Polyester polymer containing cyclic imide structure

Abstract

Provided in the present invention is a polyester polymer containing a cyclic imide structure. A cyclic imide side group or side chain is introduced into a polyester polymer by means of a diacid monomer or a diol monomer, thereby overcoming the defects of the polyester polymer being hard and brittle, improving the comprehensive mechanical properties of toughness, etc., thereof, and improving the heat resistance of the polyester polymer.

Description

Polyester polymer containing cyclic imide structure

[0001] The present invention claims priority from the prior application entitled “Polyester polymer containing cyclic imide structure” and application number 202410066595.4 filed on January 16, 2024. The contents of the above-mentioned prior application are incorporated into this text by reference. Technical Field

[0002] The invention belongs to the field of polymers, and in particular relates to a polyester polymer containing a cyclic imide structure. Background Art

[0003] Ethylene glycol-based polyesters, such as PES (polyethylene succinate), are aliphatic polyesters with good biodegradability similar to PBS (polybutylene succinate), good overall mechanical properties, and a lower price than PBS. Moreover, all of its monomers can be derived from biomass, making it a biodegradable material with great application prospects. However, compared to PBS, which is currently widely used in the market, PES has a lower melting temperature (Tm of approximately 100°C), which limits its application in some heat-resistant products. Due to its shorter aliphatic carbon chain, the material itself is relatively hard and brittle, with poor toughness, resulting in limited large-scale application.

[0004] CN103788379B discloses a method for modifying and toughening PES, using a hyperbranched polymer to react with PES to produce a modified PES with high tensile strength and elongation at break. Specifically, a hyperbranched polymer produced by reacting 2,2-dimethylolpropionic acid with a trifunctional or higher polyol is reacted with PES in a kettle to produce the modified PES. This method uses non-biologically derived functional monomers for modification and requires a lengthy preparation process. CN113999373A achieves complementary properties of polylactic acid (PLA) and PES through copolymerization, but the high cost of PLA significantly reduces the cost advantage of PES. Summary of the Invention

[0005] The present invention first provides a polyester comprising a polyester main structural unit and a modification unit, wherein a portion (e.g., greater than 30%, greater than 40%, greater than 50%, greater than 60%, greater than 70%, greater than 90%) or all of the polyester main structural unit comprises ethylene glycol residues; the modification unit comprises a first modification unit and / or a second modification unit, wherein the first modification unit comprises a structure of formula (I):

[0006] R1 is selected from an alkylene group having 1 to 7 carbon atoms, preferably a straight or branched alkylene group having 1, 2, 3 or 4 carbon atoms in the main chain, an arylene group having 6 to 12 carbon atoms, a heteroarylene group having 5 to 11 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, a heterocycloalkylene group having 2 to 11 carbon atoms or a combination thereof, optionally containing the following substituents: halogen, nitro, C1-C4 alkyl, halogenated C1-C4 alkyl, C6-C 12 Aryl, C6-C 12 Aryl-C1-C4 alkyl or halogenated, C1-C4 alkyl substituted C6-C 12 Aryl or C6-C 12 Aryl-C1-C4 alkyl;

[0007] R2 is selected from a linear alkylene group having 2 to 12 carbon atoms, a branched alkylene group having 3 to 12 carbon atoms, an arylene group having 6 to 12 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, or a trivalent C1-C5 alkyl-C6-C8 aryl-C1-C5 alkyl group, optionally containing the following substituents: halogen, nitro, C1-C4 alkyl, halogenated C1-C4 alkyl, C6-C8 alkyl, C1-C5 ... 12 Aryl, C6-C 12 Aryl-C1-C4 alkyl or halogenated, C1-C4 alkyl substituted C6-C 12 Aryl or C6-C 12 Aryl-C1-C4 alkyl;

[0008] The second modifying unit comprises a structure of formula (II):

[0009] Wherein Asp is the residue of aspartic acid;

[0010] X is selected from -C=C-, an alkylene group having 1 to 7 carbon atoms, preferably a straight or branched alkylene group having 1, 2, 3 or 4 carbon atoms in the main chain, an arylene group having 6 to 12 carbon atoms, a heteroarylene group having 5 to 11 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, a heterocycloalkylene group having 2 to 11 carbon atoms or a combination thereof, optionally containing the following substituents: halogen, nitro, C1-C4 alkyl, halogenated C1-C4 alkyl, C6-C 12 Aryl, C6-C 12 Aryl-C1-C4 alkyl or halogenated, C1-C4 alkyl substituted C6-C 12 Aryl or C6-C 12 Aryl-C1-C4 alkyl;

[0011] n is an integer of 0 or greater than 0, preferably, n is any integer of 0-7; preferably, n is greater than 0 and the content of the second modified unit is greater than 0;

[0012] Preferably, the second modification unit further comprises a structure obtained by ring-opening a portion of the imide in (Formula II).

[0013] In a specific embodiment of the present invention, the structure of the first modifying unit in the polyester of the present invention is:

[0014] wherein R3 is a C2-C4 straight or branched alkylene, 1,4-cyclohexylene or 1,4-phenylene, and * indicates the connection position with other units;

[0015] Preferably, R2 is a residue of 2-amino-1,3-propanediol or 3-amino-1,2-propanediol;

[0016] Preferably, R1 is a succinic acid residue (i.e., ethylene);

[0017] Preferably, R3 is a dibasic acid residue, more preferably a succinic acid residue.

