WO2020213519A1 - Polyester composition - Google Patents

Abstract

The present invention provides a polyester composition that exhibits a very good water absorption capacity at room temperature and is capable of conjugate spinning with polyethylene terephthalate resin or polyamide resin. A polyester composition according to the present invention is a polyester composition obtained by the polycondensation reaction of alkylene glycol with at least one of dicarboxylic acid and an ester-forming derivative of dicarboxylic acid. The polyester composition can be melt-formed in the range of 230°C to 300°C, and the volume of the composition increases by 50% to 3,000% when the composition is allowed to stand for 1 week at 50°C and is then immersed for 1 hour in ion-exchanged water at 30°C.

Description

Polyester composition

The present invention relates to a polyester composition, and more particularly to a polyester composition used for melt spinning.

Composite fibers that can be made multifunctional by combining multiple polymers are widely used not only for clothing but also for diapers and face masks, and have extremely high industrial value. The required characteristics required for these applications are becoming more sophisticated, and one of the characteristics is excellent water absorption capacity. Since the water absorption capacity of the composite fiber largely depends on the water absorption capacity of the polymer constituting the composite fiber, a polymer having an excellent water absorption capacity is required.

Sodium polyacrylate is well known as a polymer having excellent water absorption capacity, but its molding cost is very high because it requires solution spinning and post-crosslinking to be used as a fiber, and it can be developed as a textile product. There is a problem that it is difficult. Further, since melt spinning is not possible, composite fibers with nylon, polyester resin, or the like cannot be obtained (Patent Document 1). Therefore, as a water-absorbent polymer capable of melt spinning, a copolymerized polybutylene terephthalate composition to which a large amount of polyalkylene glycol compound is added has been proposed (Patent Documents 2 and 3).

Japanese Patent Application Laid-Open No. 4-80234 Japanese Patent Application Laid-Open No. 2003-253100 Japanese Patent Application Laid-Open No. 2004-137418

However, although the copolymer polybutylene terephthalate composition described in Patent Documents 2 and 3 has sufficient melt moldability and can be melt-composite molded with other polymers, it is used for applications such as diapers and face masks. The problem was found that the water absorption capacity was insufficient. That is, the amount of water absorbed by these copolymer polybutylene terephthalate compositions in water at 30 ° C. for 1 hour was less than 0.4 g per 1 g of the polymer.

Therefore, an object of the present invention is that it can be melt-composite molded with a general thermoplastic polymer such as polyethylene terephthalate or nylon 6, and has a sufficient water absorption capacity, specifically, water absorption for 1 hour in water at 30 ° C. It is an object of the present invention to provide a polyester composition having an amount of 0.4 g or more per 1 g of the polymer.

The above problem is solved by any of the following (1) to (7).
(1) A polyester composition obtained by a polycondensation reaction of at least one of a dicarboxylic acid and an ester-forming derivative of a dicarboxylic acid with an alkylene glycol, which can be melt-molded in the range of 230 to 300 ° C. A polyester composition whose volume is increased to 50 to 3000% by allowing it to stand at 50 ° C. for 1 week and then immersing it in ion-exchanged water at 30 ° C. for 1 hour.
(2) In the above (1), the glass transition point obtained by measuring the differential scanning calorimetry after allowing to stand at 50 ° C. for one week is 0 to 30 ° C., and the heat of crystal melting is in the range of 0 to 12 J / g. The polyester composition described.
(3) Polyethylene glycol in which the isophthalic acid component containing a metal sulfonate group is copolymerized in an amount of 4.0 to 15.0 mol% with respect to the total acid component and the number average molecular weight is 1000 to 20000 is 0 to 12 with respect to the entire composition. The polyester composition according to (1) or (2) above, which is contained in the range of 5.5% by weight.
(4) At least one selected from the group consisting of 5.0 to 30.0 mol% of the terephthalic acid component with respect to the total acid component, and isophthalic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, adipic acid and sebacic acid. The polyester composition according to any one of (1) to (3) above, wherein the total of the dicarboxylic acid components of the above is 60.0 to 85.0 mol% copolymerized with respect to the total acid components.
(5) The polyester composition according to any one of (1) to (4) above, wherein the weight average molecular weight is in the range of 35,000 to 80,000.
(6) One of the above (3) to (5) containing a titanium metal atom in the range of 0.01 to 0.65% by weight and a lithium metal atom in the range of 0.02 to 0.10% by weight. The polyester composition described.
(7) The polyester composition according to any one of (3) to (6) above, wherein the amount of carboxyl terminal groups is in the range of 10.0 to 45.0 eq / ton.

According to the present invention, since stable melt moldability at high temperature and a high volume increase rate can be achieved at the same time, composite spinning with polyethylene terephthalate or nylon 6 is possible, and extremely excellent water absorption capacity at room temperature is achieved. The polyester composition shown is obtained. Such a composition can be suitably used for diapers, face masks and the like.

The composition of the present invention is subjected to a polycondensation reaction between at least one of a dicarboxylic acid and an ester-forming derivative of a dicarboxylic acid (hereinafter, also referred to as "dicarboxylic acid and / or an ester-forming derivative thereof") and an alkylene glycol. The obtained polyester composition can be melt-molded in the range of 230 to 300 ° C., and is allowed to stand at 50 ° C. for 1 week and then immersed in ion-exchanged water at 30 ° C. for 1 hour to have a volume of 50. A composition that increases to ~ 3000%.

