Examples 8 and 9], [Comparative Examples 7 to 10]
Example 8 is Example 1 except that the addition amount of the phosphorus compound is 22 ppm in terms of phosphorus element in the vicinity of the lower limit of the present invention, and Example 9 is that the amount of addition of the phosphorus compound is 35 ppm in terms of phosphorus element in the vicinity of the upper limit of the present invention. According to the conditions.
In Example 8, both the polymer heat resistance and the yarn forming property were good. In addition, Example 9 also had good polymerization reactivity. Both levels had good dissolution properties with no undissolved polymer.

  On the other hand, in Comparative Example 7, heat resistance deteriorated due to insufficient addition of the phosphorus compound, yarn breakage occurred frequently during spinning, and both the yarn-making property and the elution property were poor. In Comparative Example 8, the polymerization reactivity was lowered, the polymerization reaction was delayed, and a polymer having a target viscosity could not be obtained. In Comparative Example 9, foreign matters derived from alkali metal were produced, and the yarn-making property was poor. In Comparative Example 10, foreign matters derived from a titanium compound, a phosphorus compound and an alkali metal were produced, and the elution due to undissolved residue was poor. The results are shown in Table 2.

[Comparative Examples 11 to 13]
In Comparative Examples 11 and 13, the polymerization activity decreased due to the reaction between the titanium compound and the phosphorus compound, the polymerization reaction was delayed, and a polymer having the target viscosity could not be obtained. In Comparative Example 12, a phosphorus compound foreign matter was produced, and the dissolution property due to undissolved residue was poor. The results are shown in Table 2.

Claims (2)

In the production of an environmentally-friendly easily-eluting polyester composition capable of completely eluting easily-eluting components in composite fibers, polyester is obtained by polycondensation of terephthalic acid or its ester-forming derivative and ethylene glycol in the presence of a polymerization catalyst. In the method for producing the composition, 7 to 10 mol% of an isophthalic acid component having a metal sulfonate group is added to the total acid component constituting the polyester composition, and the composition is soluble in the polyester represented by the following formula as a polymerization catalyst. The titanium compound is added to the polyester composition in an amount of 0.3 to 3 ppm in terms of titanium element, the alkali metal compound is added in an amount of 315 to 410 ppm in terms of metal element, the phosphorus compound is added in an amount of 20 to 36 ppm in terms of P element, and the titanium compound Ester reaction started as the order of addition of alkali metal compound and phosphorus compound Method of manufacturing a titanium compound and an alkali metal compound mixture was added, followed by environmentally friendly easy dissolution polyester composition characterized by the addition of the phosphorus compound after the esterification reaction completed.

(R1 represents a hydrocarbon group having 1 to 10 carbon atoms that does not contain an oxygen element.) 2. The eco-friendly easy elution according to claim 1, wherein alkali metal and phosphorus element are added so as to satisfy the following formula 1 in terms of molar amount in the method for producing an environmentally-friendly elution polyester composition. For producing a conductive polyester composition.
M / P = 39 to 92 Formula 1
(M: alkali metal element molar amount, P: phosphorus element molar amount)