A weather-resistant TPU composite material and its production process

Abstract

The present invention relates to a weather-resistant TPU composite material and a production process thereof, and belongs to the technical field of polyurethane. The composite material comprises, by weight, 100 parts of TPU masterbatch, 1.5-2.2 parts of high-stability weathering agent, 8-12 parts of plasticizer, 1.2-1.4 parts of opening agent and 0.5-0.7 parts of processing aid; the high-stability weathering agent is made by substitution reaction of tetramethyl piperidine amine and diethyl bromomalonate to prepare a double ester with a hindered amine structure, i.e., an intermediate, and then amine ester exchange is carried out by diethanolamine and the ester group in the intermediate to prepare a compound with polyhydroxyl, i.e., a modifier, and then it is polymerized with polypropylene glycol and aliphatic diisocyanate to form an oligomer, which has high compatibility with a TPU matrix and is conducive to dispersion, and the polymer chain is in a comb-like structure, which is not easy to free migrate after curing, and the hindered amine structure on the side chain can stably play the role of light and heat aging resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane, and in particular relates to a weather-resistant TPU composite material and a production process thereof. Background Art

[0002] Thermoplastic polyurethane (TPU) composites have been widely used in many fields, such as footwear, automotive interiors, and outdoor sports equipment, due to their excellent wear resistance, tear resistance, bending resistance, and good elasticity. However, during outdoor use, TPU composites are exposed to environmental factors such as ultraviolet rays, oxygen, and heat for a long time, which can easily lead to a decline in performance, especially insufficient weather resistance, which limits its development in some fields. In order to improve the weather resistance of TPU composites, researchers have tried to modify them by adding light stabilizers.

[0003] At present, the common light stabilizers on the market mainly include ultraviolet absorbers, hindered amine light stabilizers and light shielding agents. Although these light stabilizers can improve the weather resistance of TPU composites to a certain extent, there are still the following problems: First, the light stabilizer has limited effect on the weather resistance of TPU. Increasing the proportion of light stabilizers can increase weather resistance to a certain extent, but the common hindered amine light stabilizers are not compatible with the TPU matrix, and increasing the dosage has a greater impact on the mechanical properties of the matrix; second, the common hindered amine light stabilizers are not compatible with the matrix, and most of them are small molecular compounds, which are easy to migrate freely under light and heat environments, resulting in a decrease in the overall weather resistance of the matrix. Summary of the invention

[0004] In order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide a weather-resistant TPU composite material and a production process thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A weather-resistant TPU composite material comprises, by weight, 100 parts of TPU masterbatch, 1.5-2.2 parts of a high-stability weather-resistant agent, 8-12 parts of a plasticizer, 1.2-1.4 parts of an anti-blocking agent and 0.5-0.7 parts of a processing aid.

[0007] The high stability weathering agent is prepared by the following method:

[0008] Step A1: diethyl bromomalonate, tetramethylpiperidinamine, triethylamine and tetrahydrofuran are mixed, nitrogen is introduced for protection, the temperature is raised to 40-50° C., and stirring is applied at 60-90 rpm. The reaction is carried out for 1.5-2 h. After the reaction is completed, tetrahydrofuran is removed by rotary evaporation, and the mixture is washed with water and dried in vacuo to obtain an intermediate;

[0009] Furthermore, the dosage ratio of diethyl bromomalonate, tetramethylpiperidinamine, triethylamine and tetrahydrofuran is 0.1 mol: 0.1 mol: 5-8 mL: 55-70 mL. Under low heat conditions, triethylamine acts as an acid binding agent to promote the substitution of tetramethylpiperidinamine with diethyl bromomalonate to form a diester with a hindered amine structure.