Examples of the dicarboxylic acid that can be used in the polyester composition of the present invention include aromatic dicarboxylic acid compounds typified by terephthalic acid and isophthalic acid, aliphatic dicarboxylic acid compounds typified by adipic acid and sebacic acid, and cyclohexanedicarboxylic acid. Examples thereof include, but are not limited to, alicyclic dicarboxylic acid compounds. For example, it is preferable to use an aromatic dicarboxylic acid compound, and it is more preferable to use terephthalic acid or isophthalic acid from the viewpoint of excellent polycondensation reactivity. Examples of the ester-forming derivative of the dicarboxylic acid include methyl esters of the dicarboxylic acids, alkyl esters such as ethyl esters, acid halides such as acid chlorides and acid halides thereof, and acid anhydrides. For example, an alkyl ester of a dicarboxylic acid is preferable, and a methyl ester of a dicarboxylic acid is particularly preferable from the viewpoint of excellent polycondensation reactivity. As the dicarboxylic acid component, one of these compound types may be used, or two or more types may be combined.

In the polyester composition of the present invention, the type of the alkylene glycol to be polycondensed with the dicarboxylic acid and / or its ester-forming derivative is not particularly limited, but 1,4-butanediol and 1 are excellent in polycondensation reactivity. , 3-Propanediol, ethylene glycol, or a combination thereof is preferable.

Since the suitable molding temperature of polyethylene terephthalate is 280 to 300 ° C. and the suitable molding temperature of polybutylene terephthalate or nylon 6 is 230 to 280 ° C., the polyester composition of the present invention assuming melt composite molding with these polymers. It is essential that the product has a melt-moldable temperature in the range of 230 to 300 ° C. Here, the determination as to whether or not the melt moldable temperature is in the range of 230 to 300 ° C. is based on the melt moldability evaluation method described later in the column of Examples. From the viewpoint of suppressing thermal decomposition of polybutylene terephthalate, nylon 6 and the like during composite molding, the melt molding temperature of the polyester composition of the present invention is preferably 285 ° C. or lower. The melt molding temperature of the polyester composition of the present invention is preferably 260 ° C. or higher from the viewpoint of sufficiently melting polyethylene terephthalate during composite molding.

In order for the polyester composition of the present invention to have an excellent water absorption capacity particularly when formed in a composite form, it should be allowed to stand (pretreatment) at 50 ° C. for 1 week and then immersed in ion-exchanged water at 30 ° C. for 1 hour. It is essential that the volume be increased in the range of 50% or more and 3000% or less. Here, the degree of increase in volume may indicate a volume increase, volume increase rate is 50%, for example, the volume of 100 m ³ is meant to increase the 150 meters ^3. When the volume increase rate is 50% or more, a water absorption amount of 0.4 g or more per 1 g of the polymer can be achieved. From the viewpoint of exhibiting more excellent water absorption capacity, the volume increase rate is preferably 100% or more, more preferably 200% or more, further preferably 500% or more, and further preferably 1000% or more. Is the most preferable. On the other hand, when the volume increase rate is higher than 3000%, the distance between the polymer molecular chains increases in water, the intermolecular force decreases, and the polymer disintegrates and dissolves. Therefore, the polyester composition of the present invention It is essential that the volume increase rate is 3000% or less.

From the viewpoint of making the polyester composition of the present invention excellent in water absorption capacity, the glass transition point obtained by measuring the differential scanning calorimetry after standing at 50 ° C. for 1 week is 30 ° C. or less and the amount of heat of crystal melting. Is preferably 12 J / g or less. When the glass transition point is near room temperature, which is common, the molecular motility is increased and the volume increase in water is promoted. Further, since it is the amorphous portion of the polymer that increases in volume when immersed in water, the effect of the present invention can be easily obtained as the number of crystalline portions decreases. The amount of heat of crystal melting is more preferably 9 J / g or less, further preferably 6 J / g or less, particularly preferably 3 J / g or less, and most preferably 0 J / g. Incidentally, the lower limit of the amount of heat of crystal melting that can be taken is 0 J / g.

On the other hand, if the heat of crystal melting is 12 J / g or less and the glass transition point is too low, the pellets are likely to be deformed and fused during storage, and the storage stability of the pellets deteriorates. Therefore, the heat of crystal melting is 12 J / g. The glass transition point is preferably 0 ° C. or higher, and more preferably 10 ° C. or higher, in order to improve the storage stability of the pellet while keeping the g or less.

In order to control the above physical properties, the polyester composition of the present invention may be copolymerized as follows when undergoing a polycondensation reaction.

In the polyester composition of the present invention, at least one of the metal sulfonate group-containing isophthalic acid and the ester-forming derivative thereof is copolymerized when the dicarboxylic acid and / or the ester-forming derivative thereof is polycondensed with the alkylene glycol. You may.

By copolymerizing the isophthalic acid component containing a metal sulfonate group, the hydrophilicity of the polymer is improved, and a polyester composition having excellent water absorption ability can be obtained. The copolymerization amount of the metal sulfonate group-containing isophthalic acid component is preferably 4.0 mol% or more, more preferably 7.0 mol% or more, based on the total acid component, from the viewpoint of improving the water absorption capacity. preferable. On the other hand, if the amount of the metal sulfonate group-containing isophthalic acid component is excessive, the melt moldability of the polymer deteriorates. Therefore, the copolymerization amount is preferably 15.0 mol% or less, and more preferably 10.0 mol% or less. preferable.

