High-strength impact-resistant TPU composite material and preparation method thereof

Abstract

The invention relates to the technical field of polyurethane, and discloses a high-strength impact-resistant TPU composite material and a preparation method, the high-strength impact-resistant TPU composite material comprises 60-85 parts by weight of polyurethane resin, 15-40 parts by weight of polyformaldehyde, and 1-4 parts by weight of hydroxyl polyurethane; the hydroxyl polyurethane is similar to a molecular main chain of polyurethane resin, a side chain contains hydroxyl, and the hydroxyl polyurethane and an ether bond of polyformaldehyde are subjected to hydrogen-bond interaction, so that the hydroxyl polyurethane plays a role in compatibilizing the polyurethane resin and the polyformaldehyde, the compatibility between the polyurethane resin and the polyformaldehyde is remarkably improved, and an alloy system with better mechanical properties is formed; the TPU composite material has higher tensile strength and keeps good impact strength; hydroxyl polyurethane contains a fused ring structure with high-temperature resistance and is not prone to thermal decomposition, the heat resistance of the TPU composite material is improved, and the initial thermal decomposition temperature is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane, specifically to a high-strength and impact-resistant TPU composite material and a preparation method thereof. Background Art

[0002] Polyurethane has the advantages of high toughness, good impact resistance, excellent weather resistance, etc., and is widely used in materials such as pipes, fibers, foams, and films. Ordinary polyurethane has problems such as low mechanical strength. Combining polyurethane with engineering plastics such as polyoxymethylene, nylon, and polyimide, the resulting alloy plastics have higher mechanical properties.

[0003] Polyoxymethylene has high strength, large modulus, and good wear resistance, and is widely used. However, the compatibility between polyoxymethylene and polyurethane is poor, and adding it to polyurethane will affect its toughness, impact strength and other properties. The patent application with the publication number CN118307949A discloses a thermoplastic polyurethane composite material, a preparation method and an application thereof. Using polymers containing epoxy groups such as acrylonitrile-styrene-glycidyl methacrylate as compatibilizers, blending thermoplastic polyurethane elastomer and polyoxymethylene, the resulting polyurethane composite material has good mechanical properties and excellent electrical conductivity. However, this patent application does not improve the impact strength and heat resistance of the polyoxymethylene-polyurethane material. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a high-strength and impact-resistant TPU composite material and a preparation method thereof, which solve the problems of poor compatibility between polyurethane and polyoxymethylene, and low mechanical strength of polyurethane.

[0005] The high-strength and impact-resistant TPU composite material of the present invention comprises 60-85 parts by weight of polyurethane resin, 15-40 parts by weight of polyoxymethylene, and 1-4 parts by weight of hydroxyl polyurethane.

[0006] The preparation method of the high-strength and impact-resistant TPU composite material phenol is as follows: (1) Add diisocyanate, 5,7-dihydroxy-4'-methoxyflavone, and dibutyltin dilaurate to a solvent, stir and react, after vacuum distillation, wash the product with ethanol, and dry to obtain methoxy polyurethane.

[0007] (2) Add methoxy polyurethane to dichloromethane, under a nitrogen atmosphere, dropwise add a dichloromethane solution containing boron tribromide, after the reaction, pour the solution into ice water, stir and filter, wash with water and ethanol, and dry to obtain hydroxyl polyurethane. The reaction formula is: .

[0008] (3) Mix polyurethane resin, polyoxymethylene, and hydroxyl polyurethane, add them to a twin-screw extruder, extrude, and pelletize to obtain a high-strength and impact-resistant TPU composite material.

[0009] Further, the solvent in (1) includes toluene, tetrahydrofuran, or dichloromethane.

[0010] Further, the reaction temperature in (1) is 60 - 80 °C, and the reaction time is 2 - 3 h.

[0011] Further, the molar ratio of diisocyanate, 5,7-dihydroxy-4'-methoxyflavone, and dibutyltin dilaurate in (1) is 1:(1 - 1.06):(0.05 - 0.07).

[0012] Further, the diisocyanate in (1) is diphenylmethane-4,4'-diisocyanate, toluene-2,4-diisocyanate, or isophorone diisocyanate.

[0013] Further, the mass ratio of methoxypolyurethane to boron tribromide in (2) is 100:(56 - 72).

[0014] Further, the reaction in (2) is first carried out at 0 - 5 °C for 2 - 3 h, and then at 15 - 25 °C for 8 - 12 h.

[0015] Further, the temperature of the 1 - 6 zones of the twin-screw extruder in (3) is 150 - 190 °C, and the screw speed is 200 - 300 r / min.