[0010] Step A2: The intermediate, diethanolamine, potassium tert-butoxide and anhydrous dioxane are mixed, nitrogen is introduced for protection, the temperature is raised to 95-105° C., stirring is applied at 120-150 rpm, and reflux reaction is performed for 4-5 hours. After the reaction is completed, the dioxane is removed by vacuum rotary evaporation to obtain a modifier;

[0011] Furthermore, the usage ratio of the intermediate, diethanolamine, potassium tert-butoxide and anhydrous dioxane is 0.1 mol: 0.2 mol: 0.6-0.8 g: 100-120 mL. Under high heat conditions, potassium tert-butoxide promotes amine ester exchange between diethanolamine and the ester group in the intermediate to form a compound with multiple hydroxyl groups.

[0012] Step A3: premixing aliphatic diisocyanate, a modifier, polypropylene glycol and butyl acetate, adding dibutyltin dilaurate, mixing, introducing nitrogen protection, heating to 70-80° C., stirring at 40-60 rpm, reacting for 1.6-2.2 hours, then adding methanol for washing, and removing butyl acetate by vacuum rotary evaporation to obtain a high-stability weathering agent;

[0013] Further, the aliphatic diisocyanate, the modifier, the polypropylene glycol, the dibutyltin dilaurate and the butyl acetate are used in a ratio of 1 mol: 0.07-0.1 mol: 0.55-0.7 mol: 0.35-0.42 g: 80-110 mL, the modifier and the polypropylene glycol are polymerized with the aliphatic diisocyanate, and then quenched by excess methanol to form oligomers;

[0014] Preferably, the aliphatic diisocyanate is hexamethylene diisocyanate, and the molecular weight of the polypropylene glycol is not higher than 600.

[0015] Preferably, the opening agent is selected from erucamide.

[0016] Preferably, the processing aid is selected from fluorinated PPA.

[0017] A production process of a weather-resistant TPU composite material, which specifically comprises the following steps: uniformly mixing the raw materials with a high-speed mixer, transferring the raw materials into a mixing kettle and mixing them at 120-130° C. until the torque is stable, discharging the raw materials and cutting them into slices to prepare the weather-resistant TPU composite material.

[0018] Beneficial effects of the present invention:

[0019] The invention discloses a high-stability weathering agent suitable for TPU products. The high-stability weathering agent is prepared by substitution reaction of tetramethylpiperidinamine and diethyl bromomalonate to form a double ester with a hindered amine structure, i.e., an intermediate. Then, diethanolamine and the ester group in the intermediate are subjected to amine ester exchange to form a compound with polyhydroxyl groups, i.e., a modifier. The compound is then polymerized with polypropylene glycol and aliphatic diisocyanate to form an oligomer. The main chain of the high-stability weathering agent contains a large amount of carbamate structures, has high compatibility with a TPU matrix, can be uniformly dispersed in the matrix during high-heat blending, and is a macromolecular material after curing. It is not easy to separate and segregate when heated, and the hindered amine structure on its side chain can stably play the role of light and heat aging resistance; in addition, the modifier has multiple hydroxyl groups, and after copolymerization with polypropylene glycol with a long-chain structure and diisocyanate, a micro-cross-linked structure with the modifier as a chain link is formed in the polymer chain, so that the polymer chain has a comb-like structure and is entangled with the macromolecular chain of TPU, which on the one hand enhances the migration resistance of the high-stability weathering agent and on the other hand strengthens the TPU matrix; in the test, compared with the composite material blended with the light stabilizer, the composite material disclosed in the present invention has better toughness and long-term weather resistance. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example 1, preparation of weather-resistant TPU composite material, the specific implementation process is as follows:

[0022] (1) Preparation of high stability weathering agent

[0023] Step A1: Take diethyl bromomalonate, tetramethylpiperidinamine, triethylamine and tetrahydrofuran, mix them, introduce nitrogen protection, heat to 50°C, stir at 90rpm, and react for 1.5h, wherein the amount ratio of diethyl bromomalonate, tetramethylpiperidinamine, triethylamine and tetrahydrofuran is 0.1mol:0.1mol:8mL:70mL. After the reaction, remove tetrahydrofuran by rotary evaporation, wash with water, and vacuum dry to obtain an intermediate.

