Modified polyurethane elastic material with high elastic modulus and application

Abstract

The invention discloses a modified polyurethane elastic material with high elastic modulus and application, the material comprises a component A and a component B, and the mass ratio of the component A to the component B is 1: 2; wherein the component A comprises, by mass, 55-65 parts of 3-functionality polyether polyol, 16-22 parts of 4-functionality polyether polyol, 8-12 parts of high-functionality polyether polyol, 4-8 parts of small-molecular diol, 3-6 parts of silicon dioxide and 0.8-2 parts of a lead octanoate catalyst, and the component B is an isocyanate prepolymer which is prepared from polymethylene polyphenyl polyisocyanate, 4, 4 '-biphenyl polyisocyanate, a polyurethane prepolymer, a polyurethane prepolymer, a polyurethane prepolymer, a polyurethane prepolymer, a polyurethane prepolymer, a polyurethane prepolymer, a polyurethane prepolymer, a polyurethane prepolymer and a polyurethane prepolymer. And the content of-NCO in the component B is 16%-20%. The invention aims at obtaining the elastic material with good mechanical property and sealing property, and providing a key material support for large-scale commercial application of an air energy storage technology.

Description

Technical Field

[0001] This invention relates to the field of polyurethane materials technology, and in particular to a modified polyurethane elastic material with high elastic modulus and its application. Background Technology

[0002] Air energy storage, as a highly promising large-scale physical energy storage technology, is mainly divided into compressed air energy storage and liquid air energy storage. Compressed air energy storage utilizes electricity to compress air and store it in high-pressure containers or underground caverns during periods of low electricity load, converting electrical energy into the internal energy of the air. During peak electricity load periods, the compressed air is released to drive a turbine to generate electricity, converting the internal energy back into electrical energy. Liquid air energy storage, on the other hand, uses cryogenic technology to liquefy and store air, utilizing the vaporization and expansion of the liquid air to generate electricity when needed. Air energy storage systems, with their advantages of large storage capacity, long service life, and environmental friendliness, show broad application prospects in areas such as power peak shaving, backup power, and renewable energy consumption.

[0003] In air energy storage systems, key components such as sealing devices, storage container liners, and flexible connections need to withstand frequent pressure changes, mechanical deformations, and environmental factors. Traditional materials such as rubber and plastics are insufficient to meet the requirements of air energy storage systems for high strength, high elasticity, fatigue resistance, and excellent sealing performance. Taking sealing devices as an example, if the material lacks elasticity, gaps can easily appear under pressure fluctuations, leading to compressed air leakage and reduced energy storage efficiency. If the material has poor fatigue resistance, frequent compression-release cycles will cause rapid aging and damage, affecting the stability and service life of the system. Polyurethane elastomers are a class of polymer materials containing urethane groups in their molecular chains, combining the high strength of plastics with the high elasticity of rubber. Their unique soft and hard segment structure allows for diverse performance characteristics to be achieved through molecular design and formulation adjustments.

[0004] Existing invention application CN104817683A discloses a polyurethane elastomer and its preparation method. The disclosed polyurethane elastomer comprises two parts, by weight: Component A: 100 parts of macromolecular diol, 5-20 parts of 1,5-naphthalene diisocyanate (NDI), 10-30 parts of terephthalic diisocyanate (PPDI), or 10-50 parts of 3,3-dimethyl-4,4-biphenyl diisocyanate (TODI); Component B: 0-100 parts of macromolecular diol, 8-30 parts of chain extender, and 0.02-0.5 parts of catalyst; the A / B weight ratio is 100 / 8-30. Although the prepolymer prepared by component A has good storage stability, low viscosity, and simplifies the production and casting process, it focuses on low viscosity, long operating time, and fluidity, thus failing to meet rigidity requirements. Summary of the Invention

[0005] The main objective of this invention is to provide a modified polyurethane elastic material with high elastic modulus and its application, aiming to solve the technical problem that existing polyurethane elastomers cannot meet the requirements of high strength, high elasticity, fatigue resistance and excellent sealing performance.

