Low dynamic fatigue type polyurethane elastomer

Abstract

The invention discloses a low dynamic fatigue type polyurethane elastomer, and relates to the technical field of organic polymer compounds, the low dynamic fatigue type polyurethane elastomer comprises 50-70 parts of polytetramethylene ether glycol, 75-100 parts of 1, 6-hexamethylene diisocyanate, 5-10 parts of a chain extender, 3-8 parts of a dispersant, 1-5 parts of a lubricant, 4-10 parts of a plasticizer, and 6-12 parts of a flame retardant filler. According to the low-dynamic-fatigue type polyurethane elastomer, due to the addition of the flame-retardant filler, during combustion, melamine is decomposed to generate non-combustible gases such as ammonia gas, the gases can dilute the concentration of oxygen and combustible gas in a combustion area and reduce the intensity of a combustion reaction, and meanwhile, phosphorus elements can form substances such as phosphoric acid and metaphosphoric acid at high temperature, so that the flame-retardant property of the polyurethane elastomer is improved. According to the present invention, the polyurethane elastomer and the flame retardant can capture free radicals in the gas phase and interrupt the chain reaction of combustion so as to inhibit the flame propagation, and can promote the char formation during the combustion process to form a compact carbon layer covering the surface of the polyurethane elastomer so as to provide good thermal insulation and oxygen insulation effects;

Description

Technical Field

[0001] The invention relates to the technical field of organic polymer compounds, in particular to a low dynamic fatigue type polyurethane elastomer. Background Art

[0002] The Chinese patent with the publication number CN101880369A discloses a polyurethane elastomer, which is obtained by chain extension of isocyanate prepolymer obtained by reaction of a composite polyol and an organic isocyanate, wherein the composite polyol is composed of a polyester polyol and a polyether polyol, wherein the polyester polyol is formed by polycondensation of a dibasic acid and propylene glycol and ethylene glycol, wherein the polyether polyol is formed by polymerization of ethylene oxide and / or propylene oxide, wherein the organic isocyanate is composed of an aromatic isocyanate and an aliphatic isocyanate, and the chain extender used for chain extension is an amine chain extender; the invention is based on the theory of polyurethane structure and performance, adopts the known prepolymerization, casting molding, and bulk synthesis of a solvent-free and environmentally friendly polyurethane elastomer, and the polyurethane elastomer has an ultra-high ultimate elongation at break (greater than 1000%) to meet the application in special fields such as special bonding, shock absorption and sealing. However, the polyurethane elastomer prepared above has a high tendency to fatigue failure after long-term use or repeated use; for this reason, the present invention proposes a low dynamic fatigue type polyurethane elastomer to solve the above-mentioned problems. Summary of the invention

[0003] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides a low dynamic fatigue polyurethane elastomer, which solves the problems mentioned in the above background technology.

[0004] (II) Technical solution To achieve the above objectives, the present invention is implemented through the following technical scheme: a low dynamic fatigue polyurethane elastomer, including 50-70 parts of polytetramethylene ether glycol, 75-100 parts of 1,6-hexamethylene diisocyanate, 5-10 parts of chain extender, 3-8 parts of dispersant, 1-5 parts of lubricant, 4-10 parts of plasticizer, and 6-12 parts of flame retardant filler.

[0005] Preferably, the preparation method of the chain extender is: (1) Dissolve 2.5-5 mL of triethylamine in 40-50 mL of N,N-dimethylformamide, then add 3.8-4.4 g of 4-hydroxybenzaldehyde and stir to react; (2) Add 0.9-1.5 mL of phosphorus oxychloride dropwise and continue stirring until the reaction is complete; (3) After the reaction is completed, extraction is performed, and then the organic layer is washed, dried with anhydrous sodium sulfate, filtered, and finally concentrated and purified under reduced pressure; (4) At room temperature, take 82.5-88.2 g of the product in (3), pour it into 135-150 mL of anhydrous methanol, add 4.5-4.96 g of hydroxylamine hydrochloride and 8.5-10 mL of triethylamine, and stir to react; (5) After the reaction is completed, repeat (3) to obtain the chain extender.

[0006] Preferably, in (1), the reaction temperature is 0°C and the reaction time is 30-40 min.

[0007] Preferably, in (3), the organic layer is washed 3-5 times with 250-300 mL of distilled water and 250-300 mL of saturated brine.

