Preparation method and application of high-melting-point high-strength thermoplastic polyester elastomer

Abstract

The invention relates to the field of thermoplastic polyester elastomer materials, in particular to a preparation method and application of a high-melting-point high-strength thermoplastic polyester elastomer, the preparation method comprises the following steps: S1, mixing: adding an antioxidant, a catalyst and BDO into a mixing kettle, and stirring for 20-30 minutes at 160-200 DEG C to obtain a mixing kettle product; s2, pre-polycondensation: putting the material mixing kettle product obtained in the step S1 into a pre-polycondensation kettle, pumping molten polyester, polyether and a modifier into the pre-polycondensation kettle after passing through a pipeline, stirring for 20-30 minutes, heating to 230-250 DEG C, and reacting for 1-3 hours under the pressure of-0.4 kg / cm < 2 > to-0.7 kg / cm < 2 >, so as to obtain a prepolymer; and S3, polycondensation: pumping the prepolymer obtained in the step S2 into a polycondensation kettle, reacting at 240-260 DEG C for 1-3 hours under the vacuum degree of 20-50 Pa, and carrying out cold cutting and grain-sized dicing to obtain the high-melting-point high-strength thermoplastic polyester elastomer. The high-melting-point and high-strength thermoplastic polyester elastomer produced by the invention not only has higher melting point and melt strength and excellent mechanical properties, but also has more stable processability and can be applied to preparation of air fiber mats.

Description

Technical Field

[0001] The present invention relates to the field of thermoplastic polyester elastomer materials, and specifically relates to a preparation method and application of a high-melting-point and high-strength thermoplastic polyester elastomer. Background Art

[0002] Thermoplastic polyester elastomer (TPEE) is a block copolymer formed by polymerizing a polyester hard segment with good crystallinity and a polyether or polyester soft segment. The hard segment endows TPEE with outstanding strength, good high-temperature resistance, oil resistance, creep resistance, solvent resistance and impact resistance, while the soft segment endows TPEE with excellent low-temperature resistance and anti-aging properties. The performance characteristics presented by this unique structure have enabled TPEE to achieve rapid development and application in fields such as automotive, electronic and electrical, industrial products, and sports goods. However, most of the TPEE synthesized on the market at present have characteristics such as high processing fluidity, low melt viscosity and low melt strength, which lead to relatively harsh processing conditions and limit the application fields of TPEE. Therefore, TPEE materials with high melting points have gradually attracted attention.

[0003] Patent CN115340752B discloses a high-melting-point and high-melt-strength thermoplastic polyester elastomer material and its preparation method. This material is prepared from the following components: TPEE resin, isocyanate monomer, polyester polyol, catalyst, antioxidant. This invention increases the melting point, melt strength and mechanical properties of TPEE by introducing heat-resistant groups and molecular chain extension, and uses a one-step reactive extrusion technology to prepare a high-melting-point and high-melt-strength TPEE material with good processing performance. However, the content of hydroxyl active groups on the TPEE resin is relatively low, and the reactivity with polyisocyanate and polyester polyol may not be good, resulting in failure to achieve the best modification effect.

[0004] Patent CN102786676B discloses a polyester elastomer containing a branched structure and its preparation method. This material is prepared from the following components: polyester hard segment, polyether soft segment, polyfunctional epoxide; its preparation method includes the following steps: sequentially carrying out an esterification reaction or transesterification reaction and a polycondensation reaction on an aromatic dicarboxylic acid or its esterification derivative, an aliphatic diol, and a polyether copolymer to obtain a prepolyester elastomer; then adding a polyfunctional epoxide for reaction to obtain a polyester elastomer containing a branched structure. This invention obtains a polyester elastomer with better appearance quality by introducing a branched polyether into the polyester system, and the processing process is relatively easy, with excellent mechanical properties, and its reaction is easier to control, and gels are not easily formed during the reaction process. However, the reaction activity of the polyfunctional epoxide is relatively high, difficult to control, and prone to unstable melt processing performance.