[0006] To achieve the above objectives, the present invention provides a modified polyurethane elastic material with high elastic modulus, the material comprising component A and component B in a mass ratio of 1:2;

[0007] Component A comprises the following ingredients by mass percentage:

[0008] 3-functional polyether polyol: 55~65 parts;

[0009] 4-functionality polyether polyols: 16-22 parts;

[0010] High-functionality polyether polyols: 8-12 parts;

[0011] Small molecule diols: 4-8 parts;

[0012] Silica: 3-6 parts;

[0013] Lead isooctanoate catalyst: 0.8~2 parts;

[0014] Component B is an isocyanate prepolymer, which is prepared by reacting polymethylene polyphenyl polyisocyanate, 4,4'-dihydroxydiphenylmethane and N-methyldiethanolamine. The -NCO content in component B is 16%~20%.

[0015] Optionally, the trifunctional polyether polyol in component A is polyoxypropylene triol, the small molecule diol is diethylene glycol, and the tetrafunctional polyether polyol is ethylenediamine polyether tetraol.

[0016] Optionally, the method for synthesizing the isocyanate prepolymer includes the following steps:

[0017] Step (1) Grind 4,4'-dihydroxydiphenylmethane to a particle size of less than 80 mesh;

[0018] In step (2), polymethylene polyphenyl polyisocyanate and 2,2-bis(4-hydroxyphenyl)propane from step (1) are mixed in a reactor at 25°C until dissolved, and then heated to 80°C to react until the -NCO content reaches 22%-23% to obtain prepolymer 1.

[0019] Step (3) Cool the prepolymer 1 to 25°C, add N-methyldiethanolamine dropwise and control the temperature to ≤35°C. After the dropwise addition is completed, raise the temperature to 80°C to react until the -NCO content reaches 16%~20%, and finally obtain the isocyanate prepolymer.

[0020] Optionally, the mass ratio of polymethylene polyphenyl polyisocyanate, 4,4'-dihydroxydiphenylmethane and N-methyldiethanolamine is (80~90):(10~15):(3~8).

[0021] Optionally, the polymethylene polyphenyl polyisocyanate is a mixture of polyisocyanates containing components with different functionalities.

[0022] Optionally, in step (1), 2,2-bis(4-hydroxyphenyl)propane needs to be dried in a vacuum drying oven before grinding.

[0023] Optionally, the reactor in step (2) is a reactor equipped with a stirring, temperature control and nitrogen protection device.

[0024] Furthermore, in order to achieve the above objectives, the present invention also provides the application of the modified polyurethane elastic material with high elastic modulus described above in sealing devices, energy storage container liners, and flexible connecting components in air energy storage systems.

[0025] Beneficial effects:

[0026] This invention employs a modified polyurethane elastic material with high elastic modulus. In component B, a benzene ring molecular structure with high cohesive energy is introduced into the molecular chain through a prepolymerization reaction. Furthermore, a nitrogen-containing tertiary amine molecular structure is regularly introduced into component B through a secondary prepolymerization reaction. The tertiary amine molecular structure enables the isocyanate prepolymer to achieve autocatalytic activity. This molecular design, through "molecular-level integration of rigid benzene ring segments and flexible methylene segments," resolves the contradiction between operating time and curing speed during the prepolymerization stage. The introduction of tertiary amine molecular segments into the modified isocyanate prepolymer in component B provides autocatalytic functionality, significantly accelerating the reaction rate and exhibiting good gel reaction selectivity, preventing the material from reacting with water. A bismuth-zinc composite catalyst is used in component A to further enhance gel reaction selectivity and resist water reaction. The introduction of polyether polyol R403 containing tertiary amine molecular segments into component A provides ultra-high activity, further improving the curing speed, minimizing contact time between the system and moisture, and reducing the possibility of foaming reactions. In summary, this integrated approach enables the material to achieve rapid curing and water-sensitivity. Ultimately, a modified polyurethane elastomer material with a high elastic modulus (above 1 GPa) was achieved, simultaneously exhibiting high elastic modulus and high toughness (maximum deformation exceeding 10%), thus combining excellent rigidity and toughness. Furthermore, the modified polyurethane elastomer material can be rapidly applied via spraying, cures quickly without sagging, and is water-sensitive, resisting damage caused by moisture in the construction environment. This provides crucial material support for the large-scale commercial application of air energy storage technology.

