JP2833094B2 - Manufacturing method of modified polyester - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a modified polyester, and more particularly to an improved method for producing a dye capable of dyeing a basic dye having a sulfonate group containing titanium oxide. It is.

[Prior art] Polyesters, especially polyethylene terephthalate, are widely used in fibers, films and industrial materials due to their excellent mechanical and chemical properties, but they do not always have good dyeing properties as clothing fibers. I can not say. In addition, since dyeing is carried out with a disperse dye, only a limited number of dyes can be used, and there are drawbacks such as inferior clarity of the dyed product.

Conventionally, in order to compensate for such a disadvantage, as disclosed in JP-B-34-10497, a polyester dyeable to a basic dye by copolymerizing isophthalic acid having a sulfonate group in the form of a metal salt (hereinafter, referred to as A method for producing a modified polyester is simply known.

However, when such a method is applied to a so-called direct-loading method using terephthalic acid and ethylene glycol as starting materials, a large amount of diethylene glycol is by-produced during the esterification reaction and the polycondensation reaction, and this is produced in the polyester main chain. As a result, the mechanical properties, heat resistance stability, ultraviolet light resistance, and hydrolysis resistance of the product are significantly reduced. As a method of improving this, it is known to add an alkali metal acetate or carbonate, or a tertiary amine to the reaction system. However, in such an improvement method, since a low-polymer having a terminal carboxyl group is present in a large number in the direct-gravity method, when a large amount of an alkali metal acetate or carbonate is added, it reacts with the terminal carboxyl group to form an insoluble substance. , Causing a reduction in spinnability.

As a method for effectively suppressing the by-product of diethylene glycol, Japanese Patent Publication No. 57-57054 and Japanese Patent Publication No. 58-454
No. 52 proposes to use 2-hydroxyethyl ester of isophthalic acid (hereinafter abbreviated as SIHE) having a sulfonate group having a transesterification rate of 40% or more as a modifier.

However, the SIHE is produced by first producing a dimethyl ester of isophthalic acid having a sulfonate group (hereinafter abbreviated as SIDM) and then reacting it with ethylene glycol. It takes a relatively long time to fabricate with, and a decrease in productivity and operability is inevitable. In addition, even if the reactants are purchased, there is only a method of purchasing as a relatively low concentration ethylene glycol slurry or ethylene glycol solution,
For this reason, the raw material cost is greatly increased, and the cost merit of the direct weight production cannot be exhibited.

In addition, a method for finely defining the conditions for holding the melt after adding SIHE to the heavy oligomer or JP-A-59-12924, or adding a three-membered mixture of SIDM, SIHE and an intermediate reactant of both. (Japanese Patent Application Laid-Open No. 59-152924) have been proposed, but none of them are complicated due to complexity during operation.

As a method of obtaining the cost advantage of the direct-gravity production, Japanese Patent Publication No. 59-1735 proposes a method in which a dialkyl ester of isophthalic acid having a sulfonate group (hereinafter abbreviated as SIDA) is added to a direct-gravity oligomer. Have been. When titanium oxide is contained by this method, large titanium oxide agglomerates are formed in the modified polymer, causing thread breakage during spinning, increase in filtration pressure, and frequent breakage during stretching. In addition, SIDA has no stability in the state of ethylene glycol slurry, and high-concentration slurry loses fluidity in several hours even if it is kept under stirring at room temperature. Was.

[Problems to be Solved by the Invention] An object of the present invention is to produce a polymer having a small amount of agglomerates of titanium oxide and by-product diethylene glycol in the production of a basic dye-dyeable polyester by a direct weight method with good productivity and operability. To manufacture.

[Means for Solving the Problems] The object of the present invention is to provide at least 90 mol% of the constituent units.
Is ethylene terephthalate, and 0.5 to 10 mol% is ethylene isoterephthalate having a sulfonate group. In producing a modified polyester containing titanium oxide, using a terephthalic acid-based straight-running oligomer, The direct polymerization oligomer having an esterification reaction rate of 90 mol% or more is added to a 2-alkyl isophthalic acid having a sulfonate group having a transesterification reaction rate of 5 to 40% from a dialkyl ester of isophthalic acid having a sulfonate group and ethylene glycol. The solution can be solved by sequentially adding hydroxyethyl ester in 5 to 40 minutes, keeping at 230 to 260 ° C. for 5 to 40 minutes to form a uniform melt, then adding titanium oxide and performing polycondensation. .

