CN116284701B - Preparation method of aliphatic-aromatic copolyester - Google Patents

Abstract

The present invention provides a method for preparing an aliphatic-aromatic copolyester, which comprises: subjecting an aliphatic dibasic acid and an aromatic dibasic acid to esterification reaction, polycondensation reaction and chain growth reaction with an aliphatic diol respectively in the presence of a first catalyst and/or a second catalyst to obtain an aliphatic-aromatic copolyester; wherein the first catalyst comprises a reaction product of a titanium-containing compound, a magnesium-containing compound, a zinc-containing compound, a hydroxyl-containing compound and a carboxyl-containing compound; and the second catalyst comprises a reaction product of a titanium-containing compound, a magnesium-containing compound, a zinc-containing compound, a hydroxyl-containing compound and an epoxy-containing compound. The auxiliary agent used in the chain growth reaction comprises a molecular weight growth agent, and the molecular weight growth agent comprises a glycerol ether compound and/or a glycerol ester compound. The aliphatic-aromatic copolyester product prepared by the preparation method has a low terminal carboxyl content, a small gel point, a high molecular weight and is easily biodegradable.

Description

Preparation method of aliphatic-aromatic copolyester

Technical Field

The invention relates to a method for preparing aliphatic-aromatic copolyester.

Technical Background

The production process of biodegradable aliphatic-aromatic copolyester film/sheet resin is divided into esterification reaction, polycondensation reaction and viscosity-increasing reaction. The copolyester intermediate is subjected to a melt viscosity-increasing reaction process in a kettle under high temperature and high vacuum conditions in a biaxial viscosity-increasing reaction equipment to prepare film/sheet polyester resin. However, the melt viscosity-increasing process has the following problems: 1. The high vacuum degree requirement and high viscosity of polyester have high requirements for viscosity-increasing equipment, resulting in high investment costs and high energy consumption; 2. Long-term high-temperature viscosity-increasing reaction will lead to thermal degradation reaction, local overreaction and other side reactions, and poor product quality (high terminal carboxyl group, many gel points of product film/sheet).

The prior art uses liquid phase melt viscosity increasing reaction or liquid phase melt mixing to prepare high molecular weight, low end carboxyl polyester products. For example, in Chinese patent application CN103497316A, a method of adding a polyepoxy compound to a polymerization process for melt viscosity increasing reaction is disclosed, which can prepare a polyester product with a terminal carboxyl group of 5 to 20 mmol/kg; in Chinese patent application CN103665777A, a co-rotating twin screw is disclosed to mix and melt extrude a polyester intermediate with a reaction aid to prepare a low end carboxyl polyester product; in Chinese patent application CN111363131 A, a dynamic mixer is disclosed to perform melt mixing and solid phase viscosity increasing to prepare a low end carboxyl aliphatic-aromatic copolyester. However, these patents still have the problem of local excessive gelation reaction during high temperature melt viscosity increasing, resulting in many gel points in the product film/sheet material.

Summary of the invention

In view of the problems existing in the prior art, the present invention provides a method for preparing an aliphatic-aromatic copolyester. The preparation method can produce an aliphatic-aromatic copolyester with low terminal carboxyl content, low gel point, high molecular weight and easy biodegradability, and has the advantages of stable product and excellent quality.

The first aspect of the present invention provides a method for preparing an aliphatic-aromatic copolyester, which comprises the following steps:

S1: conducting an esterification reaction of an aliphatic dibasic acid and an aromatic dibasic acid with an aliphatic diol in the presence of a first catalyst and/or a second catalyst, respectively, and mixing the esterification reaction products obtained to obtain an esterified product;

S2: subjecting the esterified product to a polycondensation reaction to obtain a polyester intermediate;

S3: mixing the polyester intermediate with an auxiliary agent to carry out a chain growth reaction to obtain the aliphatic-aromatic copolyester;

Wherein, the first catalyst comprises a reaction product of a titanium-containing compound, a magnesium-containing compound, a zinc-containing compound, a hydroxyl-containing compound and a carboxyl-containing compound; the second catalyst comprises a reaction product of a titanium-containing compound, a magnesium-containing compound, a zinc-containing compound, a hydroxyl-containing compound and an epoxy-containing compound;

The auxiliary agent includes a molecular weight increasing agent, and the molecular weight increasing agent includes a glyceryl ether compound and/or a glyceryl ester compound.

According to some embodiments of the present invention, the structure of the glycerol ether compound is as shown in Formula I,

In Formula I, _Ra is selected from _C1 - _C20 hydrocarbon groups, and m>1. In some embodiments, _Ra is selected from monovalent _C1 - _C20 hydrocarbon groups, divalent _C1 - _C20 hydrocarbon groups, or polyvalent _C1 - _C20 hydrocarbon groups. In some embodiments, the monovalent _C1 - _C20 hydrocarbon group is selected from _C1 - _C20 alkyl groups (e.g., _C1 - _C6 alkyl groups, _C5 - _C8 alkyl groups, _C9 - _C12 alkyl groups, _C13 - _C16 alkyl groups, _C17 - _C20 alkyl groups), _C6 - _C20 aryl groups, _C7 - _C20 alkylaryl groups, and _C7 - _C20 aralkyl groups. In some embodiments, the divalent C ₁ -C ₂₀ hydrocarbon group is selected from C ₁ -C ₂₀ alkylene (e.g., C ₁ -C ₆ alkylene, C ₅ -C ₈ alkylene, C ₉ -C 12 alkylene, C ₁₃ -C ₁₆ alkylene, C ₁₇ -C ₂₀ alkylene), C ₆ -C ₂₀ arylene, C _{7 -C 20} alkylarylene and C ₇ -C ₂₀ aralkylene. In some embodiments, the polyvalent C ₁ to C ₂₀ hydrocarbon group is selected from C ₁ to C ₂₀ trivalent alkyl (e.g., C ₁ to C ₆ trivalent alkyl, C ₅ to C ₈ trivalent alkyl, C ₉ to C ₁₂ trivalent alkyl, C ₁₃ to C ₁₆ trivalent alkyl, C ₁₇ to C ₂₀ trivalent alkyl), C ₆ to C ₂₀ trivalent aryl, C ₇ to C ₂₀ trivalent alkylaryl and C ₇ to _{C 20} trivalent aralkyl. In some embodiments, m is 1, 2, 3, 4 or 5.

According to some embodiments of the present invention, the glycerol ether compound includes one or more of ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,5-pentanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol A diglycidyl ether or resorcinol diglycidyl ether;

According to one embodiment of the present invention, the structural formula of the glyceride compound is as shown in Formula II:

In formula II, R _b is selected from C ₁ to C ₂₀ hydrocarbon groups, and t>1. In some embodiments, R _b is selected from a monovalent C ₁ to C ₂₀ hydrocarbon group, a divalent C ₁ to C ₂₀ hydrocarbon group, or a polyvalent C ₁ to C ₂₀ hydrocarbon group. In some embodiments, the monovalent C ₁ to C ₂₀ hydrocarbon group is selected from a C ₁ to C ₂₀ alkyl group (e.g., a C ₁ to C ₆ alkyl group, a C ₅ to C ₈ alkyl group, a C ₉ to C ₁₂ alkyl group, a C ₁₃ to C ₁₆ alkyl group, a C ₁₇ to C ₂₀ alkyl group), a C ₆ to C ₂₀ aryl group, a C ₇ -C ₂₀ alkylaryl group, and a C ₇ -C ₂₀ aralkyl group. In some embodiments, the divalent C ₁ -C ₂₀ hydrocarbon group is selected from C ₁ -C ₂₀ alkylene (e.g., C ₁ -C ₆ alkylene, C ₅ -C ₈ alkylene, C ₉ -C 12 alkylene, C ₁₃ -C ₁₆ alkylene, C ₁₇ -C ₂₀ alkylene), C ₆ -C ₂₀ arylene, C _{7 -C 20} alkylarylene and C ₇ -C ₂₀ aralkylene. In some embodiments, the polyvalent C ₁ to C ₂₀ hydrocarbon group is selected from C ₁ to C ₂₀ trivalent alkyl (e.g., C ₁ to C ₆ trivalent alkyl, C ₅ to C ₈ trivalent alkyl, C ₉ to C ₁₂ trivalent alkyl, C ₁₃ to C ₁₆ trivalent alkyl, C ₁₇ to C ₂₀ trivalent alkyl), C ₆ to C ₂₀ trivalent aryl, C ₇ to C ₂₀ trivalent alkylaryl and C ₇ to _{C 20} trivalent aralkyl. In some embodiments, m is 1, 2, 3, 4 or 5.