[0027] The reaction principle includes: (1) Component B of the material is a high-strength and high-toughness modified isocyanate prepolymer independently developed. Through stepwise prepolymerization, a large number of high cohesive energy benzene ring molecular chain segments are introduced, which can give the material excellent rigidity. The methylene in the 4,4'-dihydroxydiphenylmethane molecular chain segment can give the material excellent toughness; (2) Component A of the material is effectively combined with the types and proportions of 3-functional polyether polyol, 4-functional polyether polyol, high-functional polyether polyol, and diethylene glycol through formulation design and verification optimization, forming a harmonious and unified ratio of soft and hard segments and high internal cross-linking, which further improves the mechanical strength of the material. (3) Component A of the material introduces silica. The surface of silica is treated and contains a large number of hydroxyl groups, which can react with the isocyanate groups in the system and form a chemical link with the matrix, which has a strong reinforcing effect and greatly improves the elastic modulus of the material. Detailed Implementation

[0028] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0029] This invention provides a modified polyurethane elastic material with high elastic modulus. The material comprises component A and component B, with a mass ratio of component A to component B of 1:2. Component A, by mass percentage, comprises 55-65 parts of trifunctional polyether polyol, 16-22 parts of tetrafunctional polyether polyol, 8-12 parts of high-functionality polyether polyol, 4-8 parts of small molecule diol, 3-6 parts of silica, and 0.8-2 parts of lead octanoate catalyst. Component B is an isocyanate prepolymer, prepared by reacting polymethylene polyphenyl polyisocyanate, 4,4'-dihydroxydiphenylmethane, and N-methyldiethanolamine. The -NCO content in component B is 16%-20%.

[0030] Specifically, in component A, the trifunctional polyether polyol is polypropylene triol, the small molecule diol is diethylene glycol, the tetrafunctional polyether polyol is ethylenediamine polyether tetraol, and the high-functionality polyether polyol is sucrose polyether polyol. In specific embodiments, the trifunctional polyether polyol in component A is mainly R2304 produced by Wanhua Chemical Group Co., Ltd.; the tetrafunctional polyether polyol in component A is mainly R403 produced by Shandong Lanxing Dongda Co., Ltd.; the high-functionality polyether polyol in component A is mainly R4110 produced by Wanhua Chemical Group Co., Ltd.; the small molecule diol in component A is mainly diethylene glycol produced by Jinan Jinrihe Chemical Co., Ltd.; and the silica in component A is mainly D-60 produced by Jiangxi Liankai Chemical Co., Ltd. The catalyst in component A is DM-120, a lead isooctanoate catalyst produced by Yantai Sunshine Plastics Co., Ltd.

[0031] Among them, trifunctional polyether polyols serve as flexible matrices, primarily providing long-chain soft segments to form the basis of an elastic network; tetrafunctional polyether polyols serve as highly active crosslinking agents, with tertiary amine molecular segments resulting in high hydroxyl activity; high-functionality polyether polyols serve as rigid crosslinking agents, with a functionality ≥5, providing dense crosslinking points; small-molecule diols serve as phase structure regulators and short-chain extenders, promoting the formation of hard segment microdomains and adjusting the ratio of soft to hard segments; silica serves as a nano-reinforcing filler, requiring hydroxylation treatment in practical applications to allow its surface hydroxyl groups (-SiOH) to form covalent bonds with -NCO, achieving chemical bonding reinforcement (non-physical filling); lead isooctanoate catalyst DM-120 serves as a selective catalyst, preferentially catalyzing the reaction between -NCO and -NH2 / -OH, while inhibiting the side reaction between -NCO and H2O.

[0032] Furthermore, the isocyanate prepolymer is prepared by a stepwise prepolymerization reaction of polymethylene polyphenyl polyisocyanate, 4,4'-dihydroxydiphenylmethane, and N-methyldiethanolamine, and its synthesis method includes the following steps:

[0033] Step (1): Grind 4,4'-dihydroxydiphenylmethane to a particle size of less than 80 mesh; preferably, before grinding, 4,4'-dihydroxydiphenylmethane needs to be dried in a vacuum drying oven at 100°C for 3 hours, and then sealed and stored for later use.

