JPH07118373A - Production of modified polyester - Google Patents

Abstract

PURPOSE:To obtain a polyester excellent in color tone and alkali resistance, dyeable with a cationic dye, and having a high degree of polymerization by copolymerizing a prepolyester with a master polyester having units derived from a specific sulfonate comonomer. CONSTITUTION:A master polyester which comprises ethylene terephthalate units as the main component and units derived from at least one sulfonate comonomer represented by the formula [wherein A1 and A2 are the same or different ester-forming functional groups, provided that per 100 groups of A1 and A2, 10-50 groups of A2 are H; Y is the same or different alkyl or aryl groups; M is a metal; n is 1-5; and Z is an aromatic or aliphatic hydrocarbon group having a valence of (2+n)] and in which the amount of the sulfonate units is 0.5-50mol% based on the ethylene terephthalate units is mixed with a prepolyester consisting mainly of ethylene terephthalate units, in such a proportion that the amount of the sulfonate units is 0.1-5mol% based on the total amount of the ethylene terephthalate units. The mixture is polymerized with a twin-screw reactor.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for modifying a polyester containing ethylene terephthalate as a main repeating unit. More specifically, the present invention relates to a method for producing a modified polyester which is excellent in color tone, strength, moldability and alkali decomposition resistance, and further has excellent dyeability with a cationic dye.

[0002]

2. Description of the Related Art Polyesters, particularly polyesters represented by polyethylene terephthalate, have many excellent properties and are therefore widely used as materials for clothing fibers, industrial fibers, films, resins and other molded articles. Has been done. However, polyester has a low dyeing property, and it is particularly difficult to dye with a dye other than the disperse dye. Various proposals have been made to improve this dyeability.

As one of them, there has been known a method in which an isophthalic acid component containing a sulfonic acid metal base, for example, 5-sodium sulfoisophthalic acid component, is copolymerized with polyester so that it can be dyed with a cationic dye ( See Japanese Patent Publication No. 34-10497).

On the other hand, in order to give silk-like soft and good texture to a woven or knitted product made of polyester fiber, a method of alkali reduction treatment is known, and in this case, 20% by weight.
Before and after weight loss. However, by this method of alkali weight reduction treatment, a woven or knitted fabric in which a regular polyester fiber and a cationic dye-dyeable polyester fiber as described above are woven or knitted in order to obtain a good texture and a different color dyeing effect or a marbling effect, When the alkali weight reduction processing of about wt% is performed, there is a drawback that most of the cationic dye-dyeable polyester fibers are unilaterally decomposed. That is, the cationic dye-dyeable polyester fiber has a markedly large decrease in strength in the alkali treatment system, so that it is difficult to apply the alkali weight reduction processing.

Therefore, by using a sulfonate having one ester-forming functional group such as an m-metal sulfobenzoic acid compound, the polyester fiber finally obtained exhibits excellent dyeability of cationic dyes. It has been proposed that the alkali weight reduction rate is remarkably reduced, and the reduction in yarn strength due to the alkali weight reduction is also significantly reduced (see Japanese Patent Laid-Open No. 19228/1990). However, when a sulfonate having one ester-forming functional group such as an m-metal sulfonebenzoic acid compound (hereinafter referred to as "monofunctional sulfonate") is added to the polyester and polymerized, the end of the polyester molecular chain is terminated. However, there is a drawback that the polymerization rate is lowered and a polyester having a high degree of polymerization cannot be obtained. Therefore, it has been difficult to expand the application to, for example, the sportswear field where high strength is required.

[0006]

Accordingly, the present inventors have found that a method for producing a polyester dyeable with a cationic dye using a compound having a monofunctional sulfonate group can obtain a polyester having a higher molecular weight. You can
Further, research was conducted on a method capable of obtaining a polyester having a good color tone and excellent alkali decomposition resistance.