[0016] Beneficial effects: In the present invention, diisocyanate and 5,7-dihydroxy-4'-methoxyflavone are subjected to a polymerization reaction, and then demethylated by boron tribromide to obtain hydroxyl polyurethane containing a condensed ring structure and a large number of hydroxyl groups. Then, it is blended with polyurethane resin and polyoxymethylene to obtain a TPU composite material. The hydroxyl polyurethane has a molecular main chain similar to that of the polyurethane resin and contains hydroxyl groups in the side chain, which can form hydrogen bonds with the ether bonds of polyoxymethylene, enabling the hydroxyl polyurethane to play a role in compatibilizing the polyurethane resin and polyoxymethylene, significantly improving the compatibility between the two, forming an alloy system with better mechanical properties, making the TPU composite material have higher tensile strength and maintaining good impact strength. And the hydroxyl polyurethane contains a condensed ring structure with high-temperature resistance and is not easily thermally decomposed, which is beneficial to improving the heat resistance of the TPU composite material and increasing the initial thermal decomposition temperature. Specific embodiments

[0017] Next, in combination with the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0018] The following polyurethane resin model A92P4637 is sourced from Dongguan Chengjin Plastic Chemical Co., Ltd. The polyoxymethylene model POMAW-02 is purchased from Suzhou Shengxinlong Plastics Co., Ltd.

[0019] Example 1: A method for preparing a high-strength and impact-resistant TPU composite material, comprising the following steps: (1) Add 0.1 mol of toluene-2,4-diisocyanate, 0.1 mol of 5,7-dihydroxy-4'-methoxyflavone (CAS No. 480-44-4), and 6 mmol of dibutyltin dilaurate to 250 mL of toluene, heat to 70 °C, stir and react for 3 h, perform vacuum distillation, wash the product with ethanol, and dry to obtain methoxy polyurethane; (2) Add 80 g of methoxy polyurethane to 1.8 L of dichloromethane. Under a nitrogen atmosphere, dropwise add 300 mL of a dichloromethane solution containing 51.4 g of boron tribromide at 0 °C, stir and react for 3 h, then react at 20 °C for 12 h. Pour the solution into ice water, stir, filter, wash with water and ethanol, and dry to obtain hydroxy polyurethane; (3) Mix 8.5 kg of polyurethane resin, 1.5 kg of polyoxymethylene, and 100 g of hydroxy polyurethane, add them to a twin-screw extruder, with the temperatures of zones 1-6 being 150 °C, 175 °C, 185 °C, 185 °C, 190 °C, and 190 °C, the screw speed being 300 r / min, extrude, and pelletize to obtain a high-strength and impact-resistant TPU composite material.

[0020] Example 2: A method for preparing a high-strength and impact-resistant TPU composite material, comprising the following steps: (1) Add 0.1 mol of isophorone diisocyanate, 0.106 mol of 5,7-dihydroxy-4'-methoxyflavone, and 5 mmol of dibutyltin dilaurate to 300 mL of dichloromethane, heat to 80 °C, stir and react for 2 h, perform vacuum distillation, wash the product with ethanol, and dry to obtain methoxy polyurethane; (2) Add 80 g of methoxy polyurethane to 2 L of dichloromethane. Under a nitrogen atmosphere, dropwise add 320 mL of a dichloromethane solution containing 57.6 g of boron tribromide at 0 °C, stir and react for 3 h, then react at 25 °C for 8 h. Pour the solution into ice water, stir, filter, wash with water and ethanol, and dry to obtain hydroxy polyurethane; (3) Mix 8 kg of polyurethane resin, 2 kg of polyoxymethylene, and 170 g of hydroxyl polyurethane, add them to a twin-screw extruder. The temperatures in zones 1-6 are 150 °C, 175 °C, 185 °C, 185 °C, 190 °C, and 190 °C, the screw speed is 200 r / min, extrude, and pelletize to obtain a high-strength and impact-resistant TPU composite material.

