High-heat-resistant tpu composite material and preparation method thereof

Abstract

The application belongs to the polyurethane field, and specifically discloses a high-heat-resistance TPU composite material and a preparation method thereof, which comprises the following steps: mixing polyether polyol, isocyanate, glycidyl-POSS and a catalyst, heating and reacting under a nitrogen atmosphere, vacuum defoaming after the reaction is completed, and obtaining a polyurethane prepolymer; mixing the polyurethane prepolymer with a chain extender and a reinforcing aid, heating and reacting under a nitrogen atmosphere, pouring into a mold for solidification after the reaction is completed, cooling, and obtaining the high-heat-resistance TPU composite material. The TPU composite material prepared by the application has good thermal stability, good heat resistance and good oxidation resistance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polyurethane, and particularly relates to a high-heat-resistance TPU composite material and a preparation method thereof. BACKGROUND

[0002] Polyurethane is a typical block copolymer, which is formed by stepwise addition polymerization of polyester, polyether and polyolefin oligomer polyols, polyisocyanate and diol or diamine chain extender. As an excellent engineering material, polyurethane has good mechanical properties, low temperature resistance, corrosion resistance, chemical resistance, impact resistance, good resilience, and good adhesion with other materials, and has very wide application in sealing materials, water-lubricated bearings, oil fields, machinery, textiles, construction and other fields. Polyurethane has the characteristics of both plastics and rubber, and still maintains a certain elasticity at high hardness, but the endogenous heat of polyurethane is large, and the heat resistance is poor, which will lose its value at high temperature.

[0003] Chinese patent CN105315653A discloses a heat-resistant damping reinforced modified TPU composite material, which comprises the following components: TPU particles, hindered phenol, modified graphene, heat-resistant composite filler, wherein the heat-resistant composite filler is a mixture of diatomite and montmorillonite. The patent improves the heat resistance and mechanical properties of TPU material by adding modified graphene and heat-resistant composite filler; Chinese patent CN107778829A discloses a high-performance TPU composite material, which comprises the following components: thermoplastic polyurethane elastomer, long glass fiber, compatibilizer, flow modifier, chain extender, heat stabilizer, ultraviolet light absorber. The patent improves the flowability of the matrix by adding a flowability modifier and improves the heat resistance of the TPU material by adding a heat stabilizer. However, the above methods use a large number of additives, which can easily lead to unstable material performance, and the production process is complex, and the modification of inorganic fillers can easily cause pollution. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a high-heat-resistance TPU composite material, which introduces a POSS cage structure into the polyurethane molecular backbone, and cooperates with a specific chain extender 3,3'-dimethyl-4,4'-diamino diphenyl methane to limit the movement of polyurethane segments and enhance microphase separation, thereby improving the thermal stability of polyurethane and effectively improving the heat resistance. The present application also provides a preparation method of the above-mentioned TPU composite material.

[0005] A high-heat-resistance TPU composite material is prepared from the following raw materials by weight:

[0006] 100-150 parts by weight of polyether polyol, 30-50 parts by weight of isocyanate, 2-8 parts by weight of catalyst, 10-20 parts by weight of glycidyl-POSS, 10-15 parts by weight of chain extender, 6-12 parts by weight of reinforcing aid.

[0007] The polyurethane is composed of isocyanate rigid segments and polyol soft segments, and the two phases form physical crosslinking through hydrogen bonding, and the rigid segments and the soft segments have a spontaneous separation tendency in thermodynamics and microphase separation occurs, so the degree of microphase separation is closely related to the thermal stability of the polyurethane. The glycidyl-POSS structure is introduced into the polyurethane molecular backbone, and the POSS cage structure can limit the movement of the polyurethane segment, and based on the symmetrical and regular molecular structure, it can also enhance the microphase separation and improve the glass transition temperature of the polyurethane, thereby improving the thermal stability of the polyurethane and effectively improving the heat resistance.

[0008] Preferably, the chain extender is 3,3'-dimethyl-4,4'-diaminodiphenyl methane.