[0008] Preferably, the preparation method of the flame retardant filler is: S1, pour 3-3.6g of acetyl, 4.2-4.8g of triethylamine and 45-55mL of N,N-dimethylformamide into 2-2.5g of 2,2-dihydroxymethylpropionic acid to react; S2. After the reaction is completed, the temperature is raised, and 2.2-2.6 g of thionyl chloride and 26-32 mL of N,N-dimethylformamide are added to react; S3, under alkaline conditions, add 0.75-0.85 g of melamine and 0.2-0.26 g of triethylamine to react; S4, washing the reaction product with deionized water for 3-4 times, purifying and filtering it in sequence, and then drying it in a vacuum drying oven; S5, pour the dried product into 32-40 mL of deionized water, heat and stir to dissolve, then add 2.5-3.5 g of phytic acid aqueous solution and continue the reaction; S5. After the reaction is completed, pour the reaction product into 25-35 mL of anhydrous ethanol, stir until completely dissolved, and then add 0.22-0.3 g of palladium carbon catalyst to react; S6. After the reaction is completed, 1 mol / L sodium hydroxide solution is added dropwise to adjust the pH value of the system to 8-9, and then filtered, washed with anhydrous ethanol 2-3 times, and finally placed in a vacuum drying oven for drying to obtain a flame retardant filler.

[0009] Preferably, in S1, the reaction is carried out in an ice bath and the reaction time is 9-11 h; In S2, the temperature is raised to 70-80°C and the reaction time is 8-10h.

[0010] Preferably, in S4 and S6, the drying temperature is 40-50°C.

[0011] Preferably, in S5, the reaction is carried out under anaerobic conditions, the temperature is raised to 70-80° C., and the reaction time is 2.5-4 h.

[0012] (III) Beneficial effects The present invention provides a low dynamic fatigue polyurethane elastomer. Compared with the prior art, it has the following beneficial effects: (1) The low dynamic fatigue polyurethane elastomer, by adding flame retardant fillers, can produce non-combustible gases such as ammonia when melamine decomposes during combustion. These gases can dilute the concentration of oxygen and combustible gas in the combustion area and reduce the intensity of the combustion reaction. At the same time, phosphorus elements will form substances such as phosphoric acid and metaphosphoric acid at high temperatures. They can capture free radicals in the gas phase and interrupt the chain reaction of combustion, thereby inhibiting the spread of flames. In addition, they can promote carbonization during the combustion process, forming a dense carbon layer covering the surface of the polyurethane elastomer, which has good heat insulation and oxygen isolation effects, can prevent oxygen from entering the interior of the material, and can also inhibit the diffusion of combustible gases outward, thereby effectively slowing down the combustion rate of the material; at the same time, the functional groups in the flame retardant fillers can form intermolecular forces such as hydrogen bonds and van der Waals forces with the groups on the polyurethane molecular chains. These interactions can limit the relative sliding and deformation of the polyurethane molecular chains under dynamic loads, so that the material can better maintain its structural integrity when subjected to repeated tensile and compressive loads, reduce the accumulation of internal damage, and improve the material's fatigue resistance.

[0013] (2) The low dynamic fatigue polyurethane elastomer, through the addition of chain extender, allows multiple functional groups in the chain extender molecule to react with the isocyanate group and other active groups of the polyurethane, forming new chemical bonds between the polyurethane molecular chains, increasing the cross-linking points, and making the connection between the molecular chains tighter and more stable. When the material is subjected to dynamic load, the molecular chains are not easy to slide and dislocate relative to each other, and can better cooperate to withstand external forces, reduce internal damage caused by excessive displacement between molecular chains, and thus improve low dynamic fatigue resistance; the addition of 4-hydroxybenzaldehyde makes the chain extender have a certain rigid structure, which helps to enhance the bearing capacity and deformation resistance of the material. Under the action of dynamic load, it can more effectively resist deformation caused by external force, reduce the damage of the hard segment area and the generation of fatigue cracks, and thus improve the low dynamic fatigue performance of the polyurethane elastomer; and the chain extender can promote the hard segment and the soft segment to be more evenly distributed on a microscopic scale, so that when the material is subjected to dynamic load, the stress is more evenly transferred between the hard segment and the soft segment, avoiding the local stress concentration phenomenon caused by uneven phase distribution, reducing the risk of fatigue failure of the material, and improving its low dynamic fatigue performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A comparison chart of tensile strength tests provided by the present invention; Figure 2 This is a comparison chart of the fracture toughness test provided by the present invention. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in 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.

