CN106700050A - Composition for preparing hydrophilic polyester, hydrophilic polyester and preparation method thereof - Google Patents

Abstract

The composition for preparing the hydrophilic polyester comprises polyester oligomer, m-phthalic acid ester containing metal sulfonate groups and a compatilizer shown as a formula (I). The preparation method of the hydrophilic polyester comprises the following steps: (1) mixing organic dibasic acid and dihydric alcohol, and carrying out esterification reaction to obtain polyester oligomer; (2) mixing the polyester oligomer, the metal sulfonate group-containing isophthalate and a compatibilizer to obtain a precursor mixture: (3) the precursor mixture is subjected to a polymerization reaction to obtain the hydrophilic polyester. The hydrophilic polyester is prepared from the composition for preparing the hydrophilic polyester. In the composition of the present invention, the hydrophilic polyester prepared subsequently thereto has the isophthalic acid ester hydrophilic structure containing metal sulfonate group uniformly distributed among the polyester molecular chains.The meaning of the symbols in formula (I) are defined in the claims and the description, respectively.

Description

Composition for preparing hydrophilic polyester, hydrophilic polyester and preparation method thereof

technical field

The invention relates to a composition for preparing polyester, polyester and a preparation method thereof, in particular to a composition for preparing hydrophilic polyester, hydrophilic polyester and a preparation method thereof.

Background technique

The materials used in general polyester fibers are all hydrophobic polyesters [such as polyethylene terephthalate (PET)], resulting in general polyester fibers not being hydrophilic, resulting in clothes made from them that are usually not wearable. The sweat produced by the body makes people feel hot and uncomfortable when worn; in addition, it is also prone to static electricity due to friction in a dry environment. In addition to absorbing dust, it is also easy to wear in the presence of oil gas or gunpowder. Risk of explosion or fire from sparks generated by static electricity.

The hydrophilicity of polyester fiber can be improved by fiber surface treatment or mixing with hydrophilic materials, but its washing fastness is poor, and the hydrophilicity will gradually decrease with the increase of washing times. Another method is the copolymerization modification method, which uses a modification agent with a hydrophilic structure (such as isophthalate containing a sulfonic acid metal base) and a polyester that will form a hydrophobic polyester. Copolymerization of oligomers to improve the hydrophilicity of hydrophobic polyester. This method makes the polyester have a hydrophilic structure through chemical bonding, so the hydrophilicity of the subsequent obtained polyester fiber can exist permanently and will not be washed by water. The frequency increases and decreases.

CN 103073710A discloses a copolymerization modification method, which is to first make terephthalic acid (PTA) and ethylene glycol (EG) undergo esterification reaction to form polyester oligomers, and then mix m-benzene as a modifier Diethylene glycol diformate-5-sodium sulfonate (SIPE) is polymerized to obtain a hydrophilic structure with an isophthalic acid ester structure (that is, a hydrophilic structure) containing a sulfonic acid metal salt group between molecular chains. Water-based polyester. However, in the preparation process of the aforementioned method, since the polyester oligomer formed by the esterification reaction of PTA and EG cannot be uniformly mixed with SIPE, phase separation will occur, so the hydrophilic Polyester, its hydrophilic structure cannot be evenly distributed between PET molecular chains and will form a hydrophilic block (block); in addition, due to the high number of ionic bonds in the hydrophilic block, the intermolecular force is large , causing the polyester molecular chains to gather together and become a colloid, and then it is easy to block the spinning nozzle during subsequent spinning, and the sulfonate content of the hydrophilic block is high. When dyeing, the hydrophilic block region There will also be deep dyeing and the dyeing of the fabric will be uneven.

According to the foregoing description, it can be known how to find a method for preparing a composition for the preparation of hydrophilic polyester and a method for preparing hydrophilic polyester, so that the subsequent obtained hydrophilic polyester contains a sulfonic acid metal base The hydrophilic structure of isophthalate can be evenly distributed between polyester molecular chains, which has become a problem to be solved at present.

Contents of the invention

The first object of the present invention is to provide a kind of composition for preparing hydrophilic polyester, in the hydrophilic polyester that it makes subsequently, the isophthalic acid ester containing sulfonic acid metal salt group is hydrophilic The permanent structure can be evenly distributed among the polyester molecular chains.