[0024] Step A2: Take the intermediate, diethanolamine, potassium tert-butoxide and anhydrous dioxane, mix them, introduce nitrogen protection, heat to 105°C, stir at 150rpm, and reflux for 4h, wherein the amount ratio of the intermediate, diethanolamine, potassium tert-butoxide and anhydrous dioxane is 0.1mol:0.2mol:0.8g:120mL. After the reaction is completed, the dioxane is removed by reduced pressure rotary evaporation to obtain a modifier.

[0025] Step A3: Premix aliphatic diisocyanate, modifier, polypropylene glycol and butyl acetate, add dibutyltin dilaurate and mix, introduce nitrogen protection, heat to 80°C, stir at 60rpm, and react for 1.6h, wherein the aliphatic diisocyanate in the embodiment is selected from hexamethylene diisocyanate, the polypropylene glycol is selected from PPG-200, and the amount ratio of aliphatic diisocyanate, modifier, polypropylene glycol, dibutyltin dilaurate and butyl acetate is 1mol: 0.07mol: 0.7mol: 0.35g: 80mL. After the reaction is completed, 10wt% methanol of the reactants is added and mixed for 1h, and butyl acetate is removed by vacuum rotary evaporation to obtain a high stability weathering agent.

[0026] (2) Preparation of weather-resistant TPU composite materials

[0027] Ingredients: The raw materials are measured by weight: 100 parts of TPU masterbatch, and the HK-3125 raw material of Henan Huike New Material Technology Co., Ltd. is used in the implementation process; 1.5 parts of high-stability weathering agent, which is homemade in this embodiment; 12 parts of plasticizer, and the Benzoflex-TPU-405 raw material of Eastman Chemical Company is used in the implementation process; 1.2 parts of opening agent, and octadecyl erucamide of Jiangxi Zhilian New Materials Co., Ltd. is used in the implementation process; 0.7 parts of processing aid, and the fluorinated PPA of Shanghai Luju Polymer Technology Co., Ltd., model PPA2100, is used in the implementation process.

[0028] Blending: Add each raw material according to weight into a high-speed mixer, mix at 1200 rpm for 10 min, transfer to a mixer and mix at 120° C. until the torque change is no more than 0.5 N·m / min and the torque tends to be stable, discharging and slicing to make a weather-resistant TPU composite material.

[0029] Example 2, preparation of weather-resistant TPU composite material, the specific implementation process is as follows:

[0030] (1) Preparation of high stability weathering agent

[0031] Step A1: Mix diethyl bromomalonate, tetramethylpiperidinamine, triethylamine and tetrahydrofuran, introduce nitrogen protection, heat to 40°C, stir at 60rpm, and react for 2h, wherein the amount ratio of diethyl bromomalonate, tetramethylpiperidinamine, triethylamine and tetrahydrofuran is 0.1mol:0.1mol:5mL:55mL. After the reaction, remove tetrahydrofuran by rotary evaporation, wash with water, and vacuum dry to obtain an intermediate.

[0032] Step A2: Take the intermediate, diethanolamine, potassium tert-butoxide and anhydrous dioxane, mix them, introduce nitrogen protection, heat to 95°C, stir at 120rpm, and reflux for 5h, wherein the amount ratio of the intermediate, diethanolamine, potassium tert-butoxide and anhydrous dioxane is 0.1mol:0.2mol:0.6g:100mL. After the reaction is completed, the dioxane is removed by reduced pressure rotary evaporation to obtain a modifier.