[0018] In a specific embodiment of the present invention, the ratio of the first modified unit to the total polyester units of the polyester polymer is 1-50 mol%, preferably 5-50 mol%.

[0019] In a specific embodiment of the present invention, the structure of the second modified unit in the polyester of the present invention is:

[0020] Wherein Asp is an aspartic acid residue, X is ethylene, 1,2-cyclohexylene or 1,2-phenylene, R4 is a diol residue used for polymer synthesis, and includes an ethylene glycol residue; preferably an ethylene glycol residue, or a combination of an ethylene glycol residue and a propylene glycol or butylene glycol residue; * indicates the connection position with other units. n is an integer of 0 or greater; preferably, the content of the second modifying unit where n is greater than 0 is greater than 0;

[0021] Preferably, X is -C=C-, ethylene; preferably, R4 is ethylene.

[0022] In a specific embodiment of the present invention, the second modified structural unit in the polyester of the present invention accounts for 0.5-99.5 mol%, preferably 1-90 mol%, and more preferably 5%-30 mol% of the total structural units of the polymer.

[0023] In a specific embodiment of the present invention, the polyester main structural unit in the polyester of the present invention comprises a polyester unit obtained by polymerizing a dibasic acid / anhydride / ester used for polymer synthesis with ethylene glycol; preferably selected from one or more of PES, PET, or polyethylene adipate, and more preferably PES;

[0024] Preferably, the polyester comprises a first modification unit and a second modification unit separately or simultaneously. Preferably, the polyester polymer further comprises a third modification structural unit.

[0025] Second, the present invention provides a polymer alloy comprising the polyester of the present invention.

[0026] Thirdly, the present invention provides a polymer composition or a shaped article comprising the polyester of the present invention.

[0027] Fourthly, the present invention provides a use of the polyester, or polymer alloy, or polymer composition or molded body of the present invention, which includes use in food containers, food packaging films, disposable tableware such as spoons or straws, packaging containers such as transparent boxes for daily necessities, cosmetics, and household appliances, transparent windows for cartons, transparent folders, stationery such as ID holders, industrial films or agricultural films, and chemical fibers for clothing or industry.

[0028] Fifth, the present invention provides a method for preparing the polyester of the present invention, comprising:

[0029] 1) Provide:

[0030] The diol monomer represented by formula V is:

[0031] Wherein: R1 and R2 are as defined above;

[0032] or / and

[0033] Aspartic acid monomer represented by formula VI:

[0034] Wherein Asp is an aspartic acid residue, X is defined as described above, n is an integer of 0 or greater than 0, preferably n is any integer from 0 to 7; preferably, the content of the second modified unit where n is greater than 0 is greater than 0; preferably, the aspartic acid monomer further comprises a structure after ring-opening of a portion of the imide in (Formula VI).

[0035] 2) subjecting the above-mentioned diol monomer or / and aspartic acid monomer, ethylene glycol and a dibasic acid / ester / anhydride for polymer synthesis, or subjecting the above-mentioned diol monomer or / and aspartic acid monomer and a prepolymer (obtained by esterification / ester exchange reaction based on ethylene glycol and a dibasic acid / ester / anhydride for polymer synthesis) to an esterification / ester exchange reaction to obtain a polyester polymer comprising the first modifying unit or / and the second modifying unit.

[0036] Beneficial technical effects

[0037] The present invention provides a polyester polymer containing a cyclic imide structure. Cyclic imide side groups or side chains are introduced into the polyester polymer through a diacid monomer or a diol monomer, thereby improving the hard and brittle shortcomings of the polyester, enhancing its comprehensive mechanical properties such as toughness, and improving the heat resistance of the polyester. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1: Aspartic acid monomer in polymer synthesis example 1 1 HNMR.

[0039] Figure 2: Diol monomers in polymer synthesis example 3 1 HNMR. DETAILED DESCRIPTION

[0040] I. Polyester Polymer Containing a First Modifying Unit

[0041] The synthesis method of the polyester polymer containing the first modification unit can refer to the Chinese patent application (CN202311583766.2), including:

[0042] Step 1: A primary amino diol (such as 2-amino-1,3-propanediol or 3-amino-1,2-propanediol) is subjected to an amidation reaction with a readily cyclic dibasic acid (such as succinic acid or glutaric acid) and / or its corresponding acid anhydride to obtain a monomer composition; the monomer composition includes a diol monomer containing an imide ring structure as shown in formula (V):

[0043] Wherein: R1 is independently selected from an alkylene group having 1 to 7 carbon atoms, preferably a straight or branched alkylene group having 1, 2, 3 or 4 carbon atoms in the main chain, an arylene group having 6 to 12 carbon atoms, a heteroalkylene group having 5 to 11 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, a heterocycloalkylene group having 2 to 11 carbon atoms or a combination thereof, optionally containing the following substituents: halogen, nitro, C1-C4 alkyl, halogenated C1-C4 alkyl, C6-C 12 Aryl, C6-C 12 Aryl-C1-C4 alkyl or halogenated, C1-C4 alkyl substituted C6-C 12 Aryl or C6-C 12 Aryl-C1-C4 alkyl;

[0044] R2 is selected from a linear alkylene group having 2 to 12 carbon atoms, a branched alkylene group having 3 to 12 carbon atoms, an arylene group having 6 to 12 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, or a trivalent C1-C5 alkyl-C6-C8 aryl-C1-C5 alkyl group, optionally containing the following substituents: halogen, nitro, C1-C4 alkyl, halogenated C1-C4 alkyl, C6-C8 alkyl, C1-C5 ... 12 Aryl, C6-C 12Aryl-C1-C4 alkyl or halogenated, C1-C4 alkyl substituted C6-C 12 Aryl or C6-C 12 Aryl-C1-C4 alkyl.