Examples of the metal sulfonate group-containing isophthalic acid include 4-sulfoisophthalic acid sodium salt, 4-sulfoisophthalic acid potassium salt, 5-sulfoisophthalic acid sodium salt, 5-sulfoisophthalic acid potassium salt, and 5-sulfoisophthalic acid barium salt. Can be mentioned. Of these, 5-sulfoisophthalic acid sodium salt and 5-sulfoisophthalic acid potassium salt are preferable, and 5-sulfoisophthalic acid sodium salt is particularly preferable from the viewpoint of excellent polycondensability. As the isophthalic acid containing these metal sulfonate groups, one having one kind of chemical structure may be used, or one in combination of two or more kinds may be used.

Examples of the ester-forming derivative of the metal sulfonate group-containing isophthalic acid include alkyl esters such as their methyl esters and ethyl esters, acid halides such as their acid chlorides and acid bromides, and isophthalic acid anhydrides. .. For example, an alkyl ester of a metal sulfonate group-containing isophthalic acid is preferable, and a methyl ester of a metal sulfonate group-containing isophthalic acid is particularly preferable from the viewpoint of excellent polycondensation reactivity.

Further, in the polyester composition of the present invention, polyethylene glycol may be added when the dicarboxylic acid and / or its ester-forming derivative is polycondensed with alkylene glycol. Polyester containing polyethylene glycol has excellent molecular motility and hydrophilicity, and has improved water absorption capacity. The contained polyethylene glycol may be copolymerized in the polyester or may be present in the polyester composition in an unreacted state.

The polyethylene glycol contained in the polyester composition of the present invention has a number average molecular weight of 20000 or less as measured by gel permeation chromatography from the viewpoint of efficiently improving molecular mobility and hydrophilicity. It is preferably 8300 or less, and more preferably 8300 or less. The number average molecular weight of polyethylene glycol is preferably 1000 or more. Specifically, it is preferable to use polyethylene glycol having a number average molecular weight of 1000 to 20000, and more preferably a number average molecular weight of 1000 to 8300.

When polyethylene glycol is contained in the present invention, it is preferably contained in the range of 12.5% by weight or less, preferably 5.0% by weight to 10.0% by weight, in order to prevent deterioration of the storage stability of the pellets. More preferred. Of course, it does not have to contain polyethylene glycol. The content described here can be determined by NMR measurement.

Further, in the polyester composition of the present invention, at least one of terephthalic acid and the ester-forming derivative of terephthalic acid is copolymerized when the dicarboxylic acid and / or the ester-forming derivative thereof is polycondensed with alkylene glycol. You may. Examples of the ester-forming derivative of terephthalic acid include alkyl esters such as methyl ester and ethyl ester of terephthalic acid. For example, it is preferable to use a methyl ester of terephthalic acid from the viewpoint of excellent polycondensation reactivity.

Copolymerization of the terephthalic acid component improves the melt moldability of the polymer. From the viewpoint of excellent melt moldability, the copolymerization amount is preferably 5.0 mol% or more, more preferably 10.0 mol% or more, based on the total acid component. On the other hand, when the terephthalic acid component is excessive, a strong intermolecular force is generated between the molecular chains, the volume increase in water is suppressed, and the water absorption capacity is lowered. Therefore, the copolymerization amount should be 30.0 mol% or less. Is preferable, and it is more preferably 20.0 mol% or less.

Further, the polyester composition of the present invention comprises isophthalic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, adipic acid, sebacic acid and esters thereof in polycondensation reaction of dicarboxylic acid and / or an ester-forming derivative thereof with alkylene glycol. At least one selected from the group consisting of forming derivatives may be copolymerized. Examples of the ester-forming derivative include alkyl esters such as these methyl esters and ethyl esters. For example, it is preferable to use these methyl esters from the viewpoint of excellent polycondensation reactivity. As these dicarboxylic acid components, one kind of compound kind may be used, or two or more kinds may be combined.

When at least one dicarboxylic acid component selected from the group consisting of isophthalic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, adipic acid and sebacic acid is copolymerized within a certain range, the intermolecular force and crystallinity between the molecular chains Is greatly reduced, the volume increase in water is promoted, and the water absorption capacity is improved. From the viewpoint of improving the water absorption capacity, the total of these dicarboxylic acid components is preferably 60.0 to 85.0 mol%, preferably 65.0 to 85.0 mol%, based on the total acid components. More preferably, it is 65.0 to 80.0 mol% from the viewpoint of excellent melt moldability.

In order to control the physical properties of the polyester composition of the present invention, for example, polyethylene glycol, metal sulfonate group-containing isophthalic acid component, terephthalic acid component, isophthalic acid component, cyclohexanedicarboxylic acid component, naphthalenedicarboxylic acid component, adipic acid component and sebacic acid component. It is preferable to use a combination of any three or more of the components selected from the group consisting of the above in the above range. A synergistic effect can be obtained by combining these three or more types, and the water absorption amount of the polyester composition of the present invention can be further improved. As the combination, a metal sulfonate group-containing isophthalic acid component, a terephthalic acid component, and an isophthalic acid component are preferably exemplified, and it is more preferable that polyethylene glycol is contained in addition.

