JP3124559B2 - Alkali easily soluble polyester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a hardly soluble component and a readily soluble component.
Used as a readily soluble component in composite fibers consisting of
And a polyester which is easily soluble in an aqueous alkali solution.

[0002]

2. Description of the Related Art Polyesters, particularly polyethylene terephthalate, are widely used as clothing and industrial fibers because of their excellent mechanical and chemical properties.

[0003] In recent years, the compounding of polyester fibers has been active. Particularly, composite fibers obtained by combining a polymer which is hardly soluble in a specific solvent and a polymer which is easily soluble are used, for example, for fabrics such as woven and knitted fabrics. By removing the components, attention has been paid to various characteristics such as improvement in dyeability and texture.

For example, finely divided yarn can be obtained by dissolving and removing the easily soluble component from the splittable conjugate fiber obtained by dividing the hardly soluble component into a plurality of components by the easily soluble component. On the contrary, the easily soluble component was divided into a plurality by the hardly soluble component, and the soluble component was dissolved and removed from the splittable conjugate fiber occupying at least a part of the surface, thereby having a sharp outline. A modified cross-section yarn is obtained. Various other applications have been proposed, but the above two examples are typical.

The properties to be provided as the easily soluble polymer used in these conjugate fibers include the following. (a) The difference in the dissolution rate between the poorly soluble component and the solvent is sufficiently large. (b) Non-corrosive, safe and inexpensive. (c) The fiber has sufficient practical strength in the fiber itself and the fabric. (d) There should be no trouble such as thread breakage in the spinning and processing steps, and good operability.

Various proposals have been made to achieve these objects. For example, Japanese Patent Publication No. 47-42487,
JP-A-48-9021 proposes a composition using polystyrene, nylon 6, or the like as a readily soluble component. However, in order to remove these easily soluble portions, it is necessary to use an organic solvent or the like, which is unsatisfactory in terms of safety and cost, and furthermore, nylon 6 has a drawback that peeling easily occurs.

On the other hand, polyester is used as the hardly soluble component,
There is also known an example in which a polyester having good compatibility with this is used as a readily soluble component, and the easily soluble component is dissolved and removed by treatment with an aqueous alkali solution.

For example, Japanese Patent Publication No. 47-47532 proposes, as an easily soluble polymer, a polyester containing 5 to 16% by weight of a polyalkylene glycol having a number average molecular weight of 10,000 or more. However, the dissolution rate of this polymer is insufficient unless a large amount of polyalkylene glycol is copolymerized, and the same component cannot be completely dissolved and removed. If a large amount of the polyalkylene glycol is copolymerized, there is a disadvantage that the excellent properties (heat resistance and mechanical properties) inherent in the polyester are reduced and the yarn forming property is reduced.

Further, JP-A-56-165015 and JP-A-55-165015
JP-93819 proposes a polyester obtained by copolymerizing at least 2.4 mol% of a metal sulfonate-containing ester unit as a readily soluble component. A polyester obtained by copolymerizing a metal sulfonate-containing ester unit is easily soluble in alkali, and the alkali-soluble solubility increases as the number of metal sulfonate-containing ester units increases. However, a polyester obtained by copolymerizing a metal sulfonate-containing ester unit becomes difficult to elongate, contrary to the fact that a normal copolymerized polyester is easily elongated by copolymerization, and this tendency is remarkable as the amount of copolymerization increases. Become. As a result, the yarn in which the easily soluble component is compounded has the disadvantage that the strength is low and the metal sulfonate compound is expensive.

Furthermore, Japanese Patent Application Laid-Open No. 62-78213 proposes a polyester obtained by adding a polyalkylene glycol having a number average molecular weight of 8,000 or more to a polyester obtained by copolymerizing a metal sulfonate-containing ester unit as a readily soluble component. . However, even when using this polymer, compared to polyethylene terephthalate, the heat resistance of the polymer is largely inferior, and the reactivity with polyethylene terephthalate is low, so that the polyalkylene glycol is not substantially copolymerized. In fact, the fact is that the yarn breaks during spinning, elutes into the oil agent, or the operability during processing is poor.

Japanese Patent Application Laid-Open No. 58-31115 discloses 5-
An easily dyeable polyester obtained by copolymerizing an alkali metal sulfoisophthalic acid component and an alkylene oxide adduct of a bisphenol has been proposed. However, this polyester did not satisfy all of the above properties as a readily alkali-soluble polymer.