According to some embodiments of the present invention, the glycerol ester compound includes one or more of diglycidyl oxalate, diglycidyl 1,3-malonate, diglycidyl succinate, diglycidyl 1,5-pentanedioate, diglycidyl adipate, diglycidyl sebacate or triglycidyl citrate.

According to some embodiments of the present invention, the auxiliary agent further includes a diffusant and a promoter.

According to some embodiments of the present invention, the diffusing agent includes an ether compound having the general formula of R ₁ -OR ₂ , and R ₁ and R ₂ are each independently selected from C ₁ to C ₂₀ hydrocarbon groups. In some embodiments, R ₁ and R ₂ are each independently selected from C ₁ to C ₂₀ alkyl groups, such as C ₁ to C ₄ alkyl groups, C ₅ to C ₈ alkyl groups, C ₉ to C ₁₂ alkyl groups, C ₁₃ to C ₁₆ alkyl groups, and C ₁₇ to C ₂₀ alkyl groups. In some embodiments, R ₁ and R ₂ are each independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, or hexyl.

According to some embodiments of the present invention, the diffusing agent comprises R ₃ COOR ₄ , In one or more of the ester compounds of the general formula, R', _R3 and _R4 are each independently selected from _C1 - _C19 hydrocarbon groups, G is a divalent or trivalent _C1 - _C20 hydrocarbon group, and G is optionally substituted by a hydroxyl group. In some embodiments, R', _R3 and _R4 are each independently selected from _C1 - _C19 alkyl groups, such as _C1 - _C4 alkyl groups, _C5 - _C8 alkyl groups, _C9 - _C12 alkyl groups, _C13 - _C16 alkyl groups, and _C17 - _C20 alkyl groups. In some embodiments, R', _R3 and _R4 are each independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, hexyl, heptyl, and octyl groups. In some embodiments, G is C ₁ to C ₂₀ alkylene, C ₁ to C ₄ alkylene, C ₅ to C ₈ alkylene, C ₉ to C ₁₂ alkylene, C ₁₃ to C ₁₆ alkylene, C ₁₇ to C ₂₀ alkylene. In some embodiments, G is methylene, ethylene, propylene, isopropylene, butylene, isobutylene, tert-butylene, n-pentylene, isopentylene, tert-pentylene, hexylene, cyclopentylene, cyclohexylene, heptylene, octylene. According to some embodiments of the present invention, the diffusing agent includes In one or more of the ketone compounds of the general formula, R ₅ and R ₆ are each independently selected from a C ₁ to C ₁₉ hydrocarbon group. In some embodiments, R ₅ and R ₆ are each independently selected from a C ₁ to C ₁₉ alkyl group, such as a C ₁ to C ₄ alkyl group, a C ₅ to C ₈ alkyl group, a C ₉ to C ₁₂ alkyl group, a C ₁₃ to C ₁₆ alkyl group, a C ₁₇ to C _{19 alkyl} group. In some embodiments, R ₅ and R ₆ are each independently selected from a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a n-pentyl group, an isopentyl group, a tert-pentyl group or a hexyl group.

According to some embodiments of the present invention, the diffusing agent includes one or more of butyl ether, pentyl ether, hexyl ether, tributyl citrate, dioctyl succinate, dibutyl glutarate, dioctyl adipate, acetophenone, methyl propyl ketone or butanone.

According to some embodiments of the invention, the accelerator includes one or more of stannous octoate, magnesium acetate, zinc acetate, zinc glutarate, zinc adipate, magnesium glutarate, tin glutarate, tin acetate or magnesium stearate.

According to some embodiments of the present invention, R ₁ to R ₇ are each independently selected from C ₁ to C ₁₀ hydrocarbon groups. According to some embodiments of the present invention, R ₁ to R ₇ are each independently selected from C ₁ -C ₁₀ alkyl groups, C ₃ -C ₁₀ cycloalkyl groups, C ₆ -C ₁₀ aryl groups, C ₇ -C ₁₀ alkaryl groups and C ₇ -C ₁₀ aralkyl groups.

According to some embodiments of the present invention, the diffusing agent, molecular weight increasing agent and accelerator account for 0.1-2%, 0.5-5% and 5×10 ^-4 -15×10 ^-4 % of the mass of the polyester intermediate, respectively.

According to some embodiments of the present invention, the magnesium-containing compound is 0.01-10 moles per mole of titanium-containing compound, for example, 0.05 moles, 0.1 moles, 0.3 moles, 0.5 moles, 0.7 moles, 0.9 moles, 1.5 moles, 2.0 moles, 3.0 moles, 4.0 moles, 5.0 moles, 6.0 moles, 7.0 moles, 8.0 moles, 9.0 moles or any value therebetween. In some embodiments, the magnesium-containing compound is 0.2-5 moles, for example, 0.2-1 mole, calculated per mole of titanium-containing compound.

In some embodiments, the zinc-containing compound is 0.01-10 moles per mole of the titanium-containing compound, for example, 0.05 moles, 0.1 moles, 0.3 moles, 0.5 moles, 0.7 moles, 0.9 moles, 1.5 moles, 2.0 moles, 3.0 moles, 4.0 moles, 5.0 moles, 6.0 moles, 7.0 moles, 8.0 moles, 9.0 moles or any value therebetween. In some embodiments, the zinc-containing compound is 0.1-5 moles, for example, 0.1-1 mole, per mole of the titanium-containing compound.

In some embodiments, the hydroxyl-containing compound is 1-20 moles per mole of the titanium-containing compound, for example, 1.5 moles, 2.0 moles, 2.5 moles, 3.0 moles, 3.5 moles, 4.0 moles, 4.5 moles, 6.0 moles, 7.0 moles, 8.0 moles, 10.0 moles, 12.0 moles, 14.0 moles, 16.0 moles, 18.0 moles or any value therebetween. In some embodiments, the hydroxyl-containing compound is 1-10 moles, for example, 1-5 moles, per mole of the titanium-containing compound.

In some embodiments, the carboxyl-containing compound is 0.01-0.5 mole per mole of the titanium-containing compound, for example, 0.05 mole, 0.07 mole, 0.09 mole, 0.15 mole, 0.20 mole, 0.25 mole, 0.30 mole, 0.35 mole, 0.40 mole, 0.45 mole or any value therebetween. In some embodiments, the carboxyl-containing compound is 0.1-0.5 mole per mole of the titanium-containing compound.

In some embodiments, the epoxy-containing compound is 0.01-1 mole per mole of the titanium-containing compound, for example, 0.05 mole, 0.07 mole, 0.09 mole, 0.15 mole, 0.20 mole, 0.25 mole, 0.30 mole, 0.35 mole, 0.40 mole, 0.45 mole or any value therebetween. In some embodiments, the epoxy-containing compound is 0.1-0.5 mole per mole of the titanium-containing compound.

In some embodiments, the concentration of titanium in the catalyst is 1 to 10 wt%, such as 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, 5.5 wt%, 6.0 wt%, 6.5 wt%, 7.0 wt%, 7.5 wt%, 8.0 wt%, 8.5 wt%, 9.0 wt%, 9.5 wt% or any value therebetween. In some embodiments, the concentration of titanium in the catalyst is 3 to 10 wt%.

According to some embodiments of the present invention, the titanium-containing compound is selected from one or more compounds represented by the general formula Ti(OR ¹ ) _{m X} ⁴ _{-m and} titanium oxides, wherein R ¹ is a C ₂ -C ₁₀ hydrocarbon group; X is a halogen, such as chlorine, bromine or iodine; and m is an integer of 0-4, such as 0, 1, 2, 3 or 4. In some embodiments, R ¹ is a C ₂ -C ₁₀ hydrocarbon group. In some embodiments, R ¹ is a C ₂ -C ₆ alkyl group, such as ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl or hexyl.

According to some embodiments of the present invention, the titanium-containing compound is selected from one or more of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetraethyl titanate, tetraisopropyl titanate, tetrabutyl titanate and titanium dioxide.

According to some embodiments of the present invention, the magnesium-containing compound is selected from one or more of the compounds represented by the general formula Mg(OR ² ) ₂ X _2-n and the compounds represented by the general formula Mg(OOR ³ ) ₂ , wherein R ² in the general formula Mg(OR ² ) ₂ X _2-n is a C ₂ -C ₁₀ hydrocarbon group, X is a halogen, such as chlorine, bromine or iodine; n is an integer of 0-2, such as 0, 1 or 2; and R ³ in the general formula Mg(OOR ³ ) ₂ is a C ₂ -C ₁₀ hydrocarbon group. In some embodiments, R ² is a C ₂ -C ₆ alkyl group, such as ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl or hexyl. In some embodiments, R ³ is a C ₂ -C ₆ alkyl group, such as ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl or hexyl.