The composition that is used to prepare hydrophilic polyester of the present invention comprises polyester oligomer, the compatibilizer shown in the isophthalic acid ester and following formula (I) containing sulfonic acid metal salt base:

In formula (I),

X ¹ , X ² and X ³ respectively represent substituted or unsubstituted C ₂ to C ₄ identically or differently

Hydrocarbyl;

Y ¹ and Y ² respectively identically or differently represent a substituted or unsubstituted C ₄ -C ₁₂ aliphatic alkylene group, a substituted or unsubstituted C ₆ -C ₁₂ arylylene group, a substituted or unsubstituted C ₇ -C ₁₂ aralkylene, or substituted or unsubstituted C ₇ -C ₁₂ alkarylene;

R ¹ represents hydrogen or C ₁ to C ₂ alkylene;

M represents an alkali metal group metal ion;

k represents any integer from 1 to 10;

m and n each represent any integer of 0 to 50, the same or different, and 4≦m+n≦50.

The second object of the present invention is to provide a kind of preparation method of hydrophilic polyester, in the hydrophilic polyester that it makes, the isophthalate hydrophilic structure that contains sulfonic acid metal salt base can be uniform Distributed between polyester molecular chains.

The preparation method of hydrophilic polyester of the present invention comprises the following steps:

(1) Mix organic dibasic acid and dibasic alcohol, and carry out esterification reaction, obtain polyester oligomer;

(2) mixing the polyester oligomer, the isophthalic acid ester containing sulfonic acid metal salt base and the compatibilizer shown in the following formula (I), obtain the precursor mixture:

In formula (I),

X ¹ , X ² and X ³ respectively represent substituted or unsubstituted C ₂ -C ₄ alkylene groups identically or differently;

Y ¹ and Y ² respectively identically or differently represent a substituted or unsubstituted C ₄ -C ₁₂ aliphatic alkylene group, a substituted or unsubstituted C ₆ -C ₁₂ arylylene group, a substituted or unsubstituted C ₇ -C ₁₂ aralkylene, or substituted or unsubstituted C ₇ -C ₁₂ alkarylene;

R ¹ represents hydrogen or C ₁ to C ₂ alkylene;

M represents an alkali metal group metal ion;

k represents any integer from 1 to 10;

m and n respectively represent any integer from 0 to 50 identically or differently, and 4≤m+n≤50; and

(3) The precursor mixture is subjected to a polymerization reaction to obtain the hydrophilic polyester.

The third object of the present invention is to provide a kind of hydrophilic polyester, which is prepared from the aforementioned composition for preparing hydrophilic polyester. In the hydrophilic polyester, sulfonic acid metal salt group The isophthalate hydrophilic structure can be evenly distributed among the polyester molecular chains.

The beneficial effect of the present invention is: because the compatibilizer of this formula (I) has hydrophobic block and hydrophilic block simultaneously, so in the process of preparing hydrophilic polyester, hydrophobic block can be mixed with polyester Compatible with oligomers, the hydrophilic block is compatible with isophthalic acid esters containing sulfonic acid metal salts, so that the polyester oligomers and sulfonic acid metal salts that cannot be mixed uniformly will cause phase separation The isophthalic acid ester of the base can be uniformly mixed together in the reaction process, therefore, in the hydrophilic polyester obtained by the composition and the preparation method of the present invention, the isophthalic acid ester containing the metal sulfonic acid base The hydrophilic structure of the formate ester can be evenly distributed among the polyester molecular chains, which can avoid the problem of easy clogging of the spinning nozzle or uneven dyeing of the resulting fabric during subsequent spinning. In addition, because the compatibilizer of the formula (I) also participates in the polymerization reaction in the process of preparing the hydrophilic polyester, the compatibilizer will not remain in the final product, thereby affecting subsequent processing The progress of the job.

The content of the present invention will be described in detail below:

[Composition for preparing hydrophilic polyester]

The composition for preparing hydrophilic polyester of the present invention comprises polyester oligomer, isophthalic acid ester containing sulfonic acid metal salt group and compatibilizer. Preferably, the composition for preparing the hydrophilic polyester of the present invention may further contain additives, which are selected from catalysts, stabilizers or combinations of the foregoing.

