TPU material with high dimensional stability and preparation method thereof

Abstract

The invention relates to the technical field of polyurethane, and discloses a TPU material with high dimensional stability and a preparation method thereof.The TPU material comprises, by weight, 100 parts of polyurethane and 1.5-6 parts of grafted polyester fibers; the surface of the grafted polyester fiber contains a large number of hydroxyl groups and imino groups, the hydroxyl groups and the imino groups can form hydrogen-bond interaction with carbamate groups of polyurethane, the interface bonding strength of the polyester fiber and the polyurethane is improved, the compatibility of the polyester fiber and the polyurethane is better, the polyester fiber can be more uniformly dispersed in a TPU material, and the tensile strength and the mechanical property of the material are remarkably improved. The polyester fiber is grafted with a high-temperature-resistant imide ring structure and is added into the polyurethane, so that the heat resistance of the material can be improved, the initial thermal decomposition temperature is favorably increased, and the high-temperature dimensional stability is enhanced.

Description

Technical Field

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

[0002] Polyurethane is a high-performance polymer resin material with excellent properties and is widely used in materials such as elastomers, foams, and coatings. Ordinary polyurethane materials have problems such as low mechanical strength, easy deformation at high temperatures, and poor dimensional stability, which limit the practical applications of polyurethane. Adding high-performance fibers, such as wood fibers, polyethylene fibers, and glass fibers, 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. The patent application with the publication number CN116790202A discloses a self-adhesive waterproof coil based on palm oil-based polyurethane. The polyurethane self-adhesive waterproof coil prepared by a hot pressing process with a PET fiber mat as the reinforcing material has good properties such as tensile strength and tear strength, but this patent does not solve the problems such as poor high-temperature dimensional stability of polyurethane. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a TPU material with high dimensional stability and a preparation method thereof, solving the problems of poor mechanical strength, heat resistance, and dimensional stability of polyurethane.

[0005] The TPU material with high dimensional stability, 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 is as follows: adding polyester fiber into m-cresol solution for swelling, taking out the fiber, washing with acetone, then adding it into an acetone solution of benzophenone, soaking and taking out the fiber, adding it into an acetone solution of phthalimide monomer, placing it in a quartz tube, under a nitrogen atmosphere, irradiating with ultraviolet light for grafting reaction, taking out the fiber, adding it into xylene, heating and stirring, then filtering, washing with acetone, and drying to obtain the grafted polyester fiber.

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

[0008] Further, the soaking time is 1 - 1.5 h.

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

[0010] Further, the grafting reaction time is 1.5 - 3 h.

[0011] Furthermore, the temperature of the heating and stirring is 130 - 140 °C, and the time is 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 h, wash the product with petroleum ether after reduced pressure distillation, and then recrystallize in dichloromethane to obtain the phthalimide monomer. The preparation reaction is as follows: 。

[0014] Furthermore, the molar ratio of 2-(4-aminophenyl)-2,3-dihydro-1H-isoindole-1,3-dione to glycidyl methacrylate is (1 - 1.1):1.

[0015] The preparation method of the TPU material with high dimensional stability is as follows: Mix polyurethane and grafted polyester fiber, place them in an open mill for kneading, and discharge to obtain the TPU material with high dimensional stability.

[0016] Furthermore, the kneading is carried out at 150 - 160 °C for 30 - 50 min.

[0017] The beneficial technical effects of the present invention: Using the phthalimide monomer to carry out ultraviolet graft modification on polyester fiber to obtain grafted polyester fiber, and then kneading it with polyurethane to obtain the TPU material with high dimensional stability. The surface of the grafted polyester fiber contains a large number of hydroxyl groups and imino groups, which can form hydrogen bond interactions with the urethane groups of polyurethane, thereby improving the interfacial bonding strength between polyester fiber and polyurethane, and their compatibility 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.

[0018] The polyester fiber of the present invention is grafted with a heat-resistant imide ring structure. When added to polyurethane, it can improve the heat resistance of the material, is beneficial to increasing the initial thermal decomposition temperature, and enhancing the dimensional stability at high temperatures. Specific Embodiments

[0019] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0020] The following polyurethane, model A92P4637, is sourced from Dongguan Chengjin Plasticizing Co., Ltd. The polyester fiber is 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.

