TPU material with high dimensional stability and preparation method thereof

Abstract

The present invention relates to the field of polyurethane technology, and discloses a TPU material with high dimensional stability and a preparation method thereof. The TPU material of the present invention includes 100 parts by weight of polyurethane and 1.5-6 parts by weight of grafted polyester fibers; the grafted polyester fiber surface contains a large amount of hydroxyl and imino groups, which can form hydrogen bonds with the carbamate groups of the polyurethane, thereby improving the interfacial bonding strength of the polyester fiber and the polyurethane, and the compatibility of the two is better. The polyester fiber can be more evenly dispersed in the TPU material, significantly improving the tensile strength and mechanical properties of the material. The polyester fiber is grafted with a high-temperature resistant imide ring structure, which is added to the polyurethane to improve the heat resistance of the material, help increase the initial thermal decomposition temperature, and enhance high-temperature dimensional stability.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane, in particular to a TPU material with high dimensional stability and a preparation method thereof. Background Art

[0002] Polyurethane is a high-performance polymer resin material that is widely used in elastomers, foams, coatings and other materials. Ordinary polyurethane materials have problems such as low mechanical strength, easy deformation at high temperatures, and poor dimensional stability, which limit the practical application of polyurethane. Adding high-performance fibers such as wood fiber, polyethylene fiber, and glass fiber to polyurethane can effectively improve the mechanical strength, high-temperature resistance and other properties of polyurethane materials.

[0003] PET polyester fiber has good mechanical properties, high elasticity, and excellent heat resistance, and is widely used. Patent application with publication number CN116790202A discloses a self-adhesive waterproof membrane based on palm oil-based polyurethane. The polyurethane self-adhesive waterproof membrane, which uses PET fiber felt as a reinforcing material and is produced through a hot pressing process, has excellent tensile strength, tear strength and other properties. However, this patent does not solve the problem of poor high-temperature dimensional stability of polyurethane. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a TPU material with high dimensional stability and a preparation method thereof, which solves the problems of poor mechanical strength, heat resistance and dimensional stability of polyurethane.

[0005] The TPU material has high dimensional stability, and the TPU material comprises 100 parts by weight of polyurethane and 1.5-6 parts by weight of grafted polyester fiber.

[0006] The preparation method of the grafted polyester fiber comprises the following steps: adding the polyester fiber to a meta-cresol solution for swelling, taking out the fiber, washing it with acetone, then adding it to an acetone solution of benzophenone, taking out the fiber after soaking, adding it to an acetone solution of phthalimide monomer, placing it in a quartz tube, irradiating it under an ultraviolet lamp in a nitrogen atmosphere for grafting reaction, taking out the fiber, adding it to xylene, heating and stirring it, filtering it, washing it with acetone, and drying it to obtain the grafted polyester fiber.

[0007] Furthermore, the concentration of the benzophenone acetone solution is 0.1-0.25 mol / L.

[0008] Furthermore, the soaking time is 1-1.5 hours.

[0009] Furthermore, the power of the ultraviolet lamp is 100-200W.

[0010] Furthermore, the grafting reaction time is 1.5-3 hours.

[0011] Furthermore, the heating and stirring is performed at a temperature of 130-140° C. and for a time of 20-40 min.

[0012] Furthermore, the concentration of the acetone solution of the phthalimide monomer is 0.3-0.7 mol / L.

[0013] Furthermore, the preparation method of the phthalimide monomer is as follows: add 2-(4-aminophenyl)-2,3-dihydro-1H-isoindole-1,3-dione and glycidyl methacrylate to tetrahydrofuran, heat to 50-60°C, stir and react for 5-8 hours, distill under reduced pressure, wash the product with petroleum ether, and then recrystallize from dichloromethane to obtain the phthalimide monomer. The preparation reaction is as follows:

[0014] .

[0015] Furthermore, the molar ratio of 2-(4-aminophenyl)-2,3-dihydro-1H-isoindole-1,3-dione and glycidyl methacrylate is (1-1.1):1.

