A process for the preparation of a high resilience polyurethane material

Abstract

This invention belongs to the field of materials technology, specifically relating to a method for preparing a high-resilience polyurethane material. This invention involves preparing a flame-retardant chain extender to participate in the chain-extended polymerization of polyurethane. Firstly, the flame-retardant chain extender contains both primary and secondary amine groups, thus acting as a crosslinking agent to some extent during the chain-extended polymerization process. By strictly controlling its addition amount, a moderate crosslinking effect can be achieved on the polyurethane molecular chains, limiting irreversible slippage of the polyurethane molecular chains under stress, reducing energy dissipation, and effectively improving the resilience of the polyurethane material. Simultaneously, since the flame-retardant chain extender also contains nitrogen and phosphorus flame-retardant elements, it can promote the rapid catalytic formation of an expanding carbon layer in the early stages of combustion, reducing heat transfer and isolating gases, thus effectively improving the flame-retardant properties of the polyurethane material.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, specifically relating to a method for preparing a high-resilience polyurethane material. Background Technology

[0002] Polyurethane (PU) is a class of polymeric materials containing urethane groups (-NH-CO-O-) in its molecular chain. It is typically produced by polymerization of polyols (soft segments) with isocyanates and chain extenders (hard segments). Its unique thermodynamic incompatibility between soft and hard segments endows the material with a microphase-separated structure, giving it high elasticity, high wear resistance, high load-bearing capacity, and excellent oil and chemical corrosion resistance, earning it the reputation of a "revolutionary new polymeric material." Currently, polyurethane elastomers are widely used in industrial transmissions, footwear materials, automotive parts, and medical devices.

[0003] Resilience is one of the core indicators for evaluating the dynamic performance of polyurethane materials, especially crucial in applications involving high-frequency vibration, repeated compression, or impact absorption. For example, in high-performance athletic shoe midsoles, robotic bionic skin, and various cushioning and shock-absorbing components, materials not only need to withstand continuous dynamic loads but also need to quickly return to their original shape after each deformation to ensure the operational accuracy and long-term stability of the equipment. However, the resilience rate of traditional polyurethane materials is difficult to exceed 50%, which is insufficient for practical applications. Furthermore, polyurethane materials have poor flame retardant properties, especially foamed polyurethane materials, posing a serious fire hazard. These shortcomings limit the further application of polyurethane materials.

[0004] In summary, developing a polyurethane material that combines high resilience and good flame retardancy is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing high-resilience polyurethane materials.

[0006] In a first aspect, the present invention provides a method for preparing a high-resilience polyurethane material, wherein the polyurethane material comprises the following raw materials in parts by weight:

[0007] Polyol A: 72-78 parts;

[0008] Polyol B: 18-25 parts;

[0009] Foam stabilizer: 0.4-0.8 parts;

[0010] Catalyst A: 0.4-0.6 parts;

[0011] Catalyst B: 0.1-0.3 parts;

[0012] Diethanolamine: 1-3 parts;

[0013] Flame-retardant chain extender: 0.8-1.2 parts;

[0014] Foaming agent: 0.1-0.3 parts;

[0015] Isocyanate monomer: 45-55 parts;

[0016] The preparation method includes the following steps:

[0017] Step 1: Under normal temperature conditions, add polyol A, polyol B, foam stabilizer, catalyst A, catalyst B, diethanolamine, flame retardant chain extender and foaming agent to the mixing tank, and stir and mix evenly at a speed of 80-100 rpm to form component A.

[0018] The second step is to add the isocyanate monomer to the mixer and continue to stir and mix until component B is formed.

[0019] The third step is to mix component A and component B, then pour the mixture into a mold for foaming. The mold temperature is controlled at 50-60℃, and the foaming time is 20-40 minutes. Then, the temperature is adjusted to 60-70℃ and the mixture is cured for 1-2 hours. After heating, the mixture is cooled to room temperature and allowed to mature for 5-15 minutes. The mold is then opened to obtain the polyurethane material.

[0020] As a preferred embodiment of the present invention, the polyol A is polytetrahydrofuran ether diol with a number average molecular weight of 2000; the polyol B is polyether polyol DEP-5631ED; the foam stabilizer is TEGOSTAB® B8738 LF2; the catalyst A is catalyst A33; and the catalyst B is any one of organotin catalysts.

[0021] As a preferred embodiment of the present invention, the flame-retardant chain extender is prepared by the following method:

[0022] Step A: Preparation of intermediate agent

[0023] 4-Methylacryloxytriphenyl benzoic anhydride was added to N,N-dimethylformamide and stirred until a homogeneous reaction solution was formed. Then, pentaerythritol phosphate and an alkaline catalyst were added to the reaction solution. After the addition was complete, the temperature was controlled at 30-40℃ and stirred continuously for 3-6 hours. The solvent was then evaporated, the product was collected, and the crude product was purified to obtain an intermediate agent.