[0021] Example 1: A method for preparing a TPU material with high dimensional stability, comprising the following steps: (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 h, wash the product with petroleum ether after vacuum distillation, and then recrystallize in dichloromethane to obtain the phthalimide monomer.

[0022] (2) Add 200 g of polyester fiber to 3 L of m-cresol solution, swell at 60 °C for 2 h, take out the fiber, wash with acetone, then add it to an acetone solution of benzophenone with a concentration of 0.1 mol / L, soak for 1 h, take out the fiber, add it to an acetone solution of phthalimide monomer with a concentration of 0.3 mol / L, place it in a quartz tube, and irradiate with ultraviolet light at a power of 150 W in a nitrogen atmosphere for grafting reaction for 1.5 h. Take out the fiber, add it to xylene, heat to 130 °C, stir for 30 min, filter, wash with acetone, and dry to obtain the grafted polyester fiber.

[0023] (3) Mix 10 kg of polyurethane and 0.15 kg of grafted polyester fiber, place it in an open mill, knead at 160 °C for 30 min, discharge to obtain the TPU material with high dimensional stability.

[0024] Example 2: A method for preparing a TPU material with high dimensional stability, comprising the following steps: (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, stir and react for 5 h, carry out condensation reflux during the reaction, wash the product with petroleum ether after vacuum distillation, and then recrystallize in dichloromethane to obtain the phthalimide monomer.

[0025] (2) Add 200 g of polyester fiber to 4 L of m-cresol solution, swell it at 60 °C for 2 h, take out the fiber, wash it with acetone, then add it to an acetone solution of benzophenone with a concentration of 0.2 mol / L, soak it for 1.5 h, take out the fiber, add it to an acetone solution of phthalimide monomer with a concentration of 0.58 mol / L, place it in a quartz tube, irradiate it under a UV lamp with a power of 200 W in a nitrogen atmosphere for grafting reaction for 1.5 h, take out the fiber, add it to xylene, heat it to 140 °C, stir for 20 min, filter, wash it with acetone, and dry it to obtain grafted polyester fiber.

[0026] (3) Mix 10 kg of polyurethane and 0.3 kg of grafted polyester fiber, place it in an open mill, knead it at 160 °C for 30 min, discharge it to obtain a TPU material with high dimensional stability.

[0027] Example 3: A method for preparing a TPU material with high dimensional stability, comprising the following steps: (1) Prepare phthalimide monomer according to the method of Example 1.

[0028] (2) Add 200 g of polyester fiber to 4 L of m-cresol solution, swell it at 55 °C for 2.5 h, take out the fiber, wash it with acetone, then add it to an acetone solution of benzophenone with a concentration of 0.25 mol / L, soak it for 1.5 h, take out the fiber, add it to an acetone solution of phthalimide monomer with a concentration of 0.7 mol / L, place it in a quartz tube, irradiate it under a UV lamp with a power of 100 W in a nitrogen atmosphere for grafting reaction for 3 h, take out the fiber, add it to xylene, heat it to 130 °C, stir for 40 min, filter, wash it with acetone, and dry it to obtain grafted polyester fiber.

[0029] (3) Mix 10 kg of polyurethane and 0.45 kg of grafted polyester fiber, place it in an open mill, knead it at 150 °C for 50 min, discharge it to obtain a TPU material with high dimensional stability.

[0030] Example 4: A method for preparing a TPU material with high dimensional stability, comprising the following steps: (1) Prepare phthalimide monomer according to the method of Example 1.

[0031] (2) Add 200 g of polyester fiber to 4 L of m-cresol solution, swell it at 60 °C for 2 h, take out the fiber, wash it with acetone, then add it to an acetone solution of benzophenone with a concentration of 0.15 mol / L, soak it for 1 h, take out the fiber, add it to an acetone solution of phthalimide monomer with a concentration of 0.43 mol / L, place it in a quartz tube, under a nitrogen atmosphere, irradiate it with a UV lamp with a power of 150 W for 3 h for grafting reaction, take out the fiber, add it to xylene, heat it to 130 °C, stir for 40 min, filter, wash with acetone, and dry to obtain grafted polyester fiber.

[0032] (3) Mix 10 kg of polyurethane and 0.6 kg of grafted polyester fiber, place them in an open mill, knead at 160 °C for 40 min, discharge to obtain a TPU material with high dimensional stability.