[0033] Step A3: Premix aliphatic diisocyanate, modifier, polypropylene glycol and butyl acetate, add dibutyltin dilaurate and mix, introduce nitrogen protection, heat to 70°C, stir at 40rpm, and react for 2.2h, wherein the aliphatic diisocyanate in the embodiment is selected from hexamethylene diisocyanate, the polypropylene glycol is selected from PPG-400, and the amount ratio of aliphatic diisocyanate, modifier, polypropylene glycol, dibutyltin dilaurate and butyl acetate is 1mol: 0.08mol: 0.65mol: 0.38g: 100mL. After the reaction is completed, 10wt% methanol of the reactants is added and mixed for 1h, and butyl acetate is removed by vacuum rotary evaporation to obtain a high stability weathering agent.

[0034] (2) Preparation of weather-resistant TPU composite materials

[0035] Ingredients: The raw materials are measured by weight: 100 parts of TPU masterbatch, and the HK-3125 raw material of Henan Huike New Material Technology Co., Ltd. is used in the implementation process; 1.8 parts of high-stability weathering agent, which is homemade in this embodiment; 10 parts of plasticizer, and the Benzoflex-TPU-405 raw material of Eastman Chemical Company is used in the implementation process; 1.4 parts of opening agent, and octadecyl erucamide of Jiangxi Zhilian New Materials Co., Ltd. is used in the implementation process; 0.5 parts of processing aid, and the fluorinated PPA of Shanghai Luju Polymer Technology Co., Ltd., model PPA2100, is used in the implementation process.

[0036] Blending: Add each raw material according to weight into a high-speed mixer, mix at 1200 rpm for 10 min, transfer to a mixer and mix at 125° C. until the torque change is no more than 0.5 N·m / min and the torque tends to be stable, discharging and slicing to make a weather-resistant TPU composite material.

[0037] Example 3, preparation of weather-resistant TPU composite material, the specific implementation process is as follows:

[0038] (1) Preparation of high stability weathering agent

[0039] Step A1: Take diethyl bromomalonate, tetramethylpiperidinamine, triethylamine and tetrahydrofuran, mix them, introduce nitrogen protection, heat to 45°C, stir at 90rpm, and react for 1.8h, wherein the amount ratio of diethyl bromomalonate, tetramethylpiperidinamine, triethylamine and tetrahydrofuran is 0.1mol:0.1mol:6mL:60mL. After the reaction, remove tetrahydrofuran by rotary evaporation, then wash with water and vacuum dry to obtain an intermediate.

[0040] Step A2: Take the intermediate, diethanolamine, potassium tert-butoxide and anhydrous dioxane, mix them, introduce nitrogen protection, heat to 100°C, stir at 150rpm, and reflux for 4.5h, wherein the amount ratio of the intermediate, diethanolamine, potassium tert-butoxide and anhydrous dioxane is 0.1mol:0.2mol:0.7g:120mL. After the reaction is completed, the dioxane is removed by reduced pressure rotary evaporation to obtain a modifier.

[0041] Step A3: Premix aliphatic diisocyanate, modifier, polypropylene glycol and butyl acetate, add dibutyltin dilaurate and mix, introduce nitrogen protection, heat to 75°C, stir at 60rpm, and react for 1.8h, wherein the aliphatic diisocyanate in the embodiment is selected from hexamethylene diisocyanate, the polypropylene glycol is selected from PPG-500, and the amount ratio of aliphatic diisocyanate, modifier, polypropylene glycol, dibutyltin dilaurate and butyl acetate is 1mol: 0.09mol: 0.6mol: 0.4g: 110mL. After the reaction is completed, 10wt% methanol of the reactants is added and mixed for 1h, and butyl acetate is removed by vacuum rotary evaporation to obtain a high stability weathering agent.

[0042] (2) Preparation of weather-resistant TPU composite materials

[0043] Ingredients: The raw materials are measured by weight: 100 parts of TPU masterbatch, and the HK-3125 raw material of Henan Huike New Material Technology Co., Ltd. is used in the implementation process; 2 parts of high-stability weathering agent, which is homemade in this embodiment; 9 parts of plasticizer, and the Benzoflex-TPU-405 raw material of Eastman Chemical Company is used in the implementation process; 1.4 parts of opening agent, and octadecyl erucamide of Jiangxi Zhilian New Materials Co., Ltd. is used in the implementation process; 0.6 parts of processing aid, and the fluorinated PPA of Shanghai Luju Polymer Technology Co., Ltd., model PPA2100, is used in the implementation process.