[0045] The typical preparation process includes:

[0046] 911.1 g (10 mol) of 2-amino-1,3-propanediol and 1180.1 g (10 mol) of 1,4-butanedioic acid after vacuum drying were put into a reactor, and 100 ppm each of triphenyl phosphite (thermal stabilizer) and tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentyl erythritol ester (antioxidant) were added (compared to the weight of the entire reaction system, the same below) and stirred at room temperature. At the same time, nitrogen was used to fully replace the air in the reactor. Then, the temperature was slowly raised to 120° C. in a nitrogen atmosphere, the nitrogen flow rate was 150 mL / min, and the mixture was stirred at a constant temperature for 3 hours to obtain a diol composition.

[0047] Representative diol monomers include:

[0048] Step 2: subjecting the monomer composition to an esterification / transesterification reaction with a diol and a dibasic acid / ester / anhydride, or subjecting the monomer composition to an polyester main prepolymer, to obtain a polyester polymer containing a first modified unit, wherein the structure of the diol monomer containing an imide ring structure and the dibasic acid polymerized is:

[0049] R3 is a dibasic acid residue used for polymer synthesis or a dibasic acid residue that easily forms a ring, or a combination of the two. In a specific embodiment of the present invention, R3 is a dibasic acid residue used for polymer synthesis, preferably a succinic acid residue.

[0050] II. Polyester Polymer Containing a Second Modifying Unit

[0051] The synthesis of the polyester polymer containing the second modified unit can refer to Chinese patent application (CN202311738254.9), including:

[0052] Step 1: Synthesis of aspartic acid monomer containing an imide ring structure:

[0053] The monomer can be obtained by mixing aspartic acid and a dicarboxylic acid that is easy to form a ring in a certain proportion and performing an amidation reaction. The reaction conditions can be selected by those skilled in the art according to the aspartic acid and the dicarboxylic acid that is easy to form a ring, for example, reacting under anaerobic hot melt conditions.

[0054] A typical preparation process involves reacting aspartic acid and succinic acid in a 1:3 molar ratio in a reactor, adding 200 ppm of an antioxidant and a heat stabilizer, and heating and melting the mixture under nitrogen protection to react. Another example involves reacting aspartic acid and 1,2-cyclohexanedicarboxylic acid in a 1:3 molar ratio in a reactor, adding 200 ppm of an antioxidant and a heat stabilizer, and heating and melting the mixture under nitrogen protection to react, to obtain an aspartic acid monomer containing an imide heterocycle:

[0055] Representative monomers include:

[0056] In other embodiments, the aspartic acid monomer structure containing an imide ring structure is as shown in Formula VI, wherein:

[0057] X is -C=C-;

[0058] n is an integer of 0 or greater; preferably, n is any integer from 0 to 7; and / or, the aspartic acid monomer comprises one or more monomers containing an imide cyclic structure represented by (Formula VI) wherein a portion of the cyclic imide is ring-opened, for example:

[0059] Step 2: esterifying / transesterifying the aspartic acid monomer, diol, and dibasic acid / ester / anhydride, or the aspartic acid monomer and polyester prepolymer to obtain a polyester polymer containing a first modified unit, wherein the structure of the dibasic acid monomer containing an imide ring structure and the diol is:

[0060] Where Asp is an aspartic acid residue, X is preferably -C=C-, ethylene, 1,2-cyclohexylene, or 1,2-phenylene, and R4 is a diol residue used in polymer synthesis and comprises an ethylene glycol residue, preferably an ethylene glycol residue, or a combination of an ethylene glycol residue and a propylene glycol or butylene glycol residue. n is an integer of 0 or greater, preferably any integer from 0 to 7; preferably, when n is greater than 0, the content of the second modified unit is greater than 0; preferably, the average value of n is less than 2, and more preferably less than 1. Preferably, the polyester polymer containing the second modified unit comprises the structure of (Formula IV) after ring-opening of a portion of the cyclic imide in the polymer.

[0061] III. Polymers containing third modifying structural units

[0062] The polymer of the present invention may optionally include a third modified unit that is heat-resistant, transparent or has a high barrier property. The third modified unit may be composed of a polymerized repeating unit consisting of a dibasic acid, a diamine or an amino acid (one or more of isophthalic acid, furandicarboxylic acid, camphoric acid, adipic acid, proline, and meta-xylenediamine) and a diol (one or more of ethylene glycol, butanediol, and 1,4-cyclohexanedimethanol).

[0063] IV. Polyester Polymers Containing Modifying Units

[0064] The method for preparing the polyester containing the modified unit of the present invention comprises:

[0065] 1) Provide:

[0066] Diol monomer represented by formula V:

[0067] Wherein: R1 and R2 are as defined above;

[0068] or / and

[0069] Aspartic acid monomer represented by formula VI:

[0070] Wherein Asp is an aspartic acid residue, X is defined as described above, n is an integer of 0 or greater than 0, preferably, n is any integer from 0 to 7; preferably, the content of the second modified unit where n is greater than 0 is greater than 0; preferably, the aspartic acid monomer further comprises a structure after ring-opening of a portion of the imide in (Formula VI).