[0012]

SUMMARY OF THE INVENTION The present invention relates to a polymer, yarn property, spinning operability, alkali-soluble, and economical properties which are used as a readily soluble component in a conjugate fiber comprising a hardly soluble component and a readily soluble component. The purpose of the present invention is to provide a satisfactory alkali-soluble polyester in all aspects.

[0013]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, it has been found that not only the structure of the polymer but also the selection of the structure of the copolymerized monomer and the control of the copolymerization ratio are controlled. The present invention has been completed by finding out the necessity and optimizing them.

That is, the gist of the present invention is as follows. In composite fibers composed of poorly soluble components and easily soluble components
Alkali soluble polyester used as a readily soluble component
At least a structural unit obtained by copolymerizing A mole% of an isophthalic acid component having a sulfonate group and B mole% of 5 to 25 moles of an ethylene oxide adduct of bisphenol A or bisphenol S with respect to all acid components. 80% by mol of a polyester having an intrinsic viscosity of 0.5 or more, which is an ethylene terephthalate unit, and which is an alkali-soluble polyester satisfying the following formulas 1 ≦ A ≦ 3 40 ≦ n × B ≦ 100 120 ≦ 40 × A + n × B ≦ 180 (n is the number of moles of ethylene oxide adduct and 5 ≦ n ≦ 25)

Hereinafter, the present invention will be described in detail. The polyesters of the present invention require that at least 80 mol%, preferably 85-97 mol%, optimally 90-95 mol% of the constituent units be ethylene terephthalate units.
If the amount of the ethylene terephthalate unit is less than 80 mol%, the good physical properties of the polyester will be impaired.

The polyester of the present invention is characterized in that bis (β-hydroxyethyl) terephthalate and / or an oligomer thereof obtained by reacting terephthalic acid or dimethyl terephthalate with ethylene glycol have an isophthalic acid component having a sulfonate group and bisphenol A Alternatively, it can be obtained by adding an ethylene oxide adduct of bisphenol S and performing polycondensation by a conventional method.

The isophthalic acid component having a sulfonate group is usually used as bisethylene glycol ester of isophthalic acid having a sulfonate group (SIPG) or dimethyl ester of isophthalic acid having a sulfonate group (SIPM). It is preferably used as a mixture having a molar ratio of about 6: 4 with SIPM. (Hereinafter, SIPG and SIPM are collectively referred to as SIP.)

The SIP is usually 1 to 3 mol%, preferably 1.5 mol%.
It is necessary to copolymerize ~ 2.5 mol%. This amount is 1 mol%
If it is less, the dissolution rate in an alkaline aqueous solution will be slow,
If the amount is more than 3 mol%, the alkali solubility of the polyester increases, but not only the melt viscosity increases, but also it becomes practically difficult to sufficiently increase the degree of polymerization of the polymer, and it becomes difficult to elongate during spinning and stretching. In addition, the yarn strength is weakened because the draw ratio cannot be increased. Therefore, the hardly soluble component remaining after the alkali dissolution also has a lower strength and a higher elongation, and thus has a problem that, for example, the dimensional stability of the fabric is impaired when the final product is obtained.

As the SIPG used in the present invention, 3,
Sodium 5-di (carbo-β-hydroxyethoxy) benzenesulfonate, potassium 3,5-di (carbo-β-hydroxyethoxy) benzenesulfonate, 3,5-di (carbo-β-hydroxyethoxy) benzenesulfonate Lithium and the like. In addition, the SIPM
Examples include dimethyl sodium sulfoisophthalate, dimethyl 5-potassium sulfoisophthalate, and dimethyl 5-lithium sulfoisophthalate. These are suitably used as a 30 to 40% by weight ethylene glycol solution in operation.

In order to obtain a polyester which is easily soluble in an aqueous alkali solution simply by copolymerizing SIP, for example, the copolymerization amount of SIP may be set to 5 mol% or more, but it is not only expensive but also as described above. Problem, SIP copolymerization amount A
Is within the range of the above formula (1 to 3 mol%), and it is extremely effective to copolymerize an ethylene oxide adduct of bisphenol A or bisphenol S.

The ethylene oxide adduct of bisphenol A or bisphenol S is represented by the following formula.

[0022]

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Here, the compound where X is -C (CH ₃ ) _2- is an ethylene oxide adduct of bisphenol A (BAEO), and the compound where X is -SO _2- is an ethylene oxide adduct of bisphenol S (BSEO). The sum of n ₁ and n ₂ is the number of moles of ethylene oxide added n.