[0016] In the present application, polyethylene glycol is used as the dispersant, liquid paraffin is used as the lubricant, and dioctyl phthalate is used as the plasticizer.

[0017] Example 1 (1) Preparation method of chain extender: Under the condition of 0°C, 2.5 mL of triethylamine was dissolved in 40 mL of N,N-dimethylformamide, and then 3.8 g of 4-hydroxybenzaldehyde was added, and the mixture was stirred for reaction for 30 min; 0.9 mL of phosphorus oxychloride was added dropwise, and the mixture was stirred until the reaction was completed; after the reaction was completed, extraction was performed, and then the mixture was washed three times with 250 mL of distilled water and 250 mL of saturated saline, and then dried with anhydrous sodium sulfate and filtered, and then concentrated and purified under reduced pressure to obtain a reaction product; under room temperature, 82.5 g of the reaction product was poured into 135 mL of anhydrous methanol, and 4.5 g of hydroxylamine hydrochloride and 8.5 mL of triethylamine were added, and the mixture was stirred for reaction; after the reaction was completed, extraction was performed, and then the organic layer was washed, and then dried with anhydrous sodium sulfate and filtered, and finally concentrated and purified under reduced pressure to obtain a chain extender; (2) Preparation method of flame retardant filler: under ice bath condition, add 3g of acetyl, 4.28g of triethylamine and 45mL of N,N-dimethylformamide to 2g of 2,2-dihydroxymethylpropionic acid, and react for 9h; after the reaction is completed, heat to 70℃, add 2.2g of thionyl chloride and 26mL of N,N-dimethylformamide, and react for 8h; under alkaline condition, add 0.75g of melamine and 0.2g of triethylamine, and react; wash the reaction product with deionized water for 3 times, purify and filter it in turn, and then place it in a vacuum dryer at 40℃. Dry in a drying oven; under anaerobic conditions, pour the dried product into 32 mL of deionized water, heat to 70°C and stir to dissolve, then add 2.5 g of phytic acid aqueous solution, and continue to react for 2.5 h; after the reaction is completed, pour the reaction product into 25 mL of anhydrous ethanol, stir until completely dissolved, and then add 0.22 g of palladium carbon catalyst to react; after the reaction is completed, add 1 mol / L sodium hydroxide solution dropwise to adjust the pH value of the system to 8, then filter, wash twice with anhydrous ethanol, and finally dry in a vacuum drying oven at 40°C to obtain a flame retardant filler; (3) The low dynamic fatigue type polyurethane elastomer comprises: 50 g of polytetramethylene ether glycol, 75 g of 1,6-hexamethylene diisocyanate, 5 g of a chain extender, 3 g of a dispersant, 1 g of a lubricant, 4 g of a plasticizer, and 6 g of a flame retardant filler.

[0018] Example 2 (1) Preparation method of chain extender: Under the condition of 0°C, 3.5 mL of triethylamine was dissolved in 45 mL of N,N-dimethylformamide, and then 4.1 g of 4-hydroxybenzaldehyde was added, and the mixture was stirred for 35 min; 1.2 mL of phosphorus oxychloride was added dropwise, and the mixture was stirred until the reaction was completed; after the reaction was completed, extraction was performed, and then the mixture was washed 4 times with 270 mL of distilled water and 280 mL of saturated saline, and then dried with anhydrous sodium sulfate and filtered, and then concentrated and purified under reduced pressure to obtain a reaction product; under room temperature, 85.5 g of the reaction product was poured into 140 mL of anhydrous methanol, and 4.75 g of hydroxylamine hydrochloride and 9 mL of triethylamine were added, and the mixture was stirred for reaction; after the reaction was completed, extraction was performed, and then the organic layer was washed, and then dried with anhydrous sodium sulfate and filtered, and finally concentrated and purified under reduced pressure to obtain a chain extender; (2) Preparation method of flame retardant filler: under ice bath condition, add 3.3g of acetyl, 4.5g of triethylamine and 50mL of N,N-dimethylformamide to 2.2g of 2,2-dihydroxymethylpropionic acid, and react for 10h; after the reaction is completed, heat to 75℃, add 2.4g of thionyl chloride and 29mL of N,N-dimethylformamide, and react for 9h; under alkaline condition, add 0.8g of melamine and 0.23g of triethylamine, and react; wash the reaction product with deionized water for 3 times, purify and filter it in turn, and then place it at 45℃. Dry in a vacuum drying oven; under anaerobic conditions, pour the dried product into 36 mL of deionized water, heat to 75°C and stir to dissolve, then add 3 g of phytic acid aqueous solution, and continue to react for 3 hours; after the reaction is completed, pour the reaction product into 30 mL of anhydrous ethanol, stir until completely dissolved, and then add 0.26 g of palladium carbon catalyst to react; after the reaction is completed, add 1 mol / L sodium hydroxide solution dropwise, adjust the pH value of the system to 8.5, then filter, wash with anhydrous ethanol 3 times, and finally dry in a vacuum drying oven at 45°C to obtain a flame retardant filler; (3) The low dynamic fatigue type polyurethane elastomer comprises: 60 g of polytetramethylene ether glycol, 85 g of 1,6-hexamethylene diisocyanate, 7 g of a chain extender, 5 g of a dispersant, 3 g of a lubricant, 7 g of a plasticizer, and 9 g of a flame retardant filler.

