High-fluidity high-melting-point polyester copolymer material and preparation method thereof

Abstract

The invention discloses a high-fluidity and high-melting-point polyester copolymerization material which comprises terephthalic acid, dihydric alcohol I, dihydric alcohol II, aromatic dicarboxylic acid or derivatives thereof and an ethylene glycol antimony catalyst, and the terephthalic acid, the dihydric alcohol I, the aromatic dicarboxylic acid or the derivatives thereof and the ethylene glycol antimony catalyst are uniformly mixed and then subjected to esterification reaction; after the esterification reaction is finished, dihydric alcohol II is introduced for a pre-polycondensation reaction and a final polycondensation reaction to prepare the high-fluidity and high-melting-point polyester copolymerization material, aromatic dicarboxylic acid or derivatives thereof react with excessive dihydric alcohol I in the esterification stage, so that the aromatic dicarboxylic acid or the derivatives thereof are grafted into a polyester molecular chain, and the dihydric alcohol I is attached with a flexible chain segment, so that the high-fluidity and high-melting-point polyester copolymerization material is obtained. Dihydric alcohol I is connected into a polyester molecular chain through condensation polymerization to form the high-fluidity and high-melting-point polyester copolymer material with an aliphatic flexible chain segment. And the mechanical property is not lost while the fluidity of the polyester is improved, the melt viscosity drop is effectively controlled, the cost is low, and the application prospect is wide.

Description

Technical Field

[0001] The invention relates to the technical field of polyester preparation, and in particular to a high-fluidity high-melting-point polyester copolymer material and a preparation method thereof. Background Art

[0002] High melting point polyester copolymer is a high molecular polymer formed by polymerization of two or more monomers, and the melting point is usually above 250°C. Some common polyester copolymers include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc. High melting point polyester copolymers are widely used in engineering plastics, fibers, films and other fields. They have excellent mechanical properties, heat resistance, chemical resistance and electrical insulation properties. Due to the high regularity and high crystallinity of the molecular chain of polyester, especially some high melting point polyesters, their flow properties are poor. Therefore, polyester materials with both high flow and high melting point properties can be used in a wider range of fields. At present, patent CN101935392A discloses a polyester copolymer with high flowability, and the added flow-modifying component diol is adjusted from the structure to improve the flowability of polyester. Patent CN1986607 blends hyperbranched polymers with PET to improve the flowability of PET. However, the preparation methods for improving the fluidity of polyester mentioned in the prior art all have some shortcomings. For example, the diol, a flow-modifying component added in patent CN101935392A, is structurally difficult to obtain, which additionally increases the cost of raw materials; and the hyperbranched polymer used in patent CN1986607 requires additional synthesis, which increases the process cost from a process perspective. Summary of the invention

[0003] In order to solve one or some technical problems existing in the prior art, one of the purposes of the present application is to provide a high-fluidity high-melting point polyester copolymer material, which can improve the fluidity of polyester while ensuring that the mechanical properties are not lost.

[0004] The second purpose of the present application is to provide a method for preparing a high-fluidity high-melting-point polyester copolymer material, which has a simple process, significantly reduced flow activation, significantly improved flow performance, reduced the force between the copolyester melt and the tube wall during flow, effectively controlled the melt viscosity drop, low cost, and broad application prospects.

[0005] In order to solve the above existing technical problems, one of the purposes of this application is achieved by adopting the following technical solution:

[0006] A high-fluidity high-melting-point polyester copolymer material comprises terephthalic acid, diol I, diol II, aromatic dicarboxylic acid or its derivatives and ethylene glycol antimony catalyst. The terephthalic acid, diol I, aromatic dicarboxylic acid or its derivatives and ethylene glycol antimony catalyst are mixed evenly and then subjected to esterification reaction. After the esterification reaction is completed, diol II is introduced to carry out pre-polycondensation reaction and final polycondensation reaction to obtain the high-fluidity high-melting-point polyester copolymer material. The aromatic dicarboxylic acid or its derivative reacts with an excess of diol I in the esterification stage to be connected to the polyester molecular chain. The diol II is attached with a flexible chain segment. The diol II is connected to the polyester molecular chain through a polycondensation reaction to form a high-fluidity high-melting-point polyester copolymer material with aliphatic flexible chain segments.