That is, the modified polyester in the present invention is ethylene isophthalate having a constitutional unit of ethylene terephthalate and a sulfonic acid salt group, and other isophthalic acid, naphthalene-2,6-dicarboxylic acid, adipic acid,
Aromatic or aliphatic dicarboxylic acids such as sebacic acid, p-
Known copolymerization components such as oxycarboxylic acid such as oxybenzoic acid, propylene glycol, 1,4-cyclohexanedimethanol, and 1,4-butanediol can be used.

When the ethylene glycol slurry of SIHE is added, the esterification reaction rate of the oligomer obtained by the direct gravity method is at least 90%, preferably at least 95%. When the reaction rate is lower than 90%, the amount of diethylene glycol by-produced increases or an insoluble substance is easily formed due to the influence of terminal carboxyl groups remaining in the oligomer. The SIHE acts mainly as a modifier for the polyester, and its transesterification rate is 5 to 40%, preferably 25 to 40%. If the transesterification rate is less than 5%, either a large amount of diethylene glycol or agglomerates of titanium oxide will occur. On the other hand, when the transesterification rate exceeds 40%, the transesterification rate is increased, resulting in a decrease in productivity and operability. Further, if the reactant is purchased, the cost of the raw material is inevitably increased. In other words, SIHE with a transesterification rate of 5 to 40% can be easily produced by SIDA without impairing productivity and operability. If it is contained in the oligomer by the direct-gravity method under the conditions, it is possible to prevent the formation of a large amount of diethylene glycol and the formation of titanium oxide aggregates.

Here, the transesterification rate of SIHE refers to the alcohol component constituting the carboxylic acid ester group in SIHE.
It is represented by the ratio (%) occupied by the ethylene glycol component.

Next, the titanium oxide used in the present invention is 0.
About 0.01 to 5% by weight is added. In this case, if titanium oxide is previously added to the direct-weight method oligomer or added simultaneously with SIHE, agglomerates of titanium oxide are generated and SIHE is uniformly copolymerized. This also results in some of the titanium oxide agglomerates remaining in the polymer. Therefore, it is important that titanium oxide is added after the homopolymer oligomer and SIHE have formed a uniform melt. Specifically, SIHE is used as the oligomer
Add sequentially in 40 minutes (shorter the amount of SIHE added is shorter), then hold at 230-260 ° C for 5-40 minutes (higher temperature or shorter amount of SIHE is shorter) ,Preferably
After maintaining at 260 ° C. × 5 minutes to 240 ° C. × 20 minutes to form a uniform melt, titanium oxide is added. If the amount is out of the above range, the amount of by-products of diethylene glycol becomes excessive, and the dispersion of titanium oxide becomes poor. This sequential addition of titanium oxide is the most characteristic technology among the elemental technologies that constitute the present invention, whereby a more uniform melt can be formed, titanium oxide agglomerates are reduced, and insoluble substances due to residual SIDA Not only the formation of
It is also very effective in reducing diethylene glycol.
This sequential addition is desirably performed with a constant supply as much as possible.

The SIHE used in the present invention includes sodium 3,5-di (carbo-2-hydroxyethoxy) benzenesulfonate, potassium 3,5-di (carbo-2-hydroxyethoxy) benzenesulfonate, and 3,5-di (carbo). -2-hydroxyethoxy) lithium benzenesulfonate and the like. They are suitably used as a 30 to 40% by weight ethylene glycol slurry.

In the present invention, it is preferable to add an alkali metal compound at the same time as or before the addition of SIHE, since the formation of ether bonds due to side reactions can be further suppressed and a high-quality modified polyester can be obtained. As the alkali metal compound used at this time, hydroxide, organic carboxylate, alcoholate, inorganic weak acid salt and the like are suitable.
Specific examples include hydroxides of sodium, potassium and lithium, aliphatic carboxylate such as formate and acetate, methylate, ethylate, butyrate, carbonate, bicarbonate and borate. The amount of these additives is 5 × 10 ^{-5 to} 5 × 10 ^{-3 based on the} number of moles of the structural unit of the polyester.
Molar% is preferred.