According to some embodiments of the present invention, the magnesium-containing compound is selected from one or more of magnesium dichloride, magnesium dibromide, magnesium diiodide, diethoxymagnesium, dipropoxymagnesium, diisopropoxymagnesium, dibutoxymagnesium, diisobutoxymagnesium, magnesium acetate, magnesium propionate and magnesium butyrate.

According to some embodiments of the present invention, the zinc-containing compound is selected from one or more compounds represented by the general formula Zn(OOR ⁴ ) ₂ and zinc halides, wherein R ⁴ in the general formula Zn(OOR ⁴ ) ₂ is a C ₂ -C ₂₀ hydrocarbon group. In some embodiments, R ⁴ is a C ₂ -C ₁₀ hydrocarbon group. In some embodiments, R ⁴ is a C ₂ -C ₆ alkyl group, such as ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl or hexyl.

According to some embodiments of the present invention, the zinc-containing compound is selected from one or more of zinc dichloride, zinc dibromide, zinc diiodide, zinc acetate, zinc propionate, zinc butyrate and zinc stearate.

According to some embodiments of the present invention, the hydroxyl-containing compound is selected from one or more of a monohydric alcohol and a polyhydric alcohol. In some embodiments, the monohydric alcohol is a C ₁ -C ₁₀ monohydric alcohol. In some embodiments, the polyhydric alcohol is a 2-6-hydric alcohol, such as a C ₂ -C ₁₀ dihydric alcohol, a C ₃ -C ₁₅ trihydric alcohol, a C ₄ -C ₂₀ tetrahydric alcohol, a C ₅ -C ₂₀ pentahydric alcohol, or a C ₆ -C ₂₀ hexahydric alcohol.

According to some embodiments of the present invention, the hydroxyl-containing compound is selected from one or more of methanol, ethanol, isopropanol, n-butanol, n-pentanol, 2-pentanol, 3-pentanol, ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, pentaerythritol and sorbitol.

According to some embodiments of the present invention, the carboxyl-containing compound is selected from one or more of monocarboxylic acids and polycarboxylic acids. In some embodiments, the monocarboxylic acid is a C ₁ -C ₂₀ monocarboxylic acid. In some embodiments, the polycarboxylic acid is a C ₂ -C ₂₀ dicarboxylic acid or a C ₃ -C ₂₀ tricarboxylic acid.

According to some embodiments of the present invention, the carboxyl-containing compound is selected from at least one of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, stearic acid, oxalic acid, malonic acid, succinic acid, glutaric acid and adipic acid.

According to some embodiments of the present invention, the epoxy-containing compound is selected from the general formula One or more of the compounds shown in In some embodiments, R ⁵ and R ⁶ are the same or different and are independently selected from hydrogen or C1-C20 hydrocarbon groups. In some embodiments, R ^{5 and R 6 are independently selected from hydrogen or C1-C10 alkyl groups, such as C1-C6 alkyl groups. In some embodiments, R 5 and R 6 are independently} selected from hydrogen, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl or hexyl. In some embodiments, R ⁵ and R ⁶ are independently selected from hydrogen or C1-C10 hydrocarbon groups.

According to some embodiments of the present invention, the epoxy-containing compound is selected from one or more of ethylene oxide, propylene oxide, 1,2-butylene oxide, 1,4-butylene oxide or 1,2-pentane oxide.

According to some embodiments of the present invention, the method for preparing the first catalyst comprises the following steps:

Step A: reacting a portion of the hydroxyl group-containing compound with the carboxyl group-containing compound to obtain a first solution;

Step B: adding the remaining part of the hydroxyl-containing compound, the magnesium-containing compound, the zinc-containing compound and the titanium-containing compound to the first solution, and reacting to obtain a second solution.

According to some embodiments of the present invention, the method further comprises step C: allowing the second solution to stand and mature.

According to some embodiments of the present invention, in step A, the reaction temperature is 60-200°C, such as 70°C, 90°C, 100°C, 110°C, 130°C, 150°C, 170°C, 190°C or any value therebetween. In some embodiments, in step A, the reaction time is 0.5-5h, such as 1h, 2h, 3h or 4h. According to some embodiments of the present invention, in step B, the reaction temperature is 40-100°C, such as 50°C, 60°C, 70°C, 80°C, 90°C or any value therebetween. In some embodiments, in step B, the reaction time is 0.5-5h, such as 1h, 2h, 3h or 4h. According to some embodiments of the present invention, the aging temperature is 20-60°C, such as 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C or any value therebetween. According to some embodiments of the present invention, in step C, the aging time is 5-24h. In some embodiments, in step C, the aging time is 5-24 hours, for example, 7 hours, 9 hours, 10 hours, 13 hours, 15 hours, 17 hours, 19 hours, 20 hours or 22 hours.

The first catalyst of the present invention is compounded by a magnesium-containing compound, a zinc-containing compound and a titanium-containing compound, and dispersed by a product obtained by the reaction of a hydroxyl-containing compound and a carboxyl-containing compound to ensure the catalytic activity and selectivity of the catalyst. The first catalyst has a simple preparation process, mild configuration conditions, and low raw material cost.

According to some embodiments of the present invention, the method for preparing the second catalyst comprises the following steps:

Step M: reacting a hydroxyl-containing compound, an epoxy-containing compound, and one selected from a zinc-containing compound and a magnesium-containing compound to obtain a third solution;

Step N: adding another selected from the group consisting of the zinc-containing compound and the magnesium-containing compound, the titanium-containing compound and an optional hydroxyl-containing compound to the third solution of step M, and reacting to obtain a fourth solution.

According to some embodiments of the present invention, the preparation method comprises the following steps:

Step M1: reacting a hydroxyl-containing compound, an epoxy-containing compound and a zinc-containing compound to obtain a third solution,

Step N1: adding a magnesium-containing compound, a titanium-containing compound and an optional hydroxyl-containing compound to the third solution of step M1 to react to obtain a fourth solution.

According to some embodiments of the present invention, the preparation method comprises the following steps:

Step M1: reacting part of the hydroxyl-containing compound, the epoxy-containing compound and the zinc-containing compound to obtain a third solution. Preferably, step M1 comprises mixing part of the hydroxyl-containing compound and the epoxy-containing compound to obtain a first mixture, and reacting the first mixture with the zinc-containing compound to obtain a third solution. More preferably, the mixing temperature is 30 to 80°C, such as 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or any value therebetween. In some embodiments, the mixing time is 0.5-5h, such as 1h, 2h, 3h or 4h;

Step N1: adding the magnesium-containing compound, the titanium-containing compound and the remaining hydroxyl-containing compound to the third solution of step M1 to react to obtain a fourth solution.

According to some embodiments of the present invention, the preparation method comprises the following steps:

Step M1: reacting a hydroxyl-containing compound, an epoxy-containing compound and a zinc-containing compound to obtain a third solution. Preferably, step M1 comprises mixing a hydroxyl-containing compound and an epoxy-containing compound to obtain a first mixture, and reacting the first mixture with a zinc-containing compound to obtain a third solution. More preferably, the mixing temperature is 30 to 80°C, such as 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or any value therebetween. In some embodiments, the mixing time is 0.5-5h, such as 1h, 2h, 3h or 4h;

Step N1: adding a magnesium-containing compound and a titanium-containing compound to the first solution of step M1, and reacting to obtain a fourth solution.

According to some embodiments of the present invention, the preparation method comprises the following steps:

Step M2: reacting a hydroxyl-containing compound, an epoxy-containing compound and a magnesium-containing compound to obtain a third solution,

Step N2: adding a zinc-containing compound, a titanium-containing compound and an optional hydroxyl-containing compound to the third solution of step M2 to react to obtain a fourth solution.

According to some embodiments of the present invention, the preparation method comprises the following steps:

Step M2: reacting part of the hydroxyl-containing compound, the epoxy-containing compound and the magnesium-containing compound to obtain a third solution. Preferably, step M2 comprises mixing part of the hydroxyl-containing compound and the epoxy-containing compound to obtain a first mixture, and reacting the first mixture with the magnesium-containing compound to obtain a third solution. More preferably, the mixing temperature is 30 to 80°C, for example, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or any value therebetween. In some embodiments, the mixing time is 0.5-5h, for example, 1h, 2h, 3h or 4h;

Step N2: adding the zinc-containing compound, the titanium-containing compound and the remaining part of the hydroxyl-containing compound to the third solution of step M2, and reacting to obtain a fourth solution.

