JPS5998130A - Preparation of modified polyester - Google Patents

Abstract

PURPOSE:To provide a polyester containing a large amount of isophthalic acid component having metal sulfonate group, giving low increase of the inner pressure of a spinning pack, and having excellent heat resistance, by adding a mixture of specific metal sulfonate compounds to the raw materials of the polyester, and polymerizing the composition. CONSTITUTION:The objective polyester is prepared by adding a mixture of metal sulfonate compounds of formula II (N, L and K are molar numbers of the derivatives of sodium sulfoisophthalate, lithium sulfoisophthalate and potassium sulfoisophthalate, respectively) in the preparation of a polyester wherein at least 70mol% of the constituent unit is ethylene terephthalate and 3.5-15mol% is ethylene isophthalate unit having metal sulfonate group {e.g. the compound of formula I [M is Na, Li, or K; A and A' are lower alkyl or -(CH2)nOH; n is integer of >=2], e.g. dimethyl (5-sodium sulfo)isophthalate, etc.}, and polymerizing the obtained composition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyester copolymerized with an isophthalic acid component having a metal sulfonate group (hereinafter referred to as the S component).

More specifically, the present invention relates to a method for producing polyester that copolymerizes a large amount of the S component and that causes little increase in puncture internal pressure during spinning.

Polyester fibers, especially polyethylene terephthalate fibers, have a high melting point, high strength, high Young's modulus, good electrical properties,
It has excellent physical properties such as chemical resistance and is widely used for clothing and industrial purposes. However, the stainability is insufficient;
Therefore, high-temperature dyeing is required, and since it can only be dyed with disperse dyes and azo ink dyes, it has the drawback that it is difficult to obtain clear and deep hues.

As a means to solve these problems, various types of polyester dyeable with basic dyes, as typified by Japanese Patent Publication No. 34-10497, have been proposed, and as a result, it has become possible to use basic dyes with sharpness.

Among these, a method of copolymerizing polyester with 2 to 3 moles of 5T-sodium sulfoisophthalic acid component is known as a preferred method for making polyester dyeable with basic dyes.

However, the dyeability of the polyester fibers obtained by this method is not sufficient, and dyeing costs are high because it is necessary to dye at high temperatures of 110 to 140°C and high pressure, or to use a carrier under normal pressure. LX has its drawbacks.

The present inventors have developed a method for dyeing a sufficiently deep color at a dyeing temperature of 100°C or less without using a carrier. It was found that it was necessary to polymerize the modified polyester.Although such modified polyester itself is known in the above-mentioned Japanese Patent Publication No. 34-10497, it is necessary to polymerize it. When modified polyester containing polyester is spun at the usual polyester spinning temperature, spinner puncture sand configuration, spinneret hole diameter, and discharge rate, there are problems such as an increase in the spinning/thick internal pressure! - deplorable, and a significant decrease in operability; there were.

On the other hand, in order to give polyester fibers a soft A texture, it is required that they be made into ultrafine fibers.

Ultrafine fibers with a single filament fineness of 1.0 denier or less are difficult to manufacture using normal spinning methods. Therefore, they are composite-spun with a copolyester that has a faster alkali dissolution rate than normal polyester, and then subjected to alkali dissolution treatment. A well-known method is to elute the copolymerized polyester and obtain ultrafine fibers by dividing ordinary polyester into threads. A method is known in which a polyester copolymerized with a large amount of S component is used as the eluted component, but when producing split microfibers made of basic dye-dyeable polyester copolymerized with the S component, this It is necessary to significantly increase the dissolution rate. However, when the copolymerization rate of the S component is increased in this way, there is a problem that the pack internal pressure increases too much during spinning, making it difficult to stably spin the yarn.

In the present invention, there are two original purposes for producing a polyester copolymerized with a large amount of S component. The first option is to use a polyester dyeable with basic dyes that can be dyed under normal pressure. In this case, the copolymerization rate of the S component must be approximately 5.5 to 7 molar. Another purpose is to produce an eluted component for the production of composite split type polyester fibers, and although the composition of the split component depends on the composition, it is generally necessary to copolymerize the S component in a molar ratio of 5 to 15. As a result of studies conducted by the present inventors, it was found that when a polyester copolymerized with 6.5 to 15 mol% of the S component as described above is produced and spun, the internal puncture pressure during spinning increases significantly. .

In view of the above-mentioned problems, the present inventors have arrived at the present invention as a result of intensive studies on the increase in Sick internal pressure during spinning of an S component-rich copolymer and the heat resistance of the polymer.

That is, in the present invention, at least 70 moles of the constituent units are ethylene terephthalate (tere!). l) In producing a polyester in which 6.5 to 15 moles are ethylene isophthalate units having metal sulfonate groups, a mixture of metal sulfonate compounds represented by the following formula is added to complete the polymerization. This is a characteristic method for producing modified polyester.

0.05≦(L+K)/N≦0.40 The polyester of the tree invention has a dicarboxylic acid component whose main component is terephthalic acid or its ester-forming derivative,
Targets polyesters whose main glycol component is ethylene glycol.