[0071] 2) subjecting the above-mentioned diol monomer or / and aspartic acid monomer, ethylene glycol (optionally containing one or more other diols used for polymer synthesis such as butanediol) and a dibasic acid / ester / anhydride used for polymer synthesis to an esterification / transesterification reaction, or subjecting the above-mentioned diol monomer or / and aspartic acid monomer and a prepolymer (obtained by an esterification / transesterification reaction based on ethylene glycol and a dibasic acid / ester / anhydride used for polymer synthesis) to an esterification / transesterification reaction to obtain a polyester polymer containing the first modifying unit or / and the second modifying unit.

[0072] V. Alloy

[0073] The polymers of the present invention may form alloys with each other or optionally with other polymers.

[0074] VI. Compositions and Molded Articles

[0075] The present invention also provides a composition or a molded body of the above polymer. Methods for processing or molding various types of polymers are known in the art.

[0076] The polyester polymer composition of the present invention may further contain a plasticizer, a crystal nucleating agent or a hydrolysis inhibitor.

[0077] The polyester polymer composition of the present invention may contain, as other ingredients besides those listed above, fillers (inorganic fillers, organic fillers), flame retardants, antioxidants, hydrocarbon waxes or anionic surfactants (i.e., lubricants), ultraviolet absorbers, antistatic agents, anti-corona agents, light stabilizers, pigments, mildew inhibitors, antibacterial agents, foaming agents, etc., within the range that does not impair the effects of the present invention. Similarly, other polymer materials and other resin compositions may be added within the range that does not impair the effects of the present invention.

[0078] The polyester polymer composition of the present invention can be prepared into a molded body such as a sheet by extrusion molding or press molding; the obtained sheet can also be further thermoformed in a temperature range above the glass transition temperature (Tg) and below the melting point (Tm) of the polyester resin composition, for example, stretched into a film or fiber.

[0079] VII. Products and Applications

[0080] The polymer, alloy thereof, or composition or molded article of the present invention is suitable for use in food containers, food packaging films, disposable tableware such as spoons or straws, transparent boxes for daily necessities, cosmetics, home appliances, etc., transparent windows for cardboard boxes, etc., transparent folders, ID holders and other stationery, industrial films or agricultural films, and chemical fibers for clothing or industry.

[0081] Amino-containing diols

[0082] The amino-containing diol in the present invention has the following structure: HO-R2(NH2)-OH. The amino-containing diol can be selected from an alkanediolamine that is unsubstituted or substituted with a substituent selected from a halogen, alkyl, or nitro group, or an alkyl-aryl-alkanediolamine that is unsubstituted or substituted with a substituent selected from a halogen, alkyl, or nitro group. Preferably, the amino-containing diol can be selected from at least one of 3-amino-1,2-propylene glycol, 2-amino-1,3-propylene glycol, 2-amino-1,3-butanediol, 2-amino-1,4-butanediol, 2-amino-1,5-pentanediol, 3-amino-1,5-pentanediol, 5-amino-1,3-benzenedimethanol, and 2-amino-1,3-phenylenedimethanol.

[0083] Dicarboxylic acid HOOC-R1-COOH that is easily cyclized

[0084] The HOOC-R1-COOH is a dicarboxylic acid that readily cyclizes, i.e., a dicarboxylic acid that readily forms a cyclic anhydride in the absence of a catalyst or under catalytic conditions. Dicarboxylic acids that readily cyclize are known to those skilled in the art, for example, see CN110790906B. HOOC-R1-COOH may be selected from an alkanedicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen, alkyl, aryl, arylalkyl or alkylaryl, an alkanedicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen, alkyl, aryl, arylalkyl or alkylaryl and is interrupted by one or more O atoms, an alkenedicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen or alkyl, a cycloalkanedicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen, alkyl or nitro, a cycloalkenedicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen, alkyl or nitro, an aromatic dicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen, alkyl or nitro, or a bridged cyclic dicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen, alkyl or nitro. Preferably, HOOC-R1-COOH can be selected from at least one of succinic acid, 2-methylsuccinic acid, 2-phenylsuccinic acid, 2-benzylsuccinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, 2,3-diphenylsuccinic acid, 1,2-cyclobutanedicarboxylic acid, 2,2,3,3-tetramethylsuccinic acid, methylmaleic acid, dimethylmaleic acid, phthalic acid, hexahydrophthalic acid, norbornenic acid, tetrahydrophthalic acid, glutaric acid, 2-methylglutaric acid, 3-methylglutaric acid, 3-phenylglutaric acid, 2,2-dimethylglutaric acid, 3,3-dimethylglutaric acid, diglycolic acid, 2,3-furandicarboxylic acid, 3,4-furandicarboxylic acid, 2,3-pyridinedicarboxylic acid, and 3,4-pyridinedicarboxylic acid. The cyclic anhydride of HOOC-R1-COOH can be preferably selected from succinic anhydride, 2-methylsuccinic anhydride, 2-phenylbutyric anhydride, 2-benzylsuccinic anhydride, 2,2-dimethylsuccinic anhydride, 2,3-dimethylsuccinic anhydride, 2,3-diphenylsuccinic anhydride, 1,2-cyclosuccinic anhydride, 2,2,3,3-tetramethylsuccinic anhydride, methylmaleic anhydride, dimethylmaleic anhydride, phthalic anhydride At least one of dihydrophthalic anhydride, hexahydrophthalic anhydride, nadic anhydride, tetrahydrophthalic anhydride, glutaric anhydride, 2-methylglutaric anhydride, 3-methylglutaric anhydride, 3-phenylglutaric anhydride, 2,2-dimethylglutaric anhydride, 3,3-dimethylglutaric anhydride and diglycolic anhydride, 2,3-furandicarboxylic anhydride, 3,4-furandicarboxylic anhydride, 2,3-pyridinedicarboxylic anhydride and 3,4-pyridinedicarboxylic anhydride.