These compounds have n ₁ and n _{2 because} of their synthesis.
Values are rarely always the same,
It is obtained as a mixture of compounds having different values of n ₁ and n ₂ .
The value of the number of moles n of ethylene oxide to be added is determined from the hydroxyl value and the like, and this value needs to be 5 to 25, preferably 10 to 20, and more preferably 12 to 18. If the value of n is less than 5, the dissolution rate of the polymer in the aqueous alkali solution is low, and if it is copolymerized in a large amount to cover the same, not only the cost is increased, but also the ratio to the total acid component is increased. As a result, the heat resistance, including the melting point, decreases, and a problem occurs in processing. If the value of n is larger than 25, it is difficult to copolymerize, so that it is substantially in a state of being mixed with the polymer, and the spinning operability and the operability in the processing step deteriorate. Of course, if the value of n is within the above range, it is not always necessary to have only a constant value.

The copolymerization amount B of BAEO or BSEO is greatly affected by the number of moles of ethylene oxide added, n, and must satisfy the following equation. 40 ≦ n × B ≦ 100

When the value of n × B is less than 40, the solubility in an aqueous alkali solution is insufficient, or it takes a long time to completely dissolve the solution, which is not preferable. On the other hand, if this value exceeds 100, the physical properties of the obtained polymer are reduced, and smoke is generated due to thermal decomposition during spinning, and the yarn strength is undesirably reduced.

The copolymerization amount of BAEO or BSEO and the copolymerization amount of SIP have a correlation, and it is not enough to satisfy the formulas and the formulas, and it is necessary to further satisfy the following formulas.
120 ≦ 40 × A + n × B ≦ 180

When the value of (40 × A + n × B) is less than 120, the obtained polymer becomes difficult to dissolve in an aqueous alkali solution, and when it is more than 180, the physical properties of the obtained polymer become inferior.

No matter which of BAEO or BSEO and SIP is missing,
Further, even if the copolymerization amount is out of the range of the above formula, a polyester satisfying the desired properties cannot be obtained. Of course, BAEO
And BSEO can be used together.

For the purpose of suppressing the by-product of diethylene glycol, the polyester monomer or oligomer before the addition of SIP was added to the polyester monomer or oligomer in an amount of 50 × with respect to 1 mol of the total acid component of the polyester.
^10-4 mol% or less of an alkali metal salt or an ammonium compound such as tetraalkylammonium hydroxide may be added.

The polyester of the present invention contains, in addition to the above-mentioned copolymerization components, dicarboxylic acid components such as isophthalic acid, naphthalene-2,6-dicarboxylic acid, adipic acid and sebacic acid, p-hydroxybenzoic acid, ε- Hydroxycarboxylic acid components such as caprolactone, propylene glycol,
A diol component such as 1,4-cyclohexanedimethanol and 1,4-butanediol may be copolymerized.

The polycondensation reaction in the production of the polyester is carried out in the presence of a catalyst. As a catalyst, antimony, germanium, tin, titanium, zinc, aluminum, magnesium, calcium,
In addition to metal compounds such as manganese and cobalt, organic sulfonic acid compounds such as sulfosalicylic acid and o-sulfobenzoic anhydride are preferably used.

The amount of the catalyst to be added is 1 × 10 ^-5 to 1 × 10 ^-2 mol, preferably 5 × 10 ^{-5 to} 5 × 10 ^-3 mol, preferably 1 mol, per 1 mol of all the acid components constituting the polyester. Is 1 × 10 ^{-4 to} 3 ×
Suitably, it is 10 ^-3 mol.

The polyester of the present invention further contains additives such as a stabilizer such as a hindered phenol compound, a cobalt compound, a fluorescent agent, a color tone improving agent such as a dye, and a pigment such as titanium dioxide. No problem.

[0035]

When the polyester of the present invention is used, the operability in the spinning and processing steps is remarkably improved. This is because it does not use polyalkylene glycol, which hardly reacts with polyethylene terephthalate.
It is recognized that off-flavors and thread breakage are reduced.

Further, since an oil agent for processed yarn can be used,
There is no trouble such as dissolution of the polyester component in the oil agent.

Furthermore, since the copolymerization amount of SIP can be suppressed to a small amount, it is possible to avoid increasing the melt viscosity more than necessary. As a result, the degree of polymerization can be increased, and the yarn strength can be increased. can do. In addition, there is an advantage that it is economical because sufficient alkali solubility can be obtained without using a large amount of expensive SIP.

Further, the heat resistance of the polymer itself is also excellent, and since the decrease in viscosity after melting is small, the strength of the obtained yarn is increased. From the composite fiber using this polymer as a readily soluble component, Excellent (sharp edge) fibers can be obtained.