[0016] The preparation method of the TPU material with high dimensional stability is as follows: polyurethane and grafted polyester fiber are mixed, placed in an open mill for mixing, and discharged to obtain the TPU material with high dimensional stability.

[0017] Furthermore, the mixing is performed at 150-160° C. for 30-50 minutes.

[0018] The beneficial technical effects of the present invention are as follows: polyester fiber is modified by UV grafting with phthalimide monomer to obtain grafted polyester fiber, which is then mixed with polyurethane to obtain a TPU material with high dimensional stability. The surface of the grafted polyester fiber contains a large number of hydroxyl groups and imine groups, which can form hydrogen bonds with the carbamate groups of the polyurethane, thereby improving the interfacial bonding strength between the polyester fiber and the polyurethane, and the compatibility between the two is better. The polyester fiber can be more evenly dispersed in the TPU material, significantly improving the tensile strength and mechanical properties of the material.

[0019] The polyester fiber of the present invention is grafted with a high-temperature resistant imide ring structure and is added to polyurethane to improve the heat resistance of the material, help increase the initial thermal decomposition temperature, and enhance the dimensional stability at high temperatures. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0021] The following polyurethane, model A92P4637, was sourced from Dongguan Chengjin Plastics Co., Ltd. The polyester fiber was PET polyester fiber with a diameter of 10-25 μm and a length of approximately 6 mm, sourced from Shandong Tonghui Glass Fiber Co., Ltd.

[0022] Example 1: A method for preparing a TPU material with high dimensional stability, comprising the following steps:

[0023] (1) Add 80 mmol of 2-(4-aminophenyl)-2,3-dihydro-1H-isoindole-1,3-dione (CAS No. 21835-60-9) and 80 mmol of glycidyl methacrylate to 200 mL of tetrahydrofuran, heat to 50°C, stir and react for 8 hours, distill under reduced pressure, wash the product with petroleum ether, and then recrystallize from dichloromethane to obtain phthalimide monomer.

[0024] (2) 200 g of polyester fiber was added to 3 L of m-cresol solution and swelled at 60 ° C for 2 h. The fiber was taken out, washed with acetone, and then added to an acetone solution of benzophenone with a concentration of 0.1 mol / L and soaked for 1 h. The fiber was taken out and added to an acetone solution of phthalimide monomer with a concentration of 0.3 mol / L. The fiber was placed in a quartz tube and irradiated under a 150 W ultraviolet lamp in a nitrogen atmosphere for grafting reaction for 1.5 h. The fiber was taken out and added to xylene, heated to 130 ° C, stirred for 30 min, filtered, washed with acetone, and dried to obtain grafted polyester fiber.

[0025] (3) 10 kg of polyurethane and 0.15 kg of grafted polyester fiber were mixed, placed in an open mill, mixed at 160 ° C for 30 minutes, and discharged to obtain a TPU material with high dimensional stability.

[0026] Example 2: A method for preparing a TPU material with high dimensional stability, comprising the following steps:

[0027] (1) Add 88 mmol of 2-(4-aminophenyl)-2,3-dihydro-1H-isoindole-1,3-dione and 80 mmol of glycidyl methacrylate to 250 mL of tetrahydrofuran, heat to 60 °C, and stir to react for 5 h. During the reaction, condense and reflux. After vacuum distillation, wash the product with petroleum ether and then recrystallize it from dichloromethane to obtain phthalimide monomer.

[0028] (2) 200 g of polyester fiber was added to 4 L of m-cresol solution and swelled at 60 ° C for 2 h. The fiber was taken out, washed with acetone, and then added to an acetone solution of benzophenone with a concentration of 0.2 mol / L and soaked for 1.5 h. The fiber was taken out and added to an acetone solution of phthalimide monomer with a concentration of 0.58 mol / L. The fiber was placed in a quartz tube and irradiated under a 200 W ultraviolet lamp in a nitrogen atmosphere for grafting reaction for 1.5 h. The fiber was taken out and added to xylene, heated to 140 ° C, stirred for 20 min, filtered, washed with acetone, and dried to obtain grafted polyester fiber.