The polyester composition of the present invention preferably has a weight average molecular weight of the entire polymer in the range of 35,000 to 80,000. In a polyester composition having a glass transition point of 30 ° C. or less and a heat of crystal melting of 12 J / g or less, if the weight average molecular weight is less than 35,000, pellets are deformed and fused during storage, which makes handling difficult. The weight average molecular weight is more preferably in the range of 45,000 to 80,000 from the viewpoint of further suppressing deformation and fusion of pellets during storage. On the other hand, when the weight average molecular weight is larger than 80,000, it becomes difficult to recover the polymer after polymerization and pellet process, and the melt moldability at around 260 ° C. is inferior.

The polyester composition of the present invention can be synthesized by any method. For example, the same process as the general method for synthesizing polyethylene terephthalate shown below can be used.
Polyethylene terephthalate produces a glycol ester of terephthalic acid or a low polymer thereof by an esterification reaction between terephthalic acid and ethylene glycol or a transesterification reaction between a lower alkyl ester of terephthalic acid represented by dimethyl terephthalate and ethylene glycol. It can be synthesized by a first-step reaction to be produced, and a second-step reaction in which the reaction product of the first step is heated under reduced pressure in the presence of a polymerization catalyst and a polycondensation reaction is carried out until a desired degree of polymerization is achieved.

When synthesizing a polyester composition using a plurality of dicarboxylic acids and / or ester-forming derivatives thereof or a plurality of alkylene glycols as raw materials, the addition time of each raw material is an ester using any one of the dicarboxylic acid components and the alkylene glycol. Any at the same time that the conversion reaction or transesterification reaction is started, or from the start of the esterification reaction or transesterification reaction to the start of the polycondensation reaction, and even until the polycondensation reaction is substantially completed. It may be in stages.

The dicarboxylic acid component constituting the polyester composition of the present invention is, for example, any of a metal sulfonate group-containing isophthalic acid component, a terephthalic acid component, an isophthalic acid component, a cyclohexanedicarboxylic acid component, a naphthalenedicarboxylic acid component, an adipic acid component and a sebacic acid component. In the case of a combination of three or more kinds, it is preferable that the composition contains a titanium metal atom and a lithium metal atom at the same time.

When the titanium metal atom and the lithium metal atom are contained at the same time and in a certain range, the esterification reaction or the transesterification reaction and the polycondensation reaction proceed rapidly, resulting in a polyester composition having a molecular weight excellent in melt moldability. .. From the viewpoint of excellent pellet color tone and melt moldability, the content of titanium metal atoms is preferably 0.01 to 0.65% by weight, preferably 0.05 to 0.65, based on the synthesized polyester composition. More preferably, it is by weight%. The content of the lithium metal atom contained at the same time is preferably 0.02 to 0.10% by weight, more preferably 0.05 to 0.10% by weight.

Titanium metal atoms are titanium alkoxides such as titanium dioxide, titanium complex, tetra-i-propyl titanate, tetra-n-butyl titanate, tetra-n-butyl titanate tetramer, and titanium from the viewpoint of improving polycondensability and pellet color tone. It is preferable to use a compound such as titanium oxide or titanium acetylacetonate obtained by hydrolysis of alkoxide, and titanium dioxide or tetra-n-butyl titanate is used because it is unlikely to become a foreign substance in the polyester composition. Is more preferable.

As the lithium metal atom, a compound such as lithium chloride, lithium bromide, lithium nitrate, lithium carbonate, lithium acetylacetonate, or lithium acetate is preferably used from the viewpoint of improving the polycondensability, and is contained in the polyester composition. It is more preferable that lithium acetate is used because it does not easily become a foreign substance.

The dicarboxylic acid component of the polyester composition of the present invention is, for example, any of a metal sulfonate group-containing isophthalic acid component, a terephthalic acid component, an isophthalic acid component, a cyclohexanedicarboxylic acid component, a naphthalenedicarboxylic acid component, an adipic acid component, and a sebacic acid component. When it is composed of a combination of three or more kinds, the amount of carboxyl terminal groups in the polymer is preferably in the range of 10.0 to 45.0 eq / ton. In such a polyester composition, a decomposition reaction which is an equilibrium reaction easily proceeds during a polycondensation reaction, and it is difficult to make the amount of carboxyl terminal groups less than 10.0 eq / ton. Further, when the amount of carboxyl terminal groups is larger than 45.0 eq / ton, the inside of the polymerization apparatus becomes a strongly acidic environment during the polymerization reaction, the titanium metal catalyst is deactivated, and the polymerization reaction is significantly delayed, and the temperature is around 290 ° C. The melt moldability in the above is inferior. The amount of carboxyl terminal groups is preferably in the range of 10.0 to 35.0 eq / ton from the viewpoint of being more excellent in melt moldability.

When using the polyester composition of the present invention, depending on the purpose of use, a thermoplastic resin such as polyethylene terephthalate, polybutylene terephthalate, nylon 6, nylon 66, polyethylene, polypropylene, polymethylmethacrylate, and / or an antioxidant may be used. A resin additive such as a pigment for coloring may be kneaded.

The polyester composition of the present invention can be preferably used as a constituent component of the composite fiber. The composite fiber described here refers to a fiber in which two or more kinds of polymers are separated and exist in one fiber. As the cross-sectional form of the composite fiber, for example, a general core-sheath composite yarn having a circular core component, a core-sheath composite yarn having a star-shaped core component, and a C-type composite yarn in which a part of the core component is exposed on the outer layer of the fiber. Examples include, but are not limited to, sea-island composite yarns in which a plurality of island components are present among the sea components.

The present invention will be specifically described below with reference to examples. These are examples, and the present invention is not limited thereto.