[0009] Preferably, the chain extender is 3,3'-dimethyl-4,4'-diaminodiphenyl methane, which has good stability and is not easy to entangle, and can effectively enhance the connection strength between the soft segment and the rigid segment. At the same time, by virtue of the similar molecular structure of 4,4'-diphenyl methane diisocyanate, the 4,4'-diphenyl methane diisocyanate generates a uniform rigid segment structure under the chain extension effect of the chain extender, and this high-regular molecular structure is conducive to hard segment stacking, enhancing microphase separation, improving the crystallinity of the polyurethane, and solving the problem of crystallization performance decline caused by the destruction of the rigid segment crystallization area by the glycidyl-POSS cage structure. Moreover, the amino group contained therein can form hydrogen bonds with the polyol soft segment to limit the movement and curling of the polyol soft segment, thereby further improving the heat resistance.

[0010] Preferably, the reinforcing aid is at least one of sorbitan monostearate and 1,1'-bis(diphenylphosphine) ferrocene.

[0011] Sorbitan monostearate is used as one of the reinforcing aids in the present application, and the molecular structure of sorbitan monostearate has a flexible stearic acid chain and a rigid sorbitol core. After introducing it into the soft segment of the polyurethane, the soft segment obtains a certain rigidity, which not only improves the heat resistance of the polyurethane material, but also improves its flexibility.

[0012] When the polyurethane is used for a long time in a hot oxygen environment, oxidative decomposition occurs due to the contact of oxygen in the air, which reduces the performance of the polyurethane material and seriously affects the service life. The application uses 1,1'-bis(diphenylphosphine) ferrocene as one of the reinforcing aids, which can effectively solve the above problems. Compared with traditional anti-oxidizing aids, it has the advantages of good migration resistance and safety without pollution, and the main action mechanism is as follows: by introducing the ferrocene unit into the polyurethane molecular chain through 1,1'-bis(diphenylphosphine) ferrocene, charge transfer occurs with free radicals, and then oxidative decomposition into iron-oxygen clusters, which can form a coordination nanostructure in situ with the active groups generated by the chain scission of polyurethane and repair the polyurethane molecular chain, thereby playing a role in resisting oxidation and effectively preventing the decrease of mechanical properties.

[0013] Further preferably, the reinforcing aid is composed of sorbitan monostearate, 1,1'-bis(diphenylphosphine) ferrocene in a mass ratio of 16:1-5.

[0014] Preferably, the isocyanate is at least one of 4,4'-diphenylmethane diisocyanate, phenylene-1,4-diisocyanate, toluene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

[0015] Preferably, the polyether polyol is at least one of polytetrahydrofuran diol, THF-homopolyether diol, and polytrimethylene ether diol.

[0016] Preferably, the catalyst is at least one of dibutyltin dilaurate, tin 2-ethylhexanoate, triethylenediamine, ethylene glycol antimony, and titanium acid tetraisopropyl ester.

[0017] A preparation method of a high-heat-resistance TPU composite material, comprising the following steps:

[0018] The polyether polyol, the isocyanate, the glycidyl-POSS, and the catalyst are mixed according to the formula, and stirred and reacted under a nitrogen atmosphere at 90-100 DEG C for 90-120 min; after the reaction is completed, vacuum degassing is performed to obtain a polyurethane prepolymer;

[0019] The polyurethane prepolymer is mixed with the chain extender and the reinforcing aid, and stirred and reacted under a nitrogen atmosphere at 80-85 DEG C for 120-150 min; after the reaction is completed, the mixture is poured into a polytetrafluoroethylene mold to be solidified, and then cooled to obtain the high-heat-resistance TPU composite material.

[0020] The application has the following beneficial effects:

[0021] 1. The TPU composite material prepared by the application has good thermal stability, good heat resistance, and good oxidation resistance.

[0022] 2、The application improves the thermal stability of the polyurethane and effectively improves the heat resistance by introducing the POSS cage structure in the polyurethane molecular main chain and cooperating with the specific chain extender 3,3'-dimethyl-4,4'-diamino diphenyl methane to limit the movement of the polyurethane segment and enhance the microphase separation.

[0023] 3、The application uses sorbitan monostearate and 1,1'-bis(diphenylphosphine) ferrocene as reinforcing aids, which can not only improve the heat resistance and flexibility of the polyurethane material, but also solve the problem of performance degradation of the polyurethane in a hot oxygen environment. DETAILED DESCRIPTION

[0024] The above inventive content of the application will be further described in detail in combination with specific embodiments, but it should not be understood that the scope of the above subject matter of the application is limited to the following examples.