First, the present inventors conducted polymerization using a monofunctional sulfonate in a can-type (tank-type) reactor generally used for polymerization of polyester.
As a result, a polyester having a good color tone and giving a sharp dyeing was not obtained, and the degree of polymerization thereof was not sufficiently high. Further, the same polymerization reaction was carried out using a screw type single-screw reactor. The obtained results were almost the same as those of the can type reactor, and a modified polyester having a satisfactory high degree of polymerization was obtained. I couldn't do it.

However, a master polyester prepared by copolymerizing a monofunctional sulfonate at a relatively high concentration is prepared, and this is mixed with a separately prepared prepolyester to use a screw type twin-screw reactor. It was found that, when the polymerization is carried out, a polyester having an unexpectedly good color tone, which can be dyed in a vivid and deep color with a cationic dye, and which has a sufficiently high degree of polymerization sufficient to satisfy the resistance to alkali decomposition is obtained. It was

[0009]

The present invention has been achieved on the basis of the above findings, and has (1) an ethylene terephthalate unit as a main repeating unit and the following general formula (I):

[0010]

[Chemical 2]

(In the formula, A ₁ and A ₂ are the same or different and each represents an ester-forming functional group, provided that in the compound of the formula (I), 10 or more of A ₂ are used with respect to 100 in total of A ₁ and A _2. 50 or less are hydrogen atoms, Y is a group —SO ₃ P
R ₁ R ₂ R ₃ R ₄ or a group —SO ₃ M is shown. Where R ₁ R ₂
R ₃ and R ₄ are the same or different and each represents an alkyl group or an aryl group, M represents a metal, n represents an integer of 1 to 5, Z represents a (2 + n) -valent aromatic hydrocarbon group or aliphatic carbon group. A master polyester prepared by copolymerizing at least one kind of sulfonate represented by hydrogen group) in an amount of 0.5 to 50 mol% with respect to the ethylene terephthalate unit is prepared. A prepolyester having a terephthalate unit as a main repeating unit is prepared, and (3) the content of the sulfonate represented by the general formula (I) in the prepolyester and the master polyester is 0.1 per ethylene terephthalate unit.
Mix so as to be in the range of 1 to 5 mol%, and then (4)
A method for producing a modified polyester, characterized in that the obtained mixture is polymerized by using a screw type biaxial reactor.

The polyester having an ethylene terephthalate unit as a main repeating unit in the present invention is a polyester having a main acid component of terephthalic acid and a main glycol component of ethylene glycol, and is produced by a method known per se. can do. In the polyester of the present invention, at least 80 mol%, preferably at least 85 mol% of the following repeating units are ethylene terephthalate units.

[0013]

[Chemical 3]

It is preferable that

The polyester of the present invention may contain other components as long as the main repeating unit is an ethylene terephthalate unit as described above, and it does not matter in particular. For example, as an acid component other than terephthalic acid, aromatic compounds such as isophthalic acid, naphthalenecarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, β-hydroethoxybenzoic acid, p-oxybenzoic acid, and 1,4-cyclohexanedicarboxylic acid are used. -Or an alicyclic carboxylic acid can be used, while as the glycol component other than ethylene glycol, an alicyclic- or aromatic diol compound such as cyclohexane-1,4-dimethanol, bisphenol A or bisphenol S Can be used. Further, polycarboxylic acids such as trimellitic acid and pyromellitic acid; and polyols such as glycerin, trimethylolpropane and pentaerythritol can be used as long as the object of the present invention is not impaired.

The prepolyester in the present invention is synthesized by any method. For example, polyethylene terephthalate will be described. Usually, terephthalic acid and ethylene glycol are directly esterified, or a lower alkyl ester of terephthalic acid such as dimethyl terephthalate is transesterified with ethylene glycol, or terephthalic acid and ethylene glycol are used. Glycol ester of terephthalic acid and / or by reacting with oxide
Alternatively, it is produced by a first-stage reaction for producing the low polymer and a second-stage reaction for heating the reaction product of the first stage under reduced pressure in the presence of a polymerization catalyst to cause a polycondensation reaction until a desired degree of polymerization is obtained. It

Any catalyst can be used for these reactions, if necessary. Among them, when the transesterification method is adopted, calcium compounds, manganese compounds, magnesium compounds, zinc compounds, cobalt compounds and the like are preferable as the transesterification catalyst, and these may be used alone or in combination of two or more kinds. The amount used is preferably 0.01 to 0.1 mol% with respect to the bifunctional carboxylic acid component used as the polyester raw material.