The compatibilizer, polyester oligomer, isophthalic acid ester containing sulfonic acid metal base, catalyst and stabilizer are described below:

<Compatibilizer>

The compatibilizer used in the composition of the present invention for preparing hydrophilic polyester is represented by the following formula (I).

In formula (I), X ¹ , X ² and X ³ represent substituted or unsubstituted C ₂ -C ₄ alkylene groups which are the same or different, preferably, X ¹ , X ² and X ³ are the same or differently represent a substituted or unsubstituted C ₂ -C ₄ alkylene group. More preferably, X ¹ , X ² and X ³ are the same or different representing C ₂ -C ₄ alkylene groups. In a specific embodiment of the present invention, X ¹ , X ² and X ³ represent ethylidene.

In the formula (I), Y ¹ and Y ² represent the same or different substituted or unsubstituted C ₄ -C ₁₂ aliphatic alkylene groups, substituted or unsubstituted C ₆ -C ₁₂ arylylene groups , substituted or unsubstituted C ₇ -C ₁₂ aralkylene, or substituted or unsubstituted C ₇ -C ₁₂ alkylene aryl, preferably, Y ¹ and Y ² are the same or different represents a substituted or unsubstituted C ₄ -C ₁₂ alkylene group or a substituted or unsubstituted C ₆ -C ₁₂ arylylene group. More preferably, Y ¹ and Y ² represent C ₄ -C ₁₂ alkylene or C ₆ -C ₁₂ arylylene respectively the same or different. Still more preferably, Y ¹ and Y ² respectively represent the same or different phenylene groups, C ₄ -C ₁₀ alkylene groups or In a specific embodiment of the present invention, Y ¹ and Y ² represent phenylene or hexylene respectively identically or differently.

In formula (I), R ¹ represents hydrogen or a C ₁ -C ₂ alkylene group. Preferably, R ¹ represents hydrogen, methyl or ethyl. In a particular embodiment of the invention, R ¹ represents methyl.

In formula (I), M represents an alkali metal group metal ion. In a particular embodiment of the invention, M represents sodium ions.

In formula (I), k represents any integer of 1-10, preferably, k represents any integer of 2-5.

In formula (I), m and n represent any integer from 0 to 50 identically or differently, and 4≤m+n≤50, preferably, 10≤m+n≤30.

In a specific embodiment of the present invention, the compatibilizer has the structure of the following formula (IV):

<Polyester oligomer>

The polyester oligomer is obtained by esterification of an organic dibasic acid and a dibasic alcohol, and the detailed description of the organic dibasic acid and the dibasic alcohol is the same as that of the following [preparation method of hydrophilic polyester] The organic dibasic acid and dibasic alcohol in <step (1)> are as described.

<Isophthalic acid ester containing sulfonic acid metal base>

Preferably, the isophthalic acid ester containing a sulfonic acid metal base is obtained by esterifying dimethyl-5-sodium isophthalate (SIPM) with dibasic alcohol. In a specific embodiment of the present invention, the isophthalate containing a sulfonic acid metal base is diethylene glycol isophthalate-5-sodium sulfonate (SIPE).

Preferably, the molar ratio of the isophthalic acid ester containing metal sulfonic acid groups to the organic dibasic acid used for synthesizing the polyester oligomer ranges from 0.01:1 to 0.1:1.

Preferably, the weight ratio of the compatibilizer to the isophthalic acid ester containing metal sulfonic acid groups is in the range of 0.1:100˜5:100. When the weight ratio of the compatibilizer to the isophthalic acid ester containing the sulfonic acid metal salt group was greater than 5:100, the number average sequence distribution length (L) of the subsequent obtained hydrophilic polyester was higher, That is to say, the hydrophilic structure is less likely to disperse among the polyester molecular chains. More preferably, the weight ratio of the compatibilizer to the isophthalic acid ester containing metal sulfonic acid groups is in the range of 0.5:100-2:100.

<catalyst>

More preferably, the catalyst is an antimony catalyst, such as but not limited to antimony acetate or antimony trioxide. In a specific embodiment of the present invention, the catalyst is antimony acetate.

More preferably, the weight ratio of the catalyst to the organic dibasic acid used to synthesize the polyester oligomer ranges from 150:1,000,000 to 400:1,000,000.