[0034] Step (2) involves mixing polymethylene polyphenyl polyisocyanate and 4,4'-dihydroxydiphenylmethane from step (1) in a reactor at 30°C until dissolved, then heating to 80°C and reacting until the -NCO content reaches 22%-23%, yielding prepolymer 1. Specifically, in a reactor equipped with stirring, temperature control, and nitrogen protection devices, polymethylene polyphenyl polyisocyanate is added first, followed by 4,4'-dihydroxydiphenylmethane. The specific reaction equations for both are shown below:

[0035] .

[0036] In step (2), a rigid framework prepolymer is achieved. Specifically, the isocyanate group (-NCO) electrophilically attacks the hydroxyl group (-OH) to form a carbamate bond (-NHCOO-). The steric hindrance effect of the benzene ring inhibits the free rotation of the molecular chain, resulting in a rigid framework structure of the prepolymer. PMDI provides multiple -NCO groups. After reacting with bisphenol A, prepolymer 1 still contains ≥2 unreacted -NCO groups, reserving active sites for subsequent chain extension.

[0037] Step (3): Cool prepolymer 1 to 25°C, slowly add N-methyldiethanolamine dropwise, maintaining the temperature ≤35°C during the dropwise addition. After the dropwise addition is complete, raise the temperature to 80°C to react until the -NCO content reaches 16%~20%, obtaining the target isocyanate prepolymer with autocatalytic function. The specific reaction equation is shown below:

[0038] .

[0039] In step (3), a tertiary amine intercalation catalytic structure is formed. Specifically, the secondary amine group (-NH-) of MDEA preferentially reacts with the -NCO of prepolymer 1 to form a flexible ether bond segment (-O-CH2-CH2-), thereby enhancing the deformation capability. The tertiary amine group is activated by the -NCO group through a proton transfer mechanism, and the reaction formula is R3N:+R'NCO→[R3N + -C(O - [NR'], and can be used to accelerate the reaction with component A. The final -NCO content is 16–20%, ensuring the reactivity of component B.

[0040] Preferably, in the above synthesis steps, the mass ratio of polymethylene polyphenyl polyisocyanate, 4,4'-dihydroxydiphenylmethane, and N-methyldiethanolamine is (80~90):(10~15):(3~8). Polymethylene polyphenyl polyisocyanate (PAPI) is a mixture of polyisocyanates containing components with different functionalities. Approximately 40%-50% of PAPI consists of diisocyanates (including isomers such as 4,4'-MDI and 2,4'-MDI), with the remainder being triisocyanates and polyisocyanates. It is prepared by condensing aniline and formaldehyde under acidic conditions, followed by reaction with phosgene. Its composition includes various compounds with different degrees of polymerization and functionality based on the diphenylmethane diisocyanate structure. Here, "functionality" specifically refers to the number of isocyanate groups (-NCO) carried on each molecule.

[0041] Furthermore, to better illustrate the synthesis method of isocyanate prepolymers, the following specific examples are provided:

[0042] Example 1

[0043] (1) Raw material ratio

[0044]

[0045] (2) Synthesis steps

[0046] 1) Raw material pretreatment: Dry 4,4'-dihydroxydiphenylmethane in a vacuum drying oven at 100℃ for 3 hours, grind it until the particle size is less than 80 mesh, and store it in a sealed container.

[0047] 2) Synthesis of Prepolymer 1: In a reactor equipped with a stirrer, temperature control, and nitrogen protection device, 830g of WANNATE® PM-200 was first added, followed by 120g of 4,4'-dihydroxydiphenylmethane. The mixture was stirred and mixed at 30°C for 3 hours until completely dissolved. Then, the temperature was gradually increased to 80°C, and the mixture was stirred and prepolymerized for 2 hours until the -NCO content was measured to be 22.22%, thus obtaining Prepolymer 1.

[0048] 3) Preparation of autocatalytic prepolymer: Lower the reactor temperature to 25°C, and slowly add 50g of N-methyldiethanolamine (MDEA) dropwise, keeping the temperature below 35°C during the addition process. After the addition is complete, raise the temperature to 80°C to continue the reaction. When the -NCO content reaches 17.58%, stop the reaction and package it with nitrogen.

[0049] (3) Performance testing

[0050] NCO content: 17.58%; viscosity: 650 MPa.