The polycondensation catalyst is preferably an antimony compound, a titanium compound or a germanium compound,
The amount used is 0.00 with respect to the bifunctional carboxylic acid component.
3 to 0.1 mol% is preferable.

Thus, the prepolyester of the present invention is prepared, and this prepolyester has an intrinsic viscosity [η] in the range of 0.2 to 1.0, preferably in the range of 0.4 to 0.8. It is advantageous. on the other hand. In the present invention, the master polyester mixed with the pre-polyester is prepared by polymerizing using the same or different material as the pre-polyester, in which case the following formula (I)
The sulfonate represented by is added. Polymerization means and conditions are not substantially different from the preparation of the prepolyester, except that a sulfonate is added.

The sulfonate used as a modifier in the present invention is represented by the following general formula (I).

[0021]

[Chemical 4]

Z is a (2 + n) -valent aromatic hydrocarbon group or aliphatic hydrocarbon group, preferably having 6 carbon atoms.
To 15 aromatic hydrocarbon groups or aliphatic hydrocarbon groups having 10 or less carbon atoms. Particularly preferred Z has 6 to 1 carbon atoms.
2 aromatic hydrocarbon groups, especially a benzene ring.

A is an ester-forming functional group. The ester-forming functional group is a group capable of reacting with polyester to form an ester, and is generally a hydroxyl group, a carboxyl group or an ester thereof. The following groups can be mentioned as specific examples of the ester-forming functional group.

[0024]

[Chemical 5]

(In the above formula, R'represents a lower alkyl group or a phenyl group, a and d represent an integer of 1 to 10, and b represents an integer of 2 to 6.)

However, in the above-mentioned sulfonate, all of A ₂ need not be hydrogen atoms, and some of them can be ester-forming functional groups. That is, when the total number of A ₁ and A ₂ is 100, A ₂ has 10 or more hydrogen atoms. This means that 80 mol% or less of the sulfonate is bifunctional and 20 mol% or more is monofunctional. Preferably, less than 70 mol% of the sulfonic acid salt is bifunctional and more than 30 mol% is monofunctional. Most preferably, the sulfonate is 50 mol%
The following is bifunctional and 50 mol% or more is monofunctional.

In the sulfonate of the above formula, n is 1 to 5
Is an integer of 1, preferably 1 to 3, and 1 is particularly preferable. Y is a sulfonic acid quaternary phosphonium salt represented by the group —SO ₃ PR ₁ R ₂ R ₃ R ₄ or the group —SO
It represents a sulfonic acid metal salt represented by ₃ M.

In the quaternary phosphonium salt of sulfonic acid, R ₁ , R ₂ , R ₃ and R ₄ are the same or different and each represents an alkyl group or an aryl group, specifically, a C ₁ -C ₄ lower alkyl group or a phenyl group. Is. On the other hand, in the sulfonic acid metal salt, M represents a metal such as sodium, lithium, potassium, titanium, calcium, zinc, magnesium or manganese, and preferably an alkali metal such as sodium or lithium. Specific compounds of these sulfonates are shown below, but the present invention is not limited thereto.

