A copolyester material, its preparation and use

Abstract

The application provides a copolyester material and a preparation method and application thereof. The copolyester material provided by the application can simultaneously have excellent thermal performance, cooking resistance, optical performance and gas barrier performance by designing the molecular structure of the copolyester contained in the copolyester material, and can meet the application requirements in high-temperature cooking food packaging bags and other high-heat scenarios.

Description

Technical Field

[0001] This invention belongs to the field of engineering plastics technology, specifically relating to a copolyester material, its preparation method, and its application. Background Technology

[0002] Poly(1,4-cyclohexanediethanol-co-2,2,4,4-tetramethyl-1,3-cyclobutanediol) (abbreviated as PCcBT, trade name TritanTM) is a high-performance copolyester material developed by Eastman Chemical Company of the United States based on 1,4-cyclohexanediethanol (CHDM), dimethyl terephthalate (DMT), and the sterically hindered monomer 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO). It features high heat resistance (glass transition temperature >90℃), high light transmittance (transmittance >90%), high toughness, and is bisphenol A free. It has been widely used in food packaging, cosmetic packaging, medical packaging and other fields.

[0003] Currently, the thermal properties of PCcBT copolyester materials are mainly adjusted by varying the ratio of CHDM to CBDO. Specifically, increasing the proportion of CBDO in the formulation can significantly improve the glass transition temperature (Tg) of the polyester. Although homopolymers composed of CBDO and terephthalic acid have a Tg higher than 180℃, CBDO is a highly sterically hindered diol with low polymerization activity of hydroxyl groups. When the proportion of CBDO in the diol exceeds 40 mol%, it becomes difficult to obtain resins with a viscosity >0.6 dL / g. The glass transition temperature of high-viscosity copolyester materials is unlikely to exceed 125℃, meaning it is difficult to simultaneously possess both high heat resistance and high molecular weight. Furthermore, PCcBT has insufficient gas barrier properties, limiting its application in food packaging materials. These factors restrict the use of this type of material in high-temperature environments such as retort pouches for food.

[0004] Therefore, there is an urgent need to provide a copolyester material with excellent thermal properties, resistance to boiling, optical properties, and gas barrier properties. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a copolyester material, its preparation method, and its applications. The copolyester material provided by the present invention, through the design of the molecular structure of the copolyester contained therein, can simultaneously possess excellent thermal properties, retortability, optical properties, and gas barrier properties, thus meeting the application requirements in high-heat scenarios (withstanding temperatures of 100-135℃) such as high-temperature retortable food packaging bags.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a copolyester material, wherein the components of the copolyester material include a copolyester; the copolyester comprises diacid residues and diol residues.

[0008] The dicarboxylic acid residues include:

[0009] (a1) 70-98 mol% of 2,6-naphthalenedicarboxylic acid residues based on the total molar amount of (a1) and (a2);

[0010] (a2) 2-30 mol% of other dicarboxylic acid residues based on the total molar amount of (a1) and (a2);

[0011] The total molar percentage of residues (a1) and (a2) is 100%.

[0012] The diol residues comprise:

[0013] (b1) 10-60 mol% of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues based on the total molar amount of (b1) and (b2);

[0014] (b2) 40-90 mol% of other diol residues based on the total molar amount of (b1) and (b2);

[0015] The total molar percentage of residues (b1) and (b2) is 100%.

[0016] The copolyester material provided by this invention, through the design of the molecular structure of the copolyester contained therein, can simultaneously possess excellent thermal properties, retort resistance, optical properties, and gas barrier properties. Among them, the residues (a1) in the copolyester molecular structure have a rigid naphthalene ring structure, and the intermolecular interaction is more significant, which can significantly improve the heat resistance and gas barrier properties of the copolyester material, making it more conducive to the preparation of heat-resistant and high-barrier copolyester materials.

[0017] Preferably, the copolyester material has a copolyester content of 97.5-99.99% by mass, for example, 97.6%, 97.8%, 98%, 98.2%, 98.4%, 98.6%, 98.8%, 99%, 99.2%, 99.4%, 99.6%, 99.8%, 99.9%, etc., and more preferably 98-99.6%.

[0018] The molar percentage of 2,6-naphthalenedicarboxylic acid residues in the dicarboxylic acid residues is 70-98 mol%, for example, it can be 72 mol%, 74 mol%, 76 mol%, 78 mol%, 80 mol%, 82 mol%, 84 mol%, 86 mol%, 88 mol%, 90 mol%, 92 mol%, 94 mol%, 96 mol%, etc.

[0019] The molar percentage of other dicarboxylic acid residues in the dicarboxylic acid residues is 2-30 mol%, for example, it can be 4 mol%, 6 mol%, 8 mol%, 10 mol%, 12 mol%, 14 mol%, 16 mol%, 18 mol%, 20 mol%, 22 mol%, 24 mol%, 26 mol%, 28 mol%, etc.