[0029] (3) 10 kg of polyurethane and 0.3 kg of grafted polyester fiber were mixed, placed in an open mill, mixed at 160 ° C for 30 minutes, and discharged to obtain a TPU material with high dimensional stability.

[0030] Example 3: A method for preparing a TPU material with high dimensional stability, comprising the following steps:

[0031] (1) Phthalimide monomer was prepared according to the method of Example 1.

[0032] (2) 200 g of polyester fiber was added to 4 L of m-cresol solution and swelled at 55 ° C for 2.5 h. The fiber was taken out and washed with acetone. Then, it was added to an acetone solution of benzophenone with a concentration of 0.25 mol / L and soaked for 1.5 h. The fiber was taken out and added to an acetone solution of phthalimide monomer with a concentration of 0.7 mol / L. The fiber was placed in a quartz tube and irradiated under a 100 W ultraviolet lamp in a nitrogen atmosphere for grafting reaction for 3 h. The fiber was taken out and added to xylene, heated to 130 ° C, stirred for 40 min, filtered, washed with acetone, and dried to obtain grafted polyester fiber.

[0033] (3) 10 kg of polyurethane and 0.45 kg of grafted polyester fiber were mixed, placed in an open mill, mixed at 150 ° C for 50 min, and discharged to obtain a TPU material with high dimensional stability.

[0034] Example 4: A method for preparing a TPU material with high dimensional stability, comprising the following steps:

[0035] (1) Phthalimide monomer was prepared according to the method of Example 1.

[0036] (2) 200 g of polyester fiber was added to 4 L of m-cresol solution and swelled at 60 ° C for 2 h. The fiber was taken out, washed with acetone, and then added to an acetone solution of benzophenone with a concentration of 0.15 mol / L and soaked for 1 h. The fiber was taken out and added to an acetone solution of phthalimide monomer with a concentration of 0.43 mol / L. The fiber was placed in a quartz tube and irradiated under a 150 W ultraviolet lamp in a nitrogen atmosphere for grafting reaction for 3 h. The fiber was taken out and added to xylene, heated to 130 ° C, stirred for 40 min, filtered, washed with acetone, and dried to obtain grafted polyester fiber.

[0037] (3) 10 kg of polyurethane and 0.6 kg of grafted polyester fiber were mixed, placed in an open mill, mixed at 160 ° C for 40 minutes, and discharged to obtain a TPU material with high dimensional stability.

[0038] Comparative Example 1: 10 kg of polyurethane was placed in an open mill, mixed at 160° C. for 30 min, and discharged to obtain a TPU material.

[0039] Comparative Example 2: 10 kg of polyurethane and 0.15 kg of polyester fiber were mixed, placed in an open mill, mixed at 160° C. for 30 min, and discharged to obtain a TPU material.

[0040] Comparative Example 3: A method for preparing a TPU material, comprising the following steps:

[0041] (1) Add 200 g of polyester fiber to 3 L of m-cresol solution and swell at 60 ° C for 2 h. Take out the fiber, wash it with acetone, and then add it to a 0.1 mol / L benzophenone acetone solution and soak it for 1 h. Take out the fiber and add it to a 0.3 mol / L methacrylate glycidyl acetone solution. Place it in a quartz tube and irradiate it under a 150 W ultraviolet lamp in a nitrogen atmosphere for grafting reaction for 1.5 h. Take out the fiber and add it to xylene. Heat it to 130 ° C and stir it for 30 min. Filter it, wash it with acetone, and dry it to obtain grafted polyester fiber.

[0042] (2) 10 kg of polyurethane and 0.15 kg of grafted polyester fiber were mixed, placed in an open mill, mixed at 160 ° C for 30 minutes, and discharged to obtain TPU material.