[0085] Dicarboxylic acids for polymer synthesis

[0086] The dicarboxylic acid used for polymer synthesis in the present invention can be used for the synthesis of polymer bulk structural units, and can also be used for the synthesis of structural units for improving polymer strength. When used for the synthesis of structural units for improving polymer strength, that is, HOOC-R3-COOH defined in the present invention, it can be any dicarboxylic acid different from HOOC-R1-COOH, for example, it can be the easily cyclized dicarboxylic acid described above for HOOC-R1-COOH; or it can be a dicarboxylic acid that is not easily cyclized, such as terephthalic acid, 2,5-furandicarboxylic acid, oxalic acid, malonic acid, 1,6-hexanediol, 1,10-decanedioic acid, and 1,18-octadecanediol. Preferably, HOOC-R3-COOH can be selected from an alkane dicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen, alkyl, aryl, arylalkyl or alkylaryl, an alkane dicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen, alkyl, aryl, arylalkyl or alkylaryl and is interrupted by one or more O atoms, an alkene dicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen or alkyl, a cycloalkane dicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen, alkyl or nitro, a cycloalkene dicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen, alkyl or nitro, an aromatic dicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen, alkyl or nitro, or a bridged cyclic dicarboxylic acid which is unsubstituted or substituted with a substituent selected from halogen, alkyl or nitro. Preferably, HOOC-R3-COOH can be selected from succinic acid, 2-methylsuccinic acid, 2-phenylsuccinic acid, 2-benzylsuccinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, 2,3-diphenylsuccinic acid, 1,2-cyclobutanediol, 2,2,3,3-tetramethylsuccinic acid, oxalic acid, malonic acid, 1,6-hexanediol, 1,10-decanedioic acid, 1,18-octadecanedioic acid, maleic acid, methylmaleic acid, dioctadecanedioic ... 1,6-hexanediol, 1,10-decanedioic acid, 1,18-octadecanedioic acid, 1,6-hexanediol, 1,10-decanedioic acid, 1,18-octadecanedioic acid, 1,6-hexanediol, 1,6-hexanediol, 1,10-decanedioic acid, 1,18-octadecanedioic acid, 1,6-hexanediol, 1,6-hexanediol, 1,10-decanedioic acid, 1,18-octadecanedioic acid, 1,6-hexanediol, 1,6-hexanediol, 1,6-hexanediol, 1,6-hexanediol, 1,6-hex At least one of methylmaleic acid, phthalic acid, hexahydrophthalic acid, norbornenic acid, tetrahydrophthalic acid, glutaric acid, 2-methylglutaric acid, 3-methylglutaric acid, 3-phenylglutaric acid, 2,2-dimethylglutaric acid, 3,3-dimethylglutaric acid, diglycolic acid, 2,3-furandicarboxylic acid, 3,4-furandicarboxylic acid, 2,3-pyridinedicarboxylic acid, 3,4-pyridinedicarboxylic acid, terephthalic acid, and 2,5-furandicarboxylic acid.

[0087] Diols for polymer synthesis

[0088] The diol used for polymer synthesis can be selected from alkylene glycols that are unsubstituted or substituted with a substituent selected from halogen, alkyl or nitro groups, HO-alkylene-cycloalkylene-alkylene-OH that are unsubstituted or substituted with a substituent selected from halogen, alkyl or nitro groups, polyether glycols, or alkylene glycols interrupted by one or more nitrogen atoms; preferably, at least one selected from alkylene glycols containing 2 to 18 carbon atoms, polyethylene glycol, polypropylene glycol, polytetrahydrofuran diol, N-methyldiethanolamine, and N-ethyldiethanolamine. Preferably, at least one selected from ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,18-octadecanediol, polyethylene glycol, and 1,4-cyclohexanedimethanol.

[0089] Polyester structural unit

[0090] The polyester structural unit used in the present invention has the common meaning in the art, and is preferably formed by polycondensation of the above-mentioned dicarboxylic acid used for polymer synthesis and diol used for polymer synthesis.

[0091] Example

[0092] Polymer Synthesis Example 1: Aspartic acid: succinic acid = 1:3 molar ratio was reacted in a reactor, and 200ppm of antioxidant and heat stabilizer were added, and the temperature was raised under nitrogen protection to melt and react. The obtained product 1 The HNMR spectrum is shown in Figure 1. While the functional monomers were being synthesized, succinic acid and ethylene glycol were added to another reactor to control the ratio of succinic acid to ethylene glycol to be 1:1.2. 200 ppm of antioxidant and heat stabilizer were also added, and the mixture was heated and melted under nitrogen protection to carry out the esterification reaction.