[0007] The aromatic dicarboxylic acid or its derivative selected by the present invention reacts with an excess of diol I in the esterification stage and is connected to the polyester molecular chain. At the same time, the diol II introduced after the esterification is attached with a flexible chain segment, which is connected to the polyester molecular chain through a polycondensation reaction. The esterification product contains aliphatic flexible chain segments, which can effectively improve the flowability of the copolyester and reduce the difficulty of the reaction; the obtained copolymer material has excellent flowability, wherein the content of high-flowability components is relatively high, and these components are rich in flexible chain segments, so that the copolyester can be directly used as a polyester blending and modification material, and has good application prospects.

[0008] Preferably, the aromatic dicarboxylic acid or its derivative is at least one of terephthalic acid, isophthalic acid, adipic acid, succinic acid, 2,2-dimethylvaleric acid and 1,1-cyclohexanediacetic acid.

[0009] Preferably, the diol II is at least one of ethylene glycol, propylene glycol, butylene glycol, pentanediol, polyethylene glycol, and cyclohexanedimethanol.

[0010] Preferably, the diol I is the same as the diol II or is at least one of the diols used for synthesizing polyester except the diol II.

[0011] Preferably, the molar ratio of the diol I to the terephthalic acid is greater than 1, that is, the diol I is in excess.

[0012] The molar ratio of terephthalic acid to diol I in the present invention is less than 1, that is, diol I is excessive, which is mainly to ensure the introduction of aromatic dicarboxylic acid or its derivatives into the polyester molecular chain.

[0013] Preferably, the molar ratio of the aromatic dicarboxylic acid or its derivative to the diol I is 1:1.1-2.0.

[0014] Preferably, the molar ratio of the sum of the aromatic dicarboxylic acid or its derivative and terephthalic acid to the sum of the diol I and diol II is 1:1.2-1.8.

[0015] The second purpose of this application is achieved by the following technical solution:

[0016] A method for preparing a high-fluidity high-melting-point polyester copolymer material, the preparation method comprising:

[0017] S1. preparing slurry: mixing terephthalic acid, diol I, aromatic dicarboxylic acid or its derivative and ethylene glycol antimony catalyst to prepare slurry;

[0018] S2, esterification reaction: subjecting the slurry obtained in step S1 to esterification reaction;

[0019] S3, polycondensation reaction: after the reaction in step S2 is completed, diol II with a flexible chain segment is introduced to carry out a preliminary polycondensation reaction and a final polycondensation reaction to obtain a high-fluidity, high-melting-point polyester copolymer material with aliphatic flexible chain segments.

[0020] Aromatic dicarboxylic acids or their derivatives destroy the regularity of the polyester molecular chain itself, reduce the strong interaction between the molecular chains, and thus improve the flow properties of the copolyester molecular chain; the introduced diol II component contains a certain length of flexible chain segments, and the flow activation energy is low, which can enhance the flow characteristics, thereby further improving the fluidity of the polyester. By introducing the modified component, the flow activation energy is significantly reduced under their joint action, the flow properties are significantly improved, the interaction between the copolyester melt and the tube wall during the flow process is reduced, and the melt viscosity drop is effectively controlled. The process is simple, the cost is low, and it has great application prospects. This method can obtain a polycondensation product of a high melting point polyester copolymer material without adding a heat stabilizer and an antioxidant.

[0021] Preferably, the beating and mixing time in step S1 is 0.1 to 0.5 h.

[0022] Preferably, the addition amount of the ethylene glycol antimony catalyst is 20 to 200 ppm of the total mass of the aromatic dicarboxylic acid or its derivative and terephthalic acid.

