阅读说明：本技术 含芳香仲胺结构的共聚酯及其制备方法和应用 (Copolyester containing aromatic secondary amine structure and preparation method and application thereof ) 是由 王玉忠 陈琳 付腾 倪延朋 吴万寿 段平慧 汪秀丽 于 2020-06-19 设计创作，主要内容包括：本发明公开的含芳香仲胺结构的共聚酯及其制备方法和应用,该共聚酯是由Ⅰ、Ⅱ和Ⅲ表示的结构单元所组成,其特性黏数[η]为0.30～3.5dL/g；极限氧指数为23.0～55.0％；垂直燃烧等级为V-2～V-0级；拉伸强度比纯PET增加5～300％。本发明引入的含芳香仲胺结构的阻燃单元在燃烧时的增黏效应和成炭作用使共聚酯不仅具有优异的阻燃和抗熔滴性能,还具有较好的抑烟性能,可以在纤维、无纺布、工程塑料、膜材料、容器材料、自修复材料、形状记忆材料或3D打印材料领域单独应用,或作为添加剂用于高分子材料的改性。(The invention discloses a copolyester containing an aromatic secondary amine structure, a preparation method and application thereof, wherein the copolyester is composed of structural units represented by I, II and III, and the intrinsic viscosity [ eta ] is 0.30-3.5 dL/g; the limiting oxygen index is 23.0-55.0%; the vertical combustion grade is V-2 to V-0 grade; the tensile strength is increased by 5-300% compared with that of pure PET. The flame-retardant unit containing the aromatic secondary amine structure introduced by the invention has a tackifying effect and a carbonizing effect during combustion, so that the copolyester has excellent flame-retardant and anti-dripping performances and better smoke suppression performance, and can be independently applied in the fields of fibers, non-woven fabrics, engineering plastics, film materials, container materials, self-repairing materials, shape memory materials or 3D printing materials or used as an additive for modifying high polymer materials.)

1. The copolyester containing aromatic secondary amine structure is characterized by comprising the following structural units represented by I, II and III:

in the formula, R₁Represents an arylene group;

in the formula, R₂Represents an alkylene group;

in the formula, R₃、R₄Is a carbonyl group, an O atom ora is an integer of 2 to 12, R₃、R₄The same or different; x₁、X₂Is any one of H atom, hydroxyl, methyl, ethyl, cyano, phenylethynyl, methoxy or phenyl, and X is₁、X₂The same or different; x₃Is any one of H atom, hydroxyl, methyl, ethyl, phenylethynyl, methoxyl, phenyl, 1-naphthyl or 2-naphthyl;

the number of the structural units III is 1-99% of that of the structural units I.

2. The copolyester containing aromatic secondary amine structure according to claim 1, wherein the intrinsic viscosity [ η ] of the copolyester is 0.30 to 3.50 dL/g; the limiting oxygen index is 23.0-55.0%; the vertical combustion grade is V-2 to V-0 grade; the tensile strength is increased by 5-300% compared with that of pure PET.

3. The copolyester containing aromatic secondary amine structure according to claim 1, wherein the number of structural units III in the copolyester is 5-50% of the number of structural units I, and the intrinsic viscosity [ η ] of the copolyester is 0.30-3.00 dL/g; the limiting oxygen index is 24.0-50.0%; the vertical combustion grade is V-2 to V-0 grade; the tensile strength is increased by 8-200% compared with that of pure PET.

4. A method for preparing copolyester containing an aromatic secondary amine structure according to claim 1 is characterized in that 1-99% of monomer containing the aromatic secondary amine structure in terms of mole number of dibasic acid or dibasic acid ester in a polyester monomer is added into a reaction system before esterification or before polycondensation after esterification, wherein the dibasic acid or dibasic acid ester is esterified by a conventional direct esterification method or ester exchange method according to a conventional ratio of dibasic acid or dibasic acid ester to polyester monomer of dihydric alcohol and a catalyst, and then the copolyester is subjected to polycondensation reaction.

5. The method for preparing copolyester containing aromatic secondary amine structure according to claim 4, wherein the method comprises adding 5-50% of monomer containing aromatic secondary amine structure based on the mole number of dibasic acid or dibasic acid ester compound in the polyester monomer.

6. The method for preparing copolyester containing aromatic secondary amine structure according to claim 4 or 5, wherein the monomer containing aromatic secondary amine structure used in the method is at least one of the following structural formulas:

in the formula, Y₁、Y₂Is carboxyl, ester, hydroxyl ora is an integer of 2 to 12, Y₁、Y₂The same or different; x₁、X₂Is any one of H atom, hydroxyl, methyl, ethyl, cyano, phenylethynyl, methoxy or phenyl, and X is₁、X₂The same or different; x₃Is any one of H atom, hydroxyl group, methyl group, ethyl group, phenylethynyl group, methoxy group, phenyl group, 1-naphthyl group or 2-naphthyl group.

7. The method for preparing copolyester containing aromatic secondary amine structure according to claim 4 or 5, wherein the monomer containing aromatic secondary amine structure used in the method is at least one of the following structural formulas:

in the formula, Y₁、Y₂Is carboxyl, ester, hydroxyl ora is an integer of 2 to 12, Y₁、Y₂The same or different; x₁、X₂Is any one of H atom, hydroxyl, methyl, ethyl, cyano, phenylethynyl, methoxy or phenyl, and X is₁、X₂The same or different; x₃Is any one of H atom, hydroxyl group, methyl group, ethyl group, phenylethynyl group, methoxy group, phenyl group, 1-naphthyl group or 2-naphthyl group.

