JPH0741552A - Production of modified polyester - Google Patents

Abstract

PURPOSE:To provide a production method of a modified polyester which uses an isophthalic acid compd. having a sulfonate group as a comonomer to produce a modified polyester and which greatly decrease the amt. of insol. impurities causative of the pressure rise during spinning and filtering. CONSTITUTION:The modified polyester contg. at least 80mol% alkylene terephthalate units and 0.5-10mol% alkylene isophthalate units having a sulfonate groups is produced by using an isophthalic acid compd. having a sulfonate group as a comonomer under the condition that a metal alkylbenzenesulfonate in an amt. of 10-100mol% of the isophthalic acid compd. is added to the polymn. system. Thus, a high-quality polyester which has sulfonate groups and can be dyed with a basic dye is produced while inhibiting the occurrence of impurities due to the isophthalic acid compd. and enabling avoidance of thread breakage.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an improved process for the production of basic dye readily dyeable polyesters having sulfonate groups.

[0002]

2. Description of the Related Art Polyesters, particularly aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, are widely and generally used because they have excellent fiber-forming ability and excellent performance as fibers. However, it cannot be said that the dyeability is good as a fiber for clothing.

Further, since it is dyeing with a disperse dye, only limited dyes can be used, and there are drawbacks such as poor sharpness of dyed products. Conventionally, in order to compensate for such drawbacks,
A method of producing a modified polyester dyeable with a basic dye by copolymerizing an isophthalic acid compound having a sulfonate group (Japanese Patent Publication No. 34-10497) is known.

[0004] However, a method for producing a polyester, which is usually adopted a copolyester of an isophthalic acid compound having such a sulfonate group (hereinafter referred to as a modified polyester), that is, an ester of mainly terephthalic acid and mainly ethylene glycol When the product is produced by a direct esterification method in which a polycondensation reaction is carried out by a polycondensation reaction or by a transesterification method in which a transesterification reaction product of mainly dimethyl terephthalate and mainly ethylene glycol is subjected to a polycondensation reaction, insoluble foreign matters are obtained in the polymer obtained. It tends to occur, and the rate of increase in the pressure of the polymer filtration section (hereinafter referred to as spinning filtration pressure) during molding, particularly during melt spinning, becomes high. At this time, if the spinning is continued while the spinning filtration pressure is too high, the spinning process such as spinning yarn breakage and drawing yarn breakage, and increase in fluff, the deterioration of the spinning process and the twisting process, and the deterioration of the quality of the final product may result. Since a trouble occurs, the parts composed of the polymer filtration section and the spinneret section have to be replaced in a very short period of time as compared with a normal polymer, resulting in a marked decrease in productivity.

As a method for improving such a drawback of lowering productivity, Japanese Patent Application Laid-Open No. 58-138731 discloses an addition ratio of an alkali metal compound and a phosphorus-containing compound used in combination with an isophthalic acid compound having a sulfonate group. However, in reality, the resulting modified polyester does not always have satisfactory productivity.

The same applies to the modified polyester obtained by the direct esterification method. Since there are more insoluble foreign matters in the polymer than the modified polyester obtained by the transesterification method, for example, an ester of terephthalic acid and ethylene glycol. A method of adding a dialkyl ester of an isophthalic acid compound having a sulfonate group at a conversion rate of 80 to 98.5% (JP-A-51-41795).
Or a method of adding an ethylene glycol solution of an ethylene glycol ester of isophthalic acid having a sulfonate group and an alkali metal compound to an esterification reaction product (JP-A-56-106922). There is.

However, even with the modified polyester obtained by such a method, the rate of increase in spinning filtration pressure is still large, and this problem has been a problem for many years.

[0008]

DISCLOSURE OF THE INVENTION An object of the present invention is to eliminate insoluble foreign matters in a polymer, which causes an increase in spinning filtration pressure when producing a modified polyester in which an isophthalic acid compound having a sulfonate group is copolymerized. It is intended to provide a significantly reduced polymerization process.