In addition, a part of terephthalic acid can be substituted with p-β-hydroxyethynebenzoic acid, p-hydroxybenzoic acid, inphthalic acid,
4. a/-diphenylsulfonedicarboxylic acid%4.4'-diphenyl ether dicarboxylic acid
a. Ester-forming derivatives such as difunctional carboxylic acids such as 4/-diphenyldicarboxylic acid, 4,2-dibuenoxyethane-9% p'-dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, and sebacic acid. or replace a part of the glycol component with trimethylene glycol, tetramethylene glycol, hexamethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,4-cyclohexanediol, 114-cyclohexane dimetatool, 1
．． 4-bis-β-hydroxyethoxybenzene, bisphenol A, or other aliphatic, alicyclic, or aromatic dioxy compounds or their ester-forming derivatives substituted with 70 or more moles of repeating units in the main chain are ethylene terephthalate units. It may also be a certain copolymerized polyester. In particular, from the viewpoint of improving color development, it is more preferable to replace it with an inphthalic acid component having a polyalkylene glycol and an alkali metal sulfonate group.

Furthermore, in the polyester of the present invention, a small proportion of a chain branching agent such as pentaerythritol, trimethylolpronochloride, trimellitic acid, and trimesic acid, and a polymerization terminator such as monohydric polyalkylene oxide or phenylacetic acid is used. It is also possible.

Furthermore, when synthesizing polyester in the present invention, catalysts, color inhibitors, ether bond by-product inhibitors, antioxidants, flame retardants, etc. well known in the art may be appropriately used.

The metal sulfonate group-containing inphthalate component used in the present invention is specifically dimethyl (5-
Sodium sulfo) inphthalate, bis-2-hydroxyethyl (5-sodium sulfo) isophthalate,
Bis-4-hydroxybutyl (5-sodium sulfo)
Isophthalate, dimethyl (5-lithium sulfo) isophthalate, bis-2-hydroxyethyl (5-lithium sulfo) isophthalate, dimethyl (5-potassium sulfo) isophthalate, bis-2-hydroxyethyl (
5-potassium sulfo)inphthalate, etc., and its general formula is as follows.

303M The S component in the present invention needs to be in an amount of 6.5 mol % to 15 mol %, preferably 4.0 mol % to 7.0 mol %, based on the resulting polyester. S component is 3.5
If the molar ratio is less than 100°C, it will not be possible to dye deeply enough without using a carrier, and if it exceeds 15 molar ratio, the thickening effect during melting will be large, resulting in a high degree of polymerization. In particular, even if the degree of polymerization is increased by solid-phase polymerization, the melt viscosity is too high, making spinning difficult.

The S component may be added at any time until the polycondensation reaction is completed, but the particularly preferred addition time is bis-2-
In the case of bisglycol esters such as hydroxyethyl(5-sodium sulfo)inphthalate, this step is performed after the end of the transesterification reaction, or after the end of the esterification reaction and before the start of the polycondensation reaction. In the case of lower alkyl esters such as phthalates, this is a step before the start of the transesterification reaction.

The (L+K)/N ratio of the S component in the present invention is 0.05 to
It is necessary to set it as 0.4, and 0.1-0.3 is preferable.

If it is less than 1.05, the increase in pack internal pressure during spinning will become too much, and if it exceeds 0 or 4, although the increase in bag internal pressure can be suppressed, the effect will not only be saturated, but also
This is not preferred because the heat resistance of the resulting polyester decreases.

In the present invention, the alkali metal compound other than the metal sulfonate compound is added at 2 to 1
It is preferable to add 0 mol %, preferably 4 to 8 mol, from the viewpoint of more effectively suppressing the increase in bank internal pressure and from the viewpoint of heat resistance.

Such alkali metal compounds include compounds such as lithium, sodium, and potassium, and preferred specific compounds include lithium acetate, lithium carbonate, and lithium hydroxide.

An example of the method for producing polyester in the present invention is as follows.

Dimethyl terephthalate, dimethyl isophthalate with a predetermined amount of metal sulfonate groups, ethylene glycol, a predetermined amount of an alkali metal compound.

If necessary, other transesterification catalysts are added to the transesterification process, and the reaction mixture is gradually reacted from 140°C, and the temperature is raised to 230°C while distilling by-produced methanol out of the system. After the reaction is completed, antimony trioxide as a polymerization catalyst, a phosphorus compound as a stabilizer, and, if necessary, a matting agent are added, and the mixture is transferred to a polymerization vessel. Next, polymerization is carried out according to a conventional method to obtain polyester chips.

If the desired polymer is pressure-dyable polyester,
Dimethyl inophthalate with metal sulfonate group is 3
．． A 5 to 7 mol co-heavy water reester is produced, and then spun and drawn according to a conventional method.