[0005] Therefore, there is an urgent need in the market for a thermoplastic polyester elastomer that not only has a relatively high melting point and melt strength but also has relatively stable processing performance. Summary of the Invention

[0006] Aiming at the problems existing in the prior art, the object of the present invention is to provide a thermoplastic polyester elastomer that not only has a high melting point, melt strength, excellent mechanical properties, but also has relatively stable processing properties.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] On the one hand, the present invention provides a preparation method of a high melting point and high strength thermoplastic polyester elastomer, comprising the following steps:

[0009] S1. Mixing: Add antioxidant, catalyst, and BDO into the mixing kettle, stir at 160 - 200 °C for 20 - 30 min to obtain the product in the mixing kettle;

[0010] S2. Pre - polycondensation: Put the product in the mixing kettle obtained in step S1 into the pre - polycondensation kettle, then pump the molten polyester, polyether, and modifier through the pipeline and suck them into the pre - polycondensation kettle for stirring for 20 - 30 min, heat up to 230 - 250 °C, and react at a pressure of - 0.4~ - 0.7 kg / cm 2 for 1 - 3 h to obtain the prepolymer;

[0011] S3. Polycondensation: Pump the prepolymer obtained in step S2 into the polycondensation kettle, react at 240 - 260 °C for 1 - 3 h, with a vacuum degree of 20 - 50 Pa, cool and pelletize to obtain the high melting point and high strength thermoplastic polyester elastomer.

[0012] Preferably, the mass ratio of the polyester to BDO is 1:(1 - 3).

[0013] In some embodiments, the feeding method in step A2 is alternate feeding by two mixing kettles.

[0014] Currently, the mainstream TPEE is prepared by the reaction of terephthalic acid, BDO, and polyether. A large amount of tetrahydrofuran is generated during the esterification stage of terephthalic acid, which is highly harmful to the human body. By directly reacting polyester and polyether to prepare TPEE in this application, the production of THF can be significantly reduced, the harm to people can be reduced, and at the same time, the production cost can be reduced, the reaction time can be shortened, and the production efficiency can be improved. By using the continuous method to produce TPEE in this application, not only can the stable production of products be realized, the production efficiency be improved, the production process flow and cycle be shortened, the energy consumption be reduced, the pollution be reduced, and large - scale production be easily achieved, but also the occurrence of side reactions can be inhibited, the positive reaction rate of esterification can be increased, and the product yield can be increased. And the continuous polymerization method is more conducive to the regulation of the structure of TPEE, ensuring the stability of the TPEE structure.

[0015] In some embodiments, the temperature of the pipeline is 220 - 240 °C.

[0016] By limiting the temperature of the pipeline, the stability of the polymerization reaction can be ensured, the preliminary work can be reduced, which is beneficial to the stable production of products and the improvement of production efficiency.

[0017] In some embodiments, the polyester is PBT or PET.

[0018] Preferably, the PET is recycled PET.

[0019] Recycled PET is of great environmental, economic and social significance for reducing plastic pollution, saving resources and reducing greenhouse gas emissions. However, recycled PET obtained through operations such as high-temperature melting often has problems such as molecular chain breakage and low molecular weight, resulting in unstable performance, which in turn affects the performance of products and limits the application of recycled PET. In this application, recycled PET can be selected as the polyester to react with BDO to generate PBT, which can convert the broken-chain PET into long-chain PBT segments, making full use of recycled PET and saving the production cost of TPEE.

[0020] In some embodiments, the mass ratio of the polyester to the polyether is 1:(0.4 - 0.7).

[0021] In some embodiments, the mass ratio of the polyester to the modifier is 1:(0.1 - 0.4).

[0022] The introduction of a crosslinked structure may affect the flexibility of the polyester elastomer. In this application, by selecting specific ratios of polyester, polyether and modifier, the high-melting-point and high-strength thermoplastic polyester elastomer can have good flexibility while ensuring high melt strength.

[0023] In some embodiments, the antioxidant is one or more of antioxidant 1010, antioxidant 1076, and triphenyl phosphite.