[0093] Step 2: Blend the materials from the two kettles, heat to 160°C, add 200ppm of anhydrous zinc acetate, add ethylene glycol, control the system's glycol:diacid ratio to 1.2:1, and esterify for 1-2 hours.

[0094] Step 3: After the esterification is completed, 200 ppm of tetrabutyl titanate is added as a catalyst to carry out a polycondensation reaction. The vacuum in the reactor is slowly reduced, and the temperature is further raised to 230°C. The vacuum is maintained below 50 Pa for 4-6 hours before the reaction is terminated to obtain a modified product. Its structure is shown in the figure below, where u1 ranges from 100 to 300, u1:u2 = 19:1 to 1:1; u3 is an integer of 0 or greater, and the average value of u3 in the polymer is preferably less than 2, and more preferably less than 1.

[0095] Polymer Synthesis Example 2: Aspartic acid:succinic acid = 1:3 molar ratio was reacted in a reactor. 200 ppm of antioxidant and heat stabilizer were added, and the mixture was heated and melted under nitrogen protection to continue the reaction. After the monomer synthesis was completed, the remaining succinic acid and ethylene glycol were added to control the proportion of aspartic acid-modified segments to 10%. The system ratio of diol:diacid was controlled to be 1.2:1. After adding 200 ppm of zinc acetate, the esterification reaction was carried out at 160°C for 2-4 hours.

[0096] Step 3: After the esterification is completed, add 200ppm of tetrabutyl titanate as a catalyst to carry out polycondensation reaction, slowly reduce the vacuum degree in the kettle, and further increase the temperature to 230℃, maintain the vacuum degree below 50Pa, and react for 4-6 hours before ending the reaction.

[0097] Polymer Synthesis Example 3: 3-amino-1,2-propanediol: succinic acid = 1:3 molar ratio was reacted in a reactor, and 200ppm of antioxidant and heat stabilizer were added. The temperature was raised and melted under nitrogen protection to react. The obtained product 1 The HNMR spectrum is shown in Figure 2. While the functional monomers were being synthesized, succinic acid and ethylene glycol were added to another reactor to control the ratio of succinic acid to ethylene glycol to be 1:1.2. 200 ppm of antioxidant and heat stabilizer were also added, and the mixture was heated and melted under nitrogen protection to carry out the esterification reaction.

[0098] Step 2: Blend the materials from the two kettles, heat to 160°C, add 200ppm of anhydrous zinc acetate, add ethylene glycol, control the system's glycol:diacid ratio to 1.2:1, and esterify for 1-2 hours.

[0099] Step 3: After esterification, 200 ppm of tetrabutyl titanate is added as a catalyst to initiate a polycondensation reaction. The vacuum level in the reactor is slowly reduced, and the temperature is further raised to 230°C. The vacuum level is maintained below 50 Pa for 4-6 hours before the reaction is terminated to obtain a modified product. The structure is shown below, where u1:u4 = 19:1 to 1:1.

[0100] Polymer Synthesis Example 4: 3-Amino-1,2-propanediol and succinic acid were reacted in a reactor at a molar ratio of 1:3. 200 ppm of an antioxidant and a heat stabilizer were added, and the mixture was heated and melted under nitrogen to allow for further reaction. After monomer synthesis was complete, the remaining succinic acid and ethylene glycol were added to control the functional monomer modified segment ratio to 10%. The diol:diacid ratio in the system was controlled to be 1.2:1. 200 ppm of zinc acetate was added, and the esterification reaction was carried out at 160°C for 2-4 hours.

[0101] Step 3: After the esterification is completed, add 200ppm of tetrabutyl titanate as a catalyst to carry out polycondensation reaction, slowly reduce the vacuum degree in the kettle, and further increase the temperature to 230℃, maintain the vacuum degree below 50Pa, and react for 4-6 hours before ending the reaction.

[0102] Polymer Synthesis Example 5: 2-amino-1,3-propanediol:succinic acid = 1:3 molar ratio is reacted in a reactor, and 200 ppm of antioxidant and heat stabilizer are added, and the temperature is raised to melt under nitrogen protection for reaction; while the functional monomer is being synthesized, succinic acid and ethylene glycol are added to another reactor, controlling the succinic acid:ethylene glycol = 1:1.2, and 200 ppm of antioxidant and heat stabilizer are added, and the temperature is raised to melt under nitrogen protection for esterification reaction.

[0103] Step 2: Blend the materials from the two kettles, heat to 160°C, add 200ppm of anhydrous zinc acetate, add ethylene glycol, control the system's glycol:diacid ratio to 1.2:1, and esterify for 1-2 hours.

[0104] Step 3: After esterification, 200 ppm of tetrabutyl titanate is added as a catalyst to initiate a polycondensation reaction. The vacuum level in the reactor is slowly reduced, and the temperature is further raised to 230°C. The vacuum level is maintained below 50 Pa for 4-6 hours before the reaction is terminated to obtain a modified product. The structure is shown below, where u1:u5 = 19:1 to 1:1.