In the present invention, a normal esterification / polycondensation catalyst,
The use of a color tone improver such as a cobalt compound, a stabilizer such as a phosphorus compound, etc. may be used at all.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples.

In addition, each characteristic described in this example was measured by the following method.

(1) Esterification reaction rate of direct-weight method oligomer The reaction rate of the direct-weight method oligomer was calculated from the acid value and the saponification value. The acid value is obtained by dissolving the oligomer in pyridine and titrating the solution with an alkali solution. The titer is expressed as mg potassium hydroxide consumed per gram of the oligomer. The saponification value is obtained by adding an excess of an alcoholic alkali solution to the oligomer, performing a saponification, and titrating the excess alkali back with an acid and expressing the number of mg of potassium hydroxide consumed per gram of the oligomer.

(2) SIHE transesterification reaction rate This value was obtained by subjecting a sample to hydrolysis by heating in an aqueous sodium hydroxide solution and then performing gas chromatography analysis. The value of β-hydroxyethyl ester group relative to all carboxylic acid ester groups in SIHE was obtained. The percentage is expressed as a percentage (%).

(3) Concentration of SIHE in ethylene glycol slurry This is the weight percentage (%) obtained by evaporating the sample to dryness.

(4) Amount of diethylene glycol The value obtained by performing gas chromatography analysis after decomposing the polyester in a mixed solution of hydrazine and n-butanol, and the amount of the diethylene glycol component copolymerized in the polyester (unit mol% / polymer) Represents

(5) Dispersibility of Titanium Oxide 10 mg of a polymer was heated and dissolved on a slide glass, and the number of aggregates of titanium oxide having a size of 10 μm or more was counted by microscopic observation, and the result was expressed as co / 10 mg polymer.

(6) Intrinsic viscosity of polymer [η] Intrinsic viscosity (unit: dl) when the polymer is dissolved in an equivalent mixed solvent of phenol and tetrachloroethane and measured at 30 ° C.
/ g).

Examples 1 and 2 and Comparative Example 1 (Effect of Esterification Reaction Rate of Direct-Load Method Oligomer) A slurry of terephthalic acid and ethylene glycol (ethylene) was placed in an esterification reactor in which bis (2-hydroxyethyl) terephthalate and its oligomer were present. Glycol / terephthalic acid molar ratio 1.30),
The residence time was variously changed at 5 ° C. and normal pressure, and three types of esterification products having a conversion of 87%, 92%, and 96% calculated from a saponification value and an acid value were produced.

After adding 4 × 10 ^-2 % by weight of trimethylphosphite, 3 × 10 ^-2 % by weight of antimony trioxide and 4 × 10 ^-1 % by weight of sodium acetate to the respective esterified products, the present invention SIHE, i.e., sodium 3,5-di (carbo-2-hydroxyethoxy) benzenesulfonate having a transesterification rate of 35% prepared from dimethyl 5-sodium sulfoisophthalate and ethylene glycol was 4.0 mol% based on terephthalic acid. It was added sequentially over a period of 15 minutes. Then hold at 240 ° C for 20 minutes,
After forming a uniform melt, TiO ₂ was produced at a concentration of 0.1%.
3% by weight was added, and then pressure reduction was started to reach a pressure of 0.2 mmHg, and then a polycondensation reaction was performed until [η] became 0.500. Table 1 shows the physical properties of the obtained polymers.

As is clear from the above table, all of the modified polyesters of the present invention (Examples 1 and 2) produced little diethylene glycol and showed good dispersibility of titanium oxide.

Examples 3-4, Comparative Examples 2-4 (Preparation of SIHE) 300 kg of dimethyl 5-sodium sulfoisophthalate,
510 kg of ethylene glycol was charged into a transesterification reactor equipped with a rectification column. The temperature in the reactor at this point is 35 ° C
Met. Then, the temperature was raised to 120 ° C., and 0.48 kg of manganese acetate was added as a transesterification catalyst. Thereafter, by-produced methanol was taken out of the system.

After the transesterification catalyst was added, the reaction proceeded at a constant temperature of 120 ° C, and the transesterification reaction rates were 3%, 7%, 35%, and 60%.
Sodium 3,5-di (carb-2-hydroxyethoxy) benzenesulfonate was prepared with a target of and 75%.