8. The method for preparing copolyester containing aromatic secondary amine structure according to claim 6, wherein the ester group in the monomer containing aromatic secondary amine structure used in the method is methyl ester group or ethyl ester group after esterification of monohydric alcohol, or is any one of ethylene glycol ester group, propylene glycol ester group, butanediol ester group, pentanediol ester group, glycerol ester group or pentaerythritol ester group after esterification of polyhydric alcohol.

9. The method for preparing copolyester containing aromatic secondary amine structure according to claim 7, wherein the ester group in the monomer containing aromatic secondary amine structure used in the method is methyl ester group or ethyl ester group after esterification of monohydric alcohol, or is any one of ethylene glycol ester group, propylene glycol ester group, butanediol ester group, pentanediol ester group, glycerol ester group or pentaerythritol ester group after esterification of polyhydric alcohol.

10. The copolyester containing the aromatic secondary amine structure according to claim 1 is independently applied to the fields of fibers, non-woven fabrics, engineering plastics, film materials, container materials, self-repairing materials, shape memory materials or 3D printing materials, or is used as an additive for modifying high molecular materials.

Technical Field

The invention belongs to the technical field of copolyester containing an aromatic secondary amine structure and preparation and application thereof, and particularly relates to copolyester containing an aromatic secondary amine structure and having flame retardance, droplet resistance and smoke suppression, and a preparation method and application thereof.

Background

Semi-aromatic polyester (hereinafter referred to as polyester) is a linear polymer with a main chain containing a rigid aromatic ring, a flexible methylene group and a polar ester group, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and the like, and is widely applied to the fields of synthetic fibers, bottle materials, engineering plastics and the like due to excellent comprehensive properties such as high modulus, high strength, shape retention, heat resistance, corrosion resistance and the like. However, polyesters are extremely flammable polymers, which not only release large amounts of heat and smoke, but are also associated with severe dripping behavior. As a class of widely applied high polymer materials, the flame retardance, the anti-dripping and the smoke suppression modification of the polyester have very important practical significance.

Although the traditional halogen flame retardant has good flame retardant effect, hydrogen halide and dioxin gas released during combustion have high toxicity, which causes environmental and health problems, and thus the traditional halogen flame retardant is gradually eliminated. Phosphorus is introduced in a physical or chemical mode to be another effective method for improving the flame retardance of polyester, but the phosphorus-containing flame retardant sold in the market almost achieves the flame retardance purpose by promoting a mode of 'molten drops taking away heat', and the molten drops can not only cause scalding, but also easily cause 'secondary fire'. In addition, many phosphorus-containing flame retardants also cause more severe smoke release behavior and present a greater safety hazard. ZL 201010195998.7 introduces nanometer montmorillonite, silane coupling agent and 2-hydroxyethyl hypophosphorous acid into polyester by in-situ polymerization, which can improve the flame retardant property and anti-dripping property of polyester, but does not greatly improve the smoke suppression property, and the mechanical property of polyester can be damaged by adding nanometer particles. The traditional flame-retardant method is difficult to simultaneously realize the requirements of flame retardance, anti-dripping and smoke suppression of polyester, and can destroy the mechanical property and spinnability of the polyester to a certain extent.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provide a copolyester containing an aromatic secondary amine structure.

The invention also aims to provide a method for preparing the copolyester containing the aromatic secondary amine structure.

The invention also provides application of the copolyester containing the aromatic secondary amine structure.

The copolyester containing the aromatic secondary amine structure provided by the invention is composed of the following structural units represented by I, II and III:

in the formula, R₁Represents an arylene group;

in the formula, R₂Represents an alkylene group;

in the formula, R₃、R₄Is a carbonyl group, an O atom ora is an integer of 2 to 12, R₃、R₄The same or different; x₁、X₂Is any one of H atom, hydroxyl, methyl, ethyl, cyano, phenylethynyl, methoxy or phenyl, and X is₁、X₂The same or different; x₃Is any one of H atom, hydroxyl, methyl, ethyl, phenylethynyl, methoxyl, phenyl, 1-naphthyl or 2-naphthyl;

the number of the structural units III is 1-99% of that of the structural units I.

The intrinsic viscosity [ eta ] of the copolyester containing the aromatic secondary amine structure is 0.30-3.50 dL/g; the limiting oxygen index is 23.0-55.0%; the vertical combustion grade is V-2 to V-0 grade; the tensile strength is increased by 5-300% compared with that of pure PET.

The preferable structural unit number of III in the copolyester is 5-50% of that of I, and the intrinsic viscosity [ eta ] of the copolyester is 0.30-3.00 dL/g; the limiting oxygen index is 24.0-50.0%; the vertical combustion grade is V-2 to V-0 grade; the tensile strength is increased by 8-200% compared with that of pure PET.

The method for preparing the copolyester containing the aromatic secondary amine structure is characterized in that 1-99% of monomer containing the aromatic secondary amine structure in terms of mole number of dibasic acid or dibasic acid ester compound in a polyester monomer is added into a reaction system before esterification or before polycondensation after esterification, preferably 5-50%.

The monomer containing the aromatic secondary amine structure used in the preparation method is at least one of the following structural general formulas:

in the formula, Y₁、Y₂Is carboxyl, ester, hydroxyl ora is an integer of 2 to 12, Y₁、Y₂The same or different; x₁、X₂Is any one of H atom, hydroxyl, methyl, ethyl, cyano, phenylethynyl, methoxy or phenyl, and X is₁、X₂The same or different; x₃Is any one of H atom, hydroxyl group, methyl group, ethyl group, phenylethynyl group, methoxy group, phenyl group, 1-naphthyl group or 2-naphthyl group.