[0009]

In order to solve this problem, the inventors of the present invention have modified polyester obtained by copolymerizing an isophthalic acid compound having a sulfonate group, which is polymerized by a generally known polymerization method. When the clogging of the filtration part when the polymer was spun was analyzed, a polyester and an oligomer (hereinafter referred to as SI, which consisted mainly of an isophthalic acid compound having a sulfonate group and an alkylene glycol) were analyzed.
It is referred to as PP), and it was found that it is an infusible substance.

Although the cause of occurrence of this SIPP is not clear, the present inventors have found that, in the prepolymerization process, the alkylene glycol ester component of the isophthalic acid compound having a sulfonate group and the alkylene glycol ester of the dicarboxylic acid forming the base polymer. The affinity of the components is significantly different, which causes a kind of phase separation state
It was estimated that PP was in a state in which it was extremely easily generated. Therefore, if it is possible to eliminate this phase separation state, SIPP
Based on the idea that it could suppress the formation of benzene, we succeeded in producing a modified polyester polymer in which the increase rate of spinning filtration pressure was significantly suppressed by adding a metal salt of alkylbenzene sulfonate with high surface activity. .

That is, in the present invention, at least 80 mol% of the components constituting the polyester is alkylene terephthalate, and 0.5 to 10 mol% is alkylene isophthalate having a sulfonate group. In addition, 10 to 100 mol% of a metal salt of alkylbenzene sulfonic acid is added to an isophthalic acid compound having a sulfonate group which is a constituent of the alkylene isophthalate.

The alkylene terephthalate referred to in the present invention contains terephthalic acid as a main acid component and at least one selected from ethylene glycol, tetramethylene glycol, cyclohexane-1,4-dimethanol, pentamethylene glycol and hexamethylene glycol. It is a polyester as a glycol component, and a small amount of a third component, usually 10 mol% or less, may be copolymerized with the polyester. Examples of the copolymerizable component include isophthalic acid, naphthalenedicarboxylic acid, adipic acid, dicarboxylic acids such as cyclohexane-1,4-dicarboxylic acid, and P-oxybenzoic acid. Further, within the range where the polyester is substantially linear, polycarboxylic acids such as trimellitic acid and pyromellitic acid or polyols such as glycerin, trimethylolpropane and pentaerythritol, and polyalkylenes such as polyethylene glycol and polypropylene glycol. It is possible to use glycols.

Any method can be used to produce alkylene terephthalate. Explaining polyethylene terephthalate, either terephthalic acid and ethylene glycol are esterified or a lower alkyl ester such as dimethyl terephthalate and ethylene glycol are used. And a second step reaction in which a glycol ester of terephthalic acid and a low polymer thereof are formed by transesterification of and with each other, and a reaction step in which the reaction product of the first step is heated under reduced pressure to cause a polymerization reaction. The method of manufacturing is generally adopted.

Any catalyst can be used in these reactions, if necessary. Among them, when the transesterification reaction method is adopted, a manganese compound, a cobalt compound, a calcium compound, a magnesium compound or the like is preferable as the transesterification catalyst, and these may be used alone or in combination of two or more. The amount used is 0.01 to 0.01 with respect to the difunctional carboxylic acid component used as the polyester raw material.
0.1 mol% is preferable. If it is less than 0.01 mol%, the transesterification reaction takes a long time, and if it exceeds 0.1 mol%, coloring is observed, which is not preferable.

As the polycondensation catalyst, antimony compounds, titanium compounds and germanium compounds are preferable. These polycondensation catalysts may also be used alone or in combination of two or more,
The amount used is 0.00 with respect to the bifunctional carboxylic acid component.
3 to 0.1 mol% is preferable. If it is less than 0.003 mol%, the polycondensation reaction takes a long time, and if it exceeds 0.1 mol%, it is not preferable in terms of polymer coloring.

The isophthalic acid compound having a sulfonate group used in the present invention is represented by the general formula (1).