[0033] Comparative Example 1: Place 10 kg of polyurethane in an open mill, knead at 160 °C for 30 min, discharge to obtain a TPU material.

[0034] Comparative Example 2: Mix 10 kg of polyurethane and 0.15 kg of polyester fiber, place them in an open mill, knead at 160 °C for 30 min, discharge to obtain a TPU material.

[0035] Comparative Example 3: The preparation method of the TPU material includes the following steps: (1) Add 200 g of polyester fiber to 3 L of m-cresol solution, swell it at 60 °C for 2 h, take out the fiber, wash it with acetone, then add it to an acetone solution of benzophenone with a concentration of 0.1 mol / L, soak it for 1 h, take out the fiber, add it to an acetone solution of glycidyl methacrylate with a concentration of 0.3 mol / L, place it in a quartz tube, under a nitrogen atmosphere, irradiate it with a UV lamp with a power of 150 W for 1.5 h for grafting reaction, take out the fiber, add it to xylene, heat it to 130 °C, stir for 30 min, filter, wash with acetone, and dry to obtain grafted polyester fiber.

[0036] (2) Mix 10 kg of polyurethane and 0.15 kg of grafted polyester fiber, place them in an open mill, knead at 160 °C for 30 min, discharge to obtain a TPU material.

[0037] Comparative Example 4: The preparation method of the TPU material includes the following steps: (1)2-(Phthalimido)ethyl methacrylate was prepared according to the method described in the journal SYNTHETIC COMMUNICATIONS, 25(20), 3173 - 3180 (1995), the literature "Selective Synthesis of New ω-Phalimidoalkyl (Meth)acrylic Esters". 12 mmol of potassium phthalimide (CAS No. 1074 - 82 - 4) and 2 mmol of tetrabutylammonium bromide were added to 25 mL of acetonitrile. 5 mL of a solution containing 10 mmol of 2-bromoethyl methacrylate (CAS No. 4513 - 56 - 8) was added dropwise. The mixture was heated to 60 °C and reacted for 13 h. 100 mL 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. It was separated by silica gel column chromatography and eluted with a mixed solution of petroleum ether and ethyl acetate to obtain 2-(Phthalimido)ethyl methacrylate. The structural formula is .

[0038] (2)200 g of polyester fiber was added to 3 L of m-cresol solution and swollen 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 2-(Phthalimido)ethyl methacrylate with a concentration of 0.3 mol / L. It was placed in a quartz tube and irradiated under an ultraviolet lamp with a power of 150 W in a nitrogen atmosphere for 1.5 h for grafting reaction. The fiber was taken out, added to xylene, heated to 130 °C, stirred for 30 min, filtered, washed with acetone, and dried to obtain grafted polyester fiber.

[0039] (3)10 kg of polyurethane and 0.15 kg of grafted polyester fiber were mixed and kneaded on an open mill at 160 °C for 30 min, and then discharged to obtain TPU material.

[0040] The TPU material was molded by compression molding in a flat vulcanizing machine at 160 °C under a pressure of 10 MPa to make specimens. The tensile properties were tested according to the standard of GB / T 1040.1 - 2018.

[0041] 10 mg of the TPU material was weighed and placed in a thermogravimetric analyzer to test the thermal properties in a nitrogen atmosphere, and the test temperature range was 30 - 700 °C.

[0042] The TPU material was made into cube specimens. The volume V1 was measured by the drainage method. After drying, it was placed in an oven at 120 °C for 48 h, and then the volume V2 was measured by the drainage method. The volume change rate W was calculated, W = (V2 - V1) / V1 × 100%. The smaller the volume change rate W, the better the dimensional stability.

[0043] The performance test results of the TPU materials of each example and comparative example were obtained by the above methods, as shown in Table 1 below.

[0044] Table 1: Performance test results of the TPU materials of each example and comparative example

[0045] As can be seen from Table 1, the tensile strength of the TPU material in Comparative Example 1 was only 36.6 MPa, the initial thermal decomposition (5% mass loss) temperature was only 284.9 °C, and the volume change rate after high-temperature heat treatment reached 3.12%, with poor heat resistance and high-temperature dimensional stability.