The aromatic secondary amine structure-containing monomer used in the above method is preferably at least one of the following structural formulae:

in the formula, Y₁、Y₂Is carboxyl, ester, hydroxyl ora is an integer of 2 to 12, Y₁、Y₂The same or different; x₁、X₂Is any one of H atom, hydroxyl, methyl, ethyl, cyano, phenylethynyl, methoxy or phenyl, and X is₁、X₂The same or different; x₃Is any one of H atom, hydroxyl group, methyl group, ethyl group, phenylethynyl group, methoxy group, phenyl group, 1-naphthyl group or 2-naphthyl group.

The aromatic secondary amine structure-containing monomers used in The above-mentioned methods are prepared by The methods disclosed in The prior art (European Journal of Organic Chemistry,2011, 6916-.

The ester group in the monomer containing the aromatic secondary amine structure used in the method is a methyl ester group or an ethyl ester group after esterification of monohydric alcohol, or any one of an ethylene glycol ester group, a propylene glycol ester group, a butanediol ester group, a pentanediol ester group, a glycerol ester group or a pentaerythritol ester group after esterification of polyhydric alcohol.

The conventional direct esterification method or ester exchange method adopted by the invention has the following process steps and conditions:

the direct esterification method comprises the following steps: adding dibasic acid, dihydric alcohol, a catalyst and a monomer containing an aromatic secondary amine structure into a reaction kettle according to a ratio, pressurizing and heating to 200-240 ℃ to perform esterification reaction for 3-5 hours; after esterification, performing polycondensation reaction at 240-250 ℃ for 0.5-1.5 hours under low vacuum, then performing polycondensation at 250-270 ℃ for 1-3 hours under high vacuum, extruding a copolyester melt by using inert gas (preferably nitrogen), and cooling the melt by water to obtain the target copolyester. Wherein, the monomer containing aromatic secondary amine structure can be added into the reaction kettle before esterification or before polycondensation after esterification.

An ester exchange method: adding an esterified dibasic acid, dihydric alcohol, a catalyst and a monomer containing an aromatic secondary amine structure into a reaction kettle according to a ratio, and carrying out an ester exchange reaction for 3-6 hours at 180-220 ℃ under normal pressure; after the ester exchange is finished, performing polycondensation for 0.5-1.5 hours at 240-250 ℃ under low vacuum, then performing polycondensation for 1-3 hours at 250-270 ℃ under high vacuum, extruding a copolyester melt by using inert gas (preferably adopting nitrogen), and performing water cooling on the melt to obtain the target copolyester. Wherein, the monomer containing aromatic secondary amine structure can be added into the reaction kettle before ester exchange or before polycondensation after ester exchange.

The catalyst used in the preparation method is at least one of germanium catalyst, titanium catalyst, antimony catalyst, aluminum catalyst, tin catalyst and the like, such as germanium dioxide, antimony acetate, antimony trioxide, ethylene glycol antimony, titanium oxide, titanium potassium oxalate, potassium hexafluorotitanate, titanate, titanium alkoxide, titanium complex, tin oxide, aluminum hydroxide, aluminum acetate, silicon dioxide, zinc acetate, manganese acetate or magnesium acetate and the like.

The copolyester containing the aromatic secondary amine structure provided by the invention is independently applied in the fields of fibers, non-woven fabrics, engineering plastics, film materials, container materials, self-repairing materials, shape memory materials or 3D printing materials, or is used as an additive for modifying high polymer materials.

Compared with the prior art, the invention has the following beneficial effects:

1. because the structural units of the copolyester provided by the invention contain the flame-retardant units with aromatic secondary amine structures, the flame-retardant units are very stable at the processing and polymerization temperatures of the polyester, on one hand, the flame-retardant units do not generate self-crosslinking and decomposition, and can better keep the thermoplastic processability of the polyester, on the other hand, the flame-retardant units can generate crosslinking reaction at higher temperature or during combustion, and can improve the melt viscosity and melt strength of the copolyester (see figure 1), thereby effectively inhibiting the melt from dripping and playing a role in resisting the melt dripping. Meanwhile, the structures can also improve the carbon forming capability of the copolyester (shown in figures 2 and 3), promote the copolyester to form a stable carbon layer during combustion, and the carbon layer can generate good effects of insulating heat and oxygen and inhibiting volatilization of organic smoke, so that the copolyester is endowed with excellent flame retardance, smoke suppression and molten drop resistance.

2. The cross-linking temperature of the method for preparing the copolyester is controllable, and the chemical cross-linking can be generated after the copolyester is melted and before the copolyester is thermally decomposed, so that the cross-linked copolyester can be obtained by post-curing after the copolyester is processed and formed, has better thermal stability, thermal oxidation stability, chemical corrosion resistance, solvent resistance and char formation, and can be used as a novel functional polymer material.

3. The copolyester provided by the invention contains an aromatic secondary amine structure, the aromatic secondary amine structure can form a hydrogen bond effect with carbonyl, and the hydrogen bond is used as a dynamic physical crosslinking point, so that the mechanical strength of the copolyester can be improved, and the copolyester can be endowed with certain self-repairing and shape memory properties, and can be used as an intelligent high polymer material.

4. The copolyester provided by the invention has good thermoplastic processability and spinnability because no additive influencing fiber preparation is added, and can be directly used as the copolyester for fibers and also used as a macromolecular compatibilizer of an incompatible polymer blending system, so that the mechanical property of the material is improved, and the purposes of flame retardance, smoke suppression and anti-dripping modification of the material are realized.

5. The copolyester structure provided by the invention does not contain halogen elements, so that the copolyester belongs to an environment-friendly green high polymer material.