[0044] Blending: Add each raw material according to weight into a high-speed mixer, mix at 1200 rpm for 10 min, transfer to a mixing kettle and mix at 130° C. until the torque change is no more than 0.5 N·m / min and the torque tends to be stable, and cut the material into slices to make a weather-resistant TPU composite material.

[0045] Example 4, preparation of weather-resistant TPU composite material, the specific implementation process is as follows:

[0046] (1) Preparation of high stability weathering agent

[0047] Step A1: Take diethyl bromomalonate, tetramethylpiperidinamine, triethylamine and tetrahydrofuran, mix them, introduce nitrogen protection, heat to 45°C, stir at 90rpm, and react for 1.8h, wherein the amount ratio of diethyl bromomalonate, tetramethylpiperidinamine, triethylamine and tetrahydrofuran is 0.1mol:0.1mol:8mL:65mL. After the reaction, remove tetrahydrofuran by rotary evaporation, then wash with water and vacuum dry to obtain an intermediate.

[0048] Step A2: Take the intermediate, diethanolamine, potassium tert-butoxide and anhydrous dioxane, mix them, introduce nitrogen protection, heat to 102°C, stir at 150rpm, and reflux for 4.2h, wherein the amount ratio of the intermediate, diethanolamine, potassium tert-butoxide and anhydrous dioxane is 0.1mol:0.2mol:0.7g:110mL. After the reaction is completed, the dioxane is removed by reduced pressure rotary evaporation to obtain a modifier.

[0049] Step A3: Premix aliphatic diisocyanate, modifier, polypropylene glycol and butyl acetate, add dibutyltin dilaurate and mix, introduce nitrogen protection, heat to 72°C, stir at 50rpm, and react for 2h, wherein the aliphatic diisocyanate in the embodiment is selected from hexamethylene diisocyanate, the polypropylene glycol is selected from PPG-600, and the amount ratio of aliphatic diisocyanate, modifier, polypropylene glycol, dibutyltin dilaurate and butyl acetate is 1mol: 0.1mol: 0.55mol: 0.42g: 100mL. After the reaction is completed, 10wt% methanol of the reactants is added and mixed for 1h, and butyl acetate is removed by vacuum rotary evaporation to obtain a high stability weathering agent.

[0050] (2) Preparation of weather-resistant TPU composite materials

[0051] Ingredients: The raw materials are measured by weight: 100 parts of TPU masterbatch, and the HK-3125 raw material of Henan Huike New Material Technology Co., Ltd. is used in the implementation process; 2.2 parts of high-stability weathering agent, which is homemade in this embodiment; 8 parts of plasticizer, and the Benzoflex-TPU-405 raw material of Eastman Chemical Company is used in the implementation process; 1.3 parts of opening agent, and octadecyl erucamide of Jiangxi Zhilian New Materials Co., Ltd. is used in the implementation process; 0.6 parts of processing aid, and the fluorinated PPA of Shanghai Luju Polymer Technology Co., Ltd., model PPA2100, is used in the implementation process.

[0052] Blending: Add each raw material according to weight into a high-speed mixer, mix at 1200 rpm for 10 min, transfer to a mixing kettle and mix at 130° C. until the torque change is no more than 0.5 N·m / min and the torque tends to be stable, and cut the material into slices to make a weather-resistant TPU composite material.

[0053] Comparative Example 1

[0054] This comparative example refers to Example 4, except that the high stability weathering agent is replaced by light stabilizer 770 in an amount of 0.18 parts, and the rest of the implementation process is exactly the same as Example 4.