[0024] Preferably, the antioxidant is antioxidant 1010.

[0025] In some embodiments, the catalyst is a composition of tetrabutyl titanate and magnesium acetate, and the mass ratio of the two is 1:(0.3 - 0.6).

[0026] In some embodiments, the preparation method of the modifier comprises the following steps:

[0027] A1. Add IPDI trimer, PTMG, and dibutyltin dilaurate to a reaction vessel, and react at 25 - 35 °C for 2 - 4 h to obtain a compound;

[0028] A2. Add PCDL to the compound obtained in step A1 and react at 70 - 80 °C for 1 - 2 h to obtain a modifier.

[0029] In this application, an IPDI trimer and PTMG are first reacted to prepare a compound containing active NCO groups, and then the compound is reacted with PCDL to obtain a modifier containing both polyether segments and polycarbonate segments. Introducing this modifier into the segments of the polyester elastomer can improve the mechanical properties, processing properties, and elasticity of the thermoplastic polyester elastomer. This may be because, on the one hand, the thermoplastic polyester elastomer contains more cyclic structures, which can enhance the mechanical properties and melt strength of the thermoplastic polyester elastomer; on the other hand, the modifier segment contains three hydroxyl groups, which can undergo transesterification reactions with PBT to construct a network structure in the thermoplastic polyester elastomer, and this network structure is distributed in the soft segment region, which can improve the mechanical properties and processing properties of the thermoplastic polyester elastomer while ensuring the flexibility of TPEE itself; thirdly, the polycarbonate segment itself has good toughness, rigidity, and heat resistance, which can further improve the various properties of TPEE.

[0030] In some embodiments, the mass ratio of the IPDI trimer to PTMG in step A1 is 1:(2.5 - 3.5).

[0031] In some embodiments, the mass ratio of the compound to PCDL in step A2 is 1:(1.5 - 2.5).

[0032] By selecting a specific ratio of IPDI trimer to PTMG in this application, sufficient NCO groups can remain on the IPDI trimer to react with the compound, which is beneficial for the introduction of the polycarbonate segment. And by limiting the ratio of PDI trimer to PCDL, no isocyanate groups remain in the modifier, preventing it from affecting the progress of the transesterification reaction.

[0033] On the other hand, the present invention provides an application of a high melting point and high strength thermoplastic polyester elastomer in an air fiber pad.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The present invention can significantly reduce the production of THF, reduce the harm to humans, lower the production cost, reduce the reaction time, and improve the production efficiency by directly reacting polyester and polyether to prepare TPEE. Moreover, by selecting the continuous method to produce TPEE, stable production of products can be achieved, production efficiency can be improved, the production process flow and cycle can be shortened, energy consumption can be reduced, pollution can be reduced, large-scale production is easy to realize, and the continuous polymerization method can inhibit the occurrence of side reactions, improve the rate of the forward esterification reaction, and increase the product yield. The continuous polymerization method is also more conducive to regulating the structure of TPEE and ensuring the stability of the TPEE structure.

[0036] 2. The present invention can select recycled PET as the polyester to react with BDO to generate PBT, which can convert the broken-chain PET into long-chain PBT segments, making full use of recycled PET and saving the cost of thermoplastic polyester materials.

[0037] 3. The present invention first prepares a compound containing active NCO groups by reacting IPDI trimer and PTMG, and then reacts the compound with PCDL to obtain a modifier containing both polyether segments and polycarbonate segments. Introducing this modifier into the segments of the polyester elastomer can improve the mechanical properties, processing properties, and flexibility of the thermoplastic polyester elastomer. Specific Embodiments

[0038] The following will illustrate the present invention in conjunction with specific implementation examples. It should be noted that the following examples are examples of the present invention, only used to illustrate the present invention, and not used to limit the present invention. Other combinations and various improvements within the concept of the present invention can be made without departing from the main idea or scope of the present invention.