6. The preparation method provided by the invention is basically consistent with the conventional polyester synthesis method, so that the process is mature, the operation is simple and convenient, and the control and industrialization are easy.

Drawings

FIG. 1 is a constant temperature dynamic rheology plot of the copolyester prepared in example 6 of the present invention and pure PET prepared in comparative example 1. Melt viscosity and strength are direct reasons for the impact on the anti-drip properties of copolyesters, and generally, the higher the complex viscosity, the higher the melt viscosity and strength, and the better the anti-drip properties of the copolyester. As can be seen from the figure, the complex viscosity of the copolyester of example 6 increases sharply with time at a constant temperature of 300 ℃, indicating that the copolyester undergoes a self-crosslinking reaction at high temperature; the complex viscosity of pure PET is substantially unchanged, indicating that it does not undergo self-crosslinking reactions.

Fig. 2 is a thermogravimetric curve of the copolyester prepared in example 6 of the present invention and the pure PET prepared in comparative example 1 (thermogravimetric analysis is an important evaluation method for studying thermal stability of a material by monitoring the mass change of the material during temperature control procedure). As can be seen from the figure, the copolyester of example 6 maintains good thermal stability in nitrogen atmosphere, and the initial decomposition temperature of the copolyester is not lowered; in addition, the carbon residue (17.6 wt%) of the copolyester at high temperature (700 ℃) is obviously higher than that of pure PET (11.5 wt%), which indicates that the copolyester has stronger carbon forming capability.

FIG. 3 is a digital photograph of bars of copolyester prepared according to example 6 of the present invention and of pure PET prepared according to comparative example 1 after a limiting oxygen index test. It can be seen from the photograph that the top of the pure PET sample strip has no carbon layer and both sides have obvious melt drip traces, while the top of the copolyester sample strip has a large number of carbon layers and almost no melt drip traces are observed, which shows that the carbon forming capability and the melt drip resistance of the copolyester are obviously improved.

FIG. 4 is a graph of the heat release rate of copolyesters prepared according to the invention in example 6 versus pure PET prepared according to comparative example 1 in a cone calorimetry test. The peak heat release rate (p-HRR) is an important parameter for judging the flame retardant property of the material, the lower the value of the peak heat release rate (p-HRR), the better the flame retardant property of the material, and conversely, the higher the value of the p-HRR, the poorer the flame retardant property. The p-HRR of the copolyester is 389kW/m²Not only much lower than 788kW/m of pure PET²And the p-HRR of the copolyester is reduced by 50.6 percent compared with pure PET, which shows that the flame retardance of the copolyester is obviously improved.

FIG. 5 is a graph of the total smoke emission in cone calorimetry for the copolyester of example 6 of the present invention and pure PET of comparative example 1. It can be seen that pure PET has a high total smoke emission (1728 m)²/m²) While the copolyester showed lower total smoke emission (1212 m)²/m²) The copolyester has better smoke suppression performance.

Detailed Description

Examples are given below to further illustrate the present invention in detail. It should be pointed out again that the following examples are not to be construed as limiting the scope of the invention, which is intended to be covered by the following claims if a person skilled in the art shall make insubstantial modifications and adaptations of the invention in light of the above teachings.

In addition, it is worth noting that the intrinsic viscosity [ eta ] of the copolyesters obtained in the following examples]Phenol/1, 1,2, 2-tetrachloroethane (1:1, v: v) is used as a solvent to prepare a solution with the concentration of 5g/L, and the solution is tested by an Ubbelohde viscometer at 25 ℃; the limiting oxygen index of the copolyester is 120 multiplied by 6.5 multiplied by 3.2mm³According to ASTM D2863-97, on an HC-2 type oxygen index apparatus; the vertical burning test is to make the copolyester 125X 12.7X 3.2mm³According to the UL-94 standard, measured with a model CZF-2 vertical burner (UL-94); the cone calorimetric test is to prepare the copolyester into 100X 3mm³According to ISO 5660-1, measured on an FTT cone calorimeter; the tensile test was to make the copolyester 25X 4X 2mm³The bars of (D) are measured on an INSTRON 3366 universal tester at a tensile rate of 5mm/min according to ASTM D-638 test standard.

Example 1

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 47.0g of 5-phenylaminocarbonyl-1, 3-dimethyl isophthalate, 0.2g of zinc acetate and 0.3g of antimony trioxide are added into a reaction kettle, and nitrogen is filled to remove air in the kettle; reacting for 2-6 hours at the normal pressure of 180-220 ℃, and finishing the ester exchange reaction; then carrying out low vacuum polycondensation reaction at 220-240 ℃ for 0.5-1.5 h, then carrying out polycondensation reaction at 250-270 ℃ for 1-4 h under high vacuum (the pressure is less than 80Pa), discharging, and carrying out water cooling.

Intrinsic viscosity [ eta ] of the copolyester]0.95 dL/g; the limiting oxygen index is 25.0%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak heat release rate p-HRR in the cone calorimetry test is 608kW/m²The total smoke release amount TSR is 1520m²/m²(ii) a The tensile strength was 66.5 MPa.

Example 2

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 140.9g of 5-phenylaminocarbonyl-1, 3-isophthalic acid dimethyl ester, and 0.25g of isopropyl titanate were charged into a reaction vessel, subjected to transesterification and polycondensation reaction under the conditions and conditions given in example 1, and discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.80 dL/g; the limiting oxygen index is 30.2%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak value heat release rate p-HRR in the cone calorimetry test is 340kW/m²The total smoke release amount TSR is 954m²/m²(ii) a The tensile strength was 90.6 MPa.