[0024] Step B: Preparation of flame-retardant chain extender

[0025] The intermediate agent was added to methanol, and under nitrogen protection, stirring was started. After mixing evenly, tris(2-aminoethyl)amine was added while stirring continuously. After the addition was complete, the temperature was raised to 55-65℃ and stirred continuously under light-proof conditions for 18-24 hours. The nitrogen was removed, the solvent was evaporated, and the crude product was purified to obtain a flame-retardant chain extender.

[0026] As a preferred embodiment of the present invention, in step A, the molar ratio of 4-methacryloyloxytriphenyl phosphate to pentaerythritol phosphate is 1:1.

[0027] As a preferred embodiment of the present invention, in step A, the alkaline catalyst is pyridine or 4-dimethylaminopyridine.

[0028] As a preferred embodiment of the present invention, in step B, the molar ratio of the intermediate agent to tris(2-aminoethyl)amine is 1:1.

[0029] It should be noted that in the above technical solution, 4-methacryloyloxytriphenyl phosphate anhydride and pentaerythritol phosphate are first used as reactants. Under the catalysis of an alkaline catalyst, the anhydride groups in their structures undergo ring-opening esterification with the active hydroxyl groups to obtain an intermediate agent. Then, the unsaturated alkenyl substituents contained in the intermediate agent structure can undergo Michael addition reaction with the primary amine groups in the tris(2-aminoethyl)amine structure. By controlling the amount of both, a flame-retardant chain extender containing both flame-retardant elements nitrogen and phosphorus in its structure can be obtained.

[0030] As a preferred embodiment of the present invention, the foaming agent is water.

[0031] As a preferred embodiment of the present invention, the isocyanate monomer is any one of diphenylmethane-4,4'-diisocyanate, toluene diisocyanate, or isophorone diisocyanate.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The flame-retardant chain extender prepared in this invention can participate in the chain extension polymerization of polyurethane. Firstly, the flame-retardant chain extender structure contains both primary and secondary amine groups, thus it can act as a crosslinking agent to some extent during the chain extension polymerization process. By strictly controlling its addition amount, it can produce a moderate crosslinking effect on the polyurethane molecular chain. After deformation, the crosslinked polyurethane molecular chain provides a stronger thermodynamic recovery driving force, which can limit the irreversible slippage of the polyurethane molecular chain under stress, reduce energy dissipation, and thus effectively improve the resilience of the polyurethane material. Simultaneously, since the flame-retardant chain extender structure also contains nitrogen and phosphorus flame-retardant elements, it can promote the rapid catalytic formation of an expanding carbon layer in the early stages of combustion, reducing heat transfer and isolating gases, thus effectively improving the flame-retardant properties of the polyurethane material. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 Infrared analysis test results for flame-retardant chain extenders. Detailed Implementation

[0036] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0037] Example 1

[0038] This embodiment provides a method for preparing a high-resilience polyurethane material, wherein the polyurethane material comprises the following raw materials in parts by weight:

[0039] Polyol A: 72 parts;

[0040] Polyol B: 18 parts;

[0041] Foam stabilizer: 0.4 parts;

[0042] Catalyst A: 0.4 parts;

[0043] Catalyst B: 0.1 parts;

[0044] Diethanolamine: 1 part;

[0045] Flame-retardant chain extender: 0.8 parts;

[0046] Foaming agent: 0.1 parts;

[0047] Isocyanate monomer: 45 parts;

[0048] The preparation method includes the following steps:

[0049] Step 1: Under normal temperature conditions, add polyol A, polyol B, foam stabilizer, catalyst A, catalyst B, diethanolamine, flame retardant chain extender and foaming agent to the mixing tank, and stir and mix evenly at a speed of 80 rpm to form component A.

[0050] The second step is to add the isocyanate monomer to the mixer and continue to stir and mix until component B is formed.

[0051] The third step is to mix component A and component B, then pour the mixture into a mold for foaming. The mold temperature is controlled at 50°C, and the foaming time is 40 minutes. Then, the temperature is adjusted to 60°C and cured for 2 hours. After heating, the mixture is cooled to room temperature and allowed to mature for 5 minutes. The mold is then opened to obtain the polyurethane material.

[0052] Polyol A is selected from polytetrahydrofuran ether diol with a number average molecular weight of 2000; polyol B is selected from polyether polyol DEP-5631ED; foam stabilizer is selected from TEGOSTAB® B8738 LF2; catalyst A is selected from catalyst A33; catalyst B is selected from dibutyltin dilaurate; foaming agent is selected from water; isocyanate monomer is diphenylmethane-4,4'-diisocyanate; the following are the same.