[0046] Polyester fibers were added to the TPU material in Comparative Example 2, and the tensile strength of the material was slightly improved. This was mainly because the compatibility between polyester fibers and polyurethane was poor, and the dispersion in the material was not good, resulting in a weak reinforcing effect of the polyester fibers. Moreover, the initial thermal decomposition temperature of the TPU material was low, and the volume change rate after high-temperature heat treatment was large. Adding polyester fibers did not improve the heat resistance and high-temperature dimensional stability of the TPU material well.

[0047] In Examples 1 to 4, phthalimide monomers were used to carry out ultraviolet graft modification on polyester fibers, and a large number of hydroxyl groups and imino groups were introduced on the surface of the polyester fibers, which could form hydrogen bond interactions with the urethane groups of polyurethane, thereby improving the interfacial bonding strength between polyester fibers and 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. Moreover, the polyester fibers were grafted with a high-temperature-resistant imide ring structure ( ) added to polyurethane could improve the heat resistance of the material, be conducive to increasing the initial thermal decomposition temperature, and enhancing the high-temperature dimensional stability.

[0048] In Comparative Example 3, conventional glycidyl methacrylate-grafted polyester fibers were used, which did not contain hydroxyl groups and imino groups, had a low hydrogen bond force with polyurethane, and it was difficult to effectively improve the interfacial bonding strength between polyester fibers and polyurethane, resulting in a weak reinforcing effect of the polyester fibers and a low tensile strength of the material. Moreover, the initial thermal decomposition temperature of the TPU material was low, and the volume change rate after high-temperature heat treatment was large, with poor heat resistance and high-temperature dimensional stability.

[0049] In Comparative Example 4, 2-benzoyl imidazole ethyl-2-methyl-2-acrylate was used to graft-modify polyester fibers, which did not contain hydroxyl groups and imino groups, had a low hydrogen bond force with polyurethane, and it was difficult to effectively improve the interfacial bonding strength between polyester fibers and polyurethane, resulting in a weak reinforcing effect of the polyester fibers and a low tensile strength of the material.

[0050] The specific embodiments described above further elaborate on the object, technical solution, and beneficial effects of the present invention. 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 replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A TPU material with high dimensional stability, characterized in that, The TPU material includes 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 is as follows: Add the polyester fiber into m-cresol solution for swelling, take out the fiber, wash it, then add it into the acetone solution of benzophenone, soak it and take out the fiber, add it into the acetone solution of phthalimide monomer, place it in a quartz tube, under a nitrogen atmosphere, irradiate it under an ultraviolet lamp for grafting reaction, take out the fiber, add it into xylene, heat and stir, then filter, wash and dry to obtain the grafted polyester fiber; The structural formula of the phthalimide monomer is: 。 2. The high-dimension-stability TPU material according to claim 1, wherein The concentration of the acetone solution of benzophenone is 0.1 - 0.25 mol / L.

3. The high-dimension-stability TPU material according to claim 1, wherein The soaking time is 1 - 1.5 h.

4. The high-dimension-stability TPU material according to claim 1, wherein The power of the ultraviolet lamp is 100 - 200 W.

5. The high-dimension-stability TPU material according to claim 1, wherein The grafting reaction time is 1.5 - 3 h.

6. The high-dimension-stability TPU material according to claim 1, wherein, The temperature of the heating and stirring is 130 - 140 °C, and the time is 20 - 40 min.

7. The high-dimension-stability TPU material according to claim 1, wherein The concentration of the acetone solution of phthalimide monomer is 0.3 - 0.7 mol / L.

8. The high-dimension-stability TPU material according to claim 1, wherein The preparation method of the phthalimide monomer is: Add 2-(4-aminophenyl)-2,3-dihydro-1H-isoindole-1,3-dione and glycidyl methacrylate with a molar ratio of (1 - 1.1):1 into tetrahydrofuran, heat to 50 - 60 °C, stir and react for 5 - 8 h, carry out vacuum distillation, wash the product, and then recrystallize to obtain the phthalimide monomer.

9. The preparation method of the TPU material with high dimensional stability according to any one of claims 1-8, characterized in that, The preparation method is: Mix the polyurethane and the grafted polyester fiber, place them in an open mill for mixing, discharge the material to obtain the TPU material with high dimensional stability.

10. The preparation method of the TPU material with high dimensional stability according to claim 9, characterized in that, The mixing is carried out at 150 - 160 °C for 30 - 50 min.

Images