[0039] In the following examples and comparative examples, except for the modifier, the relevant reagents used can be purchased from the market. Among them, the number-average molecular weight of PTMG is 2000; the number-average molecular weight of PCDL is 1000; the recycled PET is purchased from Chenyi (Shanghai) Renewable Resources Recycling Co., Ltd.; the PBT model is PX9406-701, purchased from Shanghai Yuangao Plasticization Technology Co., Ltd.

[0040] Preparation Example 1

[0041] The preparation method of modifier-1 includes the following steps:

[0042] A1. Add 10 g of IPDI trimer, 30 g of PTMG, and 0.1 g of dibutyltin dilaurate into a reaction vessel, and react at 30 °C for 3 h to obtain a compound;

[0043] A2. Add 20 g of PCDL to 10 g of the compound obtained in step A1, and react at 75 °C for 1.5 h to obtain modifier-1.

[0044] Preparation Example 2

[0045] The preparation method of modifier - 2 is the same as that of Preparation Example 1 in specific implementation manner, except that the addition amount of PTMG is 40 g.

[0046] Preparation Example 3

[0047] The preparation method of modifier - 3 is the same as that of Preparation Example 1 in specific implementation manner, except that the addition amount of PCDL is 10 g.

[0048] Example 1

[0049] A preparation method of a high - melting - point and high - strength thermoplastic polyester elastomer comprises the following steps:

[0050] S1. Mixing: Add 3 g of antioxidant 1010, 1 g of tetrabutyl titanate, 0.45 g of magnesium acetate, and 200 g of BDO into the mixing kettle. After stirring at 180 °C for 25 min, the product in the mixing kettle is obtained;

[0051] S2. Pre - polycondensation: Put the product in the mixing kettle obtained in step S1 into the pre - polycondensation kettle. The two mixing kettles alternate in feeding. Then, 100 g of molten recycled PET, 55 g of PTMG, and 25 g of modifier - 1 are pumped through a 230 °C pipeline and then drawn into the pre - polycondensation kettle. Stir for 25 min, raise the temperature to 240 °C, and react at a pressure of - 0.5 kg / cm 2 for 2 h to obtain a prepolymer;

[0052] S3. Polycondensation: Pump the prepolymer obtained in step S2 into the polycondensation kettle, react at 250 °C for 2 h, with a vacuum degree of 35 Pa, cool and pelletize to obtain a high - melting - point and high - strength thermoplastic polyester elastomer.

[0053] Example 2

[0054] A preparation method of a high - melting - point and high - strength thermoplastic polyester elastomer comprises the following steps:

[0055] S1. Mixing: Add 3 g of antioxidant 1010, 1 g of tetrabutyl titanate, 0.45 g of magnesium acetate, and 100 g of BDO into the mixing kettle. After stirring at 160 °C for 30 min, the product in the mixing kettle is obtained;

[0056] S2. Pre - polycondensation: Put all the products in the mixing kettle obtained in step S1 into the pre - polycondensation kettle. The two mixing kettles alternate in feeding. Then, 100 g of molten recycled PET, 40 g of PTMG, and 10 g of modifier - 1 are pumped through a 220 °C pipeline and then drawn into the pre - polycondensation kettle. Stir for 20 min, raise the temperature to 230 °C, and react at a pressure of - 0.4 kg / cm 2 for 3 h to obtain a prepolymer;

[0057] S3. Polycondensation: Pump the prepolymer obtained in step S2 into a polycondensation kettle, react at 240 °C for 3 h, with a vacuum degree of 20 Pa, cool and pelletize to obtain a high melting point and high strength thermoplastic polyester elastomer.