<Stabilizer>

The stabilizer can be used to reduce the acid functional group, so that the acid functional group can not catalyze the side reaction. More preferably, the stabilizer is selected from phosphoric acid and its esters, phosphorous acid and its esters, or a combination of the foregoing, the stabilizer is for example but not limited to triphenyl phosphate.

[Preparation method of hydrophilic polyester]

<step (1)>

The step (1) of the preparation method of the hydrophilic polyester of the present invention is to mix organic dibasic acid and dibasic alcohol, and carry out esterification reaction to obtain polyester oligomer.

Preferably, the organic dibasic acid in step (1) is at least one compound selected from the group consisting of compounds of the following formula (II):

HOOC-U-COOH (II)

In formula (II), U represents a substituted or unsubstituted C ₄ -C ₁₂ aliphatic alkylene group, a substituted or unsubstituted C ₆ -C ₁₂ arylylene group, a substituted or unsubstituted C ₇ -C ₁₂ aralkylene, or a substituted or unsubstituted C ₇ -C ₁₂ alkarylene group. More preferably, U represents a substituted or unsubstituted C ₄ -C ₁₂ alkylene group, or a substituted or unsubstituted C ₆ -C ₁₂ arylylene group. Still more preferably, U represents a C ₄ -C ₁₂ alkylene group or a C ₆ -C ₁₂ arylylene group. Still more preferably, U represents C ₄ -C ₁₀ alkylene, phenylene or

The compound of formula (II) is exemplified but not limited to succinic acid, glutaric acid, adipic acid (AA), pimelic acid, suberic acid, azelaic acid, sebacic acid, terephthalic acid (PTA) or 2 ,6-naphthalene dicarboxylic acid.

In a specific embodiment of the present invention, the organic dibasic acid is terephthalic acid, and a combination of terephthalic acid and adipic acid.

Preferably, the dihydric alcohol in the step (1) is at least one compound selected from the group consisting of compounds of the following formula (III):

HO－T－OH (III)

In formula (III), T represents a substituted or unsubstituted C ₂ -C ₄ alkylene group. More preferably, T represents a substituted or unsubstituted C ₂ -C ₄ alkylene group. Still more preferably, T represents a C ₂ -C ₄ alkylene group. The compound of formula (III) is exemplified but not limited to ethylene glycol (EG), propylene glycol, 1,4-butanediol or 2-methyl-1,3-propanediol.

In a specific embodiment of the invention, the dihydric alcohol is ethylene glycol.

Preferably, the molar ratio of the diol to the organic dibasic acid ranges from 1.1:1 to 2:1. More preferably, the molar ratio of the diol to the organic dibasic acid ranges from 1.15:1 to 1.4:1.

Preferably, the temperature range of the esterification reaction in step (1) is 240-260°C.

<step (2)>

The step (2) of the preparation method of the hydrophilic polyester of the present invention is to mix the polyester oligomer, isophthalic acid ester containing sulfonic acid metal salt groups and a compatibilizer to obtain a precursor mixture. Preferably, the step (2) is to mix the polyester oligomer, isophthalic acid ester containing sulfonic acid metal salt base, compatibilizer and additive to obtain a precursor mixture, and the additive is selected from catalyst, A stabilizer or a combination of the foregoing.

And the detailed description of the isophthalic acid ester, compatibilizer, catalyst and stabilizer of the sulfonic acid metal salt base is respectively the same as the <containing sulfonic acid metal in the composition for the preparation of hydrophilic polyester]. Base-based isophthalic acid ester>, <compatibilizer>, <catalyst> and <stabilizer>.

<Step (3)>

The step (3) of the preparation method of the hydrophilic polyester of the present invention is to subject the precursor mixture to a polymerization reaction to obtain the hydrophilic polyester.

Preferably, the temperature range of the polymerization reaction in step (3) is 260-290°C.

[Preparation method of compatibilizer]

The compatibilizer in the composition of the present invention is prepared by copolymerizing the hydrophobic block oligomer and the hydrophilic block oligomer.

Preferably, the temperature range of the copolymerization reaction is 220-240°C.

<Hydrophobic block oligomer>

The hydrophobic block oligomer is obtained by the esterification reaction of an organic dibasic acid and a dibasic alcohol, and the detailed description of the organic dibasic acid and the dibasic alcohol is the same as the previous [Preparation of Hydrophilic Polyester Method] <step (1)> described in the organic dibasic acid and dibasic alcohol.