Preferred specific examples of the quaternary phosphonium sulfonate include 3-carboxybenzene sulfonic acid tetrabutyl phosphonium salt, 3-carboxy benzene sulfonic acid ethyl tributyl phosphonium salt, 3-carboxy benzene sulfonic acid benzyl tributyl phosphonium salt, 3-carboxybenzenesulfonic acid phenyltributylphosphonium salt, 3-carboxybenzenesulfonic acid tetraphenylphosphonium salt, 3-carboxybenzenesulfonic acid ethyltriphenylphosphonium salt, 3-carboxybenzenesulfonic acid butyltriphenylphosphonium salt, 3-carboxybenzene Sulfonic acid benzyltriphenylphosphonium salt, 3-carbomethoxybenzenesulfonic acid tetrabutylphosphonium salt, 3-carbometo Cibenzenesulfonic acid ethyl tributylphosphonium salt, 3-carbomethoxybenzenesulfonic acid benzyltributylphosphonium salt, 3-carbomethoxybenzenesulfonic acid phenyltributylphosphonium salt, 3-carbomethoxybenzenesulfonic acid tetraphenylphosphonium salt, 3-carbo Ethyl triphenylphosphonium methoxybenzenesulfonate, 3
-Carbomethoxybenzenesulfonic acid butyltriphenylphosphonium salt, 3-carbomethoxybenzenesulfonic acid benzyltriphenylphosphonium salt, 3-carboxybenzenesulfonic acid tetrabutylphosphonium salt,
3-Carboxybenzenesulfonic acid tetraphenylphosphonium salt, 3-carbomethoxybenzenesulfonic acid tetrabutylphosphonium salt, 3-carbomethoxybenzenesulfonic acid tetraphenylphosphonium salt, 3- (β
-Hydroxyethoxycarbonyl) benzenesulfonic acid tetrabutylphosphonium salt, 3- (β-hydroxyethoxycarbonyl) benzenesulfonic acid tetraphenylphosphonium salt, 3- (β-hydroxyethoxycarbonyl) benzenesulfonic acid tetrabutylphosphonium salt, 3- ( Examples include β-hydroxyethoxycarbonyl) benzenesulfonic acid tetraphenylphosphonium salt and 4-hydroxyethoxybenzenesulfonic acid tetrabutylphosphonium salt. These sulfonic acids 4
The primary phosphonium salts may be used alone or in combination of two or more.

Preferred specific examples of the sulfonic acid metal salt include methyl 3-sodium sulfobenzoate and 3
-Methyl lithium sulfobenzoate, 3-sodium sulfobenzoic acid hydroxyethyl ester, 3-lithium sulfobenzoic acid hydroxyethyl ester, 3-sodium sulfophenoxy hydroxyethyl ether, 3-lithium sulfophenoxy hydroxyethyl ether and the like. Among them is 3-sodium sulfobenzoic acid hydroxyethyl ester. These sulfonic acid metal salts may be used alone or in combination of two or more.

The sulfonate of the general formula (I) can be added at any stage during the polymerization reaction of the master polyester. The sulfonate is 0.5 to 5 per ethylene terephthalate unit in the master polyester.
It is added in the range of 0 mol%, preferably in the range of 1.0 to 30 mol%. The master polyester obtained by copolymerizing the sulfonate in a relatively high concentration has an intrinsic viscosity [η] in the range of 0.2 to 0.5, preferably in the range of 0.25 to 0.4. Appropriate.

In the production of such a master polyester, it is preferable to add a quaternary onium salt in order to improve heat resistance. Examples of the quaternary onium salt include a quaternary ammonium salt and a quaternary phosphonium salt.
Specific examples of the quaternary ammonium salt include tetramethylammonium hydroxide, tetramethylammonium chloride, tetramethylammonium bromide, tetraethylammonium hydroxide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, and hydroxide. Examples include tetrapropylammonium, tetrapropylammonium chloride, tetraisopropylammonium hydroxide, tetraisopropylammonium chloride, tetrabutylammonium hydroxide, tetrabutylammonium chloride, tetraphenylammonium hydroxide, tetraphenylammonium chloride and the like.