[0051] Example 2

[0052] (1) Raw material ratio

[0053]

[0054] (2) Synthesis steps

[0055] 1) Raw material pretreatment: Dry 4,4'-dihydroxydiphenylmethane in a vacuum drying oven at 100℃ for 3 hours, grind it until the particle size is less than 80 mesh, and store it in a sealed container.

[0056] 2) Synthesis of Prepolymer 1: In a reactor equipped with a stirrer, temperature control, and nitrogen protection device, 900g of WANNATE® PM-200 was first added, followed by 120g of 2,2-bis(4-hydroxyphenyl)propane. The mixture was stirred and mixed at 30°C for 3 hours until completely dissolved. Then, the temperature was gradually increased to 80°C, and the mixture was stirred and prepolymerized for 2 hours until the -NCO content was measured to be 22.85%, thus obtaining Prepolymer 1.

[0057] 3) Preparation of autocatalytic prepolymer: Lower the reactor temperature to 25°C, and slowly add 70g of N-methyldiethanolamine (MDEA) dropwise, keeping the temperature below 35°C during the addition. After the addition is complete, raise the temperature to 80°C to continue the reaction. When the -NCO content reaches 16.786%, stop the reaction and package it with nitrogen.

[0058] (3) Performance testing

[0059] NCO content: 16.86%; viscosity: 710 MPa.

[0060] Furthermore, the method of using the modified polyurethane elastic material is as follows: add the raw material of component A to a clean reactor in sequence, stir at 500 r / min for 1 hour to ensure that the materials are fully mixed to obtain component A; prepare component B by the aforementioned synthesis method of isocyanate prepolymer; then mix components A and B in a spraying machine and spray the mixture to obtain a material that can be rapidly cured.

[0061] In this material, components A and B are mixed at a mass ratio of 1:2, resulting in rapid cross-linking and curing to form a three-dimensional polyurethane network. The modified isocyanate prepolymer in component B incorporates tertiary amine molecular segments, exhibiting autocatalytic activity, significantly accelerating the reaction rate, and demonstrating excellent gel reaction selectivity, thus preventing the material from reacting with water. Component A utilizes a lead isooctanoate catalyst, further enhancing gel reaction selectivity and resisting reaction with water. The introduction of polyether polyol R403 containing tertiary amine molecular segments into the component A system provides ultra-high activity, further improving the curing speed, minimizing contact time between the system and moisture, and reducing the likelihood of foaming reactions.

[0062] Furthermore, to better illustrate the effects of modified polyurethane elastic materials with high elastic modulus, specific examples are provided below.

[0063] Example 3

[0064] (1) Raw material ratio

[0065]

[0066] (2) Preparation process

[0067] 1) Add component A raw material to a clean reactor in sequence and stir at 500 r / min for 1 hour to ensure that all materials are fully mixed and form a homogeneous material. Package the material under dry conditions for later use.

[0068] 2) Use a spraying machine (which can achieve an AB material mass ratio of 1:2 and the liquid material can be heated to 60℃) to fully mix the AB components and then spray them. After the material has been cured and matured, test its properties.

[0069] (3) Performance testing

[0070]

[0071] Example 4

[0072] (1) Raw material ratio

[0073]

[0074] (2) Preparation process

[0075] 1) Add component A raw material to a clean reactor in sequence and stir at 500 r / min for 1 hour to ensure that all materials are fully mixed and form a homogeneous material. Package the material under dry conditions for later use.

[0076] 2) Use a spraying machine (which can achieve an AB material mass ratio of 1:2 and the liquid material can be heated to 60℃) to fully mix the AB components and then spray them. After the material has been cured and matured, test its properties.

[0077] (3) Performance testing

[0078]

[0079] As demonstrated in Examples 3-4 above, the spraying and curing process requires only 5-6 seconds, does not require a vacuum environment, and the resulting material has an elastic modulus of over 1.1 GPa, a maximum deformation of ≥12.5%, and exhibits acid and alkali resistance, with no bubbles generated after spraying. Therefore, the synergistic reaction of components A and B achieves high rigidity (modulus ≥1 GPa), high toughness (deformation ≥10%), and rapid curing (5-6 seconds).