Preferably, when the organic dibasic acid is an aromatic dibasic acid, the temperature range of the esterification reaction is 240-260°C; when the organic dibasic acid is an aliphatic dibasic acid, the temperature range of the esterification reaction The temperature is not higher than 230°C.

Preferably, when performing the esterification reaction, the number of moles of the dibasic alcohol is greater than the number of moles of the organic dibasic acid.

<Hydrophilic block oligomer>

The hydrophilic block oligomer is prepared by the esterification reaction between the isophthalic acid ester containing the sulfonic acid metal base and the diol monomer, and the isophthalic acid ester containing the sulfonic acid metal base The detailed description of the formic acid ester is described in the <isophthalate containing sulfonic acid metal salt group> in the previous [composition for the preparation of hydrophilic polyester]; the detailed description of the dibasic alcohol is the same as the previous [Preparation method of hydrophilic polyester] <step (1)> in dihydric alcohol described.

Preferably, the hydrophilic block oligomer undergoes esterification reaction in the presence of a catalyst. More preferably, the catalyst is a titanium catalyst. In a specific embodiment of the present invention, the titanium catalyst is tetrabutyl titanate.

Preferably, when performing the esterification reaction, the molar number of the isophthalic acid ester containing a metal sulfonic acid group is greater than the molar number of the dihydric alcohol.

Description of drawings

Other features and effects of the present invention will be clearly presented in the implementation manner with reference to the drawings, wherein:

Fig. 1 is an NMR spectrum illustrating the signals of hydrogen at different positions on the hydrophilic polyester of Example 1;

Figure 2 is an NMR spectrum illustrating the signals of hydrogen at different positions on the hydrophilic polyester of Comparative Example 1;

Figure 3 is an NMR spectrum illustrating the signals of hydrogen at different positions on the hydrophilic polyester of Example 2; and

Figure 4 is an NMR spectrum illustrating the hydrogen signatures at different positions on the hydrophilic polyester of Example 3.

detailed description

The present invention will be further described with reference to the following examples, but it should be understood that these examples are for illustrative purposes only and should not be construed as limitations on the implementation of the present invention.

<Preparation Example 1>

Preparation of compatibilizer [formula (IV)]

The compatibilizer of Preparation Example 1 is prepared according to the following steps:

Step (a) [preparation of hydrophobic block oligomer]:

Add 0.89 mol of terephthalic acid (PTA) and 1.0 mol of ethylene glycol (EG) into a stainless steel reactor, and carry out esterification reaction after raising the external temperature to 250°C under nitrogen atmosphere to obtain the hydrophobic block oligo Polymer.

Step (b) [preparation of hydrophilic block oligomer]:

In another stainless steel reactor, add 1mol dimethyl isophthalate-5-sodium sulfonate (SIPM), 0.5mol ethylene glycol (EG) and 300ppm (relative to the total weight of SIPM and EG) tetrabutyl titanate Esters, under a nitrogen atmosphere, first raise the external temperature to 200°C, then raise the temperature to 230°C within 2 hours, and then carry out esterification reaction to obtain the hydrophilic block oligomer.

Step (c) [preparation of compatibilizer]:

The hydrophobic block oligomer obtained in step (a) and the hydrophilic block oligomer obtained in step (b) were mixed at 230° C. in an oxygen-isolated environment, and the copolymerization reaction was carried out for 1 hour to obtain the Compatibilizers of formula (IV).

<Example 1, Comparative Example 1>

Preparation of hydrophilic polyester

The hydrophilic polyesters of Example 1 and Comparative Example 1 were prepared by selecting the species and amounts of each component added according to Table 1, and then following the steps below.

Table 1

Step (1): Add organic dibasic acid and dibasic alcohol into a stainless steel reactor equipped with a vacuum system, raise the external temperature to 250°C under nitrogen atmosphere, then start stirring and carry out esterification reaction until esterification After the yield reached 92%, polyester oligomers were obtained.

Step (2): Add the isophthalic acid ester, compatibilizer and catalyzer containing sulfonic acid metal salt group in the polyester oligomer obtained in this step (1), after stirring for 10 minutes, obtain the precursor mixture [i.e. Compositions of the present invention for the preparation of hydrophilic polyesters].