[0055] Comparative Example 2

[0056] This comparative example refers to comparative example 1, except that the amount of light stabilizer 770 is increased to 0.45 parts, and the rest of the implementation process is exactly the same.

[0057] The weather-resistant TPU composite material prepared above was hot-pressed on a flat vulcanizer at a temperature of 150±2°C and a pressure of 1.2MPa. The tensile test was carried out according to GB / T 13022-1991 standard at a tensile rate of 50mm / min. The aging test was carried out according to GB / T 14522-2008 standard at a test temperature of 60±0.5°C and a UV radiation intensity of 50×10 2 μW / cm 2 The test cycles are 168h and 720h respectively. The yellowing index test of the samples after aging test characterizes the weather resistance. The specific test results are shown in the following table:

[0058]

[0059] It can be seen from the test results in the above table that the TPU composite material prepared in the embodiment has better toughness than the comparative example. Within the 168h aging cycle, the yellowing index of the embodiment and the comparative example 2 is similar, while after 720h testing, the comparative example exhibits severe yellowing.

[0060] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0061] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A weather-resistant TPU composite material, characterized in that: The composition includes: 100 parts of TPU masterbatch, 1.5-2.2 parts of high stability weathering agent, 8-12 parts of plasticizer, 1.2-1.4 parts of anti-blocking agent and 0.5-0.7 parts of fluorinated PPA by weight; The high stability weathering agent is prepared by the following method: Step A1: diethyl bromomalonate, tetramethylpiperidinamine, triethylamine and tetrahydrofuran are mixed, nitrogen is introduced for protection, the temperature is raised to 40-50°C, and the mixture is stirred for reaction for 1.5-2h. After the reaction is completed, tetrahydrofuran is removed by rotary evaporation, and the mixture is then washed with water and dried in vacuo to obtain an intermediate; Step A2: The intermediate, diethanolamine, potassium tert-butoxide and anhydrous dioxane are mixed, nitrogen is introduced for protection, the temperature is raised to 95-105° C., and the mixture is stirred and refluxed for reaction for 4-5 hours. After the reaction is completed, the dioxane is removed by vacuum rotary evaporation to obtain a modifier; Step A3: premix aliphatic diisocyanate, modifier, polypropylene glycol and butyl acetate, then add dibutyltin dilaurate and mix, introduce nitrogen protection, heat to 70-80°C, stir and react for 1.6-2.2h, then add methanol to wash, and remove butyl acetate by vacuum rotary evaporation to obtain a high-stability weathering agent.

2. A weather-resistant TPU composite material according to claim 1, characterized in that: The usage ratio of diethyl bromomalonate, tetramethylpiperidinamine, triethylamine and tetrahydrofuran is 0.1 mol: 0.1 mol: 5-8 mL: 55-70 mL.

3. A weather-resistant TPU composite material according to claim 2, characterized in that: The usage ratio of the intermediate, diethanolamine, potassium tert-butoxide and anhydrous dioxane is 0.1 mol: 0.2 mol: 0.6-0.8 g: 100-120 mL.

4. A weather-resistant TPU composite material according to claim 3, characterized in that: The usage ratio of aliphatic diisocyanate, modifier, polypropylene glycol, dibutyltin dilaurate and butyl acetate is 1 mol: 0.07-0.1 mol: 0.55-0.7 mol: 0.35-0.42 g: 80-110 mL.

5. A weather-resistant TPU composite material according to claim 4, characterized in that: The aliphatic diisocyanate is hexamethylene diisocyanate, and the molecular weight of the polypropylene glycol is not higher than 600.

6. The weather-resistant TPU composite material according to claim 1, characterized in that: The opening agent is erucamide.

7. A production process for a weather-resistant TPU composite material according to any one of claims 1 to 6, characterized in that: The specific operation is: the raw materials are mixed evenly with a high-speed mixer, transferred into a mixing kettle and mixed at 120-130°C until the torque is stable, and the material is cut into slices to make a weather-resistant TPU composite material.

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