[0025] Polytetrahydrofuran diol, number average molecular weight: 1000.

[0026] 4,4'-diphenyl methane diisocyanate, CAS: 101-68-8.

[0027] Glycidyl-POSS, CAS: 230316-12-8.

[0028] 3,3'-dimethyl-4,4'-diamino diphenyl methane, CAS: 838-88-0.

[0029] Sorbitan monostearate, CAS: 1338-41-6.

[0030] 1,1'-bis(diphenylphosphine) ferrocene, CAS: 12150-46-8.

[0031] Example 1

[0032] A high-heat-resistance TPU composite material is composed of the following raw materials by weight:

[0033] 120 parts by weight of polytetrahydrofuran diol, 45 parts by weight of 4,4'-diphenyl methane diisocyanate, 5 parts by weight of catalyst dibutyltin dilaurate, 15 parts by weight of glycidyl-POSS, 12 parts by weight of chain extender 3,3'-dimethyl-4,4'-diamino diphenyl methane, 8 parts by weight of sorbitan monostearate, 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene.

[0034] A preparation method of a high-heat-resistance TPU composite material is as follows:

[0035] Mix 120 parts by weight of polytetrahydrofuran diol, 45 parts by weight of 4,4'-diphenyl methane diisocyanate, 15 parts by weight of glycidyl-POSS and 5 parts by weight of catalyst dibutyl tin dilaurate, stir and react under nitrogen atmosphere at 97℃ for 115 minutes, after the end of the reaction, vacuum degassing, to obtain a polyurethane prepolymer;

[0036] Mix the above polyurethane prepolymer with 12 parts by weight of chain extender 3,3'-dimethyl-4,4'-diamino diphenyl methane, 8 parts by weight of sorbitan monostearate, 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene, stir and react under nitrogen atmosphere at 83℃ for 145 minutes, after the end of the reaction, pour into a polytetrafluoroethylene mold to solidify, cool, to obtain the high heat resistance TPU composite material.

[0037] Example 2

[0038] A high heat resistance TPU composite material, consisting of the following parts by weight of raw materials:

[0039] 120 parts by weight of polytetrahydrofuran diol, 45 parts by weight of 4,4'-diphenyl methane diisocyanate, 5 parts by weight of catalyst dibutyl tin dilaurate, 12 parts by weight of chain extender 3,3'-dimethyl-4,4'-diamino diphenyl methane, 8 parts by weight of sorbitan monostearate, 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene.

[0040] A method for preparing a high heat resistance TPU composite material is as follows:

[0041] Mix 120 parts by weight of polytetrahydrofuran diol, 45 parts by weight of 4,4'-diphenyl methane diisocyanate and 5 parts by weight of catalyst dibutyl tin dilaurate, stir and react under nitrogen atmosphere at 97℃ for 115 minutes, after the end of the reaction, vacuum degassing, to obtain a polyurethane prepolymer;

[0042] Mix the above polyurethane prepolymer with 12 parts by weight of chain extender 3,3'-dimethyl-4,4'-diamino diphenyl methane, 8 parts by weight of sorbitan monostearate, 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene, stir and react under nitrogen atmosphere at 83℃ for 145 minutes, after the end of the reaction, pour into a polytetrafluoroethylene mold to solidify, cool, to obtain the high heat resistance TPU composite material.

[0043] Example 3

[0044] A high heat resistance TPU composite material, consisting of the following parts by weight of raw materials:

[0045] 120 parts by weight of polytetrahydrofuran diol, 45 parts by weight of 4,4'-diphenyl methane diisocyanate, 5 parts by weight of catalyst dibutyl tin dilaurate, 15 parts by weight of glycidyl-POSS, 12 parts by weight of chain extender 3,3'-dimethyl-4,4'-diamino diphenyl methane, 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene.

[0046] A method for preparing a high-heat-resistant TPU composite material is as follows:

[0047] 120 parts by weight of polytetrahydrofuran diol, 45 parts by weight of 4,4'-diphenyl methane diisocyanate, 5 parts by weight of catalyst dibutyl tin dilaurate, 15 parts by weight of glycidyl-POSS, 12 parts by weight of chain extender 3,3'-dimethyl-4,4'-diamino diphenyl methane, 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene.