[0053] The flame-retardant chain extender is prepared using the following method:

[0054] Step A: Preparation of intermediate agent

[0055] 0.8 g of 4-methacryloyloxytriphenyl benzoic anhydride was added to N,N-dimethylformamide and stirred until a homogeneous reaction solution was formed. Then, 1.2 g of pentaerythritol phosphate and 0.3 g of 4-dimethylaminopyridine were added to the reaction solution. After the addition was complete, the temperature was controlled at 35 °C and stirred continuously for 4 h. The solvent was evaporated, the product was collected, and the crude product was purified to obtain the intermediate agent.

[0056] Step B: Preparation of flame-retardant chain extender

[0057] 0.6g of intermediate agent was added to methanol. Under nitrogen protection, stirring was started and the mixture was mixed evenly. Then, 0.11g of tris(2-aminoethyl)amine was added while stirring continuously. After the addition was complete, the temperature was raised to 60℃ and stirred continuously under light protection for 18h. The nitrogen was removed and the solvent was evaporated. The crude product was purified to obtain a flame-retardant chain extender.

[0058] Figure 1 This is the infrared analysis test pattern of the flame retardant chain extender, where 3348 cm⁻¹... -1 and 3269cm-1 The characteristic absorption peak appearing at 1759 cm⁻¹ is the characteristic absorption peak of NH. -1 The characteristic absorption peak appearing at 1728 cm⁻¹ is the characteristic absorption peak of the C=O group of the ester group. -1 The characteristic absorption peak appearing at this point is the characteristic absorption peak of the carboxyl group C=O produced by the ring-opening esterification reaction.

[0059] Example 2

[0060] This embodiment provides a method for preparing a high-resilience polyurethane material, wherein the polyurethane material comprises the following raw materials in parts by weight:

[0061] Polyol A: 75 parts;

[0062] Polyol B: 20 ​​parts;

[0063] Foam stabilizer: 0.6 parts;

[0064] Catalyst A: 0.5 parts;

[0065] Catalyst B: 0.2 parts;

[0066] Diethanolamine: 2 parts;

[0067] Flame-retardant chain extender: 1 part;

[0068] Foaming agent: 0.2 parts;

[0069] Isocyanate monomer: 50 parts;

[0070] The preparation method includes the following steps:

[0071] Step 1: Under normal temperature conditions, add polyol A, polyol B, foam stabilizer, catalyst A, catalyst B, diethanolamine, flame retardant chain extender and foaming agent to the mixing tank, and stir and mix evenly at a speed of 100 rpm to form component A.

[0072] The second step is to add the isocyanate monomer to the mixer and continue to stir and mix until component B is formed.

[0073] The third step is to mix component A and component B, then pour the mixture into a mold for foaming. The mold temperature is controlled at 55℃, and the foaming time is 30 minutes. Then, the temperature is adjusted to 65℃ and cured for 1 hour. After heating, the mixture is cooled to room temperature and allowed to mature for 10 minutes. The mold is then opened to obtain the polyurethane material.

[0074] The preparation method of the flame-retardant chain extender is the same as that in Example 1.

[0075] Example 3

[0076] This embodiment provides a method for preparing a high-resilience polyurethane material, wherein the polyurethane material comprises the following raw materials in parts by weight:

[0077] Polyol A: 78 parts;

[0078] Polyol B: 25 parts;

[0079] Foam stabilizer: 0.8 parts;

[0080] Catalyst A: 0.6 parts;

[0081] Catalyst B: 0.3 parts;

[0082] Diethanolamine: 3 parts;

[0083] Flame-retardant chain extender: 1.2 parts;

[0084] Foaming agent: 0.3 parts;

[0085] Isocyanate monomer: 55 parts;

[0086] The preparation method includes the following steps:

[0087] Step 1: Under normal temperature conditions, add polyol A, polyol B, foam stabilizer, catalyst A, catalyst B, diethanolamine, flame retardant chain extender and foaming agent to the mixing tank, and stir and mix evenly at a speed of 100 rpm to form component A.

[0088] The second step is to add the isocyanate monomer to the mixer and continue to stir and mix until component B is formed.

[0089] The third step is to mix component A and component B, then pour the mixture into a mold for foaming. The mold temperature is controlled at 60℃, and the foaming time is 20 minutes. Then, the temperature is adjusted to 70℃ and cured for 1 hour. After heating, the mixture is cooled to room temperature and allowed to mature for 15 minutes. The mold is then opened to obtain the polyurethane material.

[0090] The preparation method of the flame-retardant chain extender is the same as that in Example 1.

[0091] Comparative Example 1

[0092] The difference between this comparative example and Example 2 is that the flame-retardant chain extender is replaced with tris(2-aminoethyl)amine, otherwise they are the same.