[0020] The molar percentage of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues in the diol residues is 10-60 mol%, for example, it can be 12 mol%, 15 mol%, 18 mol%, 20 mol%, 22 mol%, 24 mol%, 26 mol%, 28 mol%, 30 mol%, 32 mol%, 35 mol%, 38 mol%, 40 mol%, 42 mol%, 45 mol%, 48 mol%, 50 mol%, 52 mol%, 55 mol%, 58 mol%, etc.

[0021] The molar percentage of other diol residues in the diol residues is 40-90 mol%, for example, it can be 42 mol%, 45 mol%, 48 mol%, 50 mol%, 52 mol%, 55 mol%, 58 mol%, 60 mol%, 62 mol%, 65 mol%, 68 mol%, 70 mol%, 72 mol%, 75 mol%, 78 mol%, 80 mol%, 82 mol%, 85 mol%, 88 mol%, etc.

[0022] In this invention, the other dicarboxylic acid residues are dicarboxylic acid residues that are different from 2,6-naphthalenedicarboxylic acid residues.

[0023] In this invention, the other diol residues are diol residues that are different from 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues.

[0024] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0025] As a preferred technical solution, the other dicarboxylic acid residues include any one or a combination of at least two of the following: terephthalic acid residues, furanyl dicarboxylic acid residues, 4,4-biphenyl dicarboxylic acid residues, 1,3-isophthalic acid residues, or phthalic acid residues.

[0026] Preferably, the dicarboxylic acid residues comprise:

[0027] (a1) 75-95 mol% of 2,6-naphthalenedicarboxylic acid residues based on the total molar amount of (a1) and (a2);

[0028] (a2) 5-25 mol% of other dicarboxylic acid residues based on the total molar amount of (a1) and (a2);

[0029] The total molar percentage of residues (a1) and (a2) is 100%.

[0030] The molar percentage of 2,6-naphthalenedicarboxylic acid residues in the dicarboxylic acid residues is 75-95 mol%, for example, it can be 77 mol%, 79 mol%, 81 mol%, 83 mol%, 85 mol%, 87 mol%, 89 mol%, 91 mol%, 93 mol%, etc.

[0031] The molar percentage of other dicarboxylic acid residues in the dicarboxylic acid residues is 5-25 mol%, for example, it can be 7 mol%, 9 mol%, 11 mol%, 13 mol%, 15 mol%, 17 mol%, 19 mol%, 21 mol%, 23 mol%, etc.

[0032] Preferably, the other diol residues include any one or a combination of at least two of the following: 1,4-cyclohexanediethanol residue, 1,4-cyclohexanediol residue, 1,2-cyclohexanediethanol residue, 1,3-cyclohexanediol residue, 1,2-cyclohexanediol residue, 1,3-cyclohexanediol residue, ethylene glycol residue, 1,3-propanediol residue, 1,4-butanediol residue, dicyclopentanediol residue, neopentanediol residue, or 2-methyl-1,3-propanediol residue.

[0033] Preferably, the diol residues comprise:

[0034] (b1) 25-50 mol% of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues based on the total molar amount of (b1) and (b2);

[0035] (b2) 50-75 mol% of other diol residues based on the total molar amount of (b1) and (b2);

[0036] The total molar percentage of residues (b1) and (b2) is 100%.

[0037] The molar percentage of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues in the diol residues is 25-50 mol%, for example, it can be 26 mol%, 29 mol%, 31 mol%, 33 mol%, 34 mol%, 37 mol%, 39 mol%, 41 mol%, 43 mol%, 44 mol%, 46 mol%, 47 mol%, 49 mol%, etc.

[0038] The molar percentage of other diol residues in the diol residues is 50-75 mol%, for example, it can be 51 mol%, 53 mol%, 54 mol%, 56 mol%, 57 mol%, 59 mol%, 61 mol%, 63 mol%, 64 mol%, 66 mol%, 67 mol%, 69 mol%, 70 mol%, 71 mol%, 72 mol%, 73 mol%, 74 mol%, etc.

[0039] Preferably, the copolyester material further includes a composite stabilizer.

[0040] Preferably, the composite stabilizer includes a phosphorus-based stabilizer and a hindered phenolic stabilizer.

[0041] Preferably, the phosphorus stabilizer comprises any one or a combination of at least two of the following: diphenyl phosphate, triphenyl phosphite, trimethyl phosphate, dimethyl phosphate, triphenyl phosphate, diphenyl phosphite, ammonium phosphite, ammonium dihydrogen phosphate, phosphorous acid, hypophosphite, pyrophosphite, tris(2,4-di-tert-butylphenyl) phosphite, or ammonium phosphate.

[0042] Preferably, the mass percentage of phosphorus-based stabilizer in the composite stabilizer is 10-90%, for example, it can be 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, etc., and more preferably 45-75%.

[0043] Preferably, the hindered phenolic stabilizer comprises any one or a combination of at least two of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), 2,4-dimethyl-6-(1-methylpentadecanyl)phenol (antioxidant 1076), N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine (antioxidant 1098), or 2,6-di-tert-butyl-4-methylphenol.