[0048] The above polyurethane prepolymer is mixed with 12 parts by weight of chain extender 3,3'-dimethyl-4,4'-diamino diphenyl methane, 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene, stirred and reacted at 83°C under a nitrogen atmosphere for 145 min, after which it is poured into a polytetrafluoroethylene mold to solidify, cooled, and the high-heat-resistant TPU composite material is obtained.

[0049] Example 4

[0050] A high-heat-resistant TPU composite material is composed of the following parts by weight of raw materials:

[0051] 120 parts by weight of polytetrahydrofuran diol, 45 parts by weight of 4,4'-diphenyl methane diisocyanate, 5 parts by weight of catalyst dibutyl tin dilaurate, 15 parts by weight of glycidyl-POSS, 12 parts by weight of chain extender 3,3'-dimethyl-4,4'-diamino diphenyl methane, 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene.

[0052] A method for preparing a high-heat-resistant TPU composite material is as follows:

[0053] 120 parts by weight of polytetrahydrofuran diol, 45 parts by weight of 4,4'-diphenyl methane diisocyanate, 5 parts by weight of catalyst dibutyl tin dilaurate, 15 parts by weight of glycidyl-POSS, 12 parts by weight of chain extender 3,3'-dimethyl-4,4'-diamino diphenyl methane, 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene.

[0054] The above polyurethane prepolymer is mixed with 12 parts by weight of chain extender 3,3'-dimethyl-4,4'-diamino diphenyl methane, 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene, stirred and reacted at 83°C under a nitrogen atmosphere for 145 min, after which it is poured into a polytetrafluoroethylene mold to solidify, cooled, and the high-heat-resistant TPU composite material is obtained.

[0055] Example 5

[0056] A high-heat-resistant TPU composite material, which is composed of the following raw materials in parts by weight:

[0057] 120 parts by weight of polytetrahydrofuran diol, 45 parts by weight of 4,4'-diphenyl methane diisocyanate, 5 parts by weight of catalyst dibutyltin dilaurate, 15 parts by weight of glycidyl-POSS, 12 parts by weight of chain extender 1,6-hexanediol, 8 parts by weight of sorbitan monostearate, and 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene.

[0058] A method for preparing a high-heat-resistant TPU composite material is as follows:

[0059] Mix 120 parts by weight of polytetrahydrofuran diol, 45 parts by weight of 4,4'-diphenyl methane diisocyanate, 15 parts by weight of glycidyl-POSS, and 5 parts by weight of catalyst dibutyltin dilaurate, and stir and react at 97°C under a nitrogen atmosphere for 115 minutes. After the reaction is completed, vacuum degassing is performed to obtain a polyurethane prepolymer.

[0060] Mix the above polyurethane prepolymer with 12 parts by weight of chain extender 1,6-hexanediol, 8 parts by weight of sorbitan monostearate, and 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene, and stir and react at 83°C under a nitrogen atmosphere for 145 minutes. After the reaction is completed, pour into a polytetrafluoroethylene mold to solidify, and cool to obtain the high-heat-resistant TPU composite material.

[0061] Test Example 1

[0062] Thermal decomposition temperature: The thermal decomposition temperature of the above TPU composite material is determined by a TGA thermal gravimetric analysis system. The temperature is raised from 25°C to 600°C at a rate of 10°C / min, and the temperature at which 5% weight loss occurs is taken as the thermal decomposition temperature, denoted as T 5％ .

[0063] Table 1. Thermal decomposition temperature of TPU composite material

[0064] T 5％ (°C) Example 1 331.5 Example 2 298.2 Example 3 317.8 Example 4 323.6 Example 5 325.0

[0065] Test Example 2

[0066] Heat resistance and mechanical properties: The above TPU composite material is heat aged at 120°C for 24 hours, the tensile strength is determined according to national standard GB / T1040.2-2022, and the tensile strength retention rate is calculated. Tensile strength retention rate % = tensile strength after heat aging / initial tensile strength × 100%.