The transesterification rate was checked by taking a small sample from the reactor as appropriate. It took time as shown in Table 2 to reach almost the target transesterification rate.

As shown in the table above, 3,5-
Sodium di (carbo-2-hydroxyethoxy) benzenesulfonate can be prepared in a relatively short time of about 1 hour 30 minutes or less including the preparation time.

(Effect of Transesterification Reaction Rate of SIHE) Sodium 3,5-di (carbo-2-hydroxyethoxy) benzenesulfonate prepared in Comparative Example 2, Examples 3 and 4, and a reaction rate of 96 prepared in Example 2 % Of each esterification product to prepare a polymer. The detailed catalyst conditions, addition conditions and polycondensation reaction conditions were the same as in Example 2.

 Table 3 shows the physical properties of the obtained polymers.

As is clear from the above table, each of the SIHEs used for the modified polyesters of the present invention (Examples 3 and 4) could be produced in a relatively short time. In addition, each of the modified polymers using the SIHE produced little diethylene glycol and had good dispersibility of titanium oxide.

Examples 5 to 8 and Comparative Examples 5 to 8 (Effects of Addition Method of SIHE and Method of Forming Melt) Slurry of terephthalic acid and ethylene glycol in an esterification reactor in which bis (2-hydroxyethyl) terephthalate and its oligomer are present (Ethylene glycol / terephthalic acid molar ratio 1.30) continuously
An esterification product having a reaction rate of 96% calculated from a saponification value and an acid value under normal pressure at 5 ° C was produced.

The esterification product contained 4 × 10 ^-2 % by weight of trimethylphosphite and 3 × 10 3 antimony trioxide with respect to the formed polymer.
^-2 % by weight and 4 × 10 ^-1 % by weight of sodium acetate were added, and then SIH having a transesterification rate of 35% was prepared from dimethyl 5-sodium sulfoisophthalate and ethylene glycol.
E, that is, sodium 3,5-di (carb-2-hydroxyethoxy) benzenesulfonate was successively added so as to be 4.0 mol% with respect to terephthalic acid, and the melt was held. Conditions for successive addition of SIHE and conditions for holding the melt were as shown in Table 4. Then TiO ₂ was added to the polymer at 0.30
% By weight, and then pressure reduction was started to reach a pressure of 0.2 mmHg, and a polycondensation reaction was carried out until [η] became 0.500. Table 4 shows the physical properties of each of the obtained polymers.

As is clear from the above table, all of the modified polyesters of the present invention (Examples 5 to 8) not only produced little diethylene glycol, but also had good dispersibility of titanium oxide.

[Effects of the Invention] By implementing the present invention, the following effects can be obtained.

It is possible to produce a basic dye-dyed polyester having good productivity and operability by the direct weight method, and to obtain the cost advantage of the direct weight method.

The content of titanium oxide agglomerates and by-product diethylene glycol in the polymer can be extremely reduced, the increase in furnace pressure during spinning and the reduction in yarn breakage can be achieved, and the spinnability is significantly improved.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Katsumata Kamata 1515 Tsutsui, Matsumae-cho, Iyo-gun, Ehime Prefecture Toray Ehime Plant Examiner Satoshi Morikawa (56) References JP-B-57-57054 (JP, B2) ( 58) Field surveyed (Int. Cl. ⁶ , DB name) C08G 63/00-64/42

Claims (1)

(57) [Claims] 1. A modified polyester containing titanium oxide, wherein at least 90 mol% of the constitutional unit is ethylene terephthalate and 0.5 to 10 mol% is ethylene isoterephthalate having a sulfonate group, using terephthalic acid as a raw material. In the production using a direct-polymerization oligomer, the esterification reaction rate of a dialkylester of isophthalic acid having a sulfonate group with ethylene glycol is converted to a direct-polymerization oligomer having an esterification reaction rate of 90 mol% or more.
The 2-hydroxyethyl ester of isophthalic acid with 4040% sulphonate groups is added sequentially over 5-40 minutes, 23
A method for producing a modified polyester, comprising holding at 0 to 260 ° C. for 5 to 40 minutes to form a uniform melt, and then adding titanium oxide to perform polycondensation.