Step (3): Polymerize the precursor mixture obtained in step (2) at an internal temperature of 275°C and a vacuum environment, stop the reaction after the torque value reaches the set value, and then cut the material into pellets and dry it , and finally obtain the hydrophilic polymer. It should be noted that the above-mentioned set value will be different depending on the reactor machine used, so the set value needs to be adjusted according to the used reactor machine.

<Embodiments 2-3>

Preparation of hydrophilic polyester

The preparation method of the hydrophilic polyester of Examples 2-3 is similar to that of Example 1, the difference is that in Examples 2-3, the species and amounts of each component added are selected according to the following Table 2.

Table 2

<Analysis of number average sequence distribution length (L) of hydrophilic structure (isophthalate structure containing sulfonic acid metal base) in polyester>

a. measure the nuclear magnetic resonance (NMR) spectrum of embodiment 1～3 and comparative example 1 gained hydrophilic polyester:

The NMR spectra of the hydrophilic polyesters obtained in Examples 1-3 and Comparative Example 1 are shown in Figures 1-4, respectively. It should be noted that in Figures 1 to 4, the signal at position a refers to the hydrogen of the benzene ring on the hydrophilic structure adjacent to another hydrophilic structure in the hydrophilic polyester (that is, in the following formula V position a), the signal at position b is the hydrogen of the benzene ring on the hydrophilic structure adjacent to PET in the hydrophilic polyester (that is, the b position in the following formula VI), and in Figures 1 to 4, a The integral values A (a position) and B (b position) of the position and b position signals are shown in Table 3 below.

table 3

A B Example 1 figure 1 0.0004 0.0065 Comparative example 1 figure 2 0.0043 0.0026 Example 2 image 3 0 0.0053 Example 3 Figure 4 0 0.0054

b. calculate the number average sequence distribution length (L) of the hydrophilic polyester obtained in Examples 1 to 3 and Comparative Example 1:

Calculate the number average sequence distribution length (L) of the hydrophilic polyester obtained in Examples 1 to 3 and Comparative Example 1 according to the integral values A and B of the a position and b position signals in the above table 3 and the following formula I, and obtain The results are organized in Table 4 below. It should be noted that when L is 1, it means that the hydrophilic structure has been completely dispersed between the polyester molecular chains (that is, the structure of the above formula VI is not included), and the larger the L value, it means that the hydrophilic structure between the polyester molecular chains The less dispersed the aqueous structure (ie, there will be a higher proportion of the structure of formula V above).

[Formula I]

Table 4

L Example 1 1.06 Comparative example 1 2.65 Example 2 1 Example 3 1

c. Results and Discussion:

According to the result of above table 4, in the process of preparing hydrophilic polyester, adding the embodiment 1～3 of formula IV compatibilizer, its L value is all obviously lower than the comparative example 1 that does not add compatibilizer, illustrates the implementation For the hydrophilic polyesters of Examples 1-3, compared with Comparative Example 1, the distribution of the hydrophilic structure among the polyester molecular chains is more dispersed, and the L value of Examples 2 and 3 is 1, indicating that they are hydrophilic The permanent structure has been completely dispersed among the polyester molecular chains (that is, the structure of the above formula V is not included); in addition, the addition of PTA, EG, SIPE and antimony acetate are all the same in Example 1 compared with Comparative Example 1, and Example 1 The L value (L=1.06) is lower than that of Comparative Example 1 (L=2.65) without adding a compatibilizer, and it can be further explained that adding a compatibilizer in the preparation process can make the hydrophilic structure evenly distributed in the polyester molecular chain between.

In summary, with the addition of a compatibilizer [formula (I)], the present invention is used to prepare the composition of hydrophilic polyester and the preparation method of hydrophilic polyester, and the subsequent obtained hydrophilic Among the permanent polyesters, the isophthalate hydrophilic structure containing the sulfonic acid metal base can be evenly distributed among the polyester molecular chains, so the purpose of the present invention can indeed be achieved.

The above is only an embodiment of the present invention, and should not limit the scope of the present invention with this, that is, all simple equivalent changes and modifications made according to the claims of the present invention and the contents of the description are still within the scope of this invention. the scope of the invention.