[0021] Example 3: A method for preparing a high-strength and impact-resistant TPU composite material, comprising the following steps: (1) Add 0.1 mol of diphenylmethane-4,4'-diisocyanate, 0.104 mol of 5,7-dihydroxy-4'-methoxyflavone, and 5.3 mmol of dibutyltin dilaurate to 300 mL of toluene, heat to 70 °C, stir and react for 3 h, carry out vacuum distillation, wash the product with ethanol, and dry to obtain methoxy polyurethane. (2) Add 80 g of methoxy polyurethane to 2 L of dichloromethane. Under a nitrogen atmosphere, dropwise add 250 mL of a dichloromethane solution containing 44.8 g of boron tribromide at 5 °C, stir and react for 3 h, then react at 20 °C for 12 h. Pour the solution into ice water, stir, filter, wash with water and ethanol, and dry to obtain hydroxyl polyurethane. (3) Mix 7 kg of polyurethane resin, 3 kg of polyoxymethylene, and 280 g of hydroxyl polyurethane, add them to a twin-screw extruder. The temperatures in zones 1-6 are 150 °C, 175 °C, 185 °C, 185 °C, 190 °C, and 190 °C, the screw speed is 200 r / min, extrude, and pelletize to obtain a high-strength and impact-resistant TPU composite material.

[0022] Example 4: A method for preparing a high-strength and impact-resistant TPU composite material, comprising the following steps: (1) Add 0.1 mol of toluene-2,4-diisocyanate, 0.106 mol of 5,7-dihydroxy-4'-methoxyflavone, and 7 mmol of dibutyltin dilaurate to 300 mL of tetrahydrofuran, heat to 60 °C, stir and react for 3 h, carry out vacuum distillation, wash the product with ethanol, and dry to obtain methoxy polyurethane. (2) Add 80 g of methoxy polyurethane to 1.8 L of dichloromethane. Under a nitrogen atmosphere, dropwise add 320 mL of a dichloromethane solution containing 49.6 g of boron tribromide at 5 °C, stir and react for 3 h, then react at 15 °C for 12 h. Pour the solution into ice water, stir, filter, wash with water and ethanol, and dry to obtain hydroxyl polyurethane. (3) Mix 6 kg of polyurethane resin, 4 kg of polyoxymethylene, and 400 g of hydroxyl polyurethane, add them to a twin-screw extruder. The temperatures in zones 1-6 are 150 °C, 175 °C, 185 °C, 185 °C, 190 °C, and 190 °C, the screw speed is 200 r / min, extrude, and pelletize to obtain a high-strength and impact-resistant TPU composite material.

[0023] Comparative Example 1: 8.5 kg of polyurethane resin and 1.5 kg of polyoxymethylene were mixed and added to a twin-screw extruder. The temperatures of zones 1-6 were 150 °C, 175 °C, 185 °C, 185 °C, 190 °C, and 190 °C, the screw speed was 300 r / min, and extrusion and pelletization were carried out to obtain a TPU composite material.

[0024] Comparative Example 2: (1) Methoxy polyurethane was prepared according to the method of Example 1. (2) 8.5 kg of polyurethane resin, 1.5 kg of polyoxymethylene, and 100 g of methoxy polyurethane were mixed and added to a twin-screw extruder. The temperatures of zones 1-6 were 150 °C, 175 °C, 185 °C, 185 °C, 190 °C, and 190 °C, the screw speed was 300 r / min, and extrusion and pelletization were carried out to obtain a TPU composite material.

[0025] Comparative Example 3: A method for preparing a TPU composite material includes the following steps: (1) 0.1 mol of toluene-2,4-diisocyanate, 0.1 mol of 5-methoxyresorcinol (CAS No. 2174-64-3), and 6 mmol of dibutyltin dilaurate were added to 250 mL of toluene, heated to 70 °C, and stirred for reaction for 3 h. After vacuum distillation, the product was washed with ethanol, dried, and methoxy polyurethane was obtained. (2) 80 g of methoxy polyurethane was added to 1.8 L of dichloromethane. In a nitrogen atmosphere, a dichloromethane solution containing 51.4 g of boron tribromide was added dropwise at 0 °C, and the mixture was stirred for reaction for 3 h, and then reacted at 20 °C for 12 h. The solution was poured into ice water, stirred, filtered, washed with water and ethanol, and dried to obtain hydroxy polyurethane. (3) 8.5 kg of polyurethane resin, 1.5 kg of polyoxymethylene, and 100 g of hydroxy polyurethane were mixed and added to a twin-screw extruder. The temperatures of zones 1-6 were 150 °C, 175 °C, 185 °C, 185 °C, 190 °C, and 190 °C, the screw speed was 300 r / min, and extrusion and pelletization were carried out to obtain a TPU composite material.

[0026] The TPU material was molded under pressure at 180 °C and 10 MPa in a flat vulcanizing machine to make a specimen. The tensile properties were tested according to the standard of GB / T 1040.1-2018. The impact strength was tested according to the standard of GB / T 1043.1-2008.