Example 3

Adding 498.0g of terephthalic acid, 250.0g of ethylene glycol, 68.7g of 3, 5-dihydroxy-N-phenyl benzamide and 0.3g of germanium dioxide into a reaction kettle, filling nitrogen to remove air in the kettle, pressurizing to 0.1MPa, heating to 220-240 ℃ to start esterification, controlling the pressure in the kettle to be 0.3-0.4 MPa, maintaining for 2-4 hours, gradually reducing the pressure to normal pressure, and finishing the esterification; then, gradually heating to 250 ℃, carrying out polycondensation for 0.5-1.5 h under low vacuum, carrying out polycondensation reaction for 1-4 h under high vacuum (the pressure is less than 80Pa) at 250-270 ℃, discharging, and carrying out water cooling.

Intrinsic viscosity [ eta ] of the copolyester]1.20 dL/g; the limiting oxygen index is 28.0%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak value heat release rate p-HRR in the cone calorimetry test is 575kW/m²The total smoke release amount TSR is 1342m²/m²(ii) a The tensile strength was 80.4 MPa.

Example 4

498.0g of terephthalic acid, 250.0g of ethylene glycol, 142.7g of 3, 5-bis (2-hydroxyethoxy) -N-phenylbenzamide and 0.25g of ethylene glycol antimony were charged into a reaction vessel, and esterification and polycondensation were carried out under the conditions and conditions given in example 3, followed by discharge.

Intrinsic viscosity [ eta ] of the copolyester]0.76 dL/g; the limiting oxygen index is 29.6%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 452kW/m²The total smoke release amount TSR is 1180m²/m²(ii) a The tensile strength was 92.0 MPa.

Example 5

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 50.7g of dimethyl 5- (3-cyano) benzamido-1, 3-isophthalate, 0.2g of antimony acetate and 0.2g of titanium tartrate were charged into a reaction vessel, and after conducting the ester exchange and polycondensation reactions according to the procedures and conditions given in example 1, the product was discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.70 dL/g; the limiting oxygen index is 26.8%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak heat release rate p-HRR in the cone calorimetry test is 514kW/m²The total smoke release amount TSR is 1396m²/m²(ii) a The tensile strength was 70.1 MPa.

Example 6

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 101.4g of dimethyl 5- (3-cyano) benzamido-1, 3-isophthalate and 0.25g of tetrabutyl titanate were put into a reaction vessel, and after ester exchange and polycondensation reactions were carried out according to the procedures and conditions given in example 1, they were discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.68 dL/g; the limiting oxygen index is 29.8%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak value heat release rate p-HRR in the cone calorimetry test is 389kW/m²Total smoke release TSR 1212m²/m²(ii) a The tensile strength was 82.7 MPa.

Example 7

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 405.6g of dimethyl 5- (4-cyano) benzamido-1, 3-isophthalate, 0.2g of titanium dioxide and 0.2g of antimony acetate were charged into a reaction vessel, and after ester exchange and polycondensation reactions were carried out according to the procedures and conditions given in example 1, the product was discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.65 dL/g; the limiting oxygen index is 40.0%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 212kW/m²The total smoke release amount TSR is 755m²/m²(ii) a The tensile strength was 135.2 MPa.

Example 8

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 150.8g of 5- (1-naphthamide) isophthalic acid, 0.2g of manganese acetate and 0.3g of potassium titanium oxalate were charged into a reaction vessel, and after ester exchange and polycondensation reactions were carried out according to the procedures and conditions given in example 1, the product was discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.74 dL/g; the limiting oxygen index is 30.0%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 313kW/m²The total smoke release amount TSR is 884m²/m²(ii) a The tensile strength was 95.5 MPa.

Example 9

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 544.5g of dimethyl 5- (2-naphthylamide) isophthalate, 0.2g of magnesium acetate and 0.2g of potassium hexafluorotitanate were charged into a reaction vessel, and after ester exchange and polycondensation reactions were carried out by the procedures and conditions given in example 1, they were discharged.

Intrinsic viscosity [ eta ] of the copolyester]1.56 dL/g; the limiting oxygen index is 45.0%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak value heat release rate p-HRR in the cone calorimetry test is 239kW/m²Total smoke release TSR is 721m²/m²(ii) a The tensile strength was 144.9 MPa.

Example 10

498.0g of terephthalic acid, 250.0g of ethylene glycol, 41.9g of 3, 5-dihydroxy-N- (naphthalen-1-yl) benzamide and 0.25g of tetraphenyl titanate were charged into a reaction vessel, and esterification and polycondensation were carried out under the conditions given in example 3, followed by discharge.

Intrinsic viscosity [ eta ] of the copolyester]0.92 dL/g; the limiting oxygen index is 28.2%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak heat release rate p-HRR in the cone calorimetry test is 521kW/m²The total smoke release amount TSR is 1349m²/m²(ii) a The tensile strength was 73.3 MPa.

Example 11

582.0g of dimethyl terephthalate, 310.0g of ethylene glycol, 150.0g of 1, 3-propanediol, 326.7g of dimethyl 5- (naphthalene-2-ylcarbamoyl) isophthalate, 0.2g of cobalt acetate and 0.25g of titanium citrate were charged into a reaction vessel, and after conducting ester exchange and polycondensation reactions according to the procedures and conditions given in example 1, they were discharged.

Intrinsic viscosity [ eta ] of the copolyester]1.23 dL/g; the limiting oxygen index is 34.5%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak value heat release rate p-HRR in the cone calorimetry test is 302kW/m²The total smoke release amount TSR is 865m²/m²(ii) a The tensile strength was 116.4 MPa.