[0067] Table 2. Heat resistance and mechanical properties of TPU composite material

[0068]

[0069] From the test results, compared with examples 2-5, the TPU composite material of example 1 has the best heat resistance and thermal stability. On the one hand, example 1 introduces glycidyl-POSS structure into the polyurethane molecular backbone, and this POSS cage structure can limit the movement of polyurethane segments, and based on its symmetrical and regular molecular structure, it can also enhance the microphase separation and improve the glass transition temperature of polyurethane, thereby improving the thermal stability of polyurethane and effectively improving the heat resistance. The preferred 3,3'-dimethyl-4,4'-diamino diphenyl methane as a chain extender can effectively enhance the connection strength between the soft segment and the rigid segment, and at the same time, using its similar molecular structure to 4,4'-diphenyl methane diisocyanate, 4,4'-diphenyl methane diisocyanate generates uniform rigid segment structure under its chain extension, which is beneficial to the accumulation of hard segments, enhances the microphase separation, limits the movement and curling of polyol soft segments, and further improves the heat resistance.

[0070] On the other hand, example 1 uses sorbitan monostearate as a reinforcing aid, which has a flexible stearic acid chain and a rigid sorbitol core. After introducing it into the soft segment of polyurethane, the soft segment obtains a certain rigidity, which not only improves the heat resistance of polyurethane material, but also improves its flexibility. 1,1'-bis(diphenylphosphine) ferrocene is used as a reinforcing aid, which has the advantages of good migration resistance, safety and no pollution. By introducing ferrocene units into the polyurethane molecular chain, it undergoes charge transfer with free radicals, and then oxidizes and decomposes into iron-oxygen clusters, which can form coordination nanostructures with the active groups generated by the chain scission of polyurethane in situ and repair the polyurethane molecular chain, play a role in oxidation resistance, and effectively prevent the decline of mechanical properties.

[0071] The above describes in detail the preferred embodiments of the present application. It should be understood that those skilled in the art can make many modifications and changes without creative labor according to the concept of the present application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment based on the prior art according to the concept of the present application should be within the scope of protection determined by the claims.

Claims

1. A high heat resistant TPU composite material, characterized in that: The raw materials include: 100-150 parts by weight of polyether polyol, 30-50 parts by weight of isocyanate, 2-8 parts by weight of catalyst, 10-20 parts by weight of glycidyl-POSS, 10-15 parts by weight of chain extender, 6-12 parts by weight of reinforcing aid; the chain extender is 3,3'-dimethyl-4,4'-diamino diphenyl methane; the reinforcing aid is composed of sorbitol anhydrous monostearate, 1,1'-bis(diphenylphosphine) ferrocene in a mass ratio of 16:1-5; the isocyanate is 4,4'-diphenyl methane diisocyanate.

2. The high heat resistant TPU composite of claim 1, wherein: The polyether polyol is at least one of polytetrahydrofuran diol and polytrimethylene ether glycol.

3. The high heat resistant TPU composite of claim 1, wherein: The catalyst is at least one of dibutyl tin dilaurate, tin 2-ethylhexanoate, triethylene diamine, ethylene glycol antimony, and titanium acid tetraisopropyl ester.

4. The high heat resistant TPU composite of claim 1, wherein: The raw materials include: 120 parts by weight of polytetrahydrofuran diol, 45 parts by weight of 4,4'-diphenyl methane diisocyanate, 5 parts by weight of dibutyl tin dilaurate, 15 parts by weight of glycidyl-POSS, 12 parts by weight of 3,3'-dimethyl-4,4'-diamino diphenyl methane, 8 parts by weight of sorbitol anhydrous monostearate, and 1.5 parts by weight of 1,1'-bis(diphenylphosphine) ferrocene.

5. The method of producing a high heat resistant TPU composite material according to any one of claims 1 to 4, characterized in that: The steps include: The polyether polyol, isocyanate, glycidyl-POSS, and catalyst are mixed according to the formula, heated and reacted under a nitrogen atmosphere, vacuum degassed after the end, and a polyurethane prepolymer is obtained; The above polyurethane prepolymer is mixed with the chain extender and reinforcing aid, heated and reacted under a nitrogen atmosphere, poured into a mold to solidify after the end, cooled, and the high-heat-resistant TPU composite material is obtained.

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