[0043] Comparative Example 4: A method for preparing a TPU material, comprising the following steps:

[0044] (1) According to the method of the journal SYNTHETIC COMMUNICATIONS, 25(20), 3173-3180 (1995), the document "Selective Synthesis of New ω-Phalimidoalkyl (Meth)acrylic Esters" was used to prepare 2-methyl-2-acrylic acid-2-benzyl imide ethyl ester. 12mmol of potassium phthalimide (CAS No. 1074-82-4) and 2mmol of tetrabutylammonium bromide were added to 25mL of acetonitrile, and 5mL of 10mmol of 2-bromoethyl methacrylate (CAS No. 4513-56-8) was added dropwise. The mixture was heated to 60℃ and reacted for 13h. 100mL of water was added and the mixture was extracted with dichloromethane. The organic phase was dried over anhydrous magnesium sulfate, filtered, and the solution was distilled under reduced pressure. The mixture was separated by silica gel column chromatography and eluted with a mixed solution of petroleum ether and ethyl acetate to obtain 2-methyl-2-acrylic acid-2-benzyl imide ethyl ester. The structural formula is .

[0045] (2) 200 g of polyester fiber was added to 3 L of m-cresol solution and swelled at 60 ° C for 2 h. The fiber was taken out, washed with acetone, and then added to an acetone solution of 0.1 mol / L of benzophenone and soaked for 1 h. The fiber was taken out and added to an acetone solution of 2-methyl-2-acrylic acid-2-benzimide ethyl ester with a concentration of 0.3 mol / L. The fiber was placed in a quartz tube and irradiated under a 150 W ultraviolet lamp in a nitrogen atmosphere for grafting reaction for 1.5 h. The fiber was taken out and added to xylene, heated to 130 ° C, stirred for 30 min, filtered, washed with acetone, and dried to obtain grafted polyester fiber.

[0046] (3) 10 kg of polyurethane and 0.15 kg of grafted polyester fiber were mixed, placed in an open mill, mixed at 160 ° C for 30 min, and discharged to obtain TPU material.

[0047] TPU material was compression molded in a flat-plate vulcanizer at 160°C and 10 MPa pressure to produce specimens. Tensile properties were tested according to GB / T 1040.1-2018.

[0048] 10 mg of TPU material was weighed and placed in a thermogravimetric analyzer to test the thermal properties in a nitrogen atmosphere at a temperature range of 30-700°C.

[0049] The TPU material is made into a cube specimen, and the volume V1 is tested by the water displacement method. After drying, it is placed in an oven at 120°C for 48 hours, and then the volume V2 is tested by the water displacement method. The volume change rate W is calculated, W = (V2-V1) / V1×100%. The smaller the volume change rate W, the better the dimensional stability.

[0050] The performance test results of the TPU materials of each embodiment and comparative example were obtained by the above method, as shown in Table 1 below.

[0051] Table 1: Performance test results of TPU materials of various embodiments and comparative examples

[0052]

[0053] As shown in Table 1, the tensile strength of the TPU material of Comparative Example 1 is only 36.6 MPa, the initial thermal decomposition (mass loss 5%) temperature is only 284.9°C, and the volume change rate after high-temperature heat treatment reaches 3.12%. The heat resistance and high-temperature dimensional stability are poor.

[0054] The addition of polyester fiber to the TPU material in Comparative Example 2 resulted in a slight increase in the material's tensile strength. This was primarily due to the poor compatibility of polyester fiber with polyurethane and its poor dispersion within the material, resulting in a weak reinforcing effect. Furthermore, the TPU material had a low initial thermal decomposition temperature and a significant volume change rate after high-temperature heat treatment. The addition of polyester fiber did not significantly improve the TPU material's heat resistance or high-temperature dimensional stability.