[0023] The reaction between terephthalic acid, diol I, aromatic dicarboxylic acid or its derivatives belongs to the organic chemical reaction of alcohol acid. Excess diol I within a certain range can promote the reaction in the positive direction. The molar ratio of terephthalic acid to diol I can be appropriately adjusted, but it should not be too much. If diol I is further increased, it will lead to waste of diol I and cause diol I to undergo self-condensation side reaction under high temperature conditions. Therefore, the molar ratio of dicarboxylic acid to diol I is 1:1.1-2.0, and the addition amount of ethylene glycol antimony is 20-200ppm of the sum of aromatic dicarboxylic acid or its derivatives and terephthalic acid.

[0024] Preferably, in step S2, an aromatic dicarboxylic acid or its derivative and diol I are subjected to an esterification reaction under the action of an ethylene glycol antimony catalyst to evaporate the generated water; the reaction temperature is 220-280° C., the esterification pressure is normal pressure to 0.4 MPa, and the reaction time is 1.5-3.0 h, ensuring that the esterification rate reaches more than 96%. When the distilled water amount is 90-98% of the theory, the esterification reaction ends.

[0025] The time of the esterification reaction can be adjusted appropriately, but it should not be too long. Too short an esterification reaction time cannot guarantee the full reaction of the alkyd functional groups. Too long an esterification reaction time not only makes it difficult to further increase the esterification rate, but will also cause an increase in side reactions.

[0026] Preferably, in the step S3, the pre-polycondensation reaction temperature is 260-300° C., the vacuum degree is 30-3000 Pa, and the reaction time is 0.5-3.5 h. The final polycondensation temperature in the final polycondensation reaction is 270-300° C., the vacuum degree is 30-240 Pa, and the reaction time is 1.0-3.5 h.

[0027] The molecular chain of the high-fluidity high-melting-point polyester copolymer material is mainly composed of a terephthalic acid segment, a diol I segment, a diol II segment and an aromatic dicarboxylic acid or a derivative segment thereof, wherein the diol I segment is the same as or different from the diol II segment, and the diol II segment is one or more of an ethylene glycol segment, a propylene glycol segment, a butanediol segment, a pentanediol segment, a polyethylene glycol segment, and a cyclohexanedimethanol segment; and the aromatic dicarboxylic acid or a derivative segment thereof is at least one of a terephthalic acid segment, an isophthalic acid segment, adipic acid segment, a succinic acid segment, a 2,2-dimethylvaleric acid segment, and a 1,1-cyclohexanediacetic acid segment.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] At present, the methods to improve the fluidity of polyester include: first, blending, which is a physical reaction and cannot improve the fluidity from the polymerization itself; second, improving the fluidity by controlling the polymerization reaction conditions to reduce the molecular weight of polyester. Generally speaking, the higher the molecular weight, the better the mechanical properties; third, adding additives, which will also affect its mechanical properties. The high melting point polyester copolymer material prepared by the above method can improve the fluidity of polyester while ensuring that the mechanical properties are not lost.

[0030] Aromatic dicarboxylic acids or their derivatives destroy the regularity of the polyester molecular chain itself, reduce the strong interaction between the molecular chains, and thus improve the flow properties of the copolyester molecular chain; the introduced diol II component contains a certain length of flexible chain segments, and the flow activation energy is low, which can enhance the flow characteristics, thereby further improving the fluidity of the polyester. By introducing two modified components, the flow activation energy is significantly reduced under their joint action, the flow properties are significantly improved, the interaction between the copolyester melt and the tube wall during the flow process is reduced, and the melt viscosity drop is effectively controlled. The process is simple, the cost is low, and it has great application prospects.