[0019] Example 3 (1) Preparation method of chain extender: Under the condition of 0°C, 5 mL of triethylamine was dissolved in 50 mL of N,N-dimethylformamide, and then 4.4 g of 4-hydroxybenzaldehyde was added, and the mixture was stirred for 40 min; 1.5 mL of phosphorus oxychloride was added dropwise, and the mixture was stirred until the reaction was completed; after the reaction was completed, extraction was performed, and then 300 mL of distilled water and 300 mL of saturated saline were used to wash the mixture 5 times, and then the mixture was dried with anhydrous sodium sulfate and filtered, and then vacuum concentrated and purified to obtain a reaction product; under room temperature, 88.2 g of the reaction product was poured into 150 mL of anhydrous methanol, and 4.96 g of hydroxylamine hydrochloride and 10 mL of triethylamine were added, and the mixture was stirred for reaction; after the reaction was completed, extraction was performed, and then the organic layer was washed, and then the mixture was dried with anhydrous sodium sulfate and filtered, and finally vacuum concentrated and purified to obtain a chain extender; (2) Preparation method of flame retardant filler: under ice bath condition, add 3.6 g of acetyl, 4.8 g of triethylamine and 55 mL of N,N-dimethylformamide to 2.5 g of 2,2-dihydroxymethylpropionic acid, and react for 11 h; after the reaction is completed, heat to 80 °C, add 2.6 g of thionyl chloride and 32 mL of N,N-dimethylformamide, and react for 10 h; under alkaline condition, add 0.85 g of melamine and 0.26 g of triethylamine to react; wash the reaction product with deionized water for 4 times, purify and filter it in turn, and then place it at 50 ℃ vacuum drying oven; under anaerobic conditions, pour the dried product into 40mL of deionized water, heat to 80℃ and stir to dissolve, then add 3.5g of phytic acid aqueous solution, and continue to react for 4h; after the reaction is completed, pour the reaction product into 35mL of anhydrous ethanol, stir until completely dissolved, and then add 0.3g of palladium carbon catalyst to react; after the reaction is completed, add 1mol / L sodium hydroxide solution dropwise to adjust the pH value of the system to 9, then filter, wash with anhydrous ethanol 3 times, and finally dry in a vacuum drying oven at 50℃ to obtain a flame retardant filler; (3) The low dynamic fatigue type polyurethane elastomer comprises: 70 g of polytetramethylene ether glycol, 100 g of 1,6-hexamethylene diisocyanate, 10 g of a chain extender, 8 g of a dispersant, 5 g of a lubricant, 10 g of a plasticizer, and 12 g of a flame retardant filler.

[0020] Comparative Example 1 Compared with Example 1, the difference is that no flame retardant filler is added; the rest remains unchanged.

[0021] Comparative Example 2 Compared with Example 1, the difference is that the chain extender is replaced by bis(4-hydroxyphenyl) disulfide; the rest remains unchanged.

[0022] Sample preparation: dehydrate polytetramethylene ether glycol at 100°C and vacuum degree of 0.1MPa for 2h, add 1,6-hexamethylene diisocyanate, react at 80°C for 2h to generate a prepolymer, vacuum degassing after the reaction is completed, cool and discharge, add dispersant, lubricant, plasticizer, chain extender in turn, heat to 90°C and stir to mix, then add flame retardant filler and continue to mix.

[0023] Limiting oxygen index (LOI): measured using HC-2 oxygen index tester; the results are shown in Table 1.