On the other hand, when the target polymer is an eluted component of split type ultrafine fibers, a polyester is produced by copolymerizing 5 to 15 moles of dimethyl isophthalate having a metal sulfonate group. Next, the fibers are made into split composite fibers using a conventional method, and after being made into a fabric, they are subjected to alkali dissolution treatment to dissolve and remove the eluted components of the present invention to produce ultrafine fibers. Note that the polyester to be divided may be a homopolyester or a copolyester, but in the case of a copolyester, it is preferable to change the copolymerization rate of the S component of the component to be divided (from this, the eluted component).

The present invention will be specifically explained below with reference to Examples.

In the examples, parts mean parts by weight, and % by weight. Further, various measurement and evaluation methods in the present invention are as follows.

(Method for measuring intrinsic viscosity [η]) A polymer is dissolved in o-chlorophenol, and the value is expressed as the value measured at 25°C.

(Heat resistance) Polyester chip 81 has a diameter of 16 mm and a length of 15 cm.
After vacuum drying at 140°C for 16 hours,
50 [Heat-treated at 1°C for 1 hour under a N2 stream and then rapidly cooled. After vacuum drying at 60° C. for 3 hours, the terminal groups are measured by a conventional method and the number average molecular weight is calculated. Next, the number average molecular weight before and after the heat treatment is calculated based on the following number.

O 6 (Mo%M indicates the respective number average molecular weights before and after heat treatment) (Method for creating tubular knitting) The filament yarn to be evaluated was stranded on a 27-gauge sock knitting machine (manufactured by Koike Kikai Seisakusho) and tubular knitted fabric. organize.

(Dyeability) The tubular knitting was refined in a conventional manner, and then malachite green (trade name, manufactured by Kanto Kagaku) 5%□wfb acetic acid 0.5 g/J s
Sodium acetate 0.2 g/l, bath ratio 1:1oo.

It was determined by the dye exhaustion rate (hereinafter abbreviated as MG exhaustion rate) by dyeing at a temperature of 100°C, a dyeing time of 1 hour, and a water solvent.

Here, if the %MG exhaustion rate is 60% or more, it can be said that there is normal pressure dyeability.

Example 1 100 parts of dimethyl terephthalate, 6 parts of ethylene glycol
2 parts, 0.19 parts of lithium acetate dihydrate (7 moles per t of S component), 0.03 parts of manganese acetate tetrahydrate, and 0.04 parts of antimony trioxide.

8 parts of dimethyl metal sulfoiphthalate (S component) having the composition ratio shown in Table 1 was charged into a transesterification tank, and methanol by-produced was added to the transesterification tank over 4 hours while stirring from 140°C to 230°C under atmospheric pressure. The reaction was carried out by raising the temperature while distilling it out.

Next, add 0.043 parts to trimethyl phosphate 7 and add 200 parts
Ethylene glycol was expelled under reduced pressure in the range of ~76[]WHg to obtain a low polymer with an ethylene glycol component/terephthalic acid component molar ratio of about 1.6.

After transferring this low polymer to a polymerization tank, 13% titanium dioxide was added.
After adding 2.47 parts of the ethylene glycol slurry, the temperature was raised from 24 parts to 285°C over 1.5 hours.
And from 76°11m Hg to 111m H over 1 hour
The pressure was then reduced to 11/m Hg or less, and the polycondensation reaction was carried out at 285° C. for 1 hour. The properties of the obtained polymer are shown in Table 1.

Next, this polyester was dried under reduced pressure at 160° C. for 5 hours, and then discharged at 131 r/min using a pack with a filtration area of 447 using 30 mesh 1001i'/60 mesh Morundum Sand 100v and a 0.25 Wφ round hole nozzle.
Melt spinning was carried out at a spinning speed of 1400 m/min and a spinning temperature of 300°C. Table 1 shows the rise in internal pressure of the spinning pack at that time.

Next, the yarn was drawn at a drawing ratio of 2.4 times, a drawing speed of 600 m/min, and a drawing temperature of 92° C. to produce a yarn of 75 denier and 36 filaments.

In Experiments A 4 and 5, which are comparative experiments to clearly demonstrate the effects of the present invention, (r, +x)/N was less than 0.05, so the increase in pack internal pressure during spinning was poor. Similarly, in Experimental Stores 6 and 7, since (L0K)/N was large, the heat resistance was poor although the effect of suppressing the pack internal pressure was recognized. On the other hand, when (L0K)/N is within the range of the present invention, a deviation of υ1 is also good.

Example 2 Example 1, except that the lithium acetate dihydrate and the amount added were changed as shown in Table 2.
Polymerization and spinning were carried out in the same manner as above. Table 2 shows the properties of the polymer and the increase in pack internal pressure.

Claims (1)

[Scope of Claims] In producing a polyester in which at least 70 mole units of the structural unit are ethylene terephthalate, and 6.5 to 15 mole units are ethylene isophthalate units having a metal sulfonate group, A method for producing a modified polyester, which comprises adding a mixture of metal sulfonate compounds to complete polymerization. 0.05≦(L+K)/N≦0.40