[0058] Example 3

[0059] A preparation method of a high melting point and high strength thermoplastic polyester elastomer, comprising the following steps:

[0060] S1. Mixing: Add 3 g of antioxidant 1010, 1 g of tetrabutyl titanate, 0.45 g of magnesium acetate, and 300 g of BDO into a mixing kettle, stir at 200 °C for 20 min to obtain a mixing kettle product;

[0061] S2. Pre-polycondensation: Put 200 g of the mixing kettle product obtained in step S1 into a pre-polycondensation kettle, alternately feed materials from two mixing kettles, then pump 100 g of molten recycled PET, 70 g of PTMG, and 40 g of modifier-1 through a pipeline at 240 °C and draw them into the pre-polycondensation kettle, stir for 20 min, raise the temperature to 250 °C, and react at a pressure of -0.7 kg / cm 2 for 1 h to obtain a prepolymer;

[0062] S3. Polycondensation: Pump the prepolymer obtained in step S2 into a polycondensation kettle, react at 260 °C for 1 h, with a vacuum degree of 50 Pa, cool and pelletize to obtain a high melting point and high strength thermoplastic polyester elastomer.

[0063] Example 4

[0064] A preparation method of a high melting point and high strength thermoplastic polyester elastomer, comprising the following steps:

[0065] S1. Mixing: Add 3 g of antioxidant 1010, 1 g of tetrabutyl titanate, 0.45 g of magnesium acetate, and 200 g of BDO into a mixing kettle, stir at 180 °C for 25 min to obtain a mixing kettle product;

[0066] S2. Pre-polycondensation: Put all the mixing kettle product obtained in step S1 into a pre-polycondensation kettle, alternately feed materials from two mixing kettles, then pump 100 g of molten PBT, 55 g of PTMG, and 25 g of modifier-1 through a pipeline at 230 °C and draw them into the pre-polycondensation kettle, stir for 25 min, raise the temperature to 240 °C, and react at a pressure of -0.5 kg / cm 2 for 2 h to obtain a prepolymer;

[0067] S3. Polycondensation: Pump the prepolymer obtained in step S2 into a polycondensation kettle, react at 250 °C for 2 h, with a vacuum degree of 35 Pa, cool and pelletize to obtain a high melting point and high strength thermoplastic polyester elastomer.

[0068] Example 5

[0069] A high melting point and high strength thermoplastic polyester elastomer and its preparation method. The specific implementation method is the same as that of Example 1, except that the addition amount of PTMG is 30 g.

[0070] Example 6

[0071] A high melting point and high strength thermoplastic polyester elastomer and its preparation method. The specific implementation method is the same as that of Example 1, except that the addition amount of modifier - 1 is 50 g.

[0072] Example 7

[0073] A high melting point and high strength thermoplastic polyester elastomer and its preparation method. The specific implementation method is the same as that of Example 1, except that modifier - 1 is replaced with modifier - 2 in equal amount.

[0074] Example 8

[0075] A high melting point and high strength thermoplastic polyester elastomer and its preparation method. The specific implementation method is the same as that of Example 1, except that modifier - 1 is replaced with modifier - 3 in equal amount.

[0076] Comparative Example 1

[0077] A high melting point and high strength thermoplastic polyester elastomer and its preparation method, comprising the following steps:

[0078] S1. Mixing: Add 3 g of antioxidant 1010, 1 g of tetrabutyl titanate, 0.45 g of magnesium acetate, and 200 g of BDO into the mixing kettle. After stirring at 180 °C for 25 min, the product in the mixing kettle is obtained;

[0079] S2. Pre - polycondensation: Put the product in the mixing kettle obtained in step S1 into the pre - polycondensation kettle. The two mixing kettles feed materials alternately. Then, 100 g of molten recycled PET and 55 g of PTMG are pumped through a pipeline at 230 °C and then drawn into the pre - polycondensation kettle, stirred for 25 min, heated to 240 °C, and reacted at a pressure of - 0.5 kg / cm 2 for 2 h to obtain a prepolymer;

[0080] S3. Polycondensation: Pump the prepolymer obtained in step S2 into the polycondensation kettle, react at 250 °C for 2 h, with a vacuum degree of 35 Pa, cool and pelletize to obtain a high melting point and high strength thermoplastic polyester elastomer.