According to some embodiments of the present invention, the preparation method comprises the following steps:

Step M2: reacting a hydroxyl-containing compound, an epoxy-containing compound and a magnesium-containing compound to obtain a third solution. Preferably, step M2 comprises mixing a hydroxyl-containing compound and an epoxy-containing compound to obtain a first mixture, and reacting the first mixture with a magnesium-containing compound to obtain a third solution. More preferably, the mixing temperature is 30 to 80°C, such as 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or any value therebetween. In some embodiments, the mixing time is 0.5-5h, such as 1h, 2h, 3h or 4h;

Step N2: adding the zinc-containing compound and the titanium-containing compound to the first solution of step M2, and reacting to obtain a fourth solution.

According to some embodiments of the present invention, the method further comprises step O: allowing the fourth solution to stand and mature.

According to some implementations of the present invention, in steps M, M1, and M2, the reaction temperature is 0-100°C, such as 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, or any value therebetween. In some embodiments, in steps M, M1, and M2, the reaction time is 0.5-5h, such as 1h, 2h, 3h, or 4h. In some embodiments, in steps N, N1, and N2, the reaction temperature is 25-100°C, such as 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, or any value therebetween. In some embodiments, in steps N, N1, and N2, the reaction time is 0.5-5h, such as 1h, 2h, 3h, or 4h. In some embodiments, in step O, the aging temperature is 20-60° C., such as 25° C., 30° C., 35° C., 40° C., 45° C., 50° C., 55° C., or any value therebetween. In some embodiments, in step O, the aging time is 5-24 h, such as 7 h, 9 h, 10 h, 13 h, 15 h, 17 h, 19 h, 20 h, or 22 h.

The second catalyst of the present invention disperses and complexes the magnesium-containing compound, the zinc-containing compound and the titanium compound through the product obtained by the reaction of the hydroxyl-containing compound and the epoxy-containing compound, thereby regulating the catalytic activity and selectivity of the titanium-based catalyst. The method has simple process, mild configuration conditions and low raw material cost.

According to some embodiments of the present invention, the aliphatic dibasic acid is one or more of a C ₂ to C ₁₆ dibasic acid, a C ₂ to C ₁₆ aliphatic dibasic acid anhydride, or a C ₂ to C ₁₆ aliphatic dibasic acid halide. According to some embodiments of the present invention, the aliphatic dibasic acid is one or more of a C ₂ to C ₁₀ dibasic acid, a C ₂ to C ₁₀ aliphatic dibasic acid anhydride, or a C ₂ to C ₁₀ aliphatic dibasic acid halide. In some embodiments of the present invention, the aliphatic dibasic acid includes one or more of succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, glutaric anhydride, or malonic acid chloride.

According to some embodiments of the present invention, the aromatic dibasic acid is selected from one or more of C ₈ to C ₁₆ aromatic dibasic acids, C ₈ to C ₁₆ aromatic dibasic acid anhydrides or C ₈ to C ₁₆ aromatic dibasic acid halides. In some embodiments of the present invention, the aromatic dibasic acid includes one or more of terephthalic acid, terephthalic anhydride, terephthalic acid halide, isophthalic acid, isophthalic anhydride, isophthalic acid halide, naphthalene dicarboxylic acid, naphthalene dicarboxylic anhydride, and naphthalene dicarboxylic acid halide.

According to some embodiments of the present invention, the aliphatic diol is selected from one or more aliphatic diols of _C2 to _C10 . According to some embodiments of the present invention, the aliphatic diol is one or more aliphatic diols of _C2 to _C6 . In some embodiments of the present invention, the aliphatic diol includes one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol or polyether diol.

According to some embodiments of the present invention, in the aliphatic dibasic acid, aromatic dibasic acid and aliphatic diol, the ratio of the molar content of hydroxyl functional groups to the molar content of the total functional groups of carboxylic acid, acid anhydride and acyl halide is (1.2-2.5):1.

According to some embodiments of the present invention, in step S1, the temperature of the esterification reaction is 150°C to 250°C, the absolute pressure is 40KPa to 110KPa, and the reaction time is 2h to 6h. According to some specific embodiments of the present invention, the temperature of the esterification reaction is 150°C, 170°C, 190°C, 210°C, 230°C, 250°C and any value therebetween. According to some specific embodiments of the present invention, the absolute pressure of the esterification reaction is 40KPa, 60KPa, 80KPa, 100KPa, 110KPa and any value therebetween. According to some specific embodiments of the present invention, the time of the esterification reaction is 2h, 3h, 4h, 5h, 6h and any value therebetween.

According to some embodiments of the present invention, in step S2, the polycondensation reaction includes a first polycondensation reaction and a second polycondensation reaction performed sequentially. According to some embodiments of the present invention, the temperature of the first polycondensation reaction is 220°C to 250°C, the absolute pressure is 1KPa to 5KPa, and the reaction time is 1h to 3h. According to some embodiments of the present invention, the temperature of the second polycondensation reaction is 220°C to 250°C, the absolute pressure is 10Pa to 300Pa, and the reaction time is 1h to 3h. According to some specific embodiments of the present invention, the temperature of the first and/or second polycondensation reaction is 220°C, 230°C, 240°C, 250°C and any value therebetween. According to some specific embodiments of the present invention, the absolute pressure of the first polycondensation reaction is 1.5KPa, 2KPa, 2.5KPa, 3KPa, 4KPa and any value therebetween. According to some specific embodiments of the present invention, the absolute pressure of the second polycondensation reaction is 50Pa, 100Pa, 150Pa, 200Pa, 250Pa and any value therebetween. According to some specific embodiments of the present invention, the time of the first and/or second polycondensation reaction is 1.5 h, 2 h, 2.5 h and any value therebetween.

According to some embodiments of the present invention, in step S3, the temperature of the chain extension reaction is 25°C to 100°C, and the time is 4h to 24h. According to some specific embodiments of the present invention, the temperature of the chain extension reaction is 25°C, 35°C, 45°C, 55°C, 65°C, 75°C, 85°C, 95°C, 100°C and any value therebetween. According to some specific embodiments of the present invention, the time of the chain extension reaction is 4h, 8h, 12h, 16h, 20h, 24h and any value therebetween.

According to some embodiments of the present invention, in step S1, the esterification rate of the esterification reaction product is ≥98%, and the esterification reaction products are mixed. In some embodiments, the esterification rate of the esterification reaction product is ≥98% means that the esterification rate of any esterification reaction product is ≥98%.

According to some embodiments of the present invention, step S2 further comprises pelletizing and drying after the polycondensation reaction to obtain the polyester intermediate. According to some embodiments of the present invention, the intrinsic viscosity of the polyester intermediate is 0.2 to 1.2 dl/g.

According to some specific embodiments of the present invention, the preparation method comprises the following steps:

(1) an esterification reaction, wherein an aliphatic dibasic acid and an aromatic dibasic acid are respectively subjected to an esterification reaction with an aliphatic diol in the presence of a first catalyst and/or a second catalyst under high temperature and appropriate pressure conditions in an esterification unit, and after the esterification rate reaches 98%, they are fully mixed to obtain an esterified product Z;

(2) polycondensation reaction, in which the ester Z is subjected to the polycondensation unit, and water, excess diol and other small molecules are removed successively under the conditions of absolute pressure of 1KPa to 5KPa and 10Pa to 300Pa, and then pelletized and dried to obtain the polyester intermediate M;

(3) Chain growth reaction: the polyester intermediate M and the additive are put into a mixer and fully mixed and undergo a chain growth reaction under low temperature conditions to prepare an aliphatic-aromatic copolyester product P.

The inventors of the present invention found in the process of studying the polymerization of biodegradable aliphatic-aromatic copolyesters that polyester polycondensation is a balanced reaction, in which chain growth, chain breakage and chain transfer reactions occur simultaneously. When the three reactions reach a balance, the polyester has a certain viscosity and a low terminal carboxyl group. At this time, the polycondensation reaction is terminated, and a chain growth reaction is carried out under low temperature and mild conditions to prepare a polyester product with low terminal carboxyl groups, few gel points and high molecular weight.

The second aspect of the present invention provides an aliphatic-aromatic copolyester obtained according to the preparation method of the first aspect.

According to some embodiments of the present invention, the intrinsic viscosity of the aliphatic-aromatic copolyester is 1.6 to 1.8 dl/g.