[0105] Polymer Synthesis Example 6: 2-Amino-1,3-propanediol:succinic acid = 1:3 molar ratio was reacted in a reactor. 200 ppm of antioxidant and heat stabilizer were added, and the mixture was heated and melted under nitrogen to allow for reaction. After monomer synthesis was complete, the remaining succinic acid and ethylene glycol were added to control the functional monomer modified segment ratio to 10%. The diol:diacid ratio in the system was controlled to be 1.2:1. After adding 200 ppm of zinc acetate, the esterification reaction was carried out at 160°C for 2-4 hours.

[0106] Step 3: After the esterification is completed, add 200ppm of tetrabutyl titanate as a catalyst to carry out polycondensation reaction, slowly reduce the vacuum degree in the kettle, and further increase the temperature to 230℃, maintain the vacuum degree below 50Pa, and react for 4-6 hours before ending the reaction.

[0107] Comparative Example

[0108] Succinic acid and ethylene glycol were added to a reactor, maintaining a diol:diacid ratio of 1.2:1. 200 ppm of zinc acetate was added and the esterification reaction was carried out at 160°C for 2-4 hours. After the esterification reaction was completed, 200 ppm of tetrabutyl titanate was added as a catalyst for polycondensation. The vacuum level in the reactor was gradually reduced, and the temperature was further increased to 230°C. The vacuum level was maintained below 50 Pa for 4-6 hours before the reaction was terminated to produce PES resin.

[0109] Effect example:

[0110] Effect Example 1: Effect of different aspartic acid modification unit ratios on PES polymerization properties

[0111] PES polyesters with varying ratios of modified units were synthesized using the method of Polymer Synthesis Example 1 (Examples 1-1 to 1-6). Modified PES polyesters were synthesized using the method of Polymer Synthesis Example 2 (Example 1-7). NMR data indicate the absence of an absorption peak near chemical shift position 8, indicating that the aspartic acid in the polymer is completely ring-closed, with no exposed -NH- or -NH2- absorption peaks. Referring to Table 1, Examples 1-7, when the aspartic acid modified unit content is 5%, the material exhibits a heat resistance temperature of 105.2°C (Example 1-1); when the aspartic acid modified unit content is 10%, the material achieves optimal heat resistance of 110.1°C (Example 1-2), while also significantly improving tensile strength. As the amount of modified units increases, the material's regularity is significantly compromised, and its heat resistance decreases somewhat. However, it maintains a high elongation at break (>300%) while maintaining a high tensile strength. The crystallization half-time is longer and can be controlled by the formulation, making it more suitable for film preparation. Furthermore, the reduced amount of succinic acid used can effectively reduce costs. When the content of aspartic acid modified units is greater than 70%, the regularity of the material is improved, but the molecular weight is difficult to increase and polymerization is difficult. More imide rings can provide better hydrophilic properties, which can reduce costs and expand applications in the field of hydrophilic polymer materials. The step-by-step block polymerization method performs better than the one-pot mixed polymerization method, which is also a reflection of higher regularity and better performance. In addition, the modification effect when aspartic acid: succinic acid = 1:1 was explored. At this time, the self-polymerization components of aspartic acid become more and more difficult to control. The regularity of the material after polymerization decreases, and the thermodynamic properties of the material decrease slightly.

[0112] Effect Example 2: Effect of different ratios of 3-amino-1,2-propanediol and 2-amino-1,3-propanediol modified units on PES polymerization performance

[0113] PES polyesters with different modified unit ratios were synthesized using the methods of Polymer Synthesis Examples 3 and 5 (Examples 2-1 to 2-5 and Examples 3-1 to 3-5), and modified PES polyesters were synthesized using the methods of Polymer Synthesis Examples 4 and 6 (Examples 2-6 and 3-6). The NMR data show that there is no absorption peak near chemical shift position 8, indicating that the -NH2 and -NH- groups in the polymer are completely closed. Referring to the examples in Table 2, when the 3-amino-1,2-propylene glycol modified unit content is 5%, the material has a heat resistance temperature of 105.1°C (Example 2-1); when the 3-amino-1,2-propylene glycol modified unit content is 10%, the material's heat resistance reaches an optimal temperature of 108.6°C (Example 2-2), and the tensile strength is also significantly improved. Table 3 shows the thermodynamic properties of the resin modified with 2-amino-1,3-propanediol. Compared to the 3-amino-1,2-propanediol-modified resin, the thermal performance of the material is somewhat reduced. This is likely due to the fact that the backbone structure of the 3-amino-1,2-propanediol-modified polymer is similar to that of PES, which ensures a certain degree of regularity and higher crystallinity. Compared to the aspartic acid-modified unit, neither amino diol system improves thermal properties beyond that of the aspartic acid-modified system. However, at appropriate addition levels, they do have a certain effect on enhancing the material's elongation at break.