[0039]

Next, the present invention will be described specifically with reference to examples. In the examples, the characteristic values of the polyester were measured as follows. The intrinsic viscosity [η] was measured at a temperature of 20.0 ° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent. After ether hydrolysis of the polymer (D%) in the polymer, the amount of ethylene glycol and diethylene glycol was quantified by gas chromatography, and the amount was determined as the number of moles of diethylene glycol relative to ethylene glycol. The melting point (Tm) was measured at a heating rate of 20 ° C./min using a differential scanning calorimeter (Model DSC-2 manufactured by PerkinElmer). The strength and elongation of the fiber were determined by the method of JIS 1015 L7.7 . Approximately 3 g of a drawn yarn having solubility (weight loss rate) in an alkali aqueous solution is precisely weighed, placed in 100 cm ^{3 of a} 20% by weight aqueous solution of sodium hydroxide at 70 ° C., treated for a predetermined time, washed with water,
After drying and weighing, the ratio of the weight difference before and after the treatment to the weight before the treatment was determined. (A weight loss rate of 100% indicates complete dissolution.)

Example 1 A slurry of terephthalic acid and ethylene glycol (ethylene glycol / terephthalic acid molar ratio 1.6) was continuously supplied to an esterification reactor in which bis (β-hydroxyethyl) terephthalate and its oligomer were present.
The esterification reaction was carried out at a temperature of 6 ° C. under a normal pressure for a residence time of 6 hours to continuously obtain an esterified product having an average degree of polymerization of 7.4.

To this, 3.5 mol% of BAEO (having an average value of n obtained from the hydroxyl value of 17.5) was added to all the acid components.

Then, 2.0 × 10 ^-4 mol of antimony trioxide and 0.4 × 10 ^-4 mol of cobalt acetate were added to 1 mol of all the acid components constituting the polyester. 3,5-di (carbo-β-
(Hydroxyethoxy) 2.5 mol% of a mixture of sodium benzenesulfonate and dimethyl 5-sodium sulfoisophthalate in a molar ratio of 60:40, and sodium acetate 15
X 10 ^-4 mol was added and the pressure was reduced in the polymerization reactor, and polycondensation was finally performed at 0.1 torr and 275 ° C for 1.5 hours to obtain a polyester having a good color tone. Table 1 shows the characteristic values of the obtained polyester.

The obtained polyester was spun and drawn according to a conventional method to obtain a drawn yarn of 75 denier / 36 filaments. The strength, elongation and solubility in an aqueous alkali solution of the obtained drawn yarn were measured, and the results shown in Table 2 were obtained.

Examples 2 to 6 A mixture of sodium 3,5-di (carbo-β-hydroxyethoxy) benzenesulfonate and dimethyl 5-sodium sulfoisophthalate used in Example 1 in a molar ratio of 60:40. A polyester was produced in the same manner as in Example 1 except that the amount of OH and BAEO were changed to those shown in Table 1. The results are shown in Tables 1 and 2.

Comparative Examples 1 to 7 A mixture obtained by mixing sodium 3,5-di (carbo-β-hydroxyethoxy) benzenesulfonate and dimethyl 5-sodium sulfoisophthalate in a molar ratio of 60:40 used in Example 1. A polyester was produced in the same manner as in Example 1 except that the amount of OH and BAEO were changed to those shown in Table 1. The results are shown in Tables 1 and 2.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

According to the present invention, according to the present invention, it is used as a readily soluble component in a conjugate fiber comprising a poorly soluble component and a readily soluble component .
Thus , an alkali-soluble polyester excellent in spinnability and processability having excellent properties inherent in polyester (heat resistance and mechanical properties) can be obtained economically.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // D06M 11/38 D06M 9/02 Z D06M 101: 32 11/12

Claims (1)

(57) [Claims] 1. A composite comprising a hardly soluble component and a readily soluble component.
Alkali readily soluble used as readily soluble component in fiber
A polyester having a mole percent of isophthalic acid having a sulfonic acid group and 5 to 25 ethylene oxide of bisphenol A or bisphenol S , based on the total acid components.
A polyester having an intrinsic viscosity of 0.5 or more, in which at least 80 mol% of the constituent units copolymerized with the molar adduct B mol% are ethylene terephthalate units, and satisfying the following formulas: 1 ≦ A ≦ 3 40 ≦ n × B ≦ 100 120 ≦ 40 × A + n × B ≦ 180 (n is the number of moles of ethylene oxide adduct and 5 ≦ n ≦ 25)