[0080] The reaction essentially involves: rigid benzene ring segments reinforced by chemical bonding with silica, achieving high rigidity; flexible methylene segments and microphase separation of hard and soft segments achieving high toughness; and the ultra-high activity of R403 combined with dual catalysis achieving rapid curing. Selective catalysis and rapid gelation block water molecules, resulting in a zero-bubble (water-sensitive) effect. Polyether polyols (-OH), including R2304 (trifunctional), R4110 (high functionality), and diethylene glycol (chain extender), can form urethane bonds (-NHCOO-) to construct a cross-linked network. The hydroxyl groups on the surface of silica D-60 (-SiOH) are covalently bonded to -NCO, achieving nanoscale reinforcement. Lead isooctanoate catalyst (DM-120) selectively catalyzes the reaction between -NCO and -NH2 / -OH (Lewis acid mechanism), inhibiting the side reaction R−NCO+H2O→R−NH2+CO2↑. The water-sensitive effect is achieved by preferentially consuming -NCO (R403 dominant), blocking water molecule contact, and thus eliminating bubbles. The autocatalytic synergy of the tertiary amine groups in component B (from MDEA) accelerates the reaction, further shortening the curing time. It also achieves a balance between rigidity and toughness: rigidity is achieved through benzene ring segments (component B) + high-functionality polyol (R4110) + silica reinforcement. Toughness is achieved through methylene segments (component B) + soft-segment polyol (R2304) + diethylene glycol chain extenders.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the protection scope of the present invention.

Claims

1. A modified polyurethane elastic material with high elastic modulus, characterized in that, The material comprises component A and component B in a mass ratio of 1:

2. Component A, by mass percentage, comprises 55-65 parts of trifunctional polyether polyol, 16-22 parts of tetrafunctional polyether polyol, 8-12 parts of high-functionality polyether polyol, 4-8 parts of small molecule diol, 3-6 parts of silica, and 0.8-2 parts of catalyst. Component B is an isocyanate prepolymer, which is prepared by reacting polymethylene polyphenyl polyisocyanate, 4,4'-dihydroxydiphenylmethane and N-methyldiethanolamine. The -NCO content in component B is 16%~20%.

2. The modified polyurethane elastic material with high elastic modulus according to claim 1, characterized in that, The trifunctional polyether polyol in component A is polyoxypropylene triol, the small molecule diol is diethylene glycol, and the tetrafunctional polyether polyol is ethylenediamine polyether tetraol.

3. The modified polyurethane elastic material with high elastic modulus according to claim 1, characterized in that, The method for synthesizing the isocyanate prepolymer includes the following steps: Step (1) Grinding 4,4'-dihydroxydiphenylmethane to a particle size of less than 80 mesh; In step (2), polymethylene polyphenyl polyisocyanate and 4,4'-dihydroxydiphenylmethane from step (1) are mixed in a reactor at 30°C until dissolved, and then heated to 80°C to react until the -NCO content reaches 22%-23% to obtain prepolymer 1. Step (3) Cool the prepolymer 1 to 25°C, add N-methyldiethanolamine dropwise and control the temperature to ≤35°C. After the dropwise addition is completed, raise the temperature to 80°C to react until the -NCO content reaches 16%~20%, and finally obtain the isocyanate prepolymer.

4. The modified polyurethane elastic material with high elastic modulus according to claim 3, characterized in that, The mass ratio of polymethylene polyphenyl polyisocyanate, 4,4'-dihydroxydiphenylmethane and N-methyldiethanolamine is (80~90):(10~15):(3~8).

5. The modified polyurethane elastic material with high elastic modulus according to claim 1, characterized in that, The polymethylene polyphenyl polyisocyanate is a mixture of polyisocyanates containing components with different functionalities.

6. The modified polyurethane elastic material with high elastic modulus according to claim 3, characterized in that, In step (1), 2,2-bis(4-hydroxyphenyl)propane needs to be dried in a vacuum drying oven before grinding.

7. The modified polyurethane elastic material with high elastic modulus according to claim 3, characterized in that, The reactor in step (2) is equipped with a stirring, temperature control and nitrogen protection device.

8. The application of the modified polyurethane elastic material with high elastic modulus according to any one of claims 1 to 7 in an air energy storage system.

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