Examples of the quaternary phosphonium salt include chlorobenzylphosphonium chloride, stearylethyldihydroxyethylphosphonium ethosulfate, tetrabutylphosphonium acetate, tetrabutylphosphonium dodecylbenzene sulfonate, tetrabutylphosphonium tosylate, tetrabutylphosphonium oleate and tetrabutyl. Phosphonium phosphate, tetrabutylphosphonium phosphite, ethyltriphenylphosphonium bromide, tetraphenylphosphonium bromide, ethyltriphenylphosphonium iodide, tetratriphenylphosphonium iodide,
Benzyltriphenylphosphonium chloride, tributylallylphosphonium bromide, ethylenebistris (2-cyanoethyl) phosphonium bromide, tris-2-cyanoethylallylphosphonium chloride,
Examples thereof include tetrakis (hydroxymethyl) phosphonium sulfate and tetrakis (hydroxymethyl) phosphonium chloride.

If the amount of the quaternary onium salt used is too small, the effect of improving the heat resistance becomes insufficient, and if it is too large, the heat resistance deteriorates. Therefore, the amount of the quaternary onium salt used is preferably in the range of 0.1 to 20 mol% with respect to the sulfonate, and particularly preferably in the range of 1.0 to 10 mol%.

The quaternary onium salt may be added at any stage until the polymerization of the master polyester is completed, for example, the same as the sulfonate addition time, or before or after the addition.

In the present invention, the prepolyester and the master polyester separately prepared by the above-mentioned method are mixed and the polymerization is carried out using a screw type twin-screw reactor. At that time, the ratio of the two is such that the master polyester is 5 to 30 when the weight of the mixture is 100.
Parts, preferably in the range 10 to 25 parts. In the case of the sulfonate in the master polyester, this ratio depends on the type of the sulfonate, the intended use of the modified polyester, and the like.

In the present invention, the master polyester and the prepolyester may be mixed into chips, or either one or both may be melted. Both are mixed to polymerize using a screw type twin screw reactor. The polymerization reaction in the screw type twin-screw reactor is carried out under melting conditions. The preferable range of the reaction temperature is 200 ° C. or higher and 320 ° C. or lower, and more preferably the melting point of the polyester or higher and 300 ° C. or lower.

The reaction pressure is 10 torr or less, preferably 1 torr or less. The reaction time is 1 to 120 minutes,
It is particularly preferably 5 to 60 minutes. The rotation speed of the screw of the biaxial reactor is desirably 20 to 500 rpm, preferably 50 to 300 rpm. The two axes may rotate in the same direction or in opposite directions, but the rotation in the same direction is preferable.

When the reaction temperature or the reaction time exceeds the above range, due to the problem of heat resistance of the sulfonate, it is decomposed by itself in the polymerization reaction process, the melt spinning process or the like, or the decomposition of the polymer is promoted to form a molded polyester product. Color it in yellow-brown,
In addition, the degree of polymerization of the modified polyester may be significantly reduced, and this coloring may deteriorate the color tone when dyed. If the degree of vacuum is 10 torr or more, the excellent degassing performance of the screw type twin-screw reactor will not be utilized, so it is difficult to expect a modified polyester with high whiteness and high strength. Needless to say, various additives such as an ultraviolet absorber, a heat stabilizer, a flame retardant, a whitening agent, a lubricant, a nucleating agent and a pigment may be added to the above polymerization reaction. Thus, in the present invention, the intrinsic viscosity [η] is 0.5.
A modified polyester of 5 or more, preferably 0.6 or more is obtained.

[0040]