A. Evaluation of melt moldability of polyester composition A capillograph was used to evaluate the melt moldability of the polyester composition. For each measurement temperature of 230, 240, 250, 260, 270, 280, 290 and 300 ° C., the characteristics when the polyester composition is formed into a fibrous form under the following conditions are evaluated in three stages of S, A and B. did.
Equipment: Capillograph 1B manufactured by Toyo Seiki Seisakusho Co., Ltd.
Capillary inner diameter: 1.0 mm
Capillary length: 40.0 mm
Polymer residence time: 5 minutes Polymer extrusion time: 5 minutes Shear rate: 12.2sec ^-1
Winding speed: 50 m / min

<Evaluation criteria>
Evaluation S: The molded product can be collected without thread breakage in all measurement temperature ranges.
Evaluation A: Thread breakage of the molded product is 3 times or less in all measurement temperature ranges.
Evaluation B: At any temperature, the molded product cannot be extruded or the thread breaks 4 times or more.
Evaluation S or A was judged to have a melt moldable temperature in the range of 230 to 300 ° C., and evaluation B was judged to have a melt moldable temperature not in the range of 230 to 300 ° C.

B. Volume increase rate of the polyester composition in water The volume increase rate of the polyester composition in water was measured using a dry automatic densitometer and a pycnometer. As a pretreatment, columnar polyester composition pellets having a diameter of 3.0 ± 1.5 mm and a height of 4.0 ± 1.0 mm were allowed to stand at 50 ° C. under nitrogen for 1 week to stabilize the crystalline state (). Preprocessing). 0.8 g of the pretreated polyester composition was weighed, and the volume of the polyester composition before immersion in water was determined using a dry densitometer under the following conditions: A [m ³ ].
Equipment: Micromeritics dry automatic density meter Accupic 1340T-10CC
Filling gas: He
Measurement temperature: 25 ° C

Subsequently, 2.0 g of the pretreated polyester composition was immersed in 200 mL of ion-exchanged water at 30 ° C. and allowed to stand for 1 hour. After 1 hour of standing, the polyester composition was immediately taken out, all the water adhering to the surface was wiped off, and the volume of the polyester composition after immersion: B [m ³ ] was determined using a pycnometer under the following conditions.
Equipment: Sansho Co., Ltd. Harvard type pycnometer constant temperature bath: Yamato Scientific Co., Ltd. constant temperature bath BK33
Measurement temperature: 25 ° C
Immersion solution: 20 mL of ion-exchanged water

Finally, the volume increase rate [%] before and after immersion of the polyester composition was determined as follows.
Volume increase rate [%] = {(BA) / A} x 100
However, if the polymer collapsed in water and it became difficult to measure, it was not possible to measure.

C. Measurement of glass transition point and crystal melting calorimeter of polyester composition As a pretreatment, columnar polyester composition pellets with a diameter of 3.0 ± 1.5 mm and a height of 4.0 ± 1.0 mm were placed at 50 ° C. for 1 week under nitrogen. The crystal state was stabilized by allowing it to stand, and the glass transition point and the amount of heat of crystal melting were measured using a suggested scanning calorimeter.
Equipment: Q-2000 manufactured by TA Instruments
Temperature rise rate: 2 ° C / min Measurement temperature: -20 ° C to 300 ° C

D. Composition analysis of polyester composition The composition analysis of the polyester composition was carried out using a nuclear magnetic resonance apparatus (NMR).
Equipment: AL-400 manufactured by JEOL Ltd.
Deuterated solvent: Deuterated HFIP
Number of integrations: 128 times Sample concentration: 50 mg of measurement sample / 1 mL of deuterated solvent

E. Measurement of Number Average Molecular Weight of Polyethylene Glycol The number average molecular weight of polyethylene glycol was measured using gel permeation chromatography under the following conditions.
Equipment: Gel Permeation Chromatograph (GPC) (Waters-2690)
Detector: Differential Refractometer RI (Waters-2410, Sensitivity 128x)
Column: TSKgelG3000PWXL (1) (manufactured by Tosoh Corporation)
Solvent: 0.1 M sodium chloride aqueous solution Flow rate: 0.8 mL / min Column temperature: 40 ° C
Injection volume: 0.05 mL
Standard sample: polyethylene glycol, polyethylene oxide

F. Measurement of Weight Average Molecular Weight of Polyester Composition The weight average molecular weight of the polyester composition was measured by using gel permeation chromatography under the following conditions.
Equipment: Gel Permeation Chromatograph (GPC) (Waters-e2695)
Detector: Differential Refractometer RI (Waters-2141, Sensitivity 128x)
Column: Showa Denko Co., Ltd. Shodex HFIP806M (two connected)
Solvent: Hexafluoroisopropanol (with 0.01N sodium trifluoroacetate added)
Flow rate: 1.0 mL / min Column temperature: 30 ° C
Injection volume: 0.10 mL
Standard sample: Standard polymethyl methacrylate

G. Metal content analysis in polyester composition The metal content in the polyester composition is determined by melt-molding the polyester composition into a plate shape at 260 ° C. and then using a fluorescent X-ray analyzer (model number: 3270) manufactured by Rigaku Co., Ltd. Measured using.

H. Measurement of carboxyl-terminal group amount in polyester composition The pellets of the obtained polyester composition are dissolved in an o-cresol solvent, and an automatic titrator (Hiranuma Sangyo Co., Ltd.) is used at 25 ° C. using a 0.02 aqueous sodium hydroxide solution. It was obtained by titration with (manufactured by the company).