[0044] Preferably, the hindered phenolic stabilizer in the composite stabilizer has a mass percentage content of 10-90%, for example, it can be 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, etc., and more preferably 25-55%.

[0045] Preferably, the mass percentage of the composite stabilizer in the copolyester material is 0.01-1%, for example, it can be 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, etc.

[0046] Preferably, the copolyester material further includes a catalyst.

[0047] Preferably, the catalyst comprises any one or a combination of at least two of the following: tin-based catalysts, antimony-based catalysts, germanium-based catalysts, titanium-based catalysts, or aluminum-based catalysts.

[0048] Preferably, the tin-based catalyst includes any one or a combination of at least two of dibutyltin oxide, stannous isooctanoate, monobutyltriisooctanoate, or dioctyltin oxide.

[0049] Preferably, the antimony-based catalyst comprises any one or a combination of at least two of antimony acetate, antimony trioxide, antimony glycolate, or antimony polyethylene glycol.

[0050] Preferably, the germanium-based catalyst comprises germanium dioxide and / or germanium oxide.

[0051] Preferably, the titanium-based catalyst includes any one or a combination of at least two of tetrabutyl titanate, isopropyl titanate, titanium dioxide, or inorganic supported titanium catalyst.

[0052] Preferably, the aluminum-based catalyst comprises aluminum chloride and / or aluminum oxide.

[0053] Preferably, the mass percentage of catalyst in the copolyester material is 0.3-1.5%, for example, it can be 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1%, 1.05%, 1.1%, 1.15%, 1.2%, 1.25%, 1.3%, 1.35%, 1.4%, 1.45%, etc.

[0054] Preferably, the light transmittance of the copolyester material is >85% (e.g., 85.5%, 86%, 86.5%, 87%, 87.5%, 88%, 88.5%, 89%, 89.5%, 90%, 90.5%, 91%, 91.5%, 92%, 92.5%, 93%, 93.5%, 94%, 94.5%, 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99%, etc.), and more preferably >88%.

[0055] Preferably, the oxygen permeability of the copolyester material is <30 cm⁻¹. 3 / m 2 ·d·Pa (for example, it can be 29.5cm) 3 / m 2 ·d·Pa, 29cm 3 / m 2 ·d·Pa, 28.5cm 3 / m 2 ·d·Pa, 28cm 3 / m 2 ·d·Pa, 27.5cm 3 / m 2 ·d·Pa, 27cm 3 / m 2 ·d·Pa, 26.5cm 3 / m 2 ·d·Pa, 26cm 3 / m 2 ·d·Pa, 25.5cm 3 / m 2 ·d·Pa, 25cm 3 / m 2 ·d·Pa, 24.5cm 3 / m 2 ·d·Pa, 24cm 3 / m 2 ·d·Pa、23cm 3 / m 2 ·d·Pa、22cm 3 / m 2 ·d·Pa、21cm 3 / m 2 ·d·Pa、20cm 3 / m 2 (e.g., d·Pa), further preferred ≤27cm 3 / m 2 ·d·Pa.

[0056] Preferably, the oxygen permeability of the copolyester material after being boiled at 100°C for 60 minutes is <40 cm⁻¹.3 / m 2 ·d·Pa (for example, 39.5cm) 3 / m 2 ·d·Pa, 39cm 3 / m 2 ·d·Pa, 38.5cm 3 / m 2 ·d·Pa, 38cm 3 / m 2 ·d·Pa, 37.5cm 3 / m 2 ·d·Pa, 37cm 3 / m 2 ·d·Pa, 36.5cm 3 / m 2 ·d·Pa, 36cm 3 / m 2 ·d·Pa, 35.5cm 3 / m 2 ·d·Pa, 35cm 3 / m 2 ·d·Pa, 34.5cm 3 / m 2 ·d·Pa, 34cm 3 / m 2 ·d·Pa、33cm 3 / m 2 ·d·Pa, 32cm 3 / m 2 ·d·Pa, 31cm 3 / m 2 ·d·Pa, 30cm 3 / m 2 ·d·Pa, 29cm 3 / m 2 ·d·Pa, 28cm 3 / m 2 ·d·Pa, 27cm 3 / m 2 ·d·Pa, 26cm 3 / m 2 ·d·Pa, 25cm 3 / m 2 ·d·Pa, 24cm 3 / m 2 (e.g., dPa), further preferred ≤31cm 3 / m 2 ·d·Pa.

[0057] Preferably, the intrinsic viscosity of the copolyester material is 0.5-0.9 dL / g, for example, it can be 0.52 dL / g, 0.55 dL / g, 0.58 dL / g, 0.6 dL / g, 0.62 dL / g, 0.65 dL / g, 0.68 dL / g, 0.7 dL / g, 0.72 dL / g, 0.75 dL / g, 0.78 dL / g, 0.8 dL / g, 0.82 dL / g, 0.85 dL / g, 0.88 dL / g, etc., and more preferably 0.6-0.8 dL / g.