[0031] The prepared copolymer material has excellent fluidity, wherein the content of high fluidity components is relatively high, and these components are rich in flexible segments, so that the copolyester can be directly used as a polyester blending and modification material, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the melting point of the polyester copolymer material in Example 1 of the present invention under the condition of a temperature increase of 20K / min;

[0033] Figure 2 Schematic diagram of the melting point of the polyester copolymer material in Example 2 of the present invention under the condition of a temperature increase of 20K / min;

[0034] Figure 3 Schematic diagram of the melting point of the polyester copolymer material in Example 3 of the present invention under the condition of a temperature increase of 20K / min;

[0035] Figure 4 Schematic diagram of the melting point of the polyester copolymer material in Comparative Example 1 of the present invention under a temperature increase condition of 20K / min. DETAILED DESCRIPTION

[0036] Below, the present application is further described in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0037] In the description of the present application, it should be understood that the terms "up", "down", "left", "right", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0038] The terms "first", "second", etc. in this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0039] Embodiment 1:

[0040] like Figure 1 As shown, a high-fluidity high-melting-point polyester copolymer material and a preparation method thereof, the specific steps are as follows:

[0041] S1. Prepare slurry; 1440 g of purified terephthalic acid, 45 g of isophthalic acid, 18 g of 1,1-cyclohexanediacetic acid, 720 g of ethylene glycol, and 0.54 g of ethylene glycol antimony catalyst are mixed and beaten to obtain slurry, and the mixing and beating time is 0.4 h;

[0042] S2, esterification reaction;

[0043] The slurry was subjected to esterification reaction under nitrogen protection, wherein the esterification temperature was 240°C, the pressure was normal pressure to 0.4 MPa, and the esterification time was 2.5 h;

[0044] S3, polycondensation reaction;

[0045] After adding 10 g of PEG-2000 to the esterified product, a pre-polycondensation reaction and a final polycondensation reaction were carried out to obtain a high-fluidity and high-melting-point polyester copolymer material, wherein the pre-polycondensation temperature was 270°C, the vacuum degree was 30-2000 Pa, and the reaction time was 1.5 h; the final polycondensation temperature was 280°C, the vacuum degree was 30-240 Pa, and the reaction time was 1.5 h.

[0046] The high-fluidity and high-melting-point polyester copolymer material finally obtained has a melting point of 255° C., a melt index of 42 g / 10 min, and an intrinsic viscosity of 0.67 dL / g.

[0047] Embodiment 2:

[0048] like Figure 2 As shown, a high-fluidity high-melting-point polyester copolymer material and a preparation method thereof, the specific steps are as follows:

[0049] S1. Prepare slurry;

[0050] 1425 g of purified terephthalic acid, 45 g of isophthalic acid, 36 g of 1,1-cyclohexanediacetic acid, 720 g of ethylene glycol, and 0.54 g of ethylene glycol antimony catalyst were mixed and beaten to prepare a slurry, and the mixing and beating time was 0.4 h;

[0051] S2, esterification reaction;

[0052] The slurry was subjected to esterification reaction under nitrogen protection, wherein the esterification temperature was 240°C, the pressure was normal pressure to 0.4 MPa, and the esterification time was 2.5 h;

[0053] S3, polycondensation reaction;

[0054] After adding 15 g of PEG-2000 to the esterified product, a pre-polycondensation reaction and a final polycondensation reaction were carried out to obtain a high-fluidity and high-melting-point polyester copolymer material, wherein the pre-polycondensation temperature was 270°C, the vacuum degree was 30-2000 Pa, and the reaction time was 1.5 h; the final polycondensation temperature was 280°C, the vacuum degree was 30-240 Pa, and the reaction time was 1.5 h.

[0055] The high-fluidity and high-melting-point polyester copolymer material finally obtained has a melting point of 253° C., a melt index of 52 g / 10 min, and an intrinsic viscosity of 0.69 dL / g.

[0056] Embodiment 3:

[0057] like Figure 3 As shown, a high-fluidity high-melting-point polyester copolymer material and a preparation method thereof, the specific steps are as follows:

[0058] S1. Prepare slurry;

[0059] 1395 g of purified terephthalic acid, 45 g of isophthalic acid, 72 g of 1,1-cyclohexanediacetic acid, 720 g of ethylene glycol, and 0.54 g of ethylene glycol antimony catalyst were mixed and beaten to prepare a slurry, and the mixing and beating time was 0.4 h;

[0060] S2, esterification reaction;

[0061] The slurry was subjected to esterification reaction under nitrogen protection, wherein the esterification temperature was 240°C, the pressure was normal pressure to 0.4 MPa, and the esterification time was 2.5 h;

[0062] S3, polycondensation reaction;

[0063] After adding 5 g of PEG-2000 to the esterified product, a pre-polycondensation reaction and a final polycondensation reaction were carried out to obtain a high-fluidity and high-melting-point polyester copolymer material, wherein the pre-polycondensation temperature was 270°C, the vacuum degree was 30-2000 Pa, and the reaction time was 1.5 h; the final polycondensation temperature was 280°C, the vacuum degree was 30-240 Pa, and the reaction time was 1.5 h.