[0017]

[Chemical 1]

The compound represented by the general formula (1) is preferably 5-sodium dimethyl sulfoisophthalate,
5-lithium sulfoisophthalic acid dimethyl, 5-sulfoisophthalic acid bis (p-hydroxyethyl) ester,
Examples include 5-lithium sulfoisophthalic acid bis (p-hydroxyethyl) ester. The copolymerization amount of the isophthalic acid compound having a sulfonate group in the present invention is preferably 0.5 to 10 mol%, and particularly preferably 1 to 4 mol% based on the bifunctional carboxylic acid component.

If the amount of the isophthalic acid compound having a sulfonate group is less than 0.5 mol%, the resulting modified polyester has an insufficient affinity for the basic dye, and 10
If it exceeds mol%, not only the excellent characteristics peculiar to polyester are impaired, but also the production cost of the polyester increases, which is industrially difficult. The alkylbenzene sulfonic acid metal salt used in the present invention is represented by the general formula (2).

[0020]

[Chemical 2]

Preferred compounds represented by the general formula (2) are sodium dodecylbenzenesulfonate, potassium dodecylbenzenesulfonate, lithium dodecylbenzenesulfonate, calcium dodecylbenzenesulfonate, magnesium dodecylbenzenesulfonate and octylbenzene. Examples thereof include sodium sulfonate and sodium stearylbenzene sulfonate, and sodium dodecylbenzene sulfonate is particularly preferable.

It is necessary to add 10 to 100 mol% of the alkylbenzene sulfonic acid metal salt to the isophthalic acid compound having a sulfonate group.
When it is less than 10 mol%, the effect of suppressing the increase in spinning filtration pressure is small, and when it exceeds 100 mol%, the cost is increased and the hue of the polymer is deteriorated, which is not preferable. More preferably, it is 10 to 60 mol%.

The alkylbenzene sulfonic acid metal salt is preferably added at either the transesterification reaction time or the prepolymerization reaction time, not the polycondensation reaction time. Particularly preferably, the prepolymerization time is preferable in order to suppress coloration of the polymer. Further, when the metal salt of alkylbenzene sulfonic acid is added, foaming easily occurs during roughing. Therefore, it is preferable to add an antifoaming agent such as defoaming silicon in an amount of 1 to 5% by weight based on the alkali metal salt of alkylbenzene sulfonic acid. Alternatively, instead of the defoaming agent, polyethylene glycol having no foaming property (average number molecular weight 500 to 6000),
Polypropylene glycol (average number molecular weight 500-60
The foaming phenomenon can be suppressed by adding polyalkylene glycols such as 00) in almost the same weight as the alkylbenzene sulfonic acid metal salt.

In the present invention, by adding an alkali metal compound at the same time as or before the addition of the isophthalic acid compound having a sulfonate group, it is possible to suppress the production of diethylene glycol due to a side reaction, and to improve the quality of the product. It is preferable because a high quality polyester can be obtained. As the alkali metal compound, hydroxides, organic carboxylates, alcoholates, weak inorganic acid salts and the like are suitable, and specifically, hydroxides of sodium, lithium and potassium, aliphatic carboxylic acids such as acetates and formates. Examples thereof include salts, aromatic carboxylic acid salts such as benzoate, methylate, ethylate, butyrate, carbonate and borate. The addition amount is 0.01 with respect to the isophthalic acid compound having a sulfonate group.
~ 0.1 mol% is preferred.

In addition, a pigment component such as titanium oxide, a heat stabilizer such as a phosphorus compound, and a color tone improving agent such as a cobalt compound may coexist.

[0026]

EXAMPLES Next, the method of the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. The reduced viscosity is 35 in orthochlorophenol.
The concentration was measured at 1 ° C (g / ml). In the examples, parts and% indicate parts by weight and% by weight, respectively.