[0058] Preferably, the glass transition temperature of the copolyester material is 140-180℃, for example, it can be 142℃, 145℃, 148℃, 150℃, 152℃, 155℃, 158℃, 160℃, 162℃, 165℃, 168℃, 170℃, 172℃, 175℃, 178℃, etc., and more preferably 150-165℃.

[0059] Preferably, the haze of the copolyester material is 1-5%, for example, it can be 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8%, etc., and more preferably 2-3.1%.

[0060] In a second aspect, the present invention provides a method for preparing a copolyester material as described in the first aspect, the method comprising the following steps:

[0061] (1) 2,6-naphthalenedicarboxylic acid and / or its esterified form, other dicarboxylic acids and / or their esterified forms, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and other diols are reacted to give the reaction product;

[0062] (2) The reaction products undergo a polycondensation reaction to obtain the copolyester material.

[0063] Preferably, the 2,6-naphthalenedicarboxylic acid and / or its esterifications comprise 2,6-naphthalenedicarboxylic acid and / or dimethyl 2,6-naphthalenedicarboxylic acid.

[0064] Preferably, the other dicarboxylic acid and / or its esterified form includes any one or a combination of at least two of the following: terephthalic acid, dimethyl terephthalate, diethyl terephthalate, furanyl dicarboxylic acid, 4,4-biphenyl dicarboxylic acid, 1,3-isophthalic acid, phthalic acid, dimethyl furanyl dicarboxylic acid, dimethyl 4,4-biphenyl dicarboxylic acid, dimethyl 1,3-isophthalic acid, or dimethyl phthalate.

[0065] Preferably, the other diols include any one or a combination of at least two of 1,4-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, ethylene glycol, 1,3-propanediol, 1,4-butanediol, dicyclopentanediol, neopentanediol, or 2-methyl-1,3-propanediol.

[0066] In this invention, the reaction in step (1) includes esterification and / or transesterification.

[0067] Preferably, the reaction in step (1) is carried out in the presence of a catalyst and / or a composite stabilizer.

[0068] Preferably, the reaction temperature in step (1) is 230-270℃, for example, it can be 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃, etc.

[0069] Preferably, the reaction time in step (1) is 3-8 hours, for example, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, etc.

[0070] Preferably, the pressure of the reaction in step (1) is 95-105 kPa, for example, it can be 96 kPa, 97 kPa, 98 kPa, 99 kPa, 100 kPa, 101 kPa, 102 kPa, 103 kPa, 104 kPa, etc.

[0071] Preferably, the temperature of the polycondensation reaction is 280-300℃, for example, it can be 282℃, 284℃, 286℃, 288℃, 290℃, 292℃, 294℃, 296℃, 298℃, etc.

[0072] Preferably, the pressure of the polycondensation reaction is 10-100 Pa, for example, it can be 15 Pa, 20 Pa, 25 Pa, 30 Pa, 35 Pa, 40 Pa, 45 Pa, 50 Pa, 55 Pa, 60 Pa, 65 Pa, 70 Pa, 75 Pa, 80 Pa, 85 Pa, 90 Pa, 95 Pa, etc.

[0073] In this invention, the polycondensation reaction is defined as ending when the stirring power reaches a fixed torque value.

[0074] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0075] Thirdly, the present invention provides the application of the copolyester material as described in the first aspect in food packaging, cosmetic packaging or medical packaging.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] The copolyester material provided by this invention possesses excellent thermal properties, resistance to boiling, optical properties, and gas barrier properties. Specifically, the glass transition temperature of the copolyester material is 144-168℃, its light transmittance is 85.5-90.5%, its haze is 2.3-4.2%, and its oxygen permeability is 20-27 cm⁻¹. 3 / m 2 Oxygen permeability after steaming at 100℃ for 60 minutes (dPa) is 24-35 cm³. 3 / m 2 With an intrinsic viscosity of 0.53-0.73 dL / g, it is suitable for packaging bags of high-temperature retortable foods. Attached Figure Description

[0078] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the copolyester in the copolyester material provided in Example 1. Detailed Implementation

[0079] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0080] The sources of some components in the examples and comparative examples are as follows:

[0081] (1) Dimethyl 2,6-naphthalenedicarboxylate: purchased from Beijing Innocare Technology Co., Ltd.;

[0082] (2) Esterifications of other dicarboxylic acids:

[0083] Dimethyl terephthalate: purchased from Beijing Inokai Technology Co., Ltd.;

[0084] Dimethyl 1,3-isophthalate: purchased from Beijing Innocare Technology Co., Ltd.;

[0085] Dimethyl furanate: purchased from Beijing Inokai Technology Co., Ltd.;

[0086] Dimethyl 4,4-biphenyl dicarboxylate: purchased from Beijing Innocare Technology Co., Ltd.;

[0087] Dimethyl phthalate: purchased from Beijing Innocare Technology Co., Ltd.;