[0055] In Examples 1 to 4, polyester fibers were modified by UV grafting using phthalimide monomers. A large number of hydroxyl groups and imine groups were introduced on the surface of the polyester fibers, which could form hydrogen bonds with the carbamate groups of the polyurethane, thereby improving the interfacial bonding strength between the polyester fibers and the polyurethane. The compatibility between the two was better, and the polyester fibers could be more evenly dispersed in the TPU material, significantly improving the tensile strength and mechanical properties of the material. In addition, the polyester fibers were grafted with a high-temperature resistant imide ring structure ( ) added to polyurethane can improve the heat resistance of the material, help increase the initial thermal decomposition temperature, and enhance high-temperature dimensional stability.

[0056] Comparative Example 3 utilizes conventional glycidyl methacrylate grafted polyester fiber, which does not contain hydroxyl groups and imino groups, and has a low hydrogen bonding force with polyurethane, making it difficult to effectively improve the interfacial bonding strength between the polyester fiber and the polyurethane, resulting in a weak reinforcing effect of the polyester fiber and a low tensile strength of the material. In addition, the initial thermal decomposition temperature of the TPU material is low, the volume change rate after high-temperature heat treatment is large, and the heat resistance and high-temperature dimensional stability are poor.

[0057] In Comparative Example 4, polyester fiber is grafted and modified using 2-methyl-2-acrylic acid-2-benzimide ethyl ester, which does not contain hydroxyl groups and imino groups, and has a low hydrogen bonding force with polyurethane, making it difficult to effectively improve the interfacial bonding strength between the polyester fiber and the polyurethane, resulting in a weak reinforcing effect of the polyester fiber and a low tensile strength of the material.

[0058] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. TPU material with high dimensional stability, characterized by: The TPU material comprises 100 parts by weight of polyurethane and 1.5-6 parts by weight of grafted polyester fiber; The preparation method of the grafted polyester fiber comprises the following steps: adding the polyester fiber to a meta-cresol solution for swelling, taking out the fiber, washing it, and then adding it to a benzophenone-acetone solution. After soaking, the fiber is taken out and added to an acetone solution of phthalimide monomer. The fiber is placed in a quartz tube and irradiated under an ultraviolet lamp in a nitrogen atmosphere for grafting reaction. The fiber is taken out and added to xylene. After heating and stirring, the fiber is filtered, washed, and dried to obtain the grafted polyester fiber. The structural formula of the phthalimide monomer is: 。 2. The TPU material with high dimensional stability according to claim 1, characterized in that The concentration of the benzophenone acetone solution is 0.1-0.25 mol / L.

3. The TPU material with high dimensional stability according to claim 1, characterized in that The soaking time is 1-1.5 hours.

4. The TPU material with high dimensional stability according to claim 1, characterized in that The power of the ultraviolet lamp is 100-200W.

5. The TPU material with high dimensional stability according to claim 1, characterized in that The grafting reaction time is 1.5-3 hours.

6. The TPU material with high dimensional stability according to claim 1, characterized in that The heating and stirring is performed at a temperature of 130-140° C. and for a time of 20-40 minutes.

7. The TPU material with high dimensional stability according to claim 1, characterized in that The concentration of the acetone solution of the phthalimide monomer is 0.3-0.7 mol / L.

8. The TPU material with high dimensional stability according to claim 1, characterized in that The preparation method of the phthalimide monomer comprises: adding 2-(4-aminophenyl)-2,3-dihydro-1H-isoindole-1,3-dione and glycidyl methacrylate in a molar ratio of (1-1.1):1 to tetrahydrofuran, heating to 50-60° C., stirring for reaction for 5-8 hours, performing reduced pressure distillation and washing the product, and then recrystallizing to obtain the phthalimide monomer.

9. The method for preparing a TPU material with high dimensional stability according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: mixing polyurethane and grafted polyester fibers, placing the mixture in an open mill for mixing, and discharging the mixture to obtain a TPU material with high dimensional stability.

10. The method for preparing a TPU material with high dimensional stability according to claim 9, characterized in that: The mixing is performed at 150-160° C. for 30-50 minutes.

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