INDUSTRIAL APPLICABILITY As described above, the present invention uses the above master polyester and pre-polyester and polymerizes them by using a screw type twin-screw reactor,
It is possible to obtain a modified polyester which is excellent in color tone, strength, moldability and alkali decomposability and which can be dyed with a cationic dye. The modified polyester thus obtained has the following advantages over those produced by conventional processes. (1) The fiber from the modified polyester obtained by the method of the present invention is dyeable with a cationic dye and has excellent alkali resistance. Therefore, it becomes possible to apply a usual alkali weight reduction treatment for improving the texture of the woven or knitted fabric. (2) Since the alkali weight loss rate is close to that of regular polyethylene terephthalate fiber, the cationic dye-dyeable polyester fiber obtained by the method of the present invention and the regular polyester fiber are woven or knitted into a woven or knitted fabric. After that, an alkali weight reduction treatment is performed to obtain a woven or knitted fabric having a silky soft and good texture and capable of expressing high-grade dyeing effects such as a different color dyeing effect and a marbling effect. (3) When a compound having one ester-forming functional group is added to a polyester and polymerized, the end of the polyester molecular chain is blocked, and the polymerization rate is lowered, so that a polyester having a high degree of polymerization cannot be obtained. However, when the process of the present invention is used, for example, a polyester fiber having a high degree of polymerization with an intrinsic viscosity [η] of 0.6 or more and a strength comparable to that of regular polyester fibers and excellent in cationic dyeability and excellent alkali resistance can be obtained. (4) A cationic dyeable polyester having a high whiteness can be obtained. Therefore, when dyed with a cationic dye, a cationic dyeable yarn having markedly excellent sharpness is obtained. Therefore, the same level of cationic dyeability can be obtained with a smaller amount of dye as compared with the modified polyester produced by the conventional process.

(5) Since the dyeing sharpness is improved, even if the copolymerization amount of the sulfonate is reduced, the same degree of cationic dyeing property as that of the modified polyester produced by the conventional process can be obtained. (6) The modified polyester of the present invention is excellent in flame retardancy and antibacterial property when it contains a quaternary phosphonium salt of sulfonic acid. (7) The modified polyester produced by the process of the present invention has very little foreign matter contained in the polyester and has excellent spinnability because of the excellent degassing performance and self-cleaning property of the screw type twin-screw reactor. . (8) Further, since the polyester is very homogeneous, there is very little uneven dyeing when dyed with a cationic dye. The modified polyester obtained by the method of the present invention can be directly processed into a fiber, a film, a resin or the like by using an appropriate molding machine such as direct spinning using a spinning machine in a molten state. . It is also possible to perform melt spinning or melt molding in the presence of an appropriate plasticizer for polyester, and to use for gel spinning using a known solvent.

[0042]

EXAMPLES The method of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.
In addition, in the present invention, the intrinsic viscosity [η] of the polyester (and the prepolyester) is 3 using a mixed solvent of tetrachloroethane and phenol of 4: 6 (weight).
It is a value calculated from the viscosity measured at 5 ° C. Further, parts mean parts by weight, and% means% by weight.

Example 1 Example 1 will be described below with reference to the drawings. FIG. 1 shows the screw type twin-screw reactor used in Example 1. In a screw type twin-screw reactor, two opposing screws rotate in the same direction or in different directions while meshing or not meshing, reacting and kneading the polymer and extruding it, and at least one or more vents for vacuum suction are provided. I have it. In addition, equipment for adding additives, equipment for adding polymers, equipment for blowing nitrogen, etc. are provided as required. Screw type 2 used for this test
The shaft reactor is a fully meshing type and rotating in the same direction.

100 parts of dimethyl terephthalate, 60 parts of ethylene glycol, 0.03 part of manganese acetate and 0.009 part of cobalt acetate as a color-adjusting agent were placed in a transesterification can and heated from 140 ° C. to 22 ° C. for 3 hours under a nitrogen gas atmosphere.
The temperature was raised to 0 ° C and the produced methanol was distilled out of the system to carry out a transesterification reaction. To the obtained product, 20% heated ethylene glycol solution of sulfonate as shown in Table 1 was added and stirred at 220 ° C. for 20 minutes, and then 0.03 part of 56% orthophosphoric acid aqueous solution as a stabilizer was added. At the same time, the temperature rise of the excess ethylene glycol was removed. 10 minutes later Antimony trioxide 0.0 as polycondensation catalyst
4 parts were added. When the internal temperature reached 240 ° C., the purging of ethylene glycol was completed, and the reaction product was transferred to a polymerization vessel. Then, the reaction is carried out at normal pressure while raising the temperature until the internal temperature reaches 260 ° C., and then 760 mm over 1 hour.
The pressure was reduced from Hg to 1 mmHg, and at the same time, the internal temperature was raised to 280 ° C. over 1 hour and 30 minutes. The polymerization reaction was terminated when the polymerization was further performed for 2 hours at a polymerization temperature of 280 ° C. under a reduced pressure of 1 mmHg or less. Table 1 shows the copolymerization amounts and the intrinsic viscosities of the obtained master polyesters A to E.