Example 12

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 202.8g of methyl 3-cyano-5- ((4- (methoxycarbonyl) phenyl) carbamoyl) benzoate, 47.0g of dimethyl 5-phenylaminocarbonyl-1, 3-isophthalate, 0.15g of tetrabutyltitanate and 0.2g of tin oxide were charged into a reaction vessel, and after conducting the transesterification and polycondensation reactions in accordance with the procedures and conditions given in example 1, they were discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.68 dL/g; the limiting oxygen index is 34.0%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 310kW/m²Total smoke release TSR 835m²/m²(ii) a The tensile strength was 105.8 MPa.

Example 13

498.0g of terephthalic acid, 250.0g of ethylene glycol, 228.6g of 3-cyano-5-hydroxy-N- (4-hydroxyphenyl) benzamide and 0.26g of titanium glycol were charged into a reaction vessel, and esterification and polycondensation were carried out under the conditions given in example 3, followed by discharging.

Intrinsic viscosity of the copolyester[η]0.70 dL/g; the limiting oxygen index is 35.0%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 284kW/m²Total smoke release TSR is 721m²/m²(ii) a The tensile strength was 114.7 MPa.

Example 14

498.0g of isophthalic acid, 360.0g of 1, 4-butanediol, 102.6g of 3-cyano-5- (2-hydroxyethoxy) -N- (4- (2-hydroxyethoxy) phenyl) benzamide, 48.2g of 5-benzenesulfonamido-isophthalic acid, 0.27g of titanium dioxide and 0.03g of silica were charged into a reaction vessel, and esterification and polycondensation reactions were carried out under the conditions and procedures given in example 3, followed by discharge.

Intrinsic viscosity [ eta ] of the copolyester]0.63 dL/g; the limiting oxygen index is 29.5%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak heat release rate p-HRR in the cone calorimetry test is 572kW/m²The total smoke release amount TSR is 1218m²/m²(ii) a The tensile strength was 76.1 MPa.

Example 15

582.0g of dimethyl isophthalate, 490.0g of 1, 3-propanediol, 101.4g of methyl 3-cyano-5- (4- (methoxycarbonyl) benzamido) benzoate, 0.2g of zinc acetate and 0.4g of alumina were charged in a reaction vessel, and after conducting ester exchange and polycondensation reactions according to the procedures and conditions given in example 1, they were discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.72 dL/g; the limiting oxygen index is 27.2%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak value heat release rate p-HRR in the cone calorimetry test is 688kW/m²The total smoke release amount TSR is 1366m²/m²(ii) a The tensile strength was 70.2 MPa.

Example 16

332.0g of terephthalic acid, 166.0g of isophthalic acid, 260.0g of ethylene glycol, 304.8g of 304.8g N- (3-cyano-5-hydroxyphenyl) -4-hydroxybenzamide, 104.7g of dimethyl 5-benzenesulfonamido-isophthalate, 201.0g of 5- (1-naphthamide) isophthalic acid, 0.15g of tetrabutyl titanate and 0.2g of tetrabutoxygermanium were charged into a reaction vessel, subjected to esterification and polycondensation under the conditions given in example 3, and then discharged.

Intrinsic viscosity [ eta ] of the copolyester]Is 2.76 dL/g; the limiting oxygen index is 52.0%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 175kW/m²The total smoke release amount TSR is 662m²/m²(ii) a The tensile strength was 165.7 MPa.

Example 17

468.0g of terephthalic acid, 30.0g of phthalic acid, 300.0g of 1, 3-propanediol, 307.8g N- (3-cyano-5- (2-hydroxyethoxy) phenyl) -4- (2-hydroxyethoxy) benzamide and 0.35g of aluminum hydroxide were charged into a reaction vessel, and esterification and polycondensation reactions were carried out in accordance with the procedure and conditions of example 3, followed by discharging.

Intrinsic viscosity [ eta ] of the copolyester]0.64 dL/g; the limiting oxygen index is 32.4%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 390kW/m²The total smoke release amount TSR is 1184m²/m²(ii) a The tensile strength was 110.5 MPa.

Example 18

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 52.4g of dimethyl 5-benzenesulphonamido isophthalate, 0.2g of manganese acetate and 0.25g of titanium glycol were charged into a reaction vessel, and after ester exchange and polycondensation reactions were carried out by the procedures and conditions given in example 1, the product was discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.86 dL/g; the limiting oxygen index is 26.5%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak heat release rate p-HRR in the cone calorimetry test is 564kW/m²The total smoke release amount TSR is 1480m²/m²(ii) a The tensile strength was 72.2 MPa.

Example 19

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 157.1g of 5-benzenesulphonamidoisophthalic acid dimethyl ester, and 0.25g of tetraisopropyl titanate were charged into a reaction vessel, subjected to transesterification and polycondensation reaction in accordance with the procedure and conditions given in example 1, and discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.72 dL/g; the limiting oxygen index is 31.2%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 430kW/m²The total smoke release amount TSR is 973m²/m²(ii) a The tensile strength was 94.5 MPa.

Example 20

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 112.2g of dimethyl 5- (3-cyano) benzenesulphonamido isophthalate and 0.30g of tetrabutyl titanate were put into a reaction vessel, and after transesterification and polycondensation were carried out by the procedure and conditions given in example 1, they were discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.68 dL/g; the limiting oxygen index is 29.6%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 476kW/m²The total smoke release amount TSR is 982m²/m²(ii) a The tensile strength was 87.6 MPa.

Example 21

448.0g of terephthalic acid, 50.0g of isophthalic acid, 250.0g of ethylene glycol, 39.8g of 39.8g N- (3, 5-dihydroxyphenyl) benzenesulfonamide, 0.29g of titanium dioxide and 0.015g of zirconium dioxide were charged into a reaction vessel, and esterification and polycondensation were carried out by the procedure and conditions given in example 3, followed by discharge.