[0024] Vertical combustion grade (UL-94): measured by CZF-3 horizontal vertical combustion tester; the results are shown in Table 1.

[0025] Table 1

[0026] Cyclic tensile test: The test was conducted using a ZQ-990LA electric tensile testing machine. The sample size was a dumbbell of 25mm×4mm×2mm. The specific test method was as follows: the tensile rate was 10mm / min, the sample was stretched to a fixed deformation of 200% and the loading and unloading cycle test was completed 3 times; the results are as follows: Figure 1 and Figure 2 shown.

[0027] Depend on Figure 1 and Figure 2 It can be seen that after repeated tensile tests, the tensile strength and fracture toughness of the samples of Examples 1-3 are significantly higher than those of Comparative Examples 1-2.

[0028] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0029] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0030] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low dynamic fatigue polyurethane elastomer, characterized in that: The invention comprises 50-70 parts of polytetramethylene ether glycol, 75-100 parts of 1,6-hexamethylene diisocyanate, 5-10 parts of chain extender, 3-8 parts of dispersant, 1-5 parts of lubricant, 4-10 parts of plasticizer and 6-12 parts of flame retardant filler.

2. The low dynamic fatigue polyurethane elastomer according to claim 1, characterized in that: The preparation method of the chain extender is: (1) Dissolve 2.5-5 mL of triethylamine in 40-50 mL of N,N-dimethylformamide, then add 3.8-4.4 g of 4-hydroxybenzaldehyde and stir to react; (2) Add 0.9-1.5 mL of phosphorus oxychloride dropwise and continue stirring until the reaction is complete; (3) After the reaction is completed, extraction is performed, and then the organic layer is washed, dried with anhydrous sodium sulfate, filtered, and finally concentrated and purified under reduced pressure in sequence; (4) At room temperature, take 82.5-88.2 g of the product in (3), pour it into 135-150 mL of anhydrous methanol, add 4.5-4.96 g of hydroxylamine hydrochloride and 8.5-10 mL of triethylamine, and stir to react; (5) After the reaction is completed, repeat (3) to obtain the chain extender.

3. The low dynamic fatigue polyurethane elastomer according to claim 2, characterized in that: In the above (1), the reaction temperature is 0°C and the reaction time is 30-40 min.

4. The low dynamic fatigue polyurethane elastomer according to claim 2, characterized in that: In the step (3), the organic layer is washed 3-5 times with 250-300 mL of distilled water and 250-300 mL of saturated brine.

5. The low dynamic fatigue polyurethane elastomer according to claim 1, characterized in that: The preparation method of the flame retardant filler is: S1, pour 3-3.6g of acetyl, 4.2-4.8g of triethylamine and 45-55mL of N,N-dimethylformamide into 2-2.5g of 2,2-dihydroxymethylpropionic acid to react; S2. After the reaction is completed, the temperature is raised, and 2.2-2.6 g of thionyl chloride and 26-32 mL of N,N-dimethylformamide are added to react; S3, under alkaline conditions, add 0.75-0.85 g of melamine and 0.2-0.26 g of triethylamine to react; S4, washing the reaction product with deionized water for 3-4 times, purifying and filtering it in sequence, and then drying it in a vacuum drying oven; S5, pour the dried product into 32-40 mL of deionized water, heat and stir to dissolve, then add 2.5-3.5 g of phytic acid aqueous solution and continue the reaction; S5. After the reaction is completed, pour the reaction product into 25-35 mL of anhydrous ethanol, stir until completely dissolved, and then add 0.22-0.3 g of palladium carbon catalyst to react; S6. After the reaction is completed, 1 mol / L sodium hydroxide solution is added dropwise to adjust the pH value of the system to 8-9, and then filtered, washed with anhydrous ethanol 2-3 times, and finally placed in a vacuum drying oven for drying to obtain a flame retardant filler.

6. The low dynamic fatigue polyurethane elastomer according to claim 5, characterized in that: In S1, the reaction is carried out in an ice bath and the reaction time is 9-11 hours; In S2, the temperature is raised to 70-80°C and the reaction time is 8-10h.

7. The low dynamic fatigue polyurethane elastomer according to claim 5, characterized in that: In S4 and S6, the drying temperature is 40-50°C.

8. The low dynamic fatigue polyurethane elastomer according to claim 5, characterized in that: In S5, the reaction is carried out under anaerobic conditions, the temperature is raised to 70-80° C., and the reaction time is 2.5-4 h.

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