I. Evaluation of Storability of Polyester Composition Magnesium stearate 750 ppm was uniformly added to the surface of 3 kg of columnar polyester composition pellets having a diameter of 3.0 ± 1.5 mm and a height of 4.0 ± 1.0 mm. The state of the pellets when 3 kg of pellets were put into a vat having a length of 400 mm, a width of 400 mm and a height of 5 mm and allowed to stand at 50 ° C. under nitrogen for 1 week was evaluated on a scale of S, A and B. When the pellet shape deviated from the columnar shape having a diameter of 3.0 ± 1.5 mm and a height of 4.0 ± 1.0 mm, it was judged that the pellet was deformed.

<Evaluation criteria>
Evaluation S: The pellets do not deform and the pellets do not fuse with each other.
Evaluation A: The pellets are deformed, but the pellets do not fuse with each other.
Evaluation B: The pellets are deformed and fusion between the pellets occurs.

J. Evaluation of composite spinnability of polyester composition The polyester composition is composite-spun with polyethylene terephthalate (PET) having a solution viscosity IV: 0.64 or nylon 6 (N6) having a specific viscosity ηr: 2.6 under the following conditions. Spinnability was evaluated on a two-point scale of A and B.
Composite spinning form: Concentric sheath Composite yarn Number of filaments: 24
Core component: Polyester composition of Example or Comparative Example: 50% by weight
Sheath component: PET or N6 ... 50% by weight
Spinning temperature: 285 ° C (sheath: PET), 260 ° C (sheath: N6)
Cooling air: Air temperature 20 ° C, wind speed 20m / sec
Winding speed: 1000m / sec
Total fineness: 270dtex

<Evaluation criteria>
Evaluation A: Regardless of whether the sheath component is PET or N6, no thread breakage occurs in 10 minutes of winding.
Evaluation B: When the sheath component is PET or N6, yarn breakage occurs in 10 minutes after winding.

K. Measurement of water absorption of polyester composition As a pretreatment, columnar polyester composition pellets with a diameter of 3.0 ± 1.5 mm and a height of 4.0 ± 1.0 mm are allowed to stand at 50 ° C. under nitrogen for 1 week to crystallize. Stabilized the condition. Subsequently, about 2.0 g of the pretreated polyester composition was immersed in 200 mL of ion-exchanged water at 30 ° C. and allowed to stand for 1 hour. After 1 hour of standing, the polyester composition was immediately taken out, all the water adhering to the surface was wiped off, and the weight: A [g] was measured. Further, the pellets after weight measurement were dried in a blower dryer set at 105 ° C. for 6 hours, and the weight after drying: B [g] was measured. The water absorption per 1 g of the polyester composition [g / g] was measured as follows. ] Was calculated.
Water absorption [g / g] = (AB) / B
However, if the polymer collapsed in water and it became difficult to recover it, measurement was not possible.

[Example 1]
1.5 kg of dimethyl terephthalic acid (DMT) (20.0 mol% with respect to total acid component), 1.2 kg of sodium dimethyl 5-sulfoisophthalate (SSIA) (15.0 mol% with respect to total acid component), 4.8 kg of dimethyl isophthalate (DMI) (65.0 mol% relative to total acid content), 6.2 kg of 1,4-butanediol (BDO), 20 wt% BDO solution of tetra-n-butyl titanate (TBT) ) 36.1 g (0.01% by weight of titanium metal amount with respect to the obtained composition), 50.6 g of lithium acetate dihydrate (LAH) (0.05 with the amount of lithium metal with respect to the obtained composition) % By weight) was added, and methanol was distilled off while raising the temperature from 120 ° C. to 190 ° C. over 180 minutes to carry out a transesterification (EI) reaction.
After completion of the EI reaction, 1.0 kg of polyethylene glycol (PEG) having a number average molecular weight of 1000 (10.0% by weight based on the obtained composition), [pentaerythritol-tetrakis (3- (3,5-di-t)). -Butyl-4-hydroxyphenol) propionate)] (BASF's "Irganox® (registered trademark; the same applies hereinafter) 1010") 25.0 g, TBT 140.4 g (0.04 weight by weight of titanium metal with respect to the obtained composition) %) Was further added, and the pressure was reduced to 0.1 kPa or less over 60 minutes at 205 ° C. After depressurization, the temperature rises from 205 ° C. to 245 ° C. over 40 minutes, and after 80 minutes, the reaction system is purged with nitrogen to return to normal pressure to stop the polycondensation reaction, extruded into a strand from the mouthpiece, and cooled in the water tank. , Pellets were cut.
The obtained polyester composition satisfied both the melt moldability and the volume increase rate within the claims of the present invention. The properties of various polymers are shown in Table 1.

[Examples 2 to 5]
The same procedure as in Example 1 was carried out except that the copolymerization amounts of SSIA and DMI used in Example 1 were changed as shown in Table 1, and a polyester composition having excellent melt moldability and volume increase rate was obtained. ..

[Examples 6 and 7]
The same procedure as in Example 1 was carried out except that the copolymerization amounts of DMT, SSIA and DMI used in Example 1 were changed as shown in Table 1, and a polyester composition having excellent melt moldability and volume increase rate was obtained. Obtained.