[0081] Performance Test

[0082] The prepared high melting point and high strength thermoplastic polyester elastomer was tested. The test items and test methods are shown in Table 1:

[0083] Table 1

[0084]

[0085]

[0086] Table 2

[0087]

[0088] As can be seen from the data in Table 2, the high melting point and high strength thermoplastic polyester elastomers obtained in Examples 1-4 have relatively high melt strength and excellent mechanical properties. From the comparison between Example 5, 6 and Example 1, it can be seen that changing the ratio of polyester and polyether or polyester and modifier will reduce the flexibility of the polyester elastomer affected by the crosslinking structure; from the comparison between Example 7 and Example 1, it can be seen that after changing the ratio of IPDI trimer and PTMG, it is not easy to introduce polycarbonate segments, resulting in poor mechanical properties of the thermoplastic polyester elastomer; from the comparison between Example 8 and Example 1, it can be seen that changing the ratio of the compound and PCDL will cause residual isocyanate groups on the modifier, affecting the transesterification reaction and resulting in poor mechanical properties of the thermoplastic polyester elastomer; from the comparison between Comparative Example 1 and Example 1, it can be seen that without adding a modifier, the melt strength of the thermoplastic polyester elastomer is relatively low and the mechanical properties are poor.

[0089] The above embodiments are only used to illustrate the technical concept and characteristics of the present invention, and their purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it, and cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a high-melting-point and high-strength thermoplastic polyester elastomer, characterized in that: The following steps are involved: S1. Mixing: Add antioxidant, catalyst and BDO into a mixing kettle, stir at 160-200°C for 20-30 minutes, and obtain a mixing kettle product; S2, pre-condensation: the mixed kettle product obtained in step S1 is put into the pre-condensation kettle, and then the molten polyester, polyether and modifier are pumped through the pipeline into the pre-condensation kettle and stirred for 20-30 minutes, and the temperature is raised to 230-250°C, and the pressure is -0.4 to -0.7 kg / cm 2 The reaction was continued for 1-3 hours to obtain a prepolymer; S3, polycondensation: pump the prepolymer obtained in step S2 into a polycondensation reactor, react at 240-260° C. for 1-3 hours, with a vacuum degree of 20-50 Pa, cool and pelletize to obtain a high-melting-point and high-strength thermoplastic polyester elastomer.

2. The method for preparing a high-melting-point and high-strength thermoplastic polyester elastomer according to claim 1, characterized in that: The method of feeding in step S2 is to feed materials alternately into two mixing kettles.

3. The method for preparing a high melting point and high strength thermoplastic polyester elastomer according to claim 1, characterized in that: The temperature of the pipeline is 220-240°C.

4. The method for preparing a high-melting-point and high-strength thermoplastic polyester elastomer according to claim 1, characterized in that: The polyester is PBT or PET.

5. The method for preparing a high melting point and high strength thermoplastic polyester elastomer according to claim 1, characterized in that: The mass ratio of the polyester to the polyether is 1:(0.4-0.7).

6. The method for preparing a high-melting-point and high-strength thermoplastic polyester elastomer according to claim 1, characterized in that: The mass ratio of the polyester to the modifier is 1:(0.1-0.4).

7. The method for preparing a high-melting-point and high-strength thermoplastic polyester elastomer according to claim 1, characterized in that: The preparation method of the modifier comprises the following steps: A1. Add IPDI trimer, PTMG and dibutyltin dilaurate into a reaction vessel and react at 25-35° C. for 2-4 hours to obtain a compound; A2. Add PCDL to the compound obtained in step A1, and react at 70-80°C for 1-2h to obtain a modifier.

8. The method for preparing a high-melting-point and high-strength thermoplastic polyester elastomer according to claim 7, characterized in that: The mass ratio of IPDI trimer to PTMG in step A1 is 1:(2.5-3.5).

9. The method for preparing a high-melting-point and high-strength thermoplastic polyester elastomer according to claim 7, characterized in that: The mass ratio of the compound to PCDL in step A2 is 1:(1.5-2.5).

10. Use of the high melting point and high strength thermoplastic polyester elastomer obtained by the preparation method according to any one of claims 1 to 9 in air fiber mats.

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