[0093] Comparative Example 2

[0094] The difference between this comparative example and Example 2 is that the flame-retardant chain extender is removed; otherwise, they are the same.

[0095] The polyurethane materials provided in the above embodiments and comparative examples were subjected to performance tests, and the test methods are as follows:

[0096] (1) Conduct a rebound rate test according to standard ISO8307;

[0097] (2) Oxygen index test shall be conducted according to standard GB / T 2406.2-2009:

[0098] The performance test data above are shown in Table 1.

[0099] Table 1 Performance Test Results

[0100] Ball drop rebound rate / % Oxygen index / % Example 1 67 32.1 Example 2 69 32.5 Example 3 67 32.4 Comparative Example 1 66 23.8 Comparative Example 2 49 22.9

[0101] As can be seen from the above, the analysis and test results show that the polyurethane material prepared in the embodiments of the present invention has a high resilience and good flame retardant properties. After replacing the flame retardant chain extender with tris(2-aminoethyl)amine, the prepared polyurethane material can still maintain a high molecular chain density, so the resilience can still be maintained. However, the loss of phosphorus flame retardant element leads to a significant reduction in the flame retardant properties of the material.

[0102] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-resilience polyurethane material, characterized in that, The polyurethane material comprises the following raw materials in parts by weight: Polyol A: 72-78 parts; Polyol B: 18-25 parts; Foam stabilizer: 0.4-0.8 parts; Catalyst A: 0.4-0.6 parts; Catalyst B: 0.1-0.3 parts; Diethanolamine: 1-3 parts; Flame-retardant chain extender: 0.8-1.2 parts; Foaming agent: 0.1-0.3 parts; Isocyanate monomer: 45-55 parts; The preparation method includes the following steps: Step 1: Under normal temperature conditions, add polyol A, polyol B, foam stabilizer, catalyst A, catalyst B, diethanolamine, flame retardant chain extender and foaming agent to the mixing tank, and stir and mix evenly at a speed of 80-100 rpm to form component A. The second step is to add the isocyanate monomer to the mixer and continue to stir and mix until component B is formed. The third step is to mix component A and component B, then pour the mixture into a mold for foaming. The mold temperature is controlled at 50-60℃, and the foaming time is 20-40 minutes. Then, the temperature is adjusted to 60-70℃ and the mixture is cured for 1-2 hours. After heating, the mixture is cooled to room temperature and allowed to mature for 5-15 minutes. The mold is then opened to obtain the polyurethane material. The flame-retardant chain extender is prepared using the following method: Step A: Preparation of intermediate agent 4-Methylacryloxytriphenyl benzoic anhydride was added to N,N-dimethylformamide and stirred until a homogeneous reaction solution was formed. Then, pentaerythritol phosphate and an alkaline catalyst were added to the reaction solution. After the addition was complete, the temperature was controlled at 30-40℃ and stirred continuously for 3-6 hours. The solvent was then evaporated, the product was collected, and the crude product was purified to obtain an intermediate agent. Step B: Preparation of flame-retardant chain extender The intermediate agent was added to methanol, and under nitrogen protection, stirring was started. After mixing evenly, tris(2-aminoethyl)amine was added while stirring continuously. After the addition was complete, the temperature was raised to 55-65℃ and stirred continuously under light-proof conditions for 18-24 hours. The nitrogen was removed, the solvent was evaporated, and the crude product was purified to obtain a flame-retardant chain extender.

2. The method for preparing a high-resilience polyurethane material according to claim 1, characterized in that, The polyol A is polytetrahydrofuran ether diol with a number average molecular weight of 2000; the polyol B is polyether polyol DEP-5631ED; the foam stabilizer is TEGOSTAB® B8738 LF2; the catalyst A is catalyst A33; and the catalyst B is any one of the organotin catalysts.

3. The method for preparing a high-resilience polyurethane material according to claim 1, characterized in that, In step A, the molar ratio of 4-methacryloyloxytriphenyl phosphate to pentaerythritol phosphate is 1:

1.

4. The method for preparing a high-resilience polyurethane material according to claim 1, characterized in that, In step A, the alkaline catalyst is pyridine or 4-dimethylaminopyridine.

5. The method for preparing a high-resilience polyurethane material according to claim 1, characterized in that, In step B, the molar ratio of the intermediate agent to tris(2-aminoethyl)amine is 1:

1.

6. The method for preparing a high-resilience polyurethane material according to claim 1, characterized in that, The foaming agent is water.

7. The method for preparing a high-resilience polyurethane material according to claim 1, characterized in that, The isocyanate monomer is any one of diphenylmethane-4,4'-diisocyanate, toluene diisocyanate, or isophorone diisocyanate.

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