Intrinsic viscosity [ eta ] of the copolyester]0.71 dL/g; the limiting oxygen index is 27.0%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak value heat release rate p-HRR in the cone calorimetry test is 601kW/m²The total smoke release amount TSR is 1562m²/m²(ii) a The tensile strength was 70.5 MPa.

Example 22

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 198.8g N- (3, 5-dihydroxyphenyl) benzenesulfonamide, 50.7g of methyl 3-cyano-5- (4- (methoxycarbonyl) benzamido) benzoate, 20.1g of 5- (1-naphthamide) isophthalic acid, 68.9g of dimethyl 5- ((1-naphthalenylamino) (phenyl) phosphoryl) isophthalate, 0.2g of aluminum acetate and 0.25g of antimony ethylene glycol were charged into a reaction vessel, and after ester exchange and polycondensation reactions were carried out according to the procedures and conditions given in example 1, the product was discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.64 dL/g; the limiting oxygen index is 40.6%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 223kW/m²Total smoke release TSR 717m²/m²(ii) a The tensile strength was 132.8 MPa.

Example 23

498.0g of terephthalic acid, 300.0g of 1, 3-propanediol, 53.0g of 53.0g N- (3, 5-bis (2-hydroxyethoxy) phenyl) benzenesulfonamide and 0.25g of antimony trioxide were charged into a reaction vessel, and esterification and polycondensation were carried out by the procedures and conditions given in example 3, followed by discharge.

Intrinsic viscosity [ eta ] of the copolyester]0.70 dL/g; the limiting oxygen index is 26.8%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak heat release rate p-HRR in the cone calorimetry test is 611kW/m²The total smoke release amount TSR is 1406m²/m²(ii) a The tensile strength was 68.8 MPa.

Example 24

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 52.4g of dimethyl 5- (N-phenylsulfamoyl) isophthalate, and 0.3g of tetrabutyl titanate were charged into a reaction vessel, subjected to transesterification and polycondensation under the conditions and conditions given in example 1, and discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.88 dL/g; the limiting oxygen index is 26.5%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak heat release rate p-HRR in the cone calorimetry test is 590kW/m²The total smoke release amount TSR is 1349m²/m²(ii) a The tensile strength was 67.3 MPa.

Example 25

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 157.1g of dimethyl 5- (N-phenylsulfamoyl) isophthalate, 61.4g of dimethyl 5- ((diphenylphosphoryl) amino) isophthalate, 0.2g of magnesium acetate and 0.2g of titanium glycol were charged into a reaction vessel, and after conducting the ester exchange and polycondensation reactions according to the procedures and conditions given in example 1, the materials were discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.76 dL/g; the limiting oxygen index is 32.2%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak value heat release rate p-HRR in the cone calorimetry test is 431kW/m²The total smoke release amount TSR is 1020m²/m²(ii) a The tensile strength was 93.4 MPa.

Example 26

498.0g of terephthalic acid, 250.0g of ethylene glycol, 119.3g of 3, 5-dihydroxy-N-phenylbenzenesulfonamide and 0.3g of germanium dioxide were charged into a reaction kettle, and esterification and polycondensation were carried out according to the procedure and conditions given in example 3, followed by discharge.

Intrinsic viscosity [ eta ] of the copolyester]0.65 dL/g; the limiting oxygen index is 30.4%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 403kW/m²The total smoke release amount TSR is 985m²/m²(ii) a The tensile strength was 89.5 MPa.

Example 27

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 119.7g of dimethyl 5- (naphthalene-1-sulfonamido) isophthalate, and 0.3g of tetrabutyl titanate were put into a reaction vessel, and after ester exchange and polycondensation reactions were carried out according to the procedure and conditions given in example 1, the product was discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.74 dL/g; the limiting oxygen index is 30.5%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak value heat release rate p-HRR in the cone calorimetry test is 422kW/m²Total smoke release amount TSR 951m²/m²(ii) a The tensile strength was 90.6 MPa.

Example 28

552.0g of dimethyl terephthalate, 30.0g of dimethyl isophthalate, 400.0g of ethylene glycol, 55.7g of 5- (naphthalene-2-sulfonamido) isophthalic acid and 0.2g of tetraisopropyl titanate were put into a reaction vessel, and subjected to ester exchange and polycondensation reaction in accordance with the procedure and conditions given in example 1, followed by discharge.

Intrinsic viscosity [ eta ] of the copolyester]1.05 dL/g; the limiting oxygen index is 28.0%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak heat release rate p-HRR in the cone calorimetry test was 473kW/m²The total smoke release amount TSR is 1167m²/m²(ii) a The tensile strength was 80.4 MPa.

Example 29

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 239.4g of dimethyl 5- (N- (naphthalene-1-yl) sulfonamide) isophthalate, 0.2g of manganese acetate and 0.2g of titanium citrate were charged into a reaction vessel, and after ester exchange and polycondensation reactions were carried out according to the procedures and conditions given in example 1, the materials were discharged.

Intrinsic viscosity [ eta ] of the copolyester]Is 2.03 dL/g; the limiting oxygen index is 31.6%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 267kW/m²The total smoke release amount TSR is 812m²/m²(ii) a The tensile strength was 116.6 MPa.