[0064] The high-fluidity and high-melting-point polyester copolymer material finally obtained has a melting point of 248° C., a melt index of 48 g / 10 min, and an intrinsic viscosity of 0.66 dL / g.

[0065] Comparative Example 1:

[0066] like Figure 4 As shown, a high-fluidity high-melting-point polyester copolymer material and a preparation method thereof, the specific steps are as follows:

[0067] (1) preparing slurry;

[0068] 1500g of purified terephthalic acid, 720g of ethylene glycol and 0.54g of ethylene glycol antimony catalyst were mixed and beaten to prepare a slurry, and the mixing and beating time was 0.4h;

[0069] (2) Esterification reaction;

[0070] The slurry was subjected to esterification reaction under nitrogen protection, wherein the esterification temperature was 240°C, the pressure was normal pressure to 0.4 MPa, and the esterification time was 2.5 h;

[0071] (3) polycondensation reaction;

[0072] The esterified product is subjected to a pre-polycondensation reaction and a final polycondensation reaction to obtain a high-fluidity high-melting point polyester copolymer material, wherein the pre-polycondensation temperature is 270°C, the vacuum degree is 30-2000Pa, and the reaction time is 1.5h; the final polycondensation temperature is 280°C, the vacuum degree is 30-240Pa, and the reaction time is 1.5h.

[0073] The high-fluidity and high-melting-point polyester copolymer material finally obtained has a melting point of 253° C., a melt index of 22 g / 10 min, and an intrinsic viscosity of 0.67 dL / g.

[0074] The corresponding polyester copolymer material indicators of the above Examples 1 to 3 and Comparative Example 1 were tested:

[0075] Thermal melting peak temperature: the PET sample was placed in a differential scanning calorimeter (DSC), heated to 280°C at 20°C / min, kept at a constant temperature for 5 min to eliminate the thermal history, then cooled to room temperature at 20°C / min, kept at a constant temperature for 5 min to eliminate the thermal history, then heated to 280°C at 20°C / min.

[0076] Melt index: The experimental temperature of the melt index of the present invention is 260° C. and the loading load is 1.2 Kg.

[0077] Intrinsic viscosity: The PET sample was dissolved in a phenol-tetrachloroethane mixed solution with a mass ratio of 1:1, with a concentration of about 5 mg / mL, and measured with an Ubbelohde viscometer at 25°C. The test results are shown in the following table:

[0078]

[0079] By comparing Examples 1 to 3 with Comparative Example 1, compared with conventional PET, the aromatic dicarboxylic acid or its derivatives destroy the regularity of the polyester molecular chain itself, reduce the strong interaction between the molecular chains, and thus improve the flow properties of the copolyester molecular chain; the introduced diol II component contains a flexible chain segment of a certain length, has a low flow activation energy, can enhance the flow characteristics, and thus further improves the flow properties of the polyester, and the intrinsic viscosity and molecular weight of the PET are not affected. Compared with conventional PET, by introducing two modified components, the flow activation energy is significantly reduced under their joint action, the flow properties are significantly improved, the interaction between the copolyester melt and the tube wall during the flow process is reduced, and the melt viscosity is effectively controlled. The melt index of the present invention is improved, that is, the flow properties are improved, and the mechanical properties are not lost while the polyester flow properties are improved; the process is simple, the cost is low, the prepared copolymer material has excellent flow properties, wherein the content of the high flow component is high, and these components are rich in flexible segments, so that the copolyester can be directly used as a polyester blending modified material, and has good application prospects.