The hue of the polymer is SM manufactured by Suga Test Instruments Co., Ltd.
Measured by color computer, CIE is 197
Of the color systems recommended for 6 years, L * is used as a parameter that expresses lightness and b * is used as a parameter that expresses the degree of yellowness.
It compared using the value of. The larger the L * value and the b * value, the better the hue of the polymer. The spinnability is 28 mesh, 42 mesh, 50 g of sand, the filter is 300 mesh wire mesh, the filtration area is 20c.
Spinning temperature of 290 ° C., spinning speed of 1500 m, using a m ² pack and a spinneret of 0.23 mmΦ and 24 holes
Spinning was carried out at a speed of about 1 / min, and changes in the spinning filtration pressure and the situation of spinning yarn breakage were examined.

[0028]

Example 1 Dimethyl terephthalate (DMT) 100
Parts, 70 parts of ethylene glycol, dimethyl 5-sodium sulfoisophthalate (hereinafter referred to as SIPM) 3.3 parts (corresponding to the case where alkylene isophthalate is 2.1 mol% in the components constituting the polyester). ,
Lithium acetate dihydrate 0.1 as an ether formation inhibitor
Parts, manganese acetate tetrahydrate as transesterification catalyst 0.0
Charge 5 parts, gradually heat from 150 ℃ to 240 ℃,
The transesterification reaction was carried out while distilling out methanol for 3 hours. Next, 0.02 part of trimethyl phosphate as a stabilizer, 0.05 part of antimony trioxide as a polycondensation catalyst, and 6.6 parts of a 30% ethylene glycol solution of sodium dodecylbenzenesulfonate (hereinafter referred to as DBS) as a pack pressure suppressor. (SIPM ratio 51.5 mol%), and 0.05 part of YSA-6403 (manufactured by Toshiba Silicon Co., Ltd.) as an antifoaming agent was added, and prepolymerization was performed for 50 minutes. The pressure is gradually reduced (final 0.5 Tor)
r) After polycondensation reaction at 275 ° C. for 2 hours and 40 minutes, ηsp
A modified polyester having /C=0.560 and a softening point of 252 ° C. was obtained. Polymer hue is L * = 65.5, b * = 6.0
It was good.

When spinning was performed using this polymer,
Spinning yarn breakage is small, and the speed of increase in spinning filtration pressure is 3.6K.
It was g / cm ² / day, and the spinning filtration pressure increase rate was about ¼ of that of the polymer of Comparative Example 1.

[0030]

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that DBS and modified silicon were not added, and ηsp / C =
A modified polyester having a softening point of 0.563 and a softening point of 253 ° C. was obtained. The polymer hue was L * = 66.6 and b * = 5.0, which were good. When spinning was carried out using this polymer, the rate of increase in spinning filtration pressure was 14.4 Kg / cm ² / day, and the pack life was as short as 7 days.

[0031]

[Examples 2 to 5]

Comparative Examples 2 to 3 The procedure of Example 1 was repeated, except that the type and amount of the isophthalic acid compound having a sulfonate group and the alkali metal alkylbenzene sulfonate were changed as shown in Table 1. Table 1 also shows the quality of the obtained modified polyester and the spinning filtration pressure increase rate.

[0032]

Example 6 88 parts of dimethyl terephthalate (DMT),
Ethylene glycol 70 parts, SIPM 10 parts (Of the polyester constituents, alkylene isophthalate is 7.
This corresponds to 5 mol%. ), 0.3 part of lithium acetate dihydrate as an ether formation inhibitor and 0.05 part of manganese acetate tetrahydrate as an ester exchange catalyst are charged at 150 ° C to 2 ° C.
The mixture was gradually heated to 40 ° C., and transesterification was performed for 3 hours while distilling out methanol. Then, 0.02 part of trimethyl phosphate as a stabilizer, 0.05 part of antimony trioxide as a polycondensation catalyst, and 30% ethylene glycol solution of DBS as a pack pressure suppressor 6.6.
Part (17 mol% relative to SIPM), number average molecular weight 2000
2.0 parts of polyethylene glycol was added and prepolymerization was carried out for 50 minutes. The pressure was further gradually reduced (final 0.5 Torr) and polycondensation reaction was carried out at 270 ° C. for 2 hours and 40 minutes to obtain a modified polyester having ηsp / C = 0.440 and a softening point of 244 ° C. Polymer hue is L * = 65.3,
b * was 7.0, which was good.