Example 30

542.0g of dimethyl terephthalate, 40.0g of dimethyl isophthalate, 400.0g of ethylene glycol, 52.4g of methyl 4- (N- (4- (methoxycarbonyl) phenyl) sulfamoyl) benzoate, 0.15g of antimony acetate and 0.2g of potassium titanium oxalate were charged into a reaction vessel, and after ester exchange and polycondensation reactions were carried out according to the procedure and conditions of example 1, the mixture was discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.82 dL/g; the limiting oxygen index is 26.0%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak value heat release rate p-HRR in the cone calorimetry test is 588kW/m²The total smoke release amount TSR is 1433m²/m²(ii) a The tensile strength was 68.9 MPa.

Example 31

498.0g of isophthalic acid, 250.0g of ethylene glycol, 119.3g of 4-hydroxy-N- (4-hydroxyphenyl) benzenesulfonamide and 0.32g of antimony acetate were charged into a reaction vessel, and esterification and polycondensation were carried out by the procedure and conditions given in example 3, followed by discharge.

The mixture isIntrinsic viscosity [ eta ] of polyester]0.65 dL/g; the limiting oxygen index is 31.0%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak value heat release rate p-HRR in the cone calorimetry test is 433kW/m²The total smoke release amount TSR is 968m²/m²(ii) a The tensile strength was 93.5 MPa.

Example 32

498.0g of terephthalic acid, 250.0g of ethylene glycol, 105.9g of 4- (2-hydroxyethoxy) -N- (4- (2-hydroxyethoxy) phenyl) benzenesulfonamide, 50.7g of dimethyl 5- (3-cyano) benzamido-1, 3-isophthalate, 66.2g of dimethyl 5- ((diphenylphosphoryl) amino) isophthalate, 0.15g of antimony acetate and 0.15g of antimony trioxide were charged into a reaction vessel, and esterification and polycondensation reactions were carried out according to the procedure and conditions of example 3, followed by discharging.

Intrinsic viscosity [ eta ] of the copolyester]0.76 dL/g; the limiting oxygen index is 32.2%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 361kW/m²The total smoke release amount TSR is 876m²/m²(ii) a The tensile strength was 101.8 MPa.

Example 33

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 61.4g of dimethyl 5- ((diphenylphosphoryl) amino) isophthalate and 0.28g of tetrabutyl titanate were charged into a reaction vessel, subjected to transesterification and polycondensation under the conditions and conditions given in example 1, and then discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.81 dL/g; the limiting oxygen index is 27.5%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak heat release rate p-HRR in the cone calorimetry test was 554kW/m²The total smoke release amount TSR is 1422m²/m²(ii) a The tensile strength was 70.7 MPa.

Example 34

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 184.1g of dimethyl 5- ((diphenylphosphoryl) amino) isophthalate, 0.2g of manganese acetate, 0.27g of titanium dioxide and 0.03g of silica were charged into a reaction vessel, and after conducting the ester exchange and polycondensation reactions in accordance with the procedures and conditions given in example 1, they were discharged.

Intrinsic viscosity [ eta ] of the copolyester]1.05 dL/g; the limiting oxygen index is 30.6%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 412kW/m²The total smoke release amount TSR is 1035m²/m²(ii) a The tensile strength was 88.3 MPa.

Example 35

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 104.1g of dimethyl 5- (methyl (phenylamino) phosphoryl) isophthalate, 0.2g of zinc acetate and 0.2g of ethylene glycol antimony were charged into a reaction vessel, and after transesterification and polycondensation were carried out by the procedure and conditions given in example 1, the product was discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.78 dL/g; the limiting oxygen index is 28.0%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak heat release rate p-HRR in the cone calorimetry test is 522kW/m²The total smoke release amount TSR is 1296m²/m²(ii) a The tensile strength was 74.5 MPa.

Example 36

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 275.4g of dimethyl 5- ((naphthalen-1-yl (phenyl) phosphoryl) amino) isophthalate, 0.15g of tetrabutyl titanate and 0.15g of titanium acetylacetonate were charged into a reaction vessel, and after conducting the ester exchange and polycondensation reactions according to the procedures and conditions given in example 1, they were discharged.

Intrinsic viscosity [ eta ] of the copolyester]1.05 dL/g; the limiting oxygen index is 33.5%; the vertical burning grade is V-0 grade, and no molten drop is generated in the test; the peak value heat release rate p-HRR in the cone calorimetry test is 368kW/m²Total smoke release TSR is 896m²/m²(ii) a The tensile strength was 95.5 MPa.

Example 37

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol, 66.2g of dimethyl 5- ((diphenoxyphosphoryl) amino) isophthalate, 0.2g of antimony acetate and 0.25g of alumina were charged into a reaction vessel, and after conducting transesterification and polycondensation reactions in accordance with the procedures and conditions given in example 1, they were discharged.

Intrinsic viscosity [ eta ] of the copolyester]0.73 dL/g; the limiting oxygen index is 28.2%; the vertical combustion grade is V-2 grade, molten drops are generated in the test, but the molten drop phenomenon is obviously improved; the peak value heat release rate p-HRR in the cone calorimetry test is 563kW/m²The total smoke release amount TSR is 1564m²/m²(ii) a The tensile strength was 70.2 MPa.

Comparative example 1

582.0g of dimethyl terephthalate, 400.0g of ethylene glycol and 0.25g of tetrabutyl titanate were put into a reaction vessel, subjected to transesterification and polycondensation reaction in accordance with the procedure and conditions given in example 1, and then discharged.

The intrinsic viscosity [ eta ] of the PET polyester]0.63 dL/g; the limiting oxygen index is 22.0%; the vertical combustion grade is stepless, and a large amount of molten drops are generated in the test; the peak heat release rate p-HRR in the cone calorimetry test is 788kW/m²(ii) a The total smoke release amount TSR is 1728m²/m²(ii) a The tensile strength was 59.6 MPa.