[0080] The above-mentioned implementation modes are only preferred implementation modes of the present application and cannot be used to limit the scope of protection of the present application. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present application shall fall within the scope of protection required by the present application.

Claims

1. A high-fluidity high-melting-point polyester copolymer material, characterized in that: The invention comprises terephthalic acid, diol I, diol II, aromatic dicarboxylic acid or its derivatives and ethylene glycol antimony catalyst. The terephthalic acid, diol I, aromatic dicarboxylic acid or its derivatives and ethylene glycol antimony catalyst are mixed evenly and then subjected to esterification reaction. After the esterification reaction is completed, diol II is introduced to carry out pre-polycondensation reaction and final polycondensation reaction to obtain a high-fluidity high-melting-point polyester copolymer material. The aromatic dicarboxylic acid or its derivative reacts with an excess of diol I in the esterification stage to be connected to the polyester molecular chain. The diol II is attached with a flexible chain segment. The diol II is connected to the polyester molecular chain through a polycondensation reaction to form a high-fluidity high-melting-point polyester copolymer material with aliphatic flexible chain segments.

2. A high-fluidity high-melting-point polyester copolymer material according to claim 1, characterized in that: The aromatic dicarboxylic acid or its derivative is at least one of terephthalic acid, isophthalic acid, adipic acid, succinic acid, 2,2-dimethylvaleric acid and 1,1-cyclohexanediacetic acid.

3. A high-fluidity high-melting-point polyester copolymer material according to claim 1, characterized in that: The diol II is at least one of ethylene glycol, propylene glycol, butylene glycol, pentanediol, polyethylene glycol, and cyclohexanedimethanol.

4. A high-fluidity high-melting-point polyester copolymer material according to claim 3, characterized in that: The diol I is the same as the diol II or is at least one of the diols used for synthesizing polyester except the diol II.

5. A high-fluidity high-melting-point polyester copolymer material according to claim 1, characterized in that: The molar ratio of the diol I to the terephthalic acid is greater than 1.

6. A method for preparing a high-fluidity high-melting-point polyester copolymer material according to any one of claims 1 to 5, the preparation method comprising: S1. preparing slurry: mixing terephthalic acid, diol I, aromatic dicarboxylic acid or its derivative and ethylene glycol antimony catalyst to prepare slurry; S2, esterification reaction: subjecting the slurry obtained in step S1 to esterification reaction; S3, polycondensation reaction: after the reaction in step S2 is completed, diol II with a flexible chain segment is introduced to carry out a preliminary polycondensation reaction and a final polycondensation reaction to obtain a high-fluidity, high-melting-point polyester copolymer material with aliphatic flexible chain segments.

7. The method for preparing a high-fluidity high-melting-point polyester copolymer material according to claim 8, characterized in that: The beating and mixing time in step S1 is 0.1 to 0.5 h.

8. The method for preparing a high-fluidity high-melting-point polyester copolymer material according to claim 9, characterized in that: The addition amount of the ethylene glycol antimony catalyst is 20 to 200 ppm of the total mass of the aromatic dicarboxylic acid or its derivative and terephthalic acid.

9. The method for preparing a high-fluidity high-melting-point polyester copolymer material according to claim 8, characterized in that: In the step S2, an aromatic dicarboxylic acid or its derivative and diol I are subjected to an esterification reaction under the action of an ethylene glycol antimony catalyst to evaporate the generated water; the reaction temperature is 220-280° C., the esterification pressure is normal pressure-0.4 MPa, and the reaction time is 1.5-3.0 h, ensuring that the esterification rate reaches more than 96%. When the distilled water amount is 90-98% of the theory, the esterification reaction is terminated.

10. The method for preparing a high-fluidity high-melting-point polyester copolymer material according to claim 8, characterized in that: In the step S3, the pre-polycondensation reaction temperature is 260-300° C., the vacuum degree is 30-3000 Pa, and the reaction time is 0.5-3.5 h. The final polycondensation reaction temperature is 270-300° C., the vacuum degree is 30-240 Pa, and the reaction time is 1.0-3.5 h.

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