[0088] (3) 2,2,4,4-Tetramethyl-1,3-cyclobutanediol: purchased from Suzhou Yake Technology Co., Ltd.;

[0089] (4) Other diols: 1,4-cyclohexanediethanol: purchased from Beijing Innocare Technology Co., Ltd.;

[0090] Neopentyl glycol: purchased from Beijing Innocare Technology Co., Ltd.;

[0091] Ethylene glycol: purchased from Beijing Innocare Technology Co., Ltd.;

[0092] 1,2-Cyclohexanediol: Purchased from Beijing Innocare Technology Co., Ltd.;

[0093] Dicyclopentanediol: Purchased from Beijing Innocare Technology Co., Ltd.;

[0094] 2-Methyl-1,3-propanediol: purchased from Beijing Innocare Technology Co., Ltd.;

[0095] (5) Dibutyltin oxide: purchased from Anhui Zesheng Technology Co., Ltd.;

[0096] (6) Phosphorus stabilizers

[0097] Antioxidant 168: Purchased from Beijing Innocare Technology Co., Ltd.;

[0098] Triphenyl phosphite: purchased from Anhui Zesheng Technology Co., Ltd.;

[0099] Diphenyl phosphate: purchased from Anhui Zesheng Technology Co., Ltd.;

[0100] Ammonium dihydrogen phosphate: purchased from Anhui Zesheng Technology Co., Ltd.;

[0101] Pyrophosphate: Purchased from Anhui Zesheng Technology Co., Ltd.;

[0102] (7) Bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate: purchased from Beijing Innocare Technology Co., Ltd.;

[0103] (8) Hindered phenolic stabilizers

[0104] Antioxidant 1010: Purchased from Beijing Innocare Technology Co., Ltd.;

[0105] 2,4-Dimethyl-6-(1-Methylpentadecanyl)-phenol: purchased from Beijing Innocare Technology Co., Ltd.;

[0106] N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine: purchased from Beijing Innocare Technology Co., Ltd.;

[0107] 2,6-Di-tert-butyl-4-methylphenol: purchased from Beijing Innocare Technology Co., Ltd.

[0108] (9) N,N'-Dicyclohexylcarbodiimide: purchased from Beijing Innocare Technology Co., Ltd.

[0109] Example 1

[0110] A copolyester material, wherein the components of the copolyester material include copolyester, dibutyltin oxide, antioxidant 1010 and antioxidant 168;

[0111] The preparation method of the copolyester material includes the following steps:

[0112] (1) In a four-necked flask equipped with a stirrer, condenser, gas inlet, feed inlet and thermometer, add 0.315 mol of dimethyl 2,6-naphthalenedicarboxylate, 0.035 mol of esterified products of other dicarboxylic acids (dimethyl terephthalate), 0.186 mol of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 0.207 mol of other diols (1,4-cyclohexanediol), then add 0.480 g of dibutyltin oxide (catalyst), 0.030 g of antioxidant 1010 and 0.030 g of antioxidant 168; under the protection of high-purity nitrogen, the temperature is raised to 270 °C with stirring and reacted at atmospheric pressure for 5 h to obtain the transesterification product;

[0113] (2) The temperature of the transesterification product is raised to 280°C under stirring. The system pressure is gradually reduced to 50Pa under constant temperature of 280°C to carry out polycondensation reaction. During the reaction, methanol produced by the reaction is removed. When the torque of the stirring paddle reaches the target value, the pressure is gradually reduced to atmospheric pressure and the material is discharged to obtain the copolyester material.

[0114] Examples 2-13, Comparative Examples 1-5

[0115] A copolyester material is provided, the raw materials for which the copolyester material is prepared are shown in Tables 1-3 below, and the preparation method of the copolyester material is described in Example 1.

[0116] Table 1

[0117]

[0118]

[0119] Table 2

[0120]

[0121] Table 3

[0122]

[0123] Performance testing

[0124] (1) Intrinsic viscosity test: The intrinsic viscosity of the copolyester material was measured in a mixed solution of phenol and tetrachloroethane (mass ratio of 3:2) at 25±0.01℃;

[0125] (2) Test of thermal properties of copolyester material: nitrogen atmosphere, flow rate of 50 mL / min; during the test, the temperature was first raised to 240℃ at 20℃ / min, held at 240℃ for 2 min to remove the thermal history of copolyester material, then cooled to 30℃ at 20℃ / min, held at 30℃ for 2 min, and then raised to 240℃ at 20℃ / min. The glass transition temperature Tg of copolyester material was calculated through the second heating curve.

[0126] (3) Characterization of the copolyester structure: The copolyester material provided in Example 1 was tested using a Bruker nuclear magnetic resonance spectrometer with deuterated chloroform containing tetramethylsilane as the solvent; the test results are as follows. Figure 1 As shown;

[0127] The test method for the molar percentage of 2,6-naphthalenedicarboxylic acid residues and the molar percentage of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues in the copolyester contained in the copolyester material is as follows: 5-10 mg of copolyester material is placed in an NMR tube, 0.55 mL of deuterated chloroform is added, and the mixture is heated in a 60 °C water bath for 6 h to dissolve it. After the copolyester material is completely dissolved and forms a transparent solution, the test is performed at room temperature in a Bruker NMR spectrometer.