According to some embodiments of the present invention, the terminal carboxyl content of the aliphatic-aromatic copolyester is ≤15 mmol/kg, preferably ≤10 mmol/kg.

According to some embodiments of the present invention, the gel point of the aliphatic-aromatic copolyester is ≤30 gel points/m ² , preferably ≤6 gel points/m ² .

According to some embodiments of the present invention, the mass average molecular weight of the aliphatic-aromatic copolyester is 5.0×10 ⁴ to 12.8×10 ⁴ , preferably 8.5×10 ⁴ to 12.8×10 ⁴ .

According to some embodiments of the present invention, the molecular weight distribution of the aliphatic-aromatic copolyester is 1.8 to 2.6, preferably 1.8 to 2.1.

The third aspect of the present invention provides use of the aliphatic-aromatic copolyester according to the second aspect in a polyester film material or a polyester sheet material.

The present invention has the following beneficial effects:

(1) The preparation method of the aliphatic-aromatic copolyester of the present invention is simple in process and eliminates the high energy consumption equipment of liquid phase viscosity increase of a twin-shaft reactor or a dynamic mixer;

(2) The aliphatic-aromatic copolyester product prepared by the preparation method of the present invention has high stability and excellent product quality. The terminal carboxyl group of the copolyester resin can be ≤15mmol/kg or even ≤10mmol/kg, the gel point can be ≤30/ ^m2 or even ≤6/ ^m2 , the mass average molecular weight can be 5.0× ^104-12.8 × ¹⁰⁴ , and the molecular weight distribution can be narrow, 1.8-2.6.

DETAILED DESCRIPTION

The present invention will be further described below by means of specific examples, but the scope of the present invention is not limited thereto.

The polymer terminal carboxyl group was tested by acid-base titration method, and the test was carried out according to the method specified in GB/T 32366-2015. The mixed solution was phenol-chloroform, with a volume ratio of 2:3. The standard titration solution was potassium hydroxide-benzyl alcohol, with a concentration of 0.01 mol/L, and was configured and calibrated according to 4.24 of GB/T 601-2002. The concentration of bromophenol blue indicator was 0.2%. Test preparation: 0.5 g sample was dissolved in 25.00 ml phenol-chloroform mixed solvent.

The projection method is used to test the gel point of the polyester sample film/sheet. The test includes 4 layers of film/sheet, and the size of each film is at least ^200mm2 , and ^254mm2 is preferred. The gel points with a size >0.6mm or between 0.3 and 0.6mm are counted and statistically analyzed.

The molecular weight and molecular weight distribution of the polymer were determined by gel permeation chromatography, with chloroform as solvent, Waters-e2695 instrument, and polystyrene as standard.

Catalyst Preparation Example

Preparation Example 1

54.9 g of 1,4-butanediol and 3.4 g of acetic acid were added to the reactor in sequence, and heated at 90°C for 0.5 h to obtain a transparent solution A1; 10.1 g of butanol, 5.2 g of ethanol, 5.2 g of magnesium bromide, 7.9 g of zinc bromide and 26.9 g of titanium tetrachloride were added in sequence, stirred evenly, and heated at 60°C for 2 h to obtain a transparent solution B1, which was allowed to stand and mature at 50°C for 12 h to obtain a catalyst solution C1.

Preparation Example 2

Add 36.0 g of ethylene glycol and 8.2 g of adipic acid to the reactor, and heat at 110°C for 1 h to obtain a transparent solution A2; then add 10.1 g of propanol, 5.2 g of ethanol, 9.3 g of magnesium butoxide, 4.8 g of zinc chloride, and 11.6 g of titanium dioxide in sequence, stir evenly, and heat at 90°C for 3 h to obtain a solution B2; and let stand and mature at 40°C for 20 h to obtain a catalyst solution C2.

Preparation Example 3

32.7 g of 1,3-propylene glycol and 16.0 g of stearic acid were added to the reactor, and the mixture was heated at 180°C for 2 h to obtain a transparent solution A3. Then, 10.2 g of sorbitol, 7.8 g of magnesium acetate, 11.2 g of zinc iodide and 41.1 g of tetraisopropyl titanate were added in sequence, the mixture was stirred evenly, and the mixture was heated at 80°C for 4 h to obtain a transparent solution B3. The catalyst solution C3 was obtained after standing and aging at 25°C for 24 h.

Preparation Example 4

31.6 g of 1,5-pentanediol and 7.2 g of succinic acid were added to the reactor, and the mixture was heated at 135°C for 1 h to obtain a transparent solution A4. Then, 10.1 g of pentaerythritol, 5.2 g of ethanol, 7.8 g of magnesium acetate, 7.9 g of zinc acetate, and 49.2 g of tetrabutyl titanate were added in sequence, the mixture was stirred evenly, and the mixture was heated at 70°C for 3 h to obtain a transparent solution B4. The catalyst solution C4 was obtained after standing and aging at 30°C for 20 h.

Preparation Example 5

62.8 g of 1,4-butanediol and 3.4 g of acetic acid were added to the reactor in sequence, and heated at 90°C for 0.5 h to obtain a transparent solution A5. Then 10.1 g of butanol, 5.2 g of ethanol, 26.9 g of titanium tetrachloride and 5.2 g of magnesium bromide were added in sequence, stirred evenly, and heated at 60°C for 2 h to obtain a transparent solution B5. After standing and aging at 50°C for 12 h, a catalyst solution C5 was obtained.

Preparation Example 6

60.1 g of 1,4-butanediol and 3.4 g of acetic acid were added to the reactor in sequence, and heated at 90°C for 0.5 h to obtain a transparent solution A6; 10.1 g of butanol, 5.2 g of ethanol, 26.9 g of titanium tetrachloride and 7.9 g of zinc bromide were then added in sequence, stirred evenly, and heated at 60°C for 2 h to obtain a transparent solution B6, which was allowed to stand and mature at 50°C for 12 h to obtain a catalyst solution C6.

Preparation Example 7

58.3 g of 1,4-butanediol was added to the reactor in sequence. After heating at 90°C for 0.5 h, 10.1 g of butanol, 5.2 g of ethanol, 26.9 g of titanium tetrachloride, 5.2 g of magnesium bromide and 7.9 g of zinc bromide were added in sequence. The mixture was stirred and heated at 60°C for 2 h to obtain a transparent solution B7. The catalyst solution C7 was obtained after standing and aging at 50°C for 12 h.

Preparation Example 8

57.3 g of 1,4-butanediol and 6.4 g of zinc acetate were added to the reactor in sequence, heated and stirred at 60°C for 4 h, and then 2.5 g of ethylene oxide was slowly added. The mixture was reacted at 10°C for 4 h to obtain solution A8. Then 10.1 g of butanol, 5.2 g of ethanol, 5.2 g of magnesium bromide and 26.9 g of titanium tetrachloride were added in sequence, stirred evenly, and heated to 60°C for 2 h to obtain solution B8. The catalyst solution C8 was obtained after standing and aging at 25°C for 24 h.

Preparation Example 9

Add 48.1 g of ethylene glycol and 7.4 g of zinc propionate to the reactor in sequence, heat and stir at 60°C for 4 h, then slowly add 3.3 g of propylene oxide, react at 40°C for 1 h to obtain solution A9; then add 8.2 g of propanol, 5.2 g of ethanol, 9.3 g of magnesium butoxide and 26.9 g of titanium tetrachloride in sequence, stir evenly, heat and react at 60°C for 2 h to obtain solution B9; let stand and mature at 40°C for 20 h to obtain catalyst solution C9.

Preparation Example 10

34.2 g of 1,3-propylene glycol and 22.0 g of zinc stearate were added to the reactor in sequence, heated and stirred at 60°C for 4 h, and then 4.1 g of butylene oxide was slowly added. The mixture was reacted at 50°C for 1 h to obtain solution A10. Then 8.2 g of amyl alcohol, 5.2 g of ethanol, 7.8 g of magnesium acetate and 26.9 g of titanium tetrachloride were added in sequence, stirred evenly, and heated at 60°C for 2 h to obtain solution B10. The catalyst solution C10 was obtained after standing and aging at 50°C for 20 h.

Preparation Example 11

Add 61.7 g of 1,4-butanediol and 5.9 g of zinc chloride to the reactor, heat and stir at 60°C for 4 h, then slowly add 2.5 g of ethylene oxide, react at 10°C for 4 h to obtain solution A11; then add 7.8 g of magnesium acetate and 41.09 g of tetraisopropyl titanate in sequence, stir evenly, heat and react at 80°C for 2 h to obtain solution B11; let stand and mature at 25°C for 24 h to obtain catalyst solution C11.