Claims (10)

1. a composition for preparing hydrophilic polyester, is characterized in that, described composition for preparing hydrophilic polyester comprises: Polyester oligomers; Isophthalic acid esters containing metal sulfonate groups; and The compatibilizer shown in the following formula (I): In formula (I), X ¹ , X ² and X ³ respectively represent substituted or unsubstituted C ₂ -C ₄ alkylene groups identically or differently; Y ¹ and Y ² respectively identically or differently represent a substituted or unsubstituted C ₄ -C ₁₂ aliphatic alkylene group, a substituted or unsubstituted C ₆ -C ₁₂ arylylene group, a substituted or unsubstituted C ₇ -C ₁₂ aralkylene, or substituted or unsubstituted C ₇ -C ₁₂ alkarylene; R ¹ represents hydrogen or C ₁ to C ₂ alkylene; M represents an alkali metal group metal ion; k represents any integer from 1 to 10; m and n each represent any integer of 0 to 50, the same or different, and 4≦m+n≦50. 2. The composition for preparing hydrophilic polyester according to claim 1, characterized in that: X ¹ , X ² and X ³ respectively represent substituted or unsubstituted C ₂ -C ₄ alkylene. 3. The composition for preparing hydrophilic polyester according to claim 1, characterized in that: Y ¹ and Y ² represent substituted or unsubstituted C ₄ -C ₁₂ alkane respectively identically or differently group, or a substituted or unsubstituted C ₆ -C ₁₂ aryl group. 4. the composition for preparing hydrophilic polyester according to claim 1, is characterized in that: the weight ratio scope of this compatibilizer and the isophthalic acid ester containing sulfonic acid metal salt base is 0.1 :100～5:100. 5. a preparation method of hydrophilic polyester, is characterized in that, the preparation method of described hydrophilic polyester comprises the following steps: (1) Mix organic dibasic acid and dibasic alcohol, and carry out esterification reaction, obtain polyester oligomer; (2) mixing the polyester oligomer, the isophthalic acid ester containing sulfonic acid metal salt base and the compatibilizer shown in the following formula (I), obtain the precursor mixture: In formula (I), X ¹ , X ² and X ³ respectively represent substituted or unsubstituted C ₂ -C ₄ alkylene groups identically or differently; Y ¹ and Y ² respectively identically or differently represent a substituted or unsubstituted C ₄ -C ₁₂ aliphatic alkylene group, a substituted or unsubstituted C ₆ -C ₁₂ arylylene group, a substituted or unsubstituted C ₇ -C ₁₂ aralkylene, or substituted or unsubstituted C ₇ -C ₁₂ alkarylene; R ¹ represents hydrogen or C ₁ to C ₂ alkylene; M represents an alkali metal group metal ion; k represents any integer from 1 to 10; m and n respectively represent any integer from 0 to 50 identically or differently, and 4≤m+n≤50; (3) The precursor mixture is subjected to a polymerization reaction to obtain the hydrophilic polyester. 6. The preparation method of hydrophilic polyester according to claim 5, characterized in that: the weight ratio range of the compatibilizer to the isophthalate containing sulfonic acid metal salt group is 0.1:100～ 5:100. 7. The preparation method of hydrophilic polyester according to claim 5, characterized in that: the organic dibasic acid of the step (1) is at least one selected from the group formed by the compound of the following formula (II) Compound: HOOC-U-COOH (II) In formula (II), U represents a substituted or unsubstituted C ₄ -C ₁₂ aliphatic alkylene group, a substituted or unsubstituted C ₆ -C ₁₂ arylylene group, a substituted or unsubstituted C ₇ -C ₁₂ aralkylene, or a substituted or unsubstituted C ₇ -C ₁₂ alkarylene group. 8. the preparation method of hydrophilic polyester according to claim 5 is characterized in that: the dibasic alcohol of this step (1) is at least one compound selected from the group formed by the compound of the following formula (III) : HO－T－OH (III) In formula (III), T represents a substituted or unsubstituted C ₂ -C ₄ alkylene group. 9. the preparation method of hydrophilic polyester according to claim 5 is characterized in that: the isophthalic acid ester of the step (2) containing metal sulfonic acid base is diethylene glycol isophthalate Sodium ester-5-sulfonate. 10. A hydrophilic polyester, characterized in that: the hydrophilic polyester is prepared from the composition for preparing hydrophilic polyester according to any one of claims 1-4.