[0128] For example, the copolyester material provided in Example 1 was tested, and the test results are as follows: Figure 1 As shown, by Figure 1 It can be seen that the chemical shifts of the two meta hydrogens of the aromatic ring carbon connected to the carbonyl group in the 2,6-naphthalenedicarboxylic acid residue of the copolyester, and the two ortho hydrogens between the aromatic ring carbon connected to the carbonyl group and the meta hydrogen, appear at 7.93-8.27 ppm, with a peak area of ​​a; the chemical shifts of the other two ortho hydrogen atoms of the aromatic ring carbon connected to the carbonyl group in the 2,6-naphthalenedicarboxylic acid residue appear at 8.51-8.92 ppm, with a peak area of ​​b; the chemical shifts of the hydrogen atoms on the benzene ring in the terephthalic acid residue appear at 8.09-8. 27 ppm, peak area c, c = a - 2b; the hydrogen atoms of CH in the 2,2,4,4-tetramethyl-1,3-cyclobutanediol residue appear at 4.6-5.0 ppm, peak area d; the hydrogen atoms of the two CH2 atoms connected to the cyclohexanediethanol residue appear at 4.12-4.48 ppm, peak area e; the formula for calculating the molar percentage of 2,6-naphthalenedicarboxylic acid residue and 2,2,4,4-tetramethyl-1,3-cyclobutanediol residue is as follows:

[0129]

[0130]

[0131] (4) Optical properties: The copolyester material was injection molded into a sample with a length of 8cm × width of 5cm × thickness of 1.7mm using an injection molding machine (Haitian Plastics Machinery Group Co., Ltd., MA250T). The transmittance and haze of the copolyester material were tested using a transmittance / haze tester (Shanghai Precision Instruments Co., Ltd., WGT-S).

[0132] (5) Gas barrier performance test: The copolyester material was made into a sheet with a thickness of 0.6 mm using a flat vulcanizing machine (Qingdao Jinjiuzhou Rubber Machinery Co., Ltd.). The oxygen permeability was measured by pressure difference method and gas permeability tester (Jinan Sike Testing Technology Co., Ltd., GTR-7006) under the conditions of 25℃ and 0%RH. The pressure difference was 0.1 MPa.

[0133] (6) Gas barrier performance test: After the parallel samples for gas barrier performance test were boiled in boiling water at 100℃ for 60 min, the oxygen permeability after boiling was measured by pressure difference method and gas permeability tester (Jinan Sike Test Technology Co., Ltd., GTR-7006) at 25℃ and 0%RH. The pressure difference was 0.1MPa.

[0134] The copolyester materials provided in Examples 1-13 and Comparative Examples 1-5, as well as the copolyesters contained therein, were tested according to the above method. The test results are shown in Tables 4-6 below:

[0135] Table 4

[0136]

[0137] Table 5

[0138]

[0139] Table 6

[0140]

[0141] The test data in the table show that the copolyester material provided by this invention has excellent thermal properties, retort resistance, optical properties, and gas barrier properties. Its glass transition temperature is 144-168℃, intrinsic viscosity is 0.53-0.73 dL / g, light transmittance is 85.5-90.5%, haze is 2.3-4.2%, and oxygen permeability before retort is 20-27 cm⁻¹. 3 / m 2 The oxygen permeability after cooking is 24-35 cm³ / dPa. 3 / m 2 ·d·Pa.

[0142] In Example 7, the molar percentage of 2,6-naphthalenedicarboxylic acid residues in the molecular structure of the copolyester decreased. In Example 8, the molar percentage of 2,2,4,4-tetramethyl-1,3-cyclobutanediol in the molecular structure of the copolyester decreased, and the glass transition temperature of the copolyester materials both decreased. In Example 9, the molar percentage of the less reactive 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues in the molecular structure of the copolyester increased, and the intrinsic viscosity of the copolyester decreased.

[0143] Examples 10 and 11 show that when the content of hindered phenolic stabilizers or phosphorus stabilizers in the composite stabilizer is low, the light transmittance of the copolyester material decreases and the haze increases. Examples 12 and 13 show that using non-phosphorus stabilizers instead of phosphorus stabilizers, or using non-hindered phenolic stabilizers instead of hindered phenolic stabilizers, results in a decrease in the intrinsic viscosity and light transmittance of the copolyester material, and an increase in haze. Using both phosphorus stabilizers and hindered phenolic stabilizers as composite stabilizers yields better technical results.

[0144] In Comparative Example 1, the molar percentage of 2,6-naphthalenedicarboxylic acid residues in the molecular structure of the copolyester is too small, resulting in a lower glass transition temperature, poorer retortability, and worse gas barrier properties. In Comparative Example 2, the copolyester does not contain 2,6-naphthalenedicarboxylic acid residues in its molecular structure, leading to a significantly lower glass transition temperature, poorer retortability, and worse gas barrier properties.