[Examples 8 to 10]
The copolymerization amount of SSIA and DMI used in Example 1 and the content of polyethylene glycol were changed as shown in Table 1, and 1,3-propanediol and / or ethylene glycol were added as alkylene glycol components as shown in Table 1. A polyester composition having excellent melt moldability and volume increase rate was obtained in the same manner as in Example 1 except that they were used in combination.

[Example 11]
It was carried out in the same manner as in Example 1 except that the copolymerization amount of SSIA and DMI used in Example 1 and the content of polyethylene glycol were changed as shown in Table 1, and the melt moldability and volume increase rate were excellent. A polyester composition was obtained.

[Examples 12 and 13]
The same procedure as in Example 1 was carried out except that the copolymerization amounts of SSIA and DMI used in Example 1 and the number average molecular weight of polyethylene glycol were changed as shown in Table 1, and the melt moldability and volume increase rate were improved. An excellent polyester composition was obtained.

[Examples 14 and 15]
The copolymerization amounts of DMT, SSIA, and DMI used in Example 1 were changed as shown in Table 2, and dimethyl cyclohexanedicarboxylic acid (CHDC) or dimethyl naphthalenedicarboxylic acid (NDCM) was copolymerized as shown in Table 2. Except for the above, the same procedure as in Example 1 was carried out to obtain a polyester composition having excellent melt moldability and volume increase rate.

[Examples 16 and 17]
The copolymerization amount of DMT, SSIA, and DMI used in Example 1 was changed as shown in Table 2, dimethyl adipate or dimethyl sebacate was copolymerized as shown in Table 2, and polyethylene glycol was not added. A polyester composition having excellent melt moldability and volume increase rate was obtained in the same manner as in Example 1 except for the above.

[Examples 18 to 21]
Example 1 except that the copolymerization amounts of SSIA and DMI used in Example 1 were changed as shown in Table 2 and the polymerization temperature and the polymerization time were adjusted so that the weight average molecular weight was set to the values shown in Table 2. The same procedure as above was carried out to obtain a polyester composition having excellent melt moldability and volume increase rate.

[Example 22]
Same as in Example 1 except that the copolymerization amounts of SSIA and DMI used in Example 1 were changed as shown in Table 2, and the addition amounts of LAH and TBT were changed as shown in Table 2 in terms of metal amount. A polyester composition having excellent melt moldability and volume increase rate was obtained.

[Example 23]
The copolymerization amount of SSIA and DMI used in Example 1 was changed as shown in Table 2, and the addition amount of LAH was changed as shown in Table 2 in terms of lithium metal amount, and 13 wt% BDO slurry of titanium dioxide was changed. Was carried out in the same manner as in Example 1 except that the amount of titanium metal was added so as to be 0.63% by weight, to obtain a polyester composition having excellent melt moldability and volume increase rate.

[Examples 24-26]
Examples except that the copolymerization amounts of SSIA and DMI used in Example 1 were changed as shown in Table 2 and the polymerization temperature and the polymerization time were adjusted so that the amount of carboxyl terminal groups was set to the values shown in Table 2. The same procedure as in No. 1 was carried out to obtain a polyester composition having excellent melt moldability and volume increase rate.

[Comparative Examples 1 and 2]
A polyester composition was obtained in the same manner as in Example 1 except that the copolymerization amounts of SSIA and DMI used in Example 1 were changed as shown in Table 3.
The composition obtained in Comparative Example 1 had poor melt moldability due to an excessive amount of SSIA copolymerization, and yarn breakage occurred during composite spinning with polyethylene terephthalate or nylon 6. In addition, the composition obtained in Comparative Example 2 had a low volume increase rate in water due in part to a shortage of SSIA copolymerization amount and a high amount of heat of crystal melting, and had insufficient water absorption capacity.

[Comparative Examples 3 and 4]
A polyester composition was obtained in the same manner as in Example 1 except that the copolymerization amounts of DMT, SSIA and DMI used in Example 1 were changed as shown in Table 3.
The composition obtained in Comparative Example 3 had poor melt moldability due to insufficient DMT copolymerization amount and excessive DMI copolymerization amount, and yarn breakage occurred during composite spinning with polyethylene terephthalate. In addition, the volume increase rate in water was low and the water absorption capacity was insufficient due in part to the excessive amount of DMI copolymerization and the high amount of heat of crystal melting. The composition obtained in Comparative Example 4 had a low volume increase rate in water due in part to an excessive amount of DMT copolymerization and a high amount of heat of crystal melting, and had insufficient water absorption capacity.

[Comparative Examples 5 and 6]
Same as Example 1 except that the copolymerization amounts of SSIA and DMI used in Example 1 were changed as shown in Table 3, and the addition amounts of LAH and TBT were changed as shown in Table 3 in terms of metal amount. To obtain a polyester composition.
In the compositions obtained in Comparative Examples 5 and 6, the melt-moldability deteriorates due to the formation of foreign matter due to the excessive amount of the added metal atomic weight, and yarn breakage occurs during composite spinning with polyethylene terephthalate and nylon 6. did.

[Comparative Example 7]
The copolymerization amounts of SSIA and DMI used in Example 1 were changed as shown in Table 3, except that 4.5 g of manganese acetate and 2.7 g of diantimony trioxide were added without adding LAH and TBT. The same procedure as in Example 1 was carried out to obtain a polyester composition.
In the composition obtained in Comparative Example 7, since the polycondensation reaction did not proceed sufficiently, the storability and melt moldability deteriorated, and yarn breakage occurred during composite spinning with polyethylene terephthalate and nylon 6. In addition, the pellets collapsed when immersed in water, making it difficult to measure the amount of water absorbed.