When spinning was carried out using this polymer,
Spinning yarn breakage is small, and the spinning filtration pressure rise rate is 6.0K.
It was g / cm ² / day.

[0034]

Comparative Example 4 Polymerization was carried out in the same manner as in Example 6 except that DBS was not added, and ηsp / C = 0.405, softening point 243 ° C., polymer hue L * = 66.0, b * = 5.
A polymer of 4 was obtained. When spinning was carried out using this polymer, the rate of increase in spinning filtration pressure was 20.0 Kg / cm ^2.
/ Day.

[0035]

Example 7 86 parts of terephthalic acid and 38 parts of ethylene glycol were heated at 180 ° C. to 235 ° C. under a pressure of 3 kg / cm 2.
The mixture was heated to 0 ° C., water was distilled off for about 3 hours to carry out the esterification reaction. Then, 0.02 part of trimethyl phosphate, 0.05 part of antimony trioxide, 4.0 parts of 5-sodium sulfoisophthalic acid bis (p-hydroxyethyl) ester (hereinafter referred to as SIPG) 4.0 parts (of the polyester constituent components, alkylene iso This corresponds to the case where the phthalate is 2.1 mol%), and lithium acetate dihydrate 0.1.
Parts, 6.6 parts of 30% ethylene glycol solution of DBS (sulfoisophthalic acid component ratio 51.5 mol%), YSA
-6403 (manufactured by Toshiba Silicon Co., Ltd.) was added, and prepolymerization was performed for 50 minutes. The pressure was gradually reduced (final 0.5 Torr), and polycondensation reaction was performed at 275 ° C. for 2 hours and 40 minutes, and ηsp / C = 0.555, softening point 25
A modified polyester of 1 ° C. was obtained. Polymer hue is L * =
66.0 and b * = 6.5, which were good.

When spinning was performed using this polymer,
Spinning yarn breakage is low and the speed of spinning filtration pressure rise is 4.0K
It was g / cm ² / day.

[0037]

Comparative Example 5 Polymerization was carried out in the same manner as in Example 7 except that DBS and antifoaming agent were not added, and ηSP / C = 0.55.
8, softening point = 251 ° C., polymer hue L * = 67.0,
A polymer with b * = 5.3 was obtained. As a result of spinning evaluation, the rate of increase in spinning filtration pressure was 16.0 Kg / cm ² / day.

[0038]

Example 8 In place of the addition of SIPM in Example 1, 4.0 parts of SIPG after addition of antimony trioxide (corresponding to 2.1 mol% of alkylene isophthalate among polyester constituents). Polymerization was performed in exactly the same manner except that the addition was performed, and ηSP / C = 0.561, softening point = 254
C., a polymer having a polymer hue L * = 66.8 and b * = 5.5 was obtained. As a result of spinning evaluation, the rate of increase in spinning filtration pressure was 3.3 Kg / cm ² / day.

[0039]

[Table 1]

[0040]

When the method for producing a modified polyester of the present invention is adopted, in the method for producing a polyester modified by copolymerizing an isophthalic acid component having a sulfonic acid group and dyeable with a basic dye, It is possible to suppress the generation of foreign matter due to the isophthalic acid component having a sulfonic acid group, and it is possible to easily produce a high-quality polyester that does not cause yarn breakage.

Claims (1)

[Claims] 1. At least 80 mol% of the components constituting the polyester is alkylene terephthalate,
When producing a modified polyester in which 0.5 to 10 mol% is an alkylene isophthalate having a sulfonate group, 10 to 10 parts by weight of an isophthalic acid compound having a sulfonate group that is a constituent of the alkylene isophthalate is used.
A method for producing a modified polyester, which comprises adding 100 mol% of a metal salt of alkylbenzenesulfonic acid.