[0145] As shown in Comparative Example 3, the molar percentage content of 2,6-naphthalenedicarboxylic acid residues is too high, which reduces the intrinsic viscosity of the copolyester material, thus rendering it unusable.

[0146] As shown in Comparative Example 4, the molar percentage content of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues is too high, resulting in a decrease in the intrinsic viscosity of the copolyester material, a deterioration in gas barrier properties, a decrease in retort resistance, and an increase in haze.

[0147] As shown in Comparative Example 5, the molar percentage of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues is too low, resulting in a significant decrease in the glass transition temperature and a marked decline in the cookability of the copolyester material.

[0148] The applicant declares that the copolyester material, its preparation method, and its application are illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A copolyester material, characterized in that, The copolyester material comprises a copolyester; the copolyester contains diacid residues and diol residues; The dicarboxylic acid residues include: (a1) 70-98 mol% of 2,6-naphthalenedicarboxylic acid residues based on the total molar amount of (a1) and (a2); (a2) 2-30 mol% of other dicarboxylic acid residues based on the total molar amount of (a1) and (a2); The total molar percentage of residues (a1) and (a2) is 100%. The diol residues comprise: (b1) 10-60 mol% of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues based on the total molar amount of (b1) and (b2); (b2) 40-90 mol% of other diol residues based on the total molar amount of (b1) and (b2); The total molar percentage of residues (b1) and (b2) is 100%.

2. The copolyester material according to claim 1, characterized in that, The other dicarboxylic acid residues include any one or a combination of at least two of the following: terephthalic acid residues, furanyl dicarboxylic acid residues, 4,4-biphenyl dicarboxylic acid residues, 1,3-isophthalic acid residues, or phthalic acid residues.

3. The copolyester material according to claim 1, characterized in that, The dicarboxylic acid residues include: (a1) 75-95 mol% of 2,6-naphthalenedicarboxylic acid residues based on the total molar amount of (a1) and (a2); (a2) 5-25 mol% of other dicarboxylic acid residues based on the total molar amount of (a1) and (a2); The total molar percentage of residues (a1) and (a2) is 100%.

4. The copolyester material according to claim 1, characterized in that, The other diol residues include any one or a combination of at least two of the following: 1,4-cyclohexanediethanol residue, 1,4-cyclohexanediol residue, 1,2-cyclohexanediethanol residue, 1,3-cyclohexanediol residue, 1,2-cyclohexanediol residue, 1,3-cyclohexanediol residue, ethylene glycol residue, 1,3-propanediol residue, 1,4-butanediol residue, dicyclopentanediol residue, neopentanediol residue, or 2-methyl-1,3-propanediol residue.

5. The copolyester material according to claim 1, characterized in that, The diol residues comprise: (b1) 25-50 mol% of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues based on the total molar amount of (b1) and (b2); (b2) 50-75 mol% of other diol residues based on the total molar amount of (b1) and (b2); The total molar percentage of residues (b1) and (b2) is 100%.

6. The copolyester material according to claim 1, characterized in that, The copolyester material also includes a composite stabilizer.

7. The copolyester material according to claim 6, characterized in that, The composite stabilizer includes phosphorus-based stabilizers and hindered phenolic stabilizers.

8. The copolyester material according to claim 7, characterized in that, The phosphorus stabilizer includes any one or a combination of at least two of the following: diphenyl phosphate, triphenyl phosphite, trimethyl phosphate, dimethyl phosphate, triphenyl phosphate, diphenyl phosphite, ammonium phosphite, ammonium dihydrogen phosphate, phosphorous acid, hypophosphite, pyrophosphite, tris(2,4-di-tert-butylphenyl) phosphite, or ammonium phosphate.

9. The copolyester material according to claim 7, characterized in that, The mass percentage of phosphorus-based stabilizers in the composite stabilizer is 10-90%.

10. The copolyester material according to claim 9, characterized in that, The mass percentage of phosphorus-based stabilizers in the composite stabilizer is 45-75%.

11. The copolyester material according to claim 7, characterized in that, The hindered phenolic stabilizer includes any one or a combination of at least two of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-dimethyl-6-(1-methylpentadecanyl)phenol, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, or 2,6-di-tert-butyl-4-methylphenol.

12. The copolyester material according to claim 7, characterized in that, The hindered phenolic stabilizer in the composite stabilizer has a mass percentage content of 10-90%.

13. The copolyester material according to claim 12, characterized in that, The hindered phenolic stabilizer in the composite stabilizer has a mass percentage content of 25-55%.

14. The copolyester material according to claim 6, characterized in that, The mass percentage of the composite stabilizer in the copolyester material is 0.01-1%.

15. The copolyester material according to claim 1, characterized in that, The copolyester material also includes a catalyst.