[Comparative Example 8]
Examples except that the copolymerization amounts of SSIA and DMI used in Example 1 were changed as shown in Table 3 and the polymerization temperature and the polymerization time were adjusted so that the amount of carboxyl terminal groups was set to the values shown in Table 3. The same procedure as in 1 was carried out to obtain a polyester composition.
In the composition obtained in Comparative Example 8, the amount of carboxyl terminal groups was excessive and decomposition proceeded rapidly during melt molding, so that yarn breakage occurred during composite spinning with polyethylene terephthalate.

[Comparative Example 9]
The content of polyethylene glycol used in Example 1 was changed as shown in Table 3, and 1,3-propanediol and ethylene glycol were used in combination as alkylene glycol components in the same manner as in Example 1. This was carried out to obtain a polyester composition.
The composition obtained in Comparative Example 9 had a low glass transition point and was inferior in storage stability. In addition, due to the high polyethylene glycol content, an excessive volume increase rate was exhibited, and pellets collapsed when immersed in water, making it difficult to measure the amount of water absorption.

[Comparative Example 10]
The copolymerization amounts of DMT, SSIA, and DMI used in Example 1 were changed as shown in Table 3, dimethyl adipate was copolymerized as shown in Table 3, and polyethylene glycol and TBT were not added and trioxidation was performed. After adding 2.7 g of diantimon and using ethylene glycol as an alkylene glycol component, the EI reaction was carried out at 140 to 230 ° C. and the polymerization reaction was carried out at 290 ° C. in the same manner as in Example 1. Polyester The composition was obtained.
The composition obtained in Comparative Example 10 had a low volume increase rate in water due in part to a high glass transition point, and had insufficient water absorption capacity.

[Comparative Example 11]
The copolymerization amounts of DMT and SSIA used in Example 1 were changed as shown in Table 3, and the number average molecular weight and content of polyethylene glycol were changed as shown in Table 3 without adding DMI, TBT and LAH. Then, after adding 4.5 g of manganese acetate and 9.0 g of germanium dioxide, the polyester composition was carried out in the same manner as in Example 1 except that the EI reaction was carried out at 140 to 230 ° C. and the polymerization reaction was carried out at 285 ° C. Got
The composition obtained in Comparative Example 11 had a low glass transition point but showed a high amount of heat of crystal melting, so that the pellets were well stored. On the other hand, the volume increase rate in water was low due in part to the high amount of heat of crystal melting, and the water absorption capacity was insufficient.

[Comparative Example 12]
The copolymerization amounts of DMT and SSIA used in Example 1 were changed as shown in Table 3, and the number average molecular weight and content of polyethylene glycol were changed as shown in Table 3 without adding DMI, TBT and LAH. Then, as shown in Table 3, ethylene glycol was used in combination as an alkylene glycol component, 4.5 g of manganese acetate and 9.0 g of germanium dioxide were added, and then the EI reaction was carried out at 140 to 230 ° C. and the polymerization reaction was carried out at 285 ° C. A polyester composition was obtained by carrying out the same procedure as in Example 1 except for the above.
Similar to Comparative Example 11, the composition obtained in Comparative Example 12 showed a high calorific value for crystal melting, so that the pellets could be stored well. On the other hand, due in part to the high amount of heat of crystal melting, the volume increase rate in water was low, and the water absorption capacity was insufficient.

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications and modifications can be made without departing from the intent and scope of the invention. This application is based on a Japanese patent application (Japanese Patent Application No. 2019-080057) filed on April 19, 2019, and the entire application is incorporated by reference.

Claims (7)

A polyester composition obtained by a polycondensation reaction of at least one of a dicarboxylic acid and an ester-forming derivative of a dicarboxylic acid with an alkylene glycol, which can be melt-molded in the range of 230 to 300 ° C. and 50 ° C. A polyester composition whose volume increases to 50 to 3000% by immersing it in ion-exchanged water at 30 ° C. for 1 hour after allowing it to stand for 1 week. The polyester composition according to claim 1, wherein the glass transition point determined by differential scanning calorimetry after allowing to stand at 50 ° C. for 1 week is 0 to 30 ° C., and the heat of crystal melting is in the range of 0 to 12 J / g. object. The metal sulfonate group-containing isophthalic acid component is copolymerized at 4.0 to 15.0 mol% with respect to the total acid component, and polyethylene glycol having a number average molecular weight of 1000 to 20000 is added to the total composition by weight of 0 to 12.5. The polyester composition according to claim 1 or 2, which is contained in the range of%. The terephthalic acid component is 5.0 to 30.0 mol% with respect to the total acid component, and at least one dicarboxylic acid selected from the group consisting of isophthalic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, adipic acid and sebacic acid. The polyester composition according to any one of claims 1 to 3, wherein the total amount of the components is 60.0 to 85.0 mol% copolymerized with respect to the total acid component. The polyester composition according to any one of claims 1 to 4, wherein the weight average molecular weight is in the range of 35,000 to 80,000. The polyester composition according to any one of claims 3 to 5, which contains a titanium metal atom in the range of 0.01 to 0.65% by weight and a lithium metal atom in the range of 0.02 to 0.10% by weight. The polyester composition according to any one of claims 3 to 6, wherein the amount of carboxyl terminal groups is in the range of 10.0 to 45.0 eq / ton.