Using the reactor shown in FIG. 1, 90 parts / h of polyethylene terephthalate chips having an intrinsic viscosity of 0.40 are supplied from the chip quantitative feeder 1 through the charging port 3, melted, and then melted from the chip quantitative feeder 2 to the master polyester A 1.
0 part / h was added through the vent port 4 and mixed. Vent 5
More degassed, under reduced pressure of 0.3 torr, rotation speed 100r
The reaction was carried out at pm and a temperature of 300 ° C. The intrinsic viscosity of the obtained polyester is shown in Table 2.

Fibers obtained by melt spinning and drawing from these polymers according to a conventional method were treated with 1.5% sodium hydroxide at a boiling temperature to obtain a cloth with a weight loss rate of 20%.
Table 2 shows the alkali weight reduction treatment time required to reach the weight reduction rate of 20% in the alkali weight reduction treatment. The cloth after this alkali treatment is a cationic dye Cathilon CD-FR
LH / cathilon Blue CD-FBLH = 1/1 (manufactured by Hodogaya Chemical Co., Ltd.) at 130 ° C. in a dye bath containing 2% owf (containing 3 g / l of Boe's salt as an auxiliary agent and 0.3 g / l of acetic acid). 6
Stained for 0 minutes. Table 2 shows the sharpness of the dyed cloth.

(Example 2) Under the polymer production conditions of Example 1, the supply ratio of polyester / master polyester was changed, and the results shown in Table 2 were obtained.

(Examples 3 to 6 and Comparative Example 2) Example 1
Under the polymer production conditions of, the type of master polyester and the supply ratio of polyester / master polyester were changed, and the results shown in Table 2 were obtained.

(Comparative Example 1) Using the reactor shown in FIG. 2, 100 parts / h of polyethylene terephthalate chips having an intrinsic viscosity of 0.40 were supplied from the chip quantitative feeder 6 through the inlet 7, melted, and then degassed through the vent 8. Then, the reaction was carried out at a rotation speed of 100 rpm and a temperature of 300 ° C. under a reduced pressure of 0.3 torr. The intrinsic viscosity of the obtained polyester is shown in Table 2.

Fibers obtained by melt spinning and drawing from these polymers in a conventional manner were treated with 1.5% sodium hydroxide at a boiling temperature to obtain a cloth with a weight loss rate of 20%.
Table 2 shows the alkali weight reduction treatment time required to reach the weight reduction rate of 20% in the alkali weight reduction treatment. The cloth after this alkali treatment is a cationic dye Cathilon CD-FR
LH / cathilon Blue CD-FBLH = 1/1 (manufactured by Hodogaya Chemical Co., Ltd.) at 130 ° C. in a dye bath containing 2% owf (containing 3 g / l of Boe's salt as an auxiliary agent and 0.3 g / l of acetic acid). 6
Stained for 0 minutes. Table 2 shows the sharpness of the dyed cloth.