16. The copolyester material according to claim 15, characterized in that, The catalyst includes any one or a combination of at least two of the following: tin-based catalysts, antimony-based catalysts, germanium-based catalysts, titanium-based catalysts, or aluminum-based catalysts.

17. The copolyester material according to claim 16, characterized in that, The tin-based catalyst includes any one or a combination of at least two of dibutyltin oxide, stannous isooctanoate, stannous monobutyltriisooctanoate, or dioctyltin oxide.

18. The copolyester material according to claim 16, characterized in that, The antimony-based catalyst includes any one or a combination of at least two of antimony acetate, antimony trioxide, antimony glycolate, or antimony polyethylene glycol.

19. The copolyester material according to claim 16, characterized in that, The germanium-based catalyst includes germanium dioxide and / or germanium oxide.

20. The copolyester material according to claim 16, characterized in that, The titanium-based catalyst includes any one or a combination of at least two of tetrabutyl titanate, isopropyl titanate, titanium dioxide, or inorganic supported titanium catalysts.

21. The copolyester material according to claim 16, characterized in that, The aluminum-based catalyst includes aluminum chloride and / or aluminum oxide.

22. The copolyester material according to claim 15, characterized in that, The catalyst in the copolyester material has a mass percentage content of 0.3-1.5%.

23. The copolyester material according to claim 1, characterized in that, The light transmittance of the copolyester material is >85%.

24. The copolyester material according to claim 23, characterized in that, The light transmittance of the copolyester material is >88%.

25. The copolyester material according to claim 1, characterized in that, The oxygen permeability of the copolyester material is <30cm. 3 / m 2 ·d·Pa.

26. The copolyester material according to claim 25, characterized in that, The oxygen permeability of the copolyester material is ≤27cm. 3 / m 2 ·d·Pa.

27. The copolyester material according to claim 1, characterized in that, The oxygen permeability of the copolyester material after being boiled at 100°C for 60 minutes is <40 cm⁻¹. 3 / m 2 ·d·Pa.

28. The copolyester material according to claim 27, characterized in that, The oxygen permeability of the copolyester material after being boiled at 100°C for 60 minutes is ≤31 cm³. 3 / m 2 ·d·Pa.

29. The copolyester material according to claim 1, characterized in that, The intrinsic viscosity of the copolyester material is 0.5-0.9 dL / g.

30. The copolyester material according to claim 29, characterized in that, The intrinsic viscosity of the copolyester material is 0.6-0.8 dL / g.

31. The copolyester material according to claim 1, characterized in that, The glass transition temperature of the copolyester material is 140-180℃.

32. The copolyester material according to claim 31, characterized in that, The glass transition temperature of the copolyester material is 150-165℃.

33. The copolyester material according to claim 1, characterized in that, The haze of the copolyester material is 1-5%.

34. The copolyester material according to claim 33, characterized in that, The haze of the copolyester material is 2-3.1%.

35. A method for preparing a copolyester material according to any one of claims 1-34, characterized in that, The preparation method includes the following steps: (1) 2,6-naphthalenedicarboxylic acid and / or its esterified form, other dicarboxylic acids and / or their esterified forms, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and other diols are reacted to give the reaction product; (2) The reaction product undergoes a polycondensation reaction to obtain the copolyester material.

36. The preparation method according to claim 35, characterized in that, The 2,6-naphthalenedicarboxylic acid and / or its esters include 2,6-naphthalenedicarboxylic acid and / or dimethyl 2,6-naphthalenedicarboxylic acid.

37. The preparation method according to claim 35, characterized in that, The other dicarboxylic acids and / or their esters include any one or a combination of at least two of the following: terephthalic acid, dimethyl terephthalate, diethyl terephthalate, furanyl dicarboxylic acid, 4,4-biphenyl dicarboxylic acid, 1,3-isophthalic acid, phthalic acid, dimethyl furanyl dicarboxylic acid, dimethyl 4,4-biphenyl dicarboxylic acid, dimethyl 1,3-isophthalic acid, or dimethyl phthalate.

38. The preparation method according to claim 35, characterized in that, The other diols include any one or a combination of at least two of the following: 1,4-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, ethylene glycol, 1,3-propanediol, 1,4-butanediol, dicyclopentanediol, neopentanediol, or 2-methyl-1,3-propanediol.

39. The preparation method according to claim 35, characterized in that, The reaction described in step (1) is carried out in the presence of a catalyst and / or a composite stabilizer.

40. The preparation method according to claim 35, characterized in that, The reaction temperature in step (1) is 230-270℃.

41. The preparation method according to claim 35, characterized in that, The reaction time in step (1) is 3-8 hours.

42. The preparation method according to claim 35, characterized in that, The pressure of the reaction in step (1) is 95-105 kPa.

43. The preparation method according to claim 35, characterized in that, The temperature of the polycondensation reaction is 280-300℃.

44. The preparation method according to claim 35, characterized in that, The pressure of the polycondensation reaction is 10-100 Pa.

45. The use of a copolyester material as described in any one of claims 1-34 in food packaging, cosmetic packaging or medical packaging.

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