Preparation Example 12

62.5 g of 1,4-butanediol and 6.4 g of zinc acetate were added to the reactor in sequence, heated and stirred at 60°C for 4 h, and then 2.5 g of ethylene oxide was slowly added. The reaction was carried out at 10°C for 4 h to obtain solution A12. Then 10.1 g of butanol, 5.2 g of ethanol and 26.9 g of titanium tetrachloride were added in sequence, and the reaction was heated at 60°C with uniform stirring for 2 h to obtain solution B12. The catalyst solution C12 was obtained after standing and aging at 25°C for 24 h.

Preparation Example 13

59.8 g of 1,4-butanediol and 6.4 g of zinc acetate were added to the reactor in sequence, heated and stirred at 60°C for 4 h, and reacted at 10°C for 4 h to obtain solution A13; then 10.1 g of butanol, 5.2 g of ethanol, 5.2 g of magnesium bromide, and 26.9 g of titanium tetrachloride were added in sequence, stirred evenly and heated at 60°C for 2 h to obtain solution B13, and allowed to stand and mature at 25°C for 24 h to obtain catalyst solution C13.

Preparation Example 14

Add 63.7 g of 1,4-butanediol to the reactor, then slowly add 2.5 g of ethylene oxide, and react at 10°C for 4 hours to obtain solution A14; then add 10.1 g of butanol, 5.2 g of ethanol, 5.2 g of magnesium bromide, and 26.9 g of titanium tetrachloride in sequence, stir evenly and heat at 60°C to react for 2 hours to obtain solution B14, and let stand and mature at 25°C for 24 hours to obtain catalyst solution C14.

Example

Example 1

2,7-naphthalene dicarboxylic acid 80.0 kg/h, 1,4-butanediol 60.0 kg/h, catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 240°C, and the absolute pressure was 60 KPa; glutaric acid 71.0 kg/h, 1,4-butanediol 77.4 kg/h, and catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 200°C, and the absolute pressure was 60 KPa. When the esterification rates of the two groups reached 98%, they were fully mixed to obtain ester Z1;

The esterified product Z1 enters the polycondensation unit, the reaction temperature is 240°C, the absolute pressure is 2KPa, the reaction time is 1h, and then the absolute pressure is adjusted to 80Pa, the reaction temperature is 240°C, the reaction time is 2h, and the polyester intermediate M1 is obtained by pelletizing and drying;

Polyester resin intermediate M1 200.0kg/h, amyl ether 0.8kg/h, butanediol diglycidyl ether 5kg/h, and tin acetate 1.5g/h continuously enter the static mixer for mixing and diffusion and undergo chain growth reaction at 80°C, and polyester product P1 is obtained after 4 hours.

Example 2

The only difference from Example 1 is that amyl ether is replaced by n-butyl ether to prepare the polyester product P2.

Example 3

The only difference from Example 1 is that butanediol diglycidyl ether is replaced by 1,6-hexanediol diglycidyl ether to prepare a polyester product P3.

Example 4

The only difference from Example 1 is that tin acetate is replaced by zinc glutarate to prepare polyester product P4.

Example 5

2,7-naphthalene dicarboxylic acid 80.0 kg/h, 1,4-butanediol 60.0 kg/h, catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 240°C, and the absolute pressure was 60 KPa; glutaric acid 71.0 kg/h and 1,4-butanediol 77.4 kg/h, and catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 200°C, and the absolute pressure was 60 KPa. When the esterification rates of the two groups reached 98%, they were fully mixed to obtain esterified product Z5;

The esterified product Z5 enters the polycondensation unit, the reaction temperature is 240°C, the absolute pressure is 2KPa, the reaction time is 1h, and then the absolute pressure is adjusted to 80Pa, the reaction temperature is 240°C, the reaction time is 2h, and the polyester intermediate M5 is obtained after pelletizing and drying;

Polyester resin intermediate M5 200.0kg/h, dibutyl glutarate 0.8kg/h, butanediol diglycidyl ether 5kg/h, tin acetate 1.5g/h continuously enter the static mixer for mixing and diffusion and undergo chain growth reaction at 80°C, and polyester product P5 is obtained after 4 hours.

Example 6

The only difference from Example 5 is that dibutyl glutarate is replaced by dioctyl adipate to prepare the polyester product P6.

Example 7

Terephthaloyl chloride 88.6 kg/h, ethylene glycol 48.7 kg/h, catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 150°C, and the absolute pressure was 101 KPa; suberic acid 87.0 kg/h, ethylene glycol 49.5 kg/h, and catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 180°C, and the absolute pressure was 110 KPa. When the esterification rates of the two groups reached 98%, they were fully mixed to obtain ester Z7;

The esterified product Z7 enters the polycondensation unit, the reaction temperature is 200°C, the absolute pressure is 1KPa, the reaction time is 1h, and then the absolute pressure is adjusted to 150Pa, the reaction temperature is 200°C, the reaction time is 2.5h, and the polyester intermediate M7 is obtained after pelletizing and drying;

Polyester intermediate M7 200.0kg/h, acetophenone 0.9kg/h, ethylene glycol diglycidyl ether 1.6kg/h, and magnesium stearate 3.0g/h were continuously fed into a static mixer for mixing and chain growth reaction was carried out at 90°C. After 6 hours, polyester product P7 was obtained.

Example 8

The only difference from Example 7 is that acetophenone is replaced by methyl propyl ketone to prepare a polyester product P8.

Example 9

Terephthalic acid 75.4 kg/h, 1,4-butanediol 73.6 kg/h, catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 240°C, and the absolute pressure was 60 KPa; glutaric acid 71.0 kg/h, 1,4-butanediol 77.4 kg/h, and catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 200°C, and the absolute pressure was 60 KPa. When the esterification rates of the two groups reached 98%, they were fully mixed to obtain ester Z9;

The esterified product Z9 enters the polycondensation unit, the reaction temperature is 240°C, the absolute pressure is 2KPa, the reaction time is 1h, and then the absolute pressure is adjusted to 80Pa, the reaction temperature is 240°C, the reaction time is 2h, and the polyester intermediate M9 is obtained after pelletizing and drying;

Polyester resin intermediate M9 200.0kg/h, amyl ether 0.8kg/h, butanediol diglycidyl ester 5kg/h, and tin acetate 1.5g/h continuously enter the static mixer for mixing and diffusion and undergo chain growth reaction at 80°C, and polyester product P9 is obtained after 4 hours.

Example 10

The only difference from Example 9 is that butanediol diglycidyl ester is replaced by 1,5-pentanedioic acid diglycidyl ester to prepare the polyester product P10.

Embodiment 11

2,7-naphthalene dicarboxylic acid 80.0 kg/h, 1,4-butanediol 60.0 kg/h, and catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 240°C, and the absolute pressure was 60 KPa; glutaric acid 71.0 kg/h and 1,4-butanediol 77.4 kg/h, and catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 200°C, and the absolute pressure was 60 KPa. When the esterification rates of the two groups reached 98%, they were fully mixed to obtain ester Z11;

The esterified product Z11 enters the polycondensation unit, the reaction temperature is 240°C, the absolute pressure is 2KPa, the reaction time is 1h, and then the absolute pressure is adjusted to 80Pa, the reaction temperature is 240°C, the reaction time is 2h, and the polyester intermediate M11 is obtained after pelletizing and drying;

200.0 kg/h of polyester resin intermediate M11, 5 kg/h of butanediol diglycidyl ether, and 1.5 g/h of tin acetate were continuously fed into a static mixer for mixing and diffusion and chain growth reaction was carried out at 80°C. After 4 hours, polyester product P11 was obtained.

Example 12

2,7-naphthalene dicarboxylic acid 80.0 kg/h, 1,4-butanediol 60.0 kg/h, and catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 240°C, and the absolute pressure was 60 KPa; glutaric acid 71.0 kg/h and 1,4-butanediol 77.4 kg/h, and catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 200°C, and the absolute pressure was 60 KPa. When the esterification rates of the two groups reached 98%, they were fully mixed to obtain esterified product Z12;

The esterified product Z12 enters the polycondensation unit, the reaction temperature is 240°C, the absolute pressure is 2KPa, the reaction time is 1h, and then the absolute pressure is adjusted to 80Pa, the reaction temperature is 240°C, the reaction time is 2h, and the polyester intermediate M12 is obtained by pelletizing and drying;

Polyester resin intermediate M12 200.0kg/h, amyl ether 0.8kg/h, butanediol diglycidyl ether 5kg/h continuously enter the static mixer for mixing and diffusion and undergo chain growth reaction at 80°C, and polyester product P6 is obtained after 4 hours.