(Comparative Examples 3 to 5) Dimethyl terephthalate 1
00 parts, 60 parts ethylene glycol, manganese acetate 0.
03 parts and 0.009 parts of cobalt acetate as a color-adjusting agent were charged in an ester exchange can, and the temperature was raised from 140 ° C to 220 ° C over 3 hours in a nitrogen gas atmosphere, and the methanol produced was distilled out of the system. Exchange reaction was performed. A 20% heated ethylene glycol solution of a sulfonate as shown in Table 2 was added to the obtained product, and the mixture was stirred at 220 ° C. for 20 minutes, and then, as a stabilizer, a 56% aqueous solution of orthophosphoric acid 0.0.
3 parts was added, and at the same time, the temperature rising drive-off of excess ethylene glycol was started. After 10 minutes, 0.04 part of antimony trioxide was added as a polycondensation catalyst. When the internal temperature reached 240 ° C., the purging of ethylene glycol was completed, and the reaction product was transferred to a polymerization vessel. Then, the reaction was carried out at normal pressure while increasing the temperature until the internal temperature reached 260 ° C., then the pressure was reduced from 760 mmHg to 1 mmHg over 1 hour, and at the same time, the internal temperature was increased to 280 ° C. over 1 hour and 30 minutes. 1m
The polymerization reaction was terminated when the polymerization was further performed at a polymerization temperature of 280 ° C. for 2 hours under a reduced pressure of mHg or less. The intrinsic viscosity of the obtained polymer is shown in Table 2.

Fibers obtained by melt spinning and drawing from these polymers according to a conventional method were treated with 1.5% sodium hydroxide at a boiling temperature to obtain a cloth with a weight loss rate of 20%.
Table 2 shows the alkali weight reduction treatment time required to reach the weight reduction rate of 20% in the alkali weight reduction treatment. The cloth after this alkali treatment is a cationic dye Cathilon CD-FR
LH / cathilon Blue CD-FBLH = 1/1 (manufactured by Hodogaya Chemical Co., Ltd.) at 130 ° C. in a dye bath containing 2% owf (containing 3 g / l of Boe's salt as an auxiliary agent and 0.3 g / l of acetic acid). 6
Stained for 0 minutes. Table 2 shows the sharpness of the dyed cloth.

Comparative Example 6 Under the polymer production conditions of Example 1, a vent type uniaxial extruder was used in place of the screw type biaxial reactor, and 95 parts of polyethylene terephthalate chips having an intrinsic viscosity of 0.96 from a chip quantitative feeder. /
After supplying and melting h, 5 parts / h of the master polyester A was added from the chip quantitative feeder through the vent port and mixed. The mixture was degassed from the vent port and reacted under a reduced pressure of 0.3 torr at a rotation speed of 100 rpm and a temperature of 300 ° C.
Table 2 shows the intrinsic viscosity of the obtained polyester, the alkali weight reduction treatment time until the weight loss rate reaches 20%, and the sharpness of the dyed cloth.

[0054]

[Table 1]

[0055]

[Table 2]

[0056]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a screw type twin-screw reactor used in Example 1 of the present invention.

FIG. 2 is a schematic cross-sectional view of a screw type twin-screw reactor used in Comparative Example 1 of the present invention.

[Explanation of symbols]

 1 Chip quantitative feeder 2 Chip quantitative feeder 3 Input port 4 Vent port 5 Vent port 6 Chip quantitative feeder 7 Input port 8 Vent port 9 Input port

Claims (1)

[Claims] (1) An ethylene terephthalate unit as a main repeating unit and the following general formula (I): (In the formula, A ₁ and A ₂ are the same or different and each represents an ester-forming functional group, provided that in the compound of formula (I)
10 or more and 50 of A ₂ for the total number of ₁ and A ₂ of 100
The following is a hydrogen atom. Y represents a group —SO ₃ PR ₁ R ₂ R ₃ R ₄ or a group —SO ₃ M. Where R ₁ R ₂ R ₃ and R ₄ are the same or different,
Represents an alkyl group or an aryl group, M represents a metal,
n represents an integer of 1 to 5, Z represents a (2 + n) -valent aromatic hydrocarbon group or aliphatic hydrocarbon group, and at least one kind of sulfonate represented by 0.5
Prepare a master polyester copolymerized in the range of ˜50 mol%, (2) prepare a pre-polyester having ethylene terephthalate units as main repeating units,
(3) The pre-polyester and the master polyester are mixed so that the content of the sulfonate represented by the general formula (I) is in the range of 0.1 to 5 mol% per ethylene terephthalate unit, and then, (4) A method for producing a modified polyester, wherein the obtained mixture is polymerized using a screw type twin-screw reactor.