[0027] 10 mg of the TPU material was weighed and placed in a thermogravimetric analyzer, and the thermal properties were tested in a nitrogen atmosphere, and the test temperature range was 30-700 °C.

[0028] The performance test results of the TPU composites of each example and comparative example obtained by the above test method are shown in Table 1 below.

[0029] Table 1: Performance test results of the TPU composites of each example and comparative example

[0030] In Comparative Example 1, polyurethane resin and polyoxymethylene were blended, and the obtained TPU composite had low tensile strength and impact strength. This was mainly because the compatibility between polyurethane resin and polyoxymethylene was poor, resulting in low mechanical strength of the composite. In the TPU composites of Examples 1 - 4, hydroxy polyurethane was added. Its molecular main chain was similar to that of polyurethane resin, and its side chain contained hydroxyl groups, which could form hydrogen bonds with the ether bonds of polyoxymethylene, enabling hydroxy polyurethane to play a role in compatibilizing polyurethane resin and polyoxymethylene, significantly improving the compatibility between the two, forming an alloy system with better mechanical properties, making the composite have higher tensile strength and maintaining good impact strength. Moreover, hydroxy polyurethane contained a fused-ring structure with high-temperature resistance ( ), was not easily thermally decomposed, which was beneficial to improving the heat resistance of the TPU composite and increasing the initial (5% mass loss) thermal decomposition temperature.

[0031] In the TPU composite of Comparative Example 2, methoxy polyurethane was added. It did not contain hydroxyl groups and had weak hydrogen bonding with the ether bonds of polyoxymethylene, making it difficult to play a role in compatibilizing polyurethane resin and polyoxymethylene, resulting in low tensile strength and impact strength of the composite.

[0032] In Comparative Example 3, hydroxy polyurethane prepared from 5-methoxyresorcinol as the raw material did not contain a fused-ring structure with high-temperature resistance, resulting in the initial thermal decomposition temperature of the polyurethane being lower than that of Example 1.

[0033] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A high-strength and impact-resistant TPU composite material, characterized in that, Comprising 60 - 85 parts by weight of polyurethane resin, 15 - 40 parts by weight of polyoxymethylene, and 1 - 4 parts by weight of hydroxy polyurethane; The preparation method of the hydroxy polyurethane is as follows: (1) Add diisocyanate, 5,7 - dihydroxy - 4'-methoxyflavone, and dibutyltin dilaurate to a solvent, stir and react, distill under reduced pressure, wash the product, and dry to obtain methoxy polyurethane; (2) Add methoxy polyurethane to dichloromethane, dropwise add a dichloromethane solution containing boron tribromide under a nitrogen atmosphere, pour the solution into ice water after the reaction, stir, filter, wash the product, and dry to obtain hydroxy polyurethane.

2. The high-strength and impact-resistant TPU composite material according to claim 1, wherein The solvent in (1) includes toluene, tetrahydrofuran, or dichloromethane.

3. The high-strength and impact-resistant TPU composite material according to claim 1, wherein, The reaction temperature in (1) is 60 - 80 °C, and the reaction time is 2 - 3 h.

4. The high-strength and impact-resistant TPU composite material according to claim 1, wherein, The molar ratio of diisocyanate, 5,7 - dihydroxy - 4'-methoxyflavone, and dibutyltin dilaurate in (1) is 1:(1 - 1.06):(0.05 - 0.07).

5. The high-strength and impact-resistant TPU composite material according to claim 4, characterized in that, The diisocyanate is diphenylmethane - 4,4'-diisocyanate, toluene - 2,4 - diisocyanate, or isophorone diisocyanate.

6. The high-strength and impact-resistant TPU composite material according to claim 1, wherein, The mass ratio of methoxy polyurethane to boron tribromide in (2) is 100:(56 - 72).

7. The high-strength and impact-resistant TPU composite material according to claim 1, wherein The reaction in (2) is first carried out at 0 - 5 °C for 2 - 3 h, and then at 15 - 25 °C for 8 - 12 h.

8. The preparation method of the high-strength and impact-resistant TPU composite material according to any one of claims 1-7, characterized in that, Comprising the following steps: Mix the polyurethane resin, polyoxymethylene, and hydroxy polyurethane, add them to a twin - screw extruder, extrude, and pelletize to obtain a high - strength impact - resistant TPU composite material.

9. The preparation method of the high-strength and impact-resistant TPU composite material according to claim 8, wherein The temperature of the 1 - 6 zones of the twin - screw extruder is 150 - 190 °C, and the screw speed is 200 - 300 r / min.

Images