Example 13

2,7-naphthalene dicarboxylic acid 80.0 kg/h, 1,4-butanediol 60.0 kg/h, catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 240°C, and the absolute pressure was 60 KPa; glutaric acid 71.0 kg/h, 1,4-butanediol 77.4 kg/h, and catalyst solution C1 0.25 kg/h were stirred and mixed, and then entered the esterification unit for esterification reaction, the reaction material temperature was 200°C, and the absolute pressure was 60 KPa. When the esterification rates of the two groups reached 98%, they were fully mixed to obtain ester Z13;

The esterified product Z13 enters the polycondensation unit, the reaction temperature is 240°C, the absolute pressure is 2KPa, the reaction time is 1h, and then the absolute pressure is adjusted to 80Pa, the reaction temperature is 240°C, the reaction time is 2h, and the polyester intermediate M13 is obtained by pelletizing and drying;

200.0 kg/h of polyester resin intermediate M13 and 5 kg/h of butanediol diglycidyl ether were continuously fed into a static mixer for mixing and diffusion and chain growth reaction was carried out at 80°C. After 4 hours, polyester product P13 was obtained.

Examples 14-16

The only difference from Example 1 is that the catalysts are replaced by catalyst solutions C2-C4, respectively, to prepare polyester products P14-P16, respectively.

Comparative Examples 1-3

The only difference from Example 1 is that the catalysts are replaced by catalyst solutions C5-C7, respectively, to prepare polyester products P17-P19, respectively.

Examples 17-20

The only difference from Example 1 is that the catalysts are replaced by catalyst solutions C8-C11, respectively, to prepare polyester products P20-P23, respectively.

Comparative Examples 4-6

The only difference from Example 1 is that the catalysts are replaced with catalyst solutions C12-C14, respectively, to prepare polyester products P24-P26, respectively.

Comparative Example 7

80.0 kg/h of 2,7-naphthalene dicarboxylic acid, 60.0 kg/h of 1,4-butanediol, and 0.25 kg/h of a 1,4-butanediol solution of tetrabutyl titanate (tetrabutyl titanate concentration is 40 wt%) were stirred and mixed, and then entered the esterification unit for esterification reaction, with a reaction material temperature of 240° C. and an absolute pressure of 60 KPa; 71.0 kg/h of glutaric acid, 77.4 kg/h of 1,4-butanediol, and 0.25 kg/h of a 1,4-butanediol solution of tetrabutyl titanate (tetrabutyl titanate concentration is 40 wt%) were stirred and mixed, and then entered the esterification unit for esterification reaction, with a reaction material temperature of 200° C. and an absolute pressure of 60 KPa, and when the esterification rates of the two groups reached 98%, they were fully mixed to obtain an esterified product Z27;

The esterified product Z27 enters the polycondensation unit, the reaction temperature is 240°C, the absolute pressure is 2KPa, the reaction time is 1h, and then the pressure is increased to 80Pa, the reaction temperature is 240°C, the reaction time is 2h, and the polyester intermediate M27 is obtained after pelletizing and drying;

Polyester resin intermediate M27 200.0kg/h, amyl ether 0.8kg/h, butanediol diglycidyl ether 5kg/h, and tin acetate 1.5g/h continuously enter the static mixer for mixing and diffusion and undergo chain growth reaction at 80°C, and polyester product P27 is obtained after 4 hours.

Comparative Example 8

The corresponding polyester product P28 was prepared according to Example 3 in patent publication number CN103497316 A.

Comparative Example 9

The corresponding polyester product P29 was prepared according to Example 1 in patent publication number CN103665777 A.

Comparative Example 10

The corresponding polyester product P30 was prepared according to Example 2 in patent publication number CN111363131 A.

The above-mentioned examples and comparative examples of biodegradable aliphatic-aromatic copolyester sample film/sheet preparation method: the polyester sample particles are melt-extruded by a single-screw extruder film blowing machine at 150°C, and then cooled and blown and pulled to prepare a film with a thickness of 20±5μm, and the blowing ratio is 3, or a single-screw extruder casting machine is melt-extruded, and then cooled and pulled to prepare a sheet with a thickness of 200±10μm. The specific performance parameters are shown in Table 1 below:

Table 1 Resin film/sheet related quality parameters

In summary, the aliphatic-aromatic copolyester prepared by the continuous production process of the present invention has stable products with excellent quality, i.e., resin terminal carboxyl group ≤15mmol/kg, gel point in film/sheet ≤30/ ^m2 , high molecular weight, i.e., mass average molecular weight 5.0× ^104-12.8 × ¹⁰⁴ , and narrow molecular weight distribution 1.8-2.6.

It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims (15)

1. A method for preparing aliphatic-aromatic copolyester, comprising the following steps:

S1: respectively carrying out esterification reaction on aliphatic dibasic acid and aromatic dibasic acid and aliphatic dibasic alcohol in the presence of a first catalyst and/or a second catalyst, and mixing the esterification reaction products respectively to obtain an esterified product, wherein the aliphatic dibasic acid is selected from one or more of aliphatic dibasic acid of C ₂～C₁₆, aliphatic dibasic anhydride of C ₂～C₁₆ or aliphatic dibasic acid halide of C ₂～C₁₆, the aromatic dibasic acid is selected from one or more of aromatic dibasic acid of C ₈～C₁₆, aromatic dibasic anhydride of C ₈～C₁₆ or aromatic dibasic acid halide of C ₈～C₁₆, and the aliphatic dibasic alcohol is selected from one or more of aliphatic dibasic alcohols of C ₂～C₁₀;

s2: carrying out polycondensation reaction on the esterified substance to obtain a polyester intermediate;

S3: mixing the polyester intermediate with an auxiliary agent, and carrying out chain growth reaction to obtain the aliphatic-aromatic copolyester;

Wherein the first catalyst comprises the reaction product of a titanium-containing compound, a magnesium-containing compound, a zinc-containing compound, a hydroxyl-containing compound, and a carboxyl-containing compound; the second catalyst comprises the reaction product of a titanium-containing compound, a magnesium-containing compound, a zinc-containing compound, a hydroxyl-containing compound, and an epoxy-containing compound;

The auxiliary agent comprises a molecular weight extender, a dispersing agent and an accelerator, wherein the molecular weight extender comprises a glycerol ether compound and/or a glycerol ester compound;

the structure of the glycerol ether compound is shown as a formula I,

In the formula I, R _a is selected from C ₁～C₂₀ alkyl, and m is more than 1;

the structural formula of the glyceride compound is shown as a formula II,

In the formula II, R _b is selected from C ₁～C₂₀ alkyl, and t is more than 1;

The dispersing agent comprises an ether compound with a general formula of R ₁-O-R₂, an ether compound with a general formula of R ₃COOR₄, Ester compounds of the general formula or havingOne or more of the ketones of the general formula;

the promoter comprises one or more of stannous octoate, magnesium acetate, zinc glutarate, zinc adipate, magnesium glutarate, tin acetate or magnesium stearate;

The titanium-containing compound is selected from one OR more of compounds shown in a general formula Ti (OR ¹)_mX_4-m and titanium oxides, wherein in the general formula Ti (OR ¹)_mX_4-m, R ¹ is C ₂～C₁₀ alkyl, X is halogen and m is an integer of 0-4;

The magnesium-containing compound is selected from one OR more of a compound shown in a general formula Mg (OR ²)_nX_2-n and a compound shown in a general formula Mg (OOR ³)₂), wherein in the general formula Mg (OR ²)_nX_2-n, R ² is a hydrocarbon group of C ₂～C₁₀, X is halogen, n is an integer of 0-2, and in the general formula Mg (OOR ³)₂, R ³ is a hydrocarbon group of C ₂～C₁₀;

The zinc-containing compound is selected from one or more of a compound represented by general formula Zn (OOR ⁴)₂ and a zinc halide), wherein in the general formula Zn (OOR ⁴)₂, R ⁴ is a hydrocarbon group of C ₂～C₂₀;

The hydroxyl-containing compound is selected from one or more of C ₁～C₁₀ monohydric alcohol, C ₂～C₁₀ dihydric alcohol, C ₃～C₁₅ trihydric alcohol, C ₄～C₂₀ tetrahydric alcohol, C ₅～C₂₀ pentahydric alcohol or C ₆～C₂₀ hexahydric alcohol;

the carboxyl-containing compound is selected from one or more of C ₁～C₂₀ monocarboxylic acid, C ₂～C₂₀ dicarboxylic acid or C ₃～C₂₀ tricarboxylic acid;

the epoxy group-containing compound is selected from the general formula One or more of the compounds shown, the general formulaWherein R ⁵ and R ⁶ are the same or different and are each independently selected from hydrogen or a hydrocarbon group of C ₁～C₂₀;

the preparation method of the first catalyst comprises the following steps:

step A: reacting a portion of the hydroxyl-containing compound with the carboxyl-containing compound to obtain a first solution;

And (B) step (B): adding the rest of hydroxyl-containing compound, magnesium-containing compound, zinc-containing compound and titanium-containing compound into the first solution, and reacting to obtain a second solution;

the preparation method of the second catalyst comprises the following steps:

Step M: reacting a hydroxyl group-containing compound, an epoxy group-containing compound, and one selected from a zinc-containing compound and a magnesium-containing compound to obtain a third solution;

Step N: adding another zinc-containing compound and magnesium-containing compound, a titanium-containing compound and optionally a hydroxyl-containing compound into the third solution in the step M, and reacting to obtain a fourth solution.