Claims

1. A polyester, the polyester comprising a polyester main structural unit and a modified unit, the polyester main structural unit comprising a polyester unit obtained by polymerizing a dibasic acid / anhydride / ester for polymer synthesis with ethylene glycol; the modified unit comprising a first modified unit or / and a second modified unit, the first modified unit comprising the structure of formula (I): R1 is selected from an alkylene group having 1 to 7 carbon atoms, preferably a straight-chain or branched alkylene group having 1 or 2 or 3 or 4 carbon atoms in the main chain, an arylene group having 6 to 12 carbon atoms, a heteroalkylene group having 5 to 11 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, a hetero cycloalkylene group having 2 to 11 carbon atoms or a combination thereof, optionally containing the following substituents: halogen, nitro, C1-C4 alkyl, halo C1-C4 alkyl, C6-C 12 aryl, C6-C 12 aryl-C1-C4 alkyl or halogenated, C1-C4 alkyl-substituted C6-C 12 aryl or C6-C 12 aryl-C1-C4 alkyl; R2 is selected from a straight-chain alkylene group having 2 to 12 carbon atoms, a branched-chain alkylene group having 3 to 12 carbon atoms, a secondary aryl group having 6 to 12 carbon atoms, a secondary cycloalkyl group having 3 to 12 carbon atoms, or a trivalent C1-C5 alkyl-C6-C8 aryl-C1-C5 alkyl group, optionally containing the following substituents: halogen, nitro, C1-C4 alkyl, halo-C1-C4 alkyl, C6-C 12 aryl, C6-C 12 aryl-C1-C4 alkyl, or halogenated, C1-C4 alkyl-substituted C6-C 12 aryl, or C6-C 12 aryl-C1-C4 alkyl; The second modification unit contains the structure of formula (II): wherein Asp is a residue of aspartic acid; X is selected from -C═C-, an alkylene group having 1 to 7 carbon atoms, preferably a straight-chain or branched alkylene group having 1, 2, 3 or 4 carbon atoms in the main chain, an arylene group having 6 to 12 carbon atoms, a heteroarylene group having 5 to 11 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, a heterocycloalkylene group having 2 to 11 carbon atoms or a combination thereof, optionally comprising the following substituents: halogen, nitro, C1-C4 alkyl, halo C1-C4 alkyl, C6-C 12 aryl, C6-C 12 aryl-C1-C4 alkyl or halogenated, C1-C4 alkyl-substituted C6-C 12 aryl or C6-C 12 aryl-C1-C4 alkyl; n is an integer of 0 or greater than 0, preferably, n is any integer from 0 to 7; preferably, the content of the second modified unit with n greater than 0 is greater than 0; Preferably, the second modified unit further comprises the structure after partial imide ring-opening in (Formula II).

2. The polyester according to claim 1, wherein the structure of the first modified unit is: wherein R3 is a straight-chain or branched alkylene group with 2 to 4 carbon atoms, 1,4-cyclohexylene or 1,4-phenylene, and * indicates the connection position to other units; Preferably, R2 is a residue of 2-amino-1,3-propanediol or 3-amino-1,2-propanediol; Preferably, R1 is a succinic acid residue (i.e., ethylene); Preferably, R3 is a succinic acid residue.

3. The polyester according to claim 1, wherein the proportion of the first modified unit in the total polyester units of the polyester polymer is 1-50 mol%, preferably 5-50 mol%.

4. The polyester according to claim 1, wherein the structure of the second modified unit is as follows: wherein Asp is a residue of aspartic acid, X is -C═C-, ethylene, 1,2-cyclohexylene or 1,2-phenylene, R4 is a residue of a diol used for polymer synthesis and comprises an ethylene glycol residue, preferably an ethylene glycol residue, or a combination of an ethylene glycol residue and a propylene glycol or butanediol residue, and * indicates the connection position to other units; n is an integer of 0 or greater than 0; preferably, the content of the second modified unit with n greater than 0 is greater than 0; Preferably, X is -C═C-, ethylene; preferably, R4 is ethylene.

5. The polyester according to claim 1, wherein the proportion of the second modified structural unit in the total structural units of the polymer is 0.5-99.5 mol%, preferably 1-90 mol%, and further preferably 5%-30 mol%.

6. The polyester according to any one of claims 1-5, wherein the main structural unit of the polyester is selected from one or more of PES, PET, or polyethylene adipate, and further preferably PES; Preferably, the polyester comprises the first modified unit and the second modified unit separately or simultaneously, and preferably, the polyester polymer further comprises a third modified structural unit.

7. A polymer alloy comprising the polyester according to any one of claims 1-6.

8. A polymer composition or molded article comprising the polyester according to any one of claims 1-6.

9. Use of the polyester according to any one of claims 1-6, or the polymer alloy according to claim 7, or the polymer composition or molded article according to claim 8, said use including for food containers, food packaging films, disposable tableware such as spoons or straws, daily necessities, cosmetics, transparent boxes for household appliances, transparent windows for cardboard boxes, etc., packaging containers, transparent folders, stationery such as document covers, industrial films or agricultural films, clothing or industrial chemical fibers.

10. A method for preparing the polyester according to any one of claims 1-6, comprising: 1) Providing: The diol monomer shown in Formula V: wherein: the definitions of R1 and R2 are as described in any one of claims 1-6; or / and The aspartic acid monomer shown in Formula VI: wherein Asp is a residue of aspartic acid, the definition of X is as described in any one of claims 1-6, and n is an integer of 0 or greater than 0; preferably, the content of the second modified unit with n greater than 0 is greater than 0; 2) Esterify / transesterify the above-mentioned diol monomer or / and aspartic acid monomer, ethylene glycol, and optionally one or more other diols for polymer synthesis and diacid / ester / anhydride for polymer synthesis, or esterify / transesterify the above-mentioned diol monomer or / and aspartic acid monomer and prepolymer to obtain a polyester polymer containing a first modified unit or / and a second modified unit, wherein the prepolymer is obtained by esterifying / transesterifying based on ethylene glycol and optionally one or more other diols for polymer synthesis and diacid / ester / anhydride for polymer synthesis.

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