2. The method according to claim 1, wherein,

The glycerol ether compound comprises one or more of ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 5-pentanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, bisphenol A diglycidyl ether or resorcinol diglycidyl ether; and/or

The glyceride compound comprises one or more of diglycidyl oxalate, diglycidyl 1, 3-malonate, diglycidyl succinate, diglycidyl 1, 5-glutarate, diglycidyl adipate, diglycidyl sebacate or triglycidyl citrate.

3. The method according to claim 1, wherein,

The dispersing agent comprises one or more of butyl ether, amyl ether, hexyl ether, tributyl citrate, dioctyl succinate, dibutyl glutarate, dioctyl adipate, acetophenone, methyl propyl ketone or butanone; and/or

The dispersing agent, the molecular weight increasing agent and the accelerating agent respectively account for 0.1 to 2 percent, 0.5 to 5 percent and 5 multiplied by 10 ^-4～15×10^-4 percent of the mass of the polyester intermediate.

4. A production method according to any one of claims 1 to 3, wherein the magnesium-containing compound is 0.01 to 10 moles per mole of the titanium-containing compound; the zinc-containing compound is 0.01 to 10 mol; the hydroxyl-containing compound is 1 to 20 moles; the carboxyl-containing compound is 0.01 to 0.5 mol; and/or the epoxy group-containing compound is 0.01 to 1 mol.

5. A production method according to any one of claims 1 to 3, wherein the magnesium-containing compound is 0.2 to 5 moles per mole of the titanium-containing compound; the zinc-containing compound is 0.1 to 5 mol; the hydroxyl-containing compound is 1 to 10 moles; the carboxyl-containing compound is 0.1 to 0.5 mol; and/or the epoxy group-containing compound is 0.1 to 0.5 mol.

6. A process according to claim 1 to 3, wherein the formula Ti (OR ¹)_mX_4-m, R ¹ is C ₂～C₆ hydrocarbon; X is chlorine, bromine OR iodine; m is 0,1, 2, 3 OR 4, and/OR)

General formula Mg (OR ²)₂X_2-n, wherein R ² is C ₂～C₆ alkyl, X is chlorine, bromine OR iodine; n is 0, 1 OR 2; general formula Mg (OOR ³)₂, R ³ is C ₂～C₆ alkyl; and/OR)

General formula Zn (OOR ⁴)₂, R ⁴ is C ₂～C₁₀ alkyl; and/or

General formula (VI)Wherein R ⁵ and R ⁶ are the same or different and are each independently selected from hydrogen or a hydrocarbon group of C ₁～C₁₀.

7. A method of preparation according to any one of claims 1 to 3, wherein the titanium-containing compound is selected from one or more of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetraethyl titanate, tetraisopropyl titanate, tetrabutyl titanate and titanium dioxide; and/or

The magnesium-containing compound is selected from one or more of magnesium dichloride, magnesium dibromide, magnesium diiodide, magnesium diethoxide, magnesium dipropoxide, magnesium diisopropyloxide, magnesium dibutoxide, magnesium diisobutoxide, magnesium acetate, magnesium propionate and magnesium butyrate; and/or

The zinc-containing compound is selected from one or more of zinc dichloride, zinc dibromide, zinc diiodide, zinc acetate, zinc propionate, zinc butyrate and zinc stearate; and/or

The hydroxyl-containing compound is selected from one or more of methanol, ethanol, isopropanol, n-butanol, n-amyl alcohol, 2-amyl alcohol, 3-amyl alcohol, ethylene glycol, 1, 3-propylene glycol, 1, 4-butanediol, 1, 5-pentanediol, pentaerythritol and sorbitol; and/or

The carboxyl-containing compound is at least one of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, stearic acid, oxalic acid, malonic acid, succinic acid, glutaric acid and adipic acid; and/or

The epoxy group-containing compound is selected from one or more of ethylene oxide, propylene oxide, 1, 2-butylene oxide, 1, 4-butylene oxide or 1, 2-pentane oxide.

8. A method of preparation according to any one of claims 1 to 3 wherein the aliphatic diacid is selected from one or more of C ₂～C₁₀ aliphatic diacid, C ₂～C₁₀ aliphatic diacid anhydride or C ₂～C₁₀ aliphatic diacid halide.

9. A method of preparation according to any one of claims 1 to 3, wherein the aliphatic dibasic acid comprises one or more of succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1, 4-cyclohexanedicarboxylic acid, glutaric anhydride or malonyl chloride;

The aromatic diacid comprises one or more of terephthalic acid, terephthalic anhydride, terephthaloyl halide, isophthalic acid, isophthalic anhydride, isophthaloyl halide, naphthalene dicarboxylic acid, naphthalene dicarboxylic anhydride and naphthalene dicarboxylic acid halide;

the aliphatic diol comprises one or more of ethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol or polyether diol.

10. A process according to any one of claim 1 to 3, wherein,

In the aliphatic dibasic acid, the aromatic dibasic acid and the aliphatic dihydric alcohol, the molar content ratio of hydroxyl functional groups to the total functional groups of carboxylic acid, anhydride and acyl halide is (1.2-2.5): 1.

11. A process according to any one of claim 1 to 3, wherein,

In the step S1, the temperature of the esterification reaction is 150-250 ℃, the absolute pressure is 40-110 KPa, and the reaction time is 2-6 h;

in the step S2, the polycondensation reaction comprises a first polycondensation reaction and a second polycondensation reaction which are sequentially carried out, wherein the temperature of the first polycondensation reaction is 220-250 ℃, the absolute pressure is 1 KPa-5 KPa, the time is 1-3 h, the temperature of the second polycondensation reaction is 220-250 ℃, the absolute pressure is 10 Pa-300 Pa, and the time is 1-3 h;

In the step S3, the temperature of the chain growth reaction is 25-100 ℃ and the time is 4-24 h.

12. The process according to any one of claims 1 to 3, wherein in step S1, the esterification rate of the esterification reaction product is not less than 98%, and the esterification reaction products are mixed; and/or

Step S2 also comprises the steps of granulating and drying after the polycondensation reaction to obtain the polyester intermediate.

13. The aliphatic-aromatic copolyester obtained by the production method according to any one of claims 1 to 8, characterized in that said aliphatic-aromatic copolyester satisfies at least one of the following conditions (a) to (e):

(a) The intrinsic viscosity of the aliphatic-aromatic copolyester is 1.6-1.8 dl/g;

(b) The carboxyl end group content of the aliphatic-aromatic copolyester is less than or equal to 15mmol/kg;

(c) The gel point of the aliphatic-aromatic copolyester is less than or equal to 30/m ²;

(d) The mass average molecular weight of the aliphatic-aromatic copolyester is 5.0 multiplied by 10 ⁴～12.8×10⁴;

(e) The molecular weight distribution of the aliphatic-aromatic copolyester is 1.8-2.6.

14. The aliphatic-aromatic copolyester according to claim 13, wherein the aliphatic-aromatic copolyester has a carboxyl end group content of 10mmol/kg or less; and/or

The gel point of the aliphatic-aromatic copolyester is less than or equal to 6/m ²; and/or

The mass average molecular weight of the aliphatic-aromatic copolyester is 8.5 multiplied by 10 ⁴～12.8×10⁴; and/or

The molecular weight distribution of the aliphatic-aromatic copolyester is 1.8-2.1.

15. Use of an aliphatic-aromatic copolyester according to claim 13 or